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Semiconductor Package Mount Manual

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1. O Applicable x Not applicable This combination should be avoided Notes 1 Pin pitch mm 1 27 1 0 0 8 0 65 0 5 0 4 Soldering Applicable Problematic The ability to withstand heat differs between individual semiconductor products Contact your Renesas sales representative for details 2 There are also certain products for which the maximum solder tank temperature is 235 C and the maximum solder tank pass through time is 5 seconds 3 Solder bridges and other problems may occur with fine pitch devices Only use this combination after verifying mountability 4 Exposed heat spreader and exposed die pad types 5 Avoid heating heat spreaders or die pads with the soldering iron R50ZZ0003EJ0500 Rev 5 00 a2 AS Page 11 of 140 Feb 03 2015 KENES 1 Overview of Soldering Technology Semiconductor Package Mount Manual 1 1 6 Solder Mounting Processes Solder mounting processes can be classified into those that support printed wiring boards with components mounted on only one side and those that support printed wiring boards with components mounted on both sides Also packages mounted on printed wiring board can be classified into lead insertion types THD and surface mounting types SMD Since there are soldering processes that are appropriate for each of these there are basically six types of process 1 1 7 Basic Mounting Processes e Single sided mounting 1 THD flo
2. lt 1 90 35 mm Pin maximum width true pin location range Maximum pin location range 40 40 mm the maximum allowable range for a pin Figure 2 10 Pin Center Position Tolerance for a 0 5 mm Pitch BGA Page 36 of 140 RENESAS o 9 Semiconductor Package Mount Manual 2 Printed Wiring Board Design 2 2 2 Mounting Pad Design for BGA and LGA Packages There are two types of mounting pad differentiated by their structure NSMD non solder mask defined and SMD solder mask defined These have the corresponding characteristics listed below The type should be determined according to the needs of the application based on these characteristics NSMD characteristics e Since the solder joint strength is greater than that for the SMD type these joints have a longer thermal cycle lifetime e Itis easier for pad peeling or open circuits at the pad neck necks to occur due to mechanical stresses SMD characteristics e Since the solder joint strength is lower than that for the NSMD type these joints have a shorter thermal cycle lifetime e Itis harder for pad peeling or open circuits at the pad neck necks to occur due to mechanical stresses Note The characteristics above apply when the land dimensions on the package and mounting pad dimensions on the printed wiring board are the same 2 2 3 Mounting Pad Dimensions Design Range eee eee eee b2 e Renesas Package dimension Example Design Range
3. Pin pitch mm io 1 00 oso proamen sb w ZE NL SN es ce E RIN b2 9 mm Figure 2 11 BGA and LGA Examples Since the stress after solder mounting is distributed evenly at the solder joint it is commonly said that it is acceptable to design the mounting pad dimensions to have the same dimensions as the diameter of the lands on the package BGA and LGA Contact your Renesas sales representative for details on the package land dimensions R50ZZ0003EJ0500 Rev 5 00 a2 AS Page 37 of 140 Feb 03 2015 KENES 2 Printed Wiring Board Design Semiconductor Package Mount Manual 2 3 THDs For THD packages the approach is basically the same as that for SMD packages However since THD devices are held in a chuck and the leads inserted in through holes TH provided in the printed wiring board it is necessary to take the dimensions in the thickness direction as well as the lead width direction into account Thus there are some differences as compared to SMD mounting Here we describe a design example for the pin location range and pin through hole diameter based on the package drawing for an 8 pin plastic DIP 7 62 mm 300 mil 2 3 1 THD Pin Location Range Figure 2 12 shows the package drawing for a 7 62 mm 300 mil pitch 8 pin plastic DIP 8 5 4 10 16 MAX 7 62 A Vv ru Le A 3 431 MAX 0 9 MIN 4 lt 1 s t lt gl wi i i t 2 54 0 51 MIN 1 1 27 MAX T 1 4 MIN
4. Underfill material 55 C 10 min to 125 C 10 min 5 mm and 3 seconds OK after 5 times 40 C 10 min to 85 C 10 min Product ppm a2 ppm al 500 None Material A Material B 800 1k 1 5k 1k 2k 3k 4k Material C R50ZZ0003EJ0500 Rev 5 00 Feb 03 2015 TENESAS Page 137 of 140 6 Solder Joint Reliability Semiconductor Package Mount Manual 6 10 Migration Along with the shift to lead free products the number of lead plating solder and other materials is increasing and ion migration risks occurring in solder joints The results of ion migration evaluation of various combinations of lead material solder plating and solder paste are shown below It was confirmed that no ion migration occurs with any of the combinations Table 6 3 Ion Migration Test Results Lead Lead Solder Paste Test Time h Material Plating 500 700 Sn 3Ag 0 5Cu Sn 3Ag 0 5Cu Sn 3Ag 0 5Cu Sn 37Pb Fe Ni 1Bi Sn 3Ag 0 5Cu 42 Alloy 3Bi Sn 3Ag 0 5Cu Sn 3Ag 0 5Cu Sn 37Pb ajaj ajaj ajl aj aj on a width 120 um Package 28 x 28 mm 208 pin QFP 0 5 mm pitch Printed wiring board P Size 125 x 125 x t 1 6 mm S Wiring Material FR 4 4 layers width Wiring pattern as shown in figure left 500 um Evaluation conditions Flux RMA type Clean
5. When designing printed wiring boards find ways to assure that for any given package there is no corresponding package in the same position on the other side of the board Type I Type II Type NI Type IV Type V 5 Pa E ee E l Single sided Mounted in the Chip edge of Chip edge of The end ball on mounting same position back side CSP back side CSP the back side aligned with aligned with CSP is displaced chip center of chip edge of one pitch distance front side CSP front side CSP from the end ball of the front side CSP F t Weibull Plot F t 99 EIO eType I single sided dp Be 10 5 1 0 1 100 e Type II Double sided 100 overlap 1000 cycle 10000 164 10 5 1 0 1 100 Package e 8 x 8 mm 121 pin FBGA 0 65 mm pitch e Ball composition Sn 3Ag 0 5Cu Printed wiring board e 4 layer built up board et 1 0 mm Solder paste e Sn 3Ag 0 5Cu Weibull Plot 0 ELA le Type II Double sided 100 overlap e Type III Double sided 50 overlap e Type IV Double sided 1 pitch overlap e Type V Double sided 1 pitch displaced 1000 cycle 10000 Figure 6 9 Weibull Plots Single Sided and Double Sided Mounting R50ZZ0003EJ0500 Rev 5 00 Feb 03 2015 TENESAS Page 131 of 140 6 Solder Joint Reliability Semiconductor Package Mount Manual 6 7 Combinations of Package Lead Pin Plating and Solder M
6. Adhesive thermal hardening THD Board reversal and component mounting insertion Figure 1 16 SMD Reflow THD Lead Type SMD Flow Soldering cont Page 18 of 140 RENESAS R50ZZ0003EJ0500 Rev 5 00 Feb 03 2015 Semiconductor Package Mount Manual 1 Overview of Soldering Technology Flux application Spray nozzle Flow soldering Melted solder Solder port Appearance inspection camera Figure 1 16 SMD Reflow THD Lead Type SMD Flow Soldering cont R50ZZ0003EJ0500 Rev 5 00 2 AS Page 19 of 140 Feb 03 2015 KENES 1 Overview of Soldering Technology Semiconductor Package Mount Manual 2 SMD Reflow SMD Reflow Soldering Solder inspection camera Solder printing Solder paste Printed wiring board Lead type SMD Mounting of component l S l l Heat Convection heating air N2 reflow l Appearance inspection camera Visual check J Figure 1 17 SMD Reflow SMD Reflow Soldering Page 20 of 140 RENESAS o Semiconductor Package Mount Manual 1 Overview of Soldering Technology Solder inspection camera Board reversal Solder printing and inspection Ball type SMD BGA Mounting of component Heat S S l S Convection heating air N2 reflow Figure 1 17 SMD Reflow SMD Reflow Soldering cont R50ZZ0003EJ0500 Rev 5 00 2 AS Page 21 of 140 Feb 03 2015 KENES 1 Overview of Soldering Technology Semiconductor Packag
7. Maximum temperature package s surface temperature 215 C or below Time of temperature higher than 200 C 25 to 40s Preheating time at 120 C to 150 C 30 to 60 s Maximum chlorine content of rosin flux percentage mass 150 C 120 C 30 to 60 s Preheating Package surface temperature C 0 2 or less Main heating 215 C max 200 C 25 to 40s Time seconds Figure 4 21 VPS Reflow Temperature Profile g Wave jet soldering WS The table below lists the soldering heat resistance conditions WS for wave jet soldering Table 4 20 Heat Resistance Conditions WS Maximum temperature 260 C molten solder temperature Flow soldering time 10 s or less Preheating conditions 120 C or below package surface temperature No time limit Times Page 100 of 140 TENESAS Once R50ZZ0003EJ0500 Rev 5 00 Feb 03 2015 Semiconductor Package Mount Manual 4 Notes on Storage and Mounting h Partial heating The table below lists the soldering heat resistance conditions for partial heating Products inserted in the board Table 4 221 Heat Resistance Conditions Partial Heating Maximum temperature 300 C or below temperature of pins Time 3 s or less per one pin Flux Rosin flux with minimal chlorine content chlorine percentage mass 0 2 or less Note The peak temperature is 300 or 350 C depending on the produ
8. 4 4 Temperature Conditions on Second Reflow When applying the heating for flow or reflow soldering a second time either for two sided mounting or for repair problems such as solder shorts and device peeling may occur in some cases The following points must be considered when setting the process conditions e If moisture is absorbed the warping characteristics of BGA packages and the printed wiring board itself may change Products must be managed to prevent moisture absorption between reflow operations e The flux and reflow atmosphere used must be optimized to assure solder spreading during remelting e The process must be optimized to assure that the package contacts do not excessively exceed the solder melting point Note that setting the temperature to a point below the solder melting point should also be considered 4 5 Mechanical Strength of Soldered Sections After Mounting After mounting soldered components can be peeled away by the application of mechanical force Products and their manufacturing processes must be designed only after first verifying the stresses that occur not only in manufacturing for example the stresses when printed wiring boards are separated or are inadvertently dropped but also in the handling environment they are subject to in the market Page 104 of 140 RENESAS EOAR Semiconductor Package Mount Manual 5 Examples of Mounting and Problems 5 Examples of Mounting and Problems 5 1 BGA Mounting Pro
9. A B C 2D Next the required amount of solder paste can be determined from the following formula Required amount of solder paste A x t optimal solder amount x 1 p1 2 p2 1 p1 Here A Stencil aperture area t Solder paste printing thickness wl Solder weight percent in the solder paste pl Specific gravity of the solder 2 Flux weight percent in the solder paste p2 Specific gravity of the solder It will be necessary to analyze the aperture dimensions and metal thickness of the stencil used for solder printing based on the result of the above calculations for the required amount of solder paste 2 Solder paste supply amounts for BGA LGA printing Take the following items into account when setting the solder paste supply amount a Solder paste printing thickness In setting the solder paste printing thickness consider the planarity of the package pins and investigate the minimum solder paste printing thickness as follows Minimum solder paste printing thickness Package pin planarity 0 to 30 um b Solder paste printing diameter In setting the solder paste printing diameter take the following items into consideration e The stencil design target is same as a mount pad size e To prevent open solder connections set the solder paste printing diameter to be a value larger than the minimum solder paste printing thickness as stipulated above in section a Solder paste printing thickness R50ZZ0003EJ0500 R
10. Causes and Resolution Measures for Reflow Soldering Defects Cause Inappropriate reflow conditions preheat or melting Degradation of the solder paste Resolution Measure Review the reflow profile Verify the solder paste storage method Replace the solder paste Not soldered No solder a present Board Mounting pad There is no solder on the mounting pad or only an extremely small amount Inappropriate printing conditions Degradation of the solder paste Clogged holes in the stencil Review the printing conditions including the stencil thickness and size Verify the solder paste storage method Replace the solder paste Clean the stencil Insufficient spreading Lead Solder N Mounting pad Bridge Mounting pad Solder Lead Solder aP Ball The solder did not spread around the mounting pad or lead adequately The solder melted and spread too far reaching over to adjacent mounting pad or pin Too little solder paste used for printing Degradation of the mounting pads leads or solder Insufficient heat Too much solder paste used for printing Displaced printing position of the solder paste Bent component pins In appropriate mounting pad or resist dimensions Review the stencil specifications Verify the storage methods for the mounting pads leads and solder paste Review the reflow profile Reduce the amount of solder used during pri
11. Metal mask Thickness 120 um Aperture diameter 0 55 mm Room temperature 210 C 217 C 218 C Note The temperatures indicated above indicate the stage temperature that is the temperature on the back of the printed wiring board and differ slightly from the temperatures of the soldered part Figure 5 16 Solderability of Solder Balls with Thick Surface Oxide Film R50ZZ0003EJ0500 Rev 5 00 2 AS Page 113 of 140 Feb 03 2015 KENES 5 Examples of Mounting and Problems Semiconductor Package Mount Manual e Workarounds 1 BGA package storage Reduce the temperature and humidity in the storage environment after the moisture proof packing has been opened as much as possible within the range of conditions stipulated for the product for example under 30 C and under 70 RH Also when storing opened products avoid leaving stand unnecessarily and consider repacking in moisture proof packing 2 Optimize the temperature profile and use a solder paste with high activity There is a close relationship between reflow temperature profile optimization surface oxidation of solder balls that use high activity solder paste and flux activity Therefore use a temperature profile that optimizes the activity when melted of the solder paste used Also note that solder paste with a high activity can suppress the growth of oxide film on the solder balls during reflow heating 3 Workarounds for BGA package and printed wiring board warping The separation of
12. 35x35 mm BGA Adjacent package Measurement 1 19x19 mm palates 2 27x27 mm 3 35x35 mm 4 40x40 mm 5 45x45 mm Reflow soldering temperature 232 to 233 C Measurement point B Spacing 10 mm BGA ball i Printed Reflow furnace Air type e e ali wiring Conveyor speed 0 9 m minute Printed wiring board Number of layers 4 Material FR 4 Thickness 1 6 mm Temperature measurement points Measurement point A A A ball close to the adjacent package B A ball distant from the adjacent package Measurement point B Thermocouples 234 232 o o 230 foj w o 228 a 5 226 D A Measurement point A Measurement point B 222 None 19x19 PBGA 27x27 PBGA 35x35 PBGA 40x40 TBGA 45x45 ABGA Adjacent package sizes spacing 10 mm Figure 3 8 Influence of the Size of an Adjacent Package Page 68 of 140 LEN ESAS R50ZZ0003EJ0500 Rev 5 00 Feb 03 2015 Semiconductor Package Mount Manual 3 Mounting Processes 2 Temperature distribution due to the separation from the adjacent package As shown in the figure below temperature differences become larger as the separation from the adjacent package decreases We see from this that temperature differences occur within the same package Temperature Measurement Conditions Package for temperature Adjacent package Package for temperature measurement measurement with different sizes 35x35 mm BGA 352 pin PBGA Measurement
13. 6 4 Influence of Printed Wiring Board Materials 2 cccccesccssccesecesecececsceeseeeneeeeeeeeeseeeseceseceaeeeeenseeseecaecnaeenneeneeas 130 6 5 Influence of Printed Wiring Board Pad Structure ee eesesecssecsceseceeseceseeecsaecaeesecseesecnecaeesesneeecsaseeesaesaeeseenees 130 6 6 Single Sided and Double Sided Mounting 0 0 0 ceceeecsssscseeeessecseesecneesecsaeeecsaeceeesecseesecnaeecsaseeesaecseesesaesaeeseenees 131 6 7 Combinations of Package Lead Pin Plating and Solder Materials 0 00 0 ecscssesssesecseeeeceeeeecaeeecsscsaeeeeesesaeeeaenees 132 6 8 Combinations of Package Ball Pin and Solder Materials ees ceeecsssscseeecsseceeesecseeseceeeeecsaseeesaecaeesessesaeeseenees 133 69 Mechanical Sttensth ss r n n areara dh kus pe ska Wee ted ied ed ra aed erin eee 134 6 9 1 QFP Lead Connection Strengtli sss ae kabeas a Sedna ole easels bulba 134 6 9 2 BGA Ball Attachment Strength after High Temperature Storage eceessssesecseeseceseeecesecatesecneeeeeaeeees 136 6 9 3 Measures to Improve Resistance to Mechanical Shock 0 eecssecssssecsseceeeseceeceeesecaeesecneesecsaeeeessecaeeseenees 136 6 10 Misrationics wisi Ade noon Boa nomas o SEKO ania eu a sa KI aie ela dinate abet 138 Digs SEPM WCU ETAS oE a e AES 139 7 1 Characteristics of Constituent Materials eseseseeeeeesesesesieeesressrstrretterstesssestetiststseststettetststetiststssesesteeretsrsesrett 139 7 1 1 Thermal Expansion C
14. C Failure definition e 20 nominal resistance increase Figure 6 11 Weibull Plots Combinations of Ball Composition and Solder Materials R50ZZ0003EJ0500 Rev 5 00 Feb 03 2015 TENESAS Page 133 of 140 6 Solder Joint Reliability Semiconductor Package Mount Manual 2 Resistance to Mechanical Shock Test rod Board Drop Strain gage Figure 6 12 Resistance to Mechanical Shock Test Method 2500 We Maximum strain 2000 1500 A 1000 j 500 F f A E 500 i 0005 2 4 6 8 10 Time ms Figure 6 13 Board Strain Test Method Strain occurring in the board ppm P TFBGA 90 BGA 256 0 45 mm ball 0 76 mm ball Shock strength ratio maximum board strain O No ball peeling Ball peeling occurred Lq Bai Sn 37Pb Sn 3Ag 0 5Cu Sn 37Pb Sn 3Ag 0 5Cu sn 37Pp STRA Sn 37Pb 5039 Figure 6 14 Shock Strength Test Method 6 9 Mechanical Strength 6 9 1 QFP Lead Connection Strength This section presents the results of thermal cycle testing for various combinations of plating materials frame materials and solder materials Although we compared lead strengths taking the earlier Sn Pb plating Sn 37Pb paste mounting as the reference these results show that the solder materials have almost no influence on the strength Page 134 of 140 LEN ESAS Eo oe Semiconductor Package Mount Manual 6 Solder Joint Reliability Printed wiring board e Size 60 x 90 xt1 2
15. LENESAS C T o T lt C I Semiconductor Package Mount Manual Renesas Electronics www renesas com Rev 5 00 Feb 2015 10 11 12 Notice Descriptions of circuits software and other related information in this document are provided only to illustrate the operation of semiconductor products and application examples You are fully responsible for the incorporation of these circuits software and information in the design of your equipment Renesas Electronics assumes no responsibility for any losses incurred by you or third parties arising from the use of these circuits software or information Renesas Electronics has used reasonable care in preparing the information included in this document but Renesas Electronics does not warrant that such information is error free Renesas Electronics assumes no liability whatsoever for any damages incurred by you resulting from errors in or omissions from the information included herein Renesas Electronics does not assume any liability for infringement of patents copyrights or other intellectual property rights of third parties by or arising from the use of Renesas Electronics products or technical information described in this document No license express implied or otherwise is granted hereby under any patents copyrights or other intellectual property rights of Renesas Electronics or others You should not alter modify copy or otherwise misappropriate any
16. Lead pins e g QFP Sn 10Pb 183 to 216 C Sn 1 5Cu 227 C Sn 2 0Bi 217 to 227 C Sn 232 C Ni Pd Au Fusible plating 4 3 5 Notes on Solder Shorts and Opens 1 Solder shorts Solder shorts may occur due to the following causes e Displacement of the solder paste printing position and excessive solder paste e Positional displacement of the package onto the printed wiring board during mounting e In addition we recommend optimizing the soldering temperature profile for the packages and printed wiring board used as a means of preventing solder shorts 2 Solder opens Due to inadequate surface activation of the product package contacts BGA solder balls QFP lead plating phenomenon such as failure of the solder paste to fuse to the product package contacts may occur This may occur due to the following causes e Degradation of the solder paste wetting activation ability e Inadequate solder paste volume applied in printing e Problems with the reflow soldering conditions temperature profile reflow atmosphere e Warping of product packages or the printed wiring board during reflow soldering We recommend that users optimize the solder paste materials used the stencil specifications and the reflow soldering conditions temperature profile reflow atmosphere R50ZZ0003EJ0500 Rev 5 00 a2 AS Page 103 of 140 Feb 03 2015 KENES 4 Notes on Storage and Mounting Semiconductor Package Mount Manual
17. Note Device thickness the rewiring layers including the silicon chip plus resin section Position indicating 50 of device thickness N Si chip mek Rewired layers TSISISISISISI SaN including resin Device thickness A Fillet for underfill Figure 5 2 Underfill Applied State 5 For other conditions use the same handling as other semiconductor devices 5 1 3 Mounting Example WLBGA 1 Evaluation Package e 5 17 x 5 17 mm 100 pin WLBGA 0 5 mm pitch e Silicon thickness 0 33 mm resin thickness 0 07 mm e Solder ball diameter 0 3 0 05 mm ball height 0 24 0 05 mm e Copper post diameter 0 28 mm Figure 5 3 External Appearance of the 5 17 x 5 17 mm 100 pin WLBGA Package Page 106 of 140 RENESAS eer Semiconductor Package Mount Manual 5 Examples of Mounting and Problems 2 Board Specifications e Double sided built up 4 layer board 1 2 1 core FR 4 t 0 6 mm e Board size 40 x 110 x t 0 8 mm e Pad structure dimensions NSMD pad diameter 0 28 mm SR aperture diameter 0 35 mm e Pad surface processing non electrolytic Ni Au flash plating Figure 5 4 External Appearance of the Package Mounting Area Pads The pad diameter is set to match the ball contact diameter copper post diameter on the package This is so that stresses after mounting will be distributed evenly over the solder joints area The NSMD structure is used for the pad structure unless there is a particula
18. equipment Also note however that for certain products there are cases where exposure to X rays may adversely affect operation Thus this equipment must only be used after thorough evaluation of its usability 3 5 1 Visual Inspection Equipment As the pitch of solder connection becomes narrower and the size of the solder joints becomes finer the amount of solder per place soldered and the area of the joint are reduced As a result inspection of the solder joints themselves and of the process up to soldering become increasingly important While these inspections were previously done visually recently a wide variety of automated inspection equipment has become available commercially Currently there are two main types of visual inspection equipment for package pin soldering and mounting visual inspection equipment for solder connections and paste printing state visual inspection equipment 1 Visual Inspection Equipment for Solder Connections While previously this equipment mainly focused on OK NG inspections recently equipment that can also inspect for the mounting state of the components has also become available Table3 8 Visual Inspection Equipment Overview Methods and Principles Defect Detected Solder defect assessment Mounting state defect assessment Insufficient Lead Lead Bridge Component Positional Incorrect solder floating displacement missing displacement orientation Step Cam
19. for printing a viscosity of from 200 to 300 Pa s at 25 C Malcolm solder paste viscometer is recommended The thixotropic properties of the solder paste also require care R50ZZ0003EJ0500 Rev 5 00 2 AS Page 47 of 140 Feb 03 2015 ENES 3 Mounting Processes Semiconductor Package Mount Manual Table3 3 Solder Paste Characteristics by Applications Application Viscosity Pa s at 25 C Dispenser 100 to 300 Printing 200 to 300 b Solder bridges and capillary balls Watch out for solder powder oxidation and select a solder powder narrow particle size distribution Select a solder paste with flux solvents that have a low boiling point and select a solder paste in which the rosin has a high molecular weight and the amount of flux is the lowest possible c Cleanability Cleaning residues are thought due to reduced rosin solubility in the cleaning agents that is caused by the rosin oxidation while the reflow process Accordingly select a solder paste that uses a rosin that is stable with respect to oxidation 3 1 2 Solder Paste Printing Processes There are two supply methods for solder paste dispenser supply and printing Usually printing is selected for its mass production efficiency Therefore we will only discuss printing in this section 1 Printing precision Printing equipment with image recognition functions is used for solder printing for fin pitch devices e g 0 5 mm and finer pitch QFP and 0 8 mm and finer pitch B
20. ray inspection For the P VQEN package no opens or shorts were recognized with solder stencil apertures from 0 20 x 0 20 mm to 0 30 x 0 95 mm Since the P VQEN package is difficult to inspect visually we recommend that printing conditions be set based on X ray peel off or other inspections to determine the mounting conditions Page 52 of 140 RENESAS EI 33 Semiconductor Package Mount Manual 3 Mounting Processes Solder Paste Supply Amount vs Mountability 240 pin FBGA This section presents an example of evaluation of solder paste supply amount and mountability for the FBGA package Evaluation Sample Package Dimension Mounting Pads Stencil Solder Paste 0 10 mm thickness P FBGA240 15x15 0 8 0 3 to 60 6 mm Sn 3Ag 0 5Cu Sn 3Ag 0 5Cu Mounting Conditions Package Dimension Placement Load The Push Distance at Placement Reflow Temperature P FBGA240 15x15 0 8 300 g ic 240 C Air reflow Note 1 The placement load shows spring loading for the mounting nozzles on the SMD placement system Mounting Results Solder Materials Stencil Aperture Dimensions 0 3 mm 0 4 mm 60 5 mm 06 mm Sn 3Ag 0 5Cu solder 0 10 0 10 0 10 4 10 Note 2 Solder short Visual Examples Stencil Aperture Dimensions 90 3 mm 0 6 mm Solder printing appearance Seseeeen oe Post reflow X ray inspection eet ee eneeneee 55546464 143 44444 Senernennreneb Seeeeeeeeneee 08 82 2 SESE SS EE For
21. 0 254010 0 15 7 1 r LUD 2 9203 H 0 50 0 10 F5 025 Gi Figure 2 12 Package Drawing of 8 Pin Plastic DIP 7 62 mm 300 mil The pin location range must be within a range determined from the pin array spacing e 2 54 mm the pin row spacing 7 62 mm the maximum value of the pin width and the pin positional tolerance x 0 25 mm The tolerance for the pin center position is a particularly important value in designing the pin location range as listed in table 2 1 e Pin pitch e 2 54 e Pin width b 0 50 010 e Pin row spacing e 7 62 e Pin thickness c 0 25 0 10 0 05 e Pin center position tolerance 9 0 25 Table 2 1 Pin Center Position Tolerance Symbol indicating the positional tolerance Numerical value indicating that the positional tolerance of the pin center is in the range of x 0 25 mm Allowable range that each pin center can deviate from the logically accurate dimensions when parallel chucking is performed at a pin row interval of e 7 62 mm for both pin rows of the DIP package Symbol indicating that the positional tolerance can be up to x 0 25 mm based on a pin width of b MAX 0 60 mm i e If the pin width b is less than the maximum value the tolerance will be greater than x 0 25 mm Location range in the pin width direction 2x b MAX 2 x 2 2 x 0 50 0 1 2 0 25 2 2x 0 85 2 0
22. 140 Feb 03 2015 KENES 2 Printed Wiring Board Design Semiconductor Package Mount Manual Page 44 of 140 RENESAS Bee IO 00n P M Semiconductor Package Mount Manual 3 Mounting Processes 3 Mounting Processes 3 1 Solder Supply Processes 3 1 1 Solder Paste 1 Material Structure The main components of solder paste are solder powder and flux The amount of solder powder contained in solder paste is generally in the 80 to 95 weight range The amount contained influences both the viscosity of the paste and the thickness of the solder after reflow The following sections discuss the solder powder and the flux a Solder powder Previously the metallic structure of solder powder consisted of a variety of alloys mainly in the Sn Pb family and the Sn Pb Ag family such as eutectic solder Sn 37Pb and solder with added silver such as the Sn 36Pb 2Ag solder However in recent years a variety of lead free metallic compositions mainly in the Sn Ag Cu family have come to be widely used to completely eliminate lead for environmental reasons The particular lead free alloy used is chosen according to the application and soldering method used Solder powder has a range of power particle sizes as shown in figure 3 1 and this range affects the printing characteristics of the solder paste Note that solder powder with spherical shape should be used for mounting packages with a fine pin pitch While solder powders with a particle diameter of 50 to 60 u
23. 21 3 Print the solder paste with a squeegee Figure 3 20 BGA Set on Jig Figure 3 21 Stencil Set on BGA 4 Remounting Package Mounting and Reflow When remounting the package it is recommended to use rework equipment that allows aligning of the solder balls of the package and the pads of the printed wiring board for correct soldering Take the following into consideration during remounting e As with removal make sure to eliminate temperature variations in the temperature profile of BGA ball device e Keep the package s surface temperature from exceeding the stipulated temperature Page 82 of 140 RENESAS Semiconductor Package Mount Manual 3 Mounting Processes 5 Visual Check Check with the same method as normal mounting 6 Solder Joint Reliability after Rework Table 3 10 lists temperature cycling test results of the reworked items described as examples Comparable connection reliability was obtained for reworked items and non reworked items in this example Table 3 10 Temperature Cycling Test Results Rework Solder Paste Supply Point Temperature Cycling Test Results Yes No No of Defective Devices Input Devices 0 cycles 500 cycles 1000 cycles 2000 cycles None Ref Yes On PWB pads Yes On BGA balls Package 35 x 35 mm 352 pin PBGA daisy chain Solder ball diameter 0 75 mm Sn Pb eutectic solder Temperature cycle conditions 409C to 125 C Failure definition 20 nominal resis
24. Adjacent package point A 35x35 mm 352 pin PBGA Reflow soldering temperature 232 to 233 C BGA ball Reflow furnace Air type Measurement point 8 4s Spacimg 5 to 40 mm Conveyor speed 0 9 m minute l Printed Printed wiring board Spacing ARPA oda Number of layers 4 Material FR 4 Thickness 1 6 mm Temperature measurement points A A ball close to the adjacent package Measurement B A ball distant from the adjacent package point B Thermocouples Measurement point A 234 _ 232 2 230 foj w 2 228 2 226 a 224 Measurement point A Measurement point B 222 5 10 15 20 30 40 None Adjacent package spacing mm Figure 3 9 Influence of the Separation of an Adjacent Package R50ZZ0003EJ0500 Rev 5 00 LEN ESAS Page 69 of 140 Feb 03 2015 3 Mounting Processes Semiconductor Package Mount Manual 3 4 Cleaning Process While a wide range of solvents have been used for flux cleaning after mounting components to the printed wiring board in the past there are now increasingly strong demands for selective use of cleaning agents for environmental reasons and for processes that do not include this cleaning at all The following items must be investigated when introducing cleaning using either solvents or water or introducing a process with no cleaning 1 On the Necessity of Cleaning The following items must be considered to determine the necessity of implementing flux c
25. Ball attachment temperature land area D 4 e 245 C Sn 3Ag 0 5Cu balls 0 e 220 C Sn 37Pb balls 0 200 400 600 800 1000 Storage temperature hr e 150 C Shear conditions e Tool height 5 um shear speed 200 um s Figure 6 16 Ball Shear Strength 6 9 3 Measures to Improve Resistance to Mechanical Shock We recommend finding ways such as using adhesives to increase mechanical strength in equipment that may be subject to excessive mechanical shocks such as manufacturing stresses during board separation accidental dropping or for portable equipment When selecting an adhesive refer to the evaluation cases shown below and perform a thorough evaluation in advance Improvement in Mechanical Strength and the Effect and Influence on Thermal Cycle Performance of an Underfill Material Evaluation case for a 0 5 mm pitch BGA package It is recognized that mechanical strength can be improved by applying an underfill adhesive In particular this is highly effective for improving resistance to fast deformation speeds due to dropping In contrast disconnection faults that depend on the physical properties of the underfill adhesive occur in thermal cycle testing and the results show a shortened life when Tg the glass transition temperature is lower than the test temperature The underfill adhesive must be selected based on thorough testing in advance for usage temperatures taking into account heat generation by the end product itself during operation
26. FR 4 boards halogen free Epoxy halogen free Glass cloth Copper foil Environmental considerations More highly elastic than ordinary FR 4 minimal warping and flexing Higher heat resistance than ordinary FR 4 Consumer electronic equipment Industrial electronic equipment Heat resistant glass epoxy FR 5 equivalent boards Heat resistant epoxy Glass cloth Copper foil e High Tg and good reliability e A low cost type of glass polyimide COB chip on board Thin form factor applications Flexible boards Polyimide Copper foil Can be freely bent Cameras calculators and similar products Ceramic substrates Alumina ceramic Ag Pd High heat resistance and high thermal conductance Superb reliability Electronic equipment for automotive applications When designing a board while the board materials must be selected based on electrical characteristics thermal dissipation and similar properties designers must also analyze the aspects discussed in sections 2 5 1 to 2 5 3 R50ZZ0003EJ0500 Rev 5 00 Feb 03 2015 TENESAS Page 41 of 140 2 Printed Wiring Board Design Semiconductor Package Mount Manual 2 5 1 Preventing Mounting Pad Oxidation The conductor used to form the mounting pads on printed wiring boards is a copper foil and surface oxidation can be promoted by storage conditions or the soldering temperature This can result
27. LGA mounting case 5 2 1 Mounting Case FLGA 1 Evaluation Package e 5x 5mm 64 pin FLGA 0 5 mm pitch 2 Board Specifications e FR 4 4 layer board e Board size 40 x 110 x 0 8 mm e Pad structure dimensions NSMD pad diameter 0 3 mm SR aperture diameter 0 35 mm e Pad surface processing heat resistant preflux Pull out wiring X Figure 5 23 Visual Appearance of Package Mounting Area and Pad Area The copper land diameter is set to match the package land diameter This is so that stresses after mounting will be distributed evenly over the solder joints area The NSMD structure is used for the pad structure unless there is a particular reason for another structure The NSMD structure improves the thermal cycle characteristics more than SMD However for the NSMD structure it is easy for wire breakage due to mechanical stress to occur in the areas where the leads intersect with the SR aperture area Therefore a teardrop shape is used and the lead width in those areas is made as wide as possible 3 Stencil Specifications e Aperture diameter 0 3 mm thickness 110 um stencil additive Figure 5 24 Appearance After Solder Printing R50ZZ0003EJ0500 Rev 5 00 2 AS Page 119 of 140 Feb 03 2015 KENES 5 Examples of Mounting and Problems Semiconductor Package Mount Manual The stencil thickness is set to be in the 100 to 120 um range and the stencil aperture diameter is matched to the board land diameter Note how
28. Note that since the physical property values for the adhesives presented here are taken from the manufacturer s catalogs we recommend referring to the technical documentation on the adhesives and consulting with the manufacturer on the intended use Page 136 of 140 RENESAS Semiconductor Package Mount Manual Table 6 1 Evaluation Item Mechanical drop test Assumed Stress Normal usage Mechanical Strength Test Results Test Conditions 100 g load dropped vertically 6 Solder Joint Reliability Results No underfill Underfill material A used Mounting complete NG after 1 to 5 times Two additional reflow operations NG after 1 to 5 times Two additional reflow operations OK after 20 times 100 g load height of 1 5 m above concrete 1 cycle vertical gt horizontal flat NG after 1 to 5 times NG after 1 to 5 times OK after 20 cyc Shock bend test Customer mounting process Span 90 mm OK after 2500 ppm NG after 3000 ppm OK after 2000 ppm NG after 2500 ppm OK after 5000 ppm Repeated bending test Normal usage Span 90 mm 2 times second OK after 10k times OK after 7k times NG after 10k times OK after 20k times Bending limit test Table 6 2 t Span 90 mm 5 mm and 3 seconds OK after 5 times 5 mm and 3 seconds OK after 5 times Thermal Cycle Test Results number of disconnects number of evaluations
29. Package Mount Manual 1 Overview of Soldering Technology ed Flow soldering Melted solder Solder port l Appearance inspection camera Figure 1 14 SMD Flow Soldering cont R50ZZ0003EJ0500 Rev 5 00 2 AS Page 15 of 140 Feb 03 2015 KENES 1 Overview of Soldering Technology Semiconductor Package Mount Manual 3 Reflow Soldering of SMD Lead type SMD Ball type SMD Solder inspection dia a Seren and inspection Solder paste Printed wiring board Solder paste J l Lead type SMD Ball type SMD BGA Mounting of component aiad 95 bh l Appearance inspection camera Visual check SMDs only Figure 1 15 SMD Reflow Soldering Page 16 of 140 RENESAS R50ZZ0003EJ0500 Rev 5 00 Feb 03 2015 Semiconductor Package Mount Manual 1 Overview of Soldering Technology 1 1 9 Double sided Soldering 1 SMD Reflow THD SMD Flow Soldering Solder inspection camera Solder paste Printed wiring board Solder printing and inspection Lead type SMD Mounting of component l Ai Convection heating air N2 reflow l Appearance inspection camera p Visual check J Figure 1 16 SMD Reflow THD Lead Type SMD Flow Soldering R50ZZ0003EJ0500 Rev 5 00 a2 AS Page 17 of 140 Feb 03 2015 KENES 1 Overview of Soldering Technology Semiconductor Package Mount Manual Board inversion Adhesive Adhesive application Chip component Mounting of component J MENI
30. Semiconductor Package Mount Manual 3 Mounting Processes 3 4 1 Flux Selection The flux used in soldering falls into two main categories rosin based fluxes and water soluble fluxes The rosin based fluxes are currently the most widely used and since under normal conditions the flux residues are nonhygroscopic and noncorrosive they are seen as being usable without cleaning Since a fairly large amount of halogens such as chlorine which are the main activating agents in the flux remain after soldering a thorough study of potential problems on insufficient cleaning is however required While the water soluble fluxes are fairly recent products they are widely used in the US and other countries due to their properties listed below e They allow a quality of visual appearance after cleaning to be obtained that is superior to that of rosin based fluxes e Good solderability e The cleaning fluid used water is not harmful or toxic and is inexpensive While the water soluble fluxes do have these merits their residues are corrosive and must be completely removed in cleaning Furthermore it may be necessary to perform thorough checking to verify that cleaning was complete Furthermore no clean fluxes have been developed by most flux manufacturers and are available commercially in bulk We recommend that you thoroughly evaluate fluxes based on consultations with the flux manufacturers e Ultralow residue flux e Low residue flux e Inactivated
31. Thickness 150 um Solder paste e Sn 3Ag 0 5Cu Sn 37Pb Reflow soldering temperature leads e Sn 3Ag 0 5Cu paste Max 245 C e Sn 37Pb paste Max 220 C Failure definition e 20 nominal resistance increase e Plating Sn Bi Paste Sn 37Pb e Plating Sn Pb Paste Sn 3Ag 0 5Cu BAe e Plating Sn Pb Paste Sn 37Pb 10 5 1 0 1 100 1000 10000 cycle Weibull Plot F t Lead material Cu ga e Plating Ni Pd Au Paste Sn 3Ag 0 5Cu e Plating Ni Pd Au Paste Sn 37Pb H Plating Sn Bi Paste Sn 3Ag 0 5Cu Se e Plating Sn Pb Paste Sn 37Pb 1090 5 1 0 1 100 1000 10000 100000 cycle Figure 6 10 Weibull Plots Combinations of Plating Compositions and Solder Materials R50ZZ0003EJ0500 Rev 5 00 Feb 03 2015 Page 132 of 140 TENESAS Semiconductor Package Mount Manual 6 Solder Joint Reliability 6 8 Combinations of Package Ball Pin and Solder Materials This section presents the results for ball type SMD packages of thermal cycle testing and mechanical shock testing of combined mounting of earlier Sn 37Pb eutectic solder products and lead free Sn 3Ag 0 5Cu ball products with both Sn 37Pb solder paste and Sn 3Ag 0 5Cu solder paste These results show that combinations of differing materials are inferior to combinations of earlier materials in both thermal cycle and mechanical shock performance Since combinations of Sn 37Pb solder materials with Sn 3Ag 0 5Cu solder materials res
32. eee 100 0 80 0 65 0 50 04 0 20 and larger 0 20 to 0 50 a 0 20 Y 0 30 Unit mm Note Reference values based on the former EIAJ ED 7402 1 standard Figure 2 2 SOP Type MIL Standard Examples Page 28 of 140 RENESAS ees Semiconductor Package Mount Manual 2 Printed Wiring Board Design 2 Mounting dimensions for TSOP type I type ID SSOP LSSOP TSSOP VSSOP and WSOP packages The mounting dimensions are those shown below l2 L Bi B2 b lt be lt e y e Renesas Package Dimension Examples TSOP type I Conan 1 27 1 00 0 80 0 65 0 55 0 50 a 0 05 to 0 10 Ba 0 20 to 0 25 p2 0 20 to 0 40 5 Y 0 30 0 25 0 20 e Renesas Package Dimension Examples TSOP type II Conan lee 1 00 0 80 0 65 0 55 0 50 0 i a 0 05 to 0 10 lt lt 1 lt 0 05 to 0 10 Bi 0 20 to 0 25 lt lt 1 lt 0 20 to 0 25 p2 0 20 to 0 40 lt lt 1 lt 0 20 to 0 40 Y 0 30 E lt uj 0 20 e Renesas Package Dimension Examples SSOP LSSOP TSSOP VSSOP and WSOP Unit mm Constant __ ae 1 00 0 80 0 65 0 55 0 50 l a 0 10 to 0 30 kuj 0 10 to 0 30 B 0 20 to 0 55 lt 0 20 to 0 40
33. etching manufacturing method with the additive and laser manufacturing methods which are new methods Page 48 of 140 RENESAS Semiconductor Package Mount Manual 3 Mounting Processes Table3 4 Stencil Manufacturing Method Comparison Method Etching Additive Laser Special Processing Material Stainless steel copper Nickel Stainless steel Stainless steel phosphor bronze Cross section A uu A B film correction 50 to 60 C C Aperture photographs Source Bon Mark Co Ltd Note There are differences in the etching precision depending on the stencil maker We recommend looking into the use of either additive or laser methods if you are considering solder printing of fine pitch patterns b Printer Settings and Conditions In this section we discuss five items 1 though 5 below that influence printability 1 Squeegee Squeegees have an elastic blade made from rubber in particular polyurethane rubber is widely used The hardness of the rubber is an important condition a hardness in the range 60 to 90 degrees is appropriate There are three cross sectional shapes used for the tip of the polyurethane squeegees described above flat angled and acute These are each used for different printing applications More recently metal squeegees that are resistant to wear and have superlative stability in the amount of solder applied have become avail
34. flux e Flux with a chlorine content under 0 2 weight 3 4 2 Cleaning Fluid Selection The cleaning fluid must be selected according to the flux residue Generally the following cleaning fluids are used for the various fluxes The cleaning fluid product names shown below are examples only Before actual use a thorough evaluation is required When rosin based flux is used e Terpene based solvents Cleaning fluids containing components extracted from oranges rinsing required Bio Oct EC 7 EC 7R e Petroleum based solvents and mixtures of petroleum based solvents and surfactants P3 Cold Cream e Hydrocarbon based solvents and semi aqueous solvents with added surfactants making water rinsing possible Pine Alpha ST 100S Clean Through 700 Series e Alcohol based solvents isopropyl alcohol IPA ethanol methanol e Alkali based solvents Mixtures of organic alkalis and surfactants When water soluble flux is used e Warm water e Warm water and an alkali neutralizer R50ZZ0003EJ0500 Rev 5 00 2 AS Page 71 of 140 Feb 03 2015 ENES 3 Mounting Processes Semiconductor Package Mount Manual 1 Rosin based Flux Cleaning Fluids The following items should be considered when selecting cleaning fluids for rosin based flux e The ability to dissolve ionic residues e The ability to dissolve non ionic residues e The boiling point e Compatibility with resins plastics the resins and plastics used in components and the printed
35. highlight method Combined laser and multi camera method Laser scanning method X ray methods Methods in which X ray transmission images are converted to 3D data showing the object s actual shape Methods in which X ray slice images are converted to 3D data showing the object s actual shape We recommend that our customers carry out a thorough analysis of the following items when adopting visual inspection equipment e Clarification of the soldering visual inspection standards to be applied to actual products e Setting up inspection items that are appropriate for an automatic system Note Since there are restrictions on what inspection items can be performed depending on the type of the visual inspection unit used it is necessary to clarify the applicable scope when determining the equipment specifications e Inspection precision and repeatability e Ease of operation of the visual inspection equipment Note Items such as the ease of setting the inspection standards programming and the time required to change equipment type must be checked e Equipment inspection tact time and price e Maintainability Page 74 of 140 LEN ESAS aa ko Semiconductor Package Mount Manual 3 Mounting Processes Note that if it is necessary to inspect the state of soldering for electronic components in Which solder connections exist in places underneath the package such as BGA and LGA packages you should consider the use of X ray inspection
36. in a degradation of the solderability of the mounting pads While the processing methods listed in table 2 4 can be used to prevent this surface oxidation since each of these has advantages and disadvantages the method used must be selected according to the application at hand For example when mounting fine pitch packages for ordinary applications Ni Au is commonly used as a preflux for cell phone and similar applications If a preflux is used an appropriate one of the many types available must be chosen for the application Also when solder surface processing is required for fine pitch mounting pads it is thought that solder plating in which the solder thickness on the surface is even has good flatness makes it harder for positional displacements to occur in solder printing and mounting Since the mounting pad surface processing affects ease of mounting and reliability as described above we strongly recommend thorough evaluation when adopting these methods Table 2 4 Mounting Pad Surface Oxidation Prevention Processing Surface Processing Strengths Weaknesses Method Solder leveler e There is no exposure of copper surfaces The amount of solder supplied during Long storage periods solder printing is unstable Since the leveler and paste are not compatible the solderability is variable Preflux Surface processing costs are lower than Rosin based fluxes include VOCs with metallic surface processing solder volatile solvents
37. leveler gold plating Since the preflux is applied to the whole Good solderability board foreign matter can adhere to the board surface e Storage periods are shorter Water soluble Does not include VOCs volatile solvents Storage periods are shorter Surface processing costs are lower than with metallic surface processing solder leveler gold plating Since the preflux is only applied to the land surfaces it is harder for foreign matter to adhere to the board surface Good solderability Ni Au flashing Good heat resistance e High costs Good solderability e Mounting reliability can be degraded by Long storage periods due to the thickness of the gold plating Page 42 of 140 TENESAS o de Semiconductor Package Mount Manual 2 Printed Wiring Board Design 2 5 2 Printed Wiring Board Warping Mounting problems that were thought to be due to warping of printed wiring board and packages during reflow have now been verified See section 5 Examples of Solder Mounting and Mounting Problems In addition to changing the type of board used or its thickness the following workarounds should also be considered if there is significant warping of the printed wiring boards and problems that could be caused by that are of concern e Equalize the ratio occupied by conductor on the printed wiring board surfaces e For double sided mounting analyze the placement of components and minimize the difference in coefficients of th
38. occurring or to combinations of multiple causes Surface oxide film growth Warping worse at room temperature or when heated Flux activity degradation Ball surface oxidation progresses Warping worse at room temperature or when heated Causes given by commonly assumed mechanisms o Other causes Figure 5 13 Fault Tree Analysis for Failure to Head in Pillow R50ZZ0003EJ0500 Rev 5 00 Feb 03 2015 TENESAS Page 111 of 140 5 Examples of Mounting and Problems Semiconductor Package Mount Manual 4 Failure to Head in Pillow Causes and the Mounting Margin Figure 5 14 shows a conceptual overview of the failure to fuse causes and the mounting margin When the danger of failure to fuse faults occurring increases with one or multiple of these causes occurring the mounting margin is reduced If this danger increases further the mounting margin may be lost leading to failure to fuse faults Large mounting margin to fuse occurring Tilting during insertion Variations in insertion depth during mounting temperature and when heate Mounting issues Solder ball surface oxidation Insufficient fusing time during main heating Ball damage or deformation Growth of oxide film on ball surface Dirt or contamination on the ball surface Flux residue on the ball surface Package issues Degradation of coplanarity Large package warping during heatin
39. or less Time of temperature higher than 210 C 30 s or less Preheating time at 1009C to 1609C 60to 120s Maximum chlorine content of rosin flux percentage mass Preheating 160 C 100 C 0 2 or less Main heating to10s 60 to 120s Package surface temperature C 230 C max 210 C Time seconds Figure 4 17 Infrared Reflow Temperature Profile IR30 c IR reflow 235 C IR35 The table below lists the soldering heat resistance conditions IR35 for IR reflow Table 4 16 Heat Resistance Conditions IR35 Maximum temperature package s surface temperature 235 C or below Time at maximum temperature 10 s or less Time of temperature higher than 210 C 30 s or less Preheating time at 1009C to 1609C 60to 120s 0 2 or less Maximum chlorine content of rosin flux percentage mass Page 98 of 140 TENESAS R50ZZ0003EJ0500 Rev 5 00 Feb 03 2015 Semiconductor Package Mount Manual Preheating 160 C 100 C 4 Notes on Storage and Mounting Main heating to10s 60 to 120s Package surface temperature C 235 C max 210 C Time seconds Figure 4 18 Infrared Reflow Temperature Profile IR35 d IR reflow 250 C IR50 The table below lists the soldering heat resistance conditions IR50 for IR reflow Table 4 17 Heat Resistance Conditions IR50 Maximum temperature package s surface tem
40. phenomenon that has occurred between the solder ball and the BGA land Package side Printed wiring board Normal product Ball drop at the package Ball drop at the printed wiring board Figure 5 21 Ball Drop Joint Cross Sectional Form Observation Example 2 Ball drop occurrence mechanism The following mechanism may be responsible for creating the ball drop phenomenon on a second reflow operation even though a normal joint is formed by the first reflow operation On the second reflow operation the solder ball is melted from the outside If any warping has occurred in the package or the printed wiring board when stress is applied in the direction in which the joints interval spreads this force is concentrated on the solder balls in the central area that are not yet melted In this state when the solder balls in the central area change from the solid phase to the solid plus liquid phase region the joint loses its constraining force and at that instant separation occurs near the intermetallic compound IMC on the copper land It is inferred that after that melting of the solder ball progresses and the solder ball takes on a rounded shape that appears as though it is dropping Package and or printed wiring board warping may increase during reflow soldering if either the package or printed wiring board absorbs moisture between the first and second reflow operations or if the reflow temperature is high As a result the frequency of ball drop oc
41. point and joinability Figure 5 19 shoes the result of a reproducibility evaluation under the conditions where the solder paste and solder balls are held apart until the melting point is reached and then brought into contact at the point the melting point is exceeded In this state failure to Head in Pillow were observed to occur when the heating time above the melting point was kept short about 6 s See the top figure R50ZZ0003EJ0500 Rev 5 00 a2 AS Page 115 of 140 Feb 03 2015 KENES 5 Examples of Mounting and Problems Semiconductor Package Mount Manual Under the same conditions however if the heating time above the melting point was extended about 30 s then good joints such as those shown in the lower figure were acquired Evaluation conditions Device 11 mm x8 mm 85 pin TFPGBA 0 8 mm pitch Sn 3Ag 0 5Cu Ball diameter 40 45 mm Preprocessing 85 C 8596 120 h Solder paste Sn 3 0Ag 05 Cu Flux content 11 2 Halogen content 0 Metal mask Thickness 150 um Aperture diameter 0 4 mm Printed wiring board FR 4 t 1 0 mm Land diameter 0 4 mm Observation point Peak temperature 225 C Time at 220 C or higher About 6 seconds Note The temperatures indicated above indicate the stage temperature that is the temperature on the back of the printed wiring board and differ slightly from the temperatures of the soldered part Figure 5 19 Time Above Melting Point and Solderability e Workarounds 1 Review the r
42. processes L Mounting Soldering processes processes Cleaning processes Other processes e g solder inspection and reworking Figure 1 1 Solder Mounting Technologies R50ZZ0003EJ0500 Rev 5 00 a2 AS Page 1 of 140 Feb 03 2015 ENES 1 Overview of Soldering Technology Semiconductor Package Mount Manual 1 1 Soldering Methods 1 1 1 Types of Soldering Method Soldering methods are broadly divided into two types the partial heating method and the total heating method Partial heating method Heat is applied to the package leads and or PWB in a localized manner Types There are four types of soldering methods 1 Soldering iron 2 Hot air 3 Laser 4 Pulse heating Feature Partial heating involves less heat stress on the device and printed wiring board but is unsuitable for large volume production Therefore this method is mainly used to correct soldering or for devices with a low heat resistance Total heating method Heat is applied to the entire package and or PWB Types There are two types of soldering methods Infrared reflow Convection reflow Infrared convection combined VPS Vapor Phase Soldering Flow wave soldering E pel am Feature Because of excellence in productivity and running cost these types are widely used However this method can place considerable heat stress on the semiconductor device and board Select the soldering method best suited to your application by taking into co
43. reflow Note The placement load shows spring loading for the mounting nozzles on the SMD placement system Mounting Results Solder Materials FBGA FBGA FBGA Displacement Displacement Displacement 0 1 mm 0 2 mm 0 3 mm Sn 37Pb solder Sn 37Pb 0 20 Sn 3Ag 0 5Cu solder Sn 3Ag 0 5Cu 0 20 Visual Examples FBGA Displacement 0 3 mm Sn Pb Solder Sn Ag Cu Solder 220 C air reflow 240 C air reflow With FBGA packages self alignment has been verified with a mounting displacement of up to 0 3 mm After verifying the solder materials and reflow conditions actually used the mounting conditions should be analyzed carefully Page 60 of 140 RENESAS Eo 3 Semiconductor Package Mount Manual 3 Mounting Processes Self Alignment LGA 0 65 mm pitch This section presents a sample evaluation for the self alignment effect for the LGA 0 65 mm pitch package Evaluation Sample Package Dimension Mounting Pads Stencil Solder Paste Terminal Plating 0 10 mm thickness LFLGA336 14x14 0 65 9035 mm 6035 mm Sn 3Ag 0 5Cu Mounting Conditions Package Dimension Placement Load The Push Distance at Reflow Temperature Placement LFLGA336 14x14 0 65 180 g ic 250 C Air reflow Note The placement load shows spring loading for the mounting nozzles on the SMD placement system Mounting Results We evaluated solder printing displacements and LGA displacements as reverse direction displacements Solder Pri
44. renesas com for the latest and detailed information Renesas Electronics America Inc 2801 Scott Boulevard Santa Clara CA 95050 2549 U S A Tel 1 408 588 6000 Fax 1 408 588 6130 Renesas Electronics Canada Limited 9251 Yonge Street Suite 8309 Richmond Hill Ontario Canada L4C 9T3 Tel 1 905 237 2004 Renesas Electronics Europe Limited Dukes Meadow Millboard Road Bourne End Buckinghamshire SL8 5FH U K Tel 44 1628 585 100 Fax 44 1628 585 900 Renesas Electronics Europe GmbH Arcadiastrasse 10 40472 Dusseldorf Germany Tel 49 211 6503 0 Fax 49 211 6503 1327 Renesas Electronics China Co Ltd Room 1709 Quantum Plaza No 27 ZhiChunLu Haidian District Beijing 100191 P R China Tel 86 10 8235 1155 Fax 86 10 8235 7679 Renesas Electronics Shanghai Co Ltd Unit 301 Tower A Central Towers 555 Langao Road Putuo District Shanghai P R China 200333 Tel 86 21 2226 0888 Fax 86 21 2226 0999 Renesas Electronics Hong Kong Limited Unit 1601 1611 16 F Tower 2 Grand Century Place 193 Prince Edward Road West Mongkok Kowloon Hong Kong Tel 852 2265 6688 Fax 852 2886 9022 Renesas Electronics Taiwan Co Ltd 13F No 363 Fu Shing North Road Taipei 10543 Taiwan Tel 886 2 8175 9600 Fax 886 2 8175 9670 Renesas Electronics Singapore Pte Ltd 80 Bendemeer Road Unit 06 02 Hyflux Innovation Centre Singapore 339949 Tel 65 6213 0200 Fax 65 6213 0300 Renesas Electronics Malaysia S
45. shown below Radiative heating Vapor phase heating Convective heating Conductive heating gt Conductive heating Conductive heating Printed BGA wiring board nM Infrared methods VPS Convection methods Figure 1 6 Heat Transmission Paths for Different Heating Methods As can clearly be seen from the transmission paths for IR methods IR reflow soldering sections that are in the package shadow are heated indirectly by transmission heating Since it is easy for uneven temperatures to occur convection methods air or N2 reflow are mostly used when soldering is performed in the areas under packages such as BGA and LGA packages Users must establish mounting heating conditions that allow adequate solder wetting of all pins to assure adequate connection strength and reliability Figure 1 7 shows cross sectional photographs of solder joints for representative packages mounted with a Sn 3 0Ag 0 5Cu solder 100 pin QFP 28 pin QFN 261 pin BGA 64 pin LGA 0 5 mm pitch 0 5 mm pitch 0 65 mm pitch 0 65 mm pitch Figure 1 7 Post Mounting Cross Sectional Photographs for Representative Packages Using a Sn 3 0Ag 0 5Cu Solder Page 6 of 140 RENESAS Semiconductor Package Mount Manual 1 Overview of Soldering Technology 1 IR Method IR Reflow In this method components are heated by emitted IR radiation radiative heating using an IR heater as the heat source Since t
46. stress high method e Direct heating of high density parts and parts that e Processing times somewhat longer than those for IR convection are in shadows is easy reflow soldering reflow e Even heating is possible e Component displacement and board vibrations can e An even temperature distribution is reached after a occur due to the flow speed certain amount of time even if the board and components have different thermal capacities Air Running costs low Solder defects due to copper foil oxidation can occur N2 It is difficult for solder defects due to copper foil Running costs high oxidation to occur Combined e Temperature variations medium e Thermal stress high IR e Processing times short e Component displacement and board vibrations can convection e Direct heating of high density parts and parts that occur due to the flow speed method are in shadows is easy e Solder defects due to copper foil oxidation can occur e Even heating is possible for convection reflow soldering e Aneven temperature distribution is reached after a certain amount of time even if the board and components have different thermal capacities Air Running costs low Solder defects due to copper foil oxidation can occur N2 It is difficult for solder defects due to copper foil Running costs high oxidation to occur VPS e Temperature variations small e Thermal stress high vapor e Precise temperature control is possible e Runn
47. the FBGA 0 8 mm pitch package no opens or shorts were recognized with stencil apertures from 60 30 mm to 0 50 mm Since the FBGA package is difficult to inspect visually we recommend that printing conditions be set based on X ray peel off or other inspections to determine the mounting conditions R50ZZ0003EJ0500 Rev 5 00 RENESAS Page 53 of 140 Feb 03 2015 3 Mounting Processes Semiconductor Package Mount Manual Solder Paste Supply Amount vs Mountability LGA This section presents an example of evaluation of solder paste supply amount and mountability for the LGA package Evaluation Sample Package Dimension Mounting Pads Stencil Solder Paste Lead Plating 0 10 mm thickness LFLGA336 14x14 0 65 0 35 mm Sn 3Ag 0 5Cu LFLGA304 13x13 0 5 Sn 3Ag 0 5Cu Mounting Conditions LFLGA336 14x14 0 65 180 g ic 0 20 mm 250 C Air reflow EEE ZE Note The placement load shows spring loading for the mounting nozzles on the SMD placement system Mounting Results Stencil Aperture Dimensions 0 20 mm 0 25 mm 0 30 mm 0 35 mm 0 40 mm 0 45 mm LFLGA336 14x14 0 65 LFLGA304 13x13 0 5 Notes 1 Solder open 2 Solder short Visual Examples Stencil Aperture LFLGA336 14x14 0 65 0 65 mm pitch LFLGA304 13x13 0 5 0 5 mm pitch 80 ou ve oe Solder 3 ie wl ou ve oe 1 printing es Solder printing displacement 0 15 mm o eo ee Paleslesseo Pasos oO poets aPC For the
48. the mounting pads must exceed the melting point of the solder Consider setting the peak temperature to be 20 to 40 C above the melting point of the solder Notes 1 This will be 200 to 220 C for eutectic solder Sn 37Pb 2 This will be 240 to 260 C for lead free solder Sn 3Ag 0 5Cu The surface temperature of the mounted components must be lower than the stipulated temperature 2 Solder melting time Solder paste consists of solder powder and a certain amount of melting time is required for the solder to wet and spread over the component contacts leads and mounting pads on the printed wiring board after this solder powder melts and aggregates For mounted components with Ag Pd contacts however if this solder melting time is too long diffusion between the Ag Pd contacts and the solder will progress and this can result in a reduction of the strength of the solder Thus care is required here We strongly recommend performing an evaluation of the soldering for the set solder melting time before proceeding to mass production Also if components and or printed wiring boards with high heat capacities are used we recommend considering reflow equipment that includes a cooling structure since the cooling rate will be slower Excessively long melting times including multiple reflow operations can lead to a degradation of solder strength in BGA packages In particular there have been cases where ball separation has occurred due to mechanical
49. the solder balls and solder paste during reflow hinders the removal of oxide film and suppression of reoxidation of the solder ball surface by the flux and thus promotes solder ball surface oxidation Thus it is important to consider suppressing warping by package moisture absorption countermeasures printed wiring board moisture absorption countermeasures and reviewing the mounting layout Factor 3 Reduced flux activity The flux activity can be reduced if the preheating time is longer or the temperature higher than the solder paste manufacturer s recommended conditions and this can lead to degradation of solder ball to solder paste solderability e Reproducibility evaluation example solderability of solder ball and solder paste with reduced activity Figure 5 17 shows an example of mounting between solder balls and solder paste with radically reduced activity observed while heating As the heating proceeds the flux in the solder paste oozes from the surface and goes no further than the state where the solder balls appear to be lifted We think that when flux looses its activity it prevents joining and leads to failure to Head in Pillow Evaluation conditions Solder ball Sn 3 0Ag 0 5Cu Ball diameter 0 5 mm Solder paste Sn 3 0Ag 05 Cu Flux content 11 5 Chlorine content 0 Metal mask Thickness 120 um Aperture diameter 0 55 mm Preprocessing of device None Printing solder paste Baking at 200 for 3 minutes Mounting s
50. to notify such third party in advance of the contents and conditions set forth in this document Renesas Electronics assumes no responsibility for any losses incurred by you or third parties as a result of unauthorized use of Renesas Electronics products This document may not be reproduced or duplicated in any form in whole or in part without prior written consent of Renesas Electronics Please contact a Renesas Electronics sales office if you have any questions regarding the information contained in this document or Renesas Electronics products or if you have any other inquiries Note 1 Renesas Electronics as used in this document means Renesas Electronics Corporation and also includes its majority owned subsidiaries Note 2 Renesas Electronics product s means any product developed or manufactured by or for Renesas Electronics 2012 4 Table of Contents kz Oyerview o polderine Technology sss AE E E A aS 1 1 1 Soldering Methods e cuidate atid neds dace Rela aA mn ep mmm mon o pe me nmn o 2 1 1 1 Types of Soldering Method siis ssh SAE PSS SAN NB An asin emia 2 1 1 2 Features of the Different Soldering Methods 00 cc ceessesecsseeeesecseeseceeeecsaeceessecaeesecseesecsaececeecsaeceeeneeseeeaees 3 1 1 3 Partial Heat Methods zas iso sb oseta sse ute dist do seek Ia plank cea E EE EEEa ASe ska IO a EEEE E EiS 4 1 1 4 Total Heating Method paver cies havin Sie ches Seed Bates MOLIERO 6 1 1 5 Adaptatio
51. type of the solder paste caused this large difference We recommend performing an evaluation under the mounting conditions you will be using and selecting a solder paste with a low failure to Head in Pillow occurrence ratio Evaluation conditions Package 35mm 484 pin PBGA Solder ball Sn 3Ag 0 5Cu Solder paste Composition Sn 3Ag 0 5Cu Preprocessing conditions 85 C 85 RH 120 hours Stencil thickness 100 mm Aperture diameter 90 63 mm Printed wiring board Materials FR 4 number of layers 4 thickness 1 6 mm Reflow temperature 230 C peak Failure to Head in Pillow occurrence ratio Number of Head in Pillow bumps number of joined bumps x100 Number of joint bumps 4840 bumps 10 PKG Q 2 E 5 0 n 10 PKG all 8 4 5 34 35 5 3 27 28 3 30 25 256 25 acon 18 19 19 20 20 8 15 iz Sao 0 7 i e 02 3 0 0 l 1 2 13 14 15 16 17 18 Solder Paste Type Figure 5 18 Solder Paste Types and Failure to Head in Pillow Occurrence Ratios Factor 4 Insufficient main heating time If the solder paste and solder ball are separated during heating the oxidation of the solder ball surface will proceed When the solder melting point has been exceeded and the melted solder paste contacts a solder ball if the flux activity has become weaker it is thought that the solder ball surface oxide film will not be quickly broken e Reproducibility evaluation example Time above the melting
52. used due to the elimination of lead in solders have a higher melting point and the corresponding peak temperatures during reflow required of semiconductor devices have increased when measured at the package surface from 235 C for eutectic solder to 260 C for lead free solders We have verified the heat resistance for existing surface mounting packages under the lead free solder heat resistance conditions Almost all packages were able to withstand a reflow peak temperature of 260 C However for thicker and larger packages since it is harder to increase the surface temperature of these packages we have set the peak temperature to be 250 or 245 C Even in these cases however the temperature of the lead sections will rise above the melting temperature of the Sn Ag Cu solders widely used as lead free solder Thus there will be no problems in mounting such packages Note that Moisture Reflow Sensitivity Classification for Non hermetic Solid State Surface Mount Devices standards are widely adopted worldwide Except for a few products the IPC JEDECJ STD 020B can be applied without problem We are also performing evaluations of products to determine whether or not they conform for the J STD 020D which was promulgated in June 2007 Please contact you Renesas sales representative for information on specific products 1 Renesas Support for the IPC JEDEC MSL Standard Reflow Conditions For prior to processing moisturization conditions verified a
53. 0 85 to 0 92 0 81 to 0 85 0 85 0 85 inner dimension mm Note The pin spacing e is a fixed 1 778 mm Page 40 of 140 TENESAS o de Semiconductor Package Mount Manual 2 Printed Wiring Board Design 2 4 Discrete Devices For mount pad dimension of discrete devices visit the discrete packages list on our web site at http www renesas com products package information discrete name list index jsp 2 5 Board Materials Board materials can be classified into two types printed wiring board based on epoxy resins and thick film circuit substrates ceramic substrates that are based on alumina ceramics The printed wiring boards used widely in consumer and industrial equipment can be classified into three types according to the purpose of the board as listed in table 2 3 Table 2 3 Printed wiring boards Examples of Substrate Materials Paper phenol FR 2 boards Composition Board Material Paper Conductor Copper foil Features Low cost ease of mass production Applications Consumer electronic equipment Paper epoxy FR 3 boards Paper Copper foil A board intermediate between paper phenol and glass epoxy Audio equipment Glass epoxy FR 4 boards Glass cloth Copper foil Superlative in electrical characteristics resistance to moisture and dimensional stability Consumer electronic equipment Industrial electronic equipment Glass epoxy
54. 00 cycle i Lead material Fe Ni 42 Alloy 14 Z 12 du 5 10 8 n 56 e 230 C S e 245 C foj e 260 C g 2 as 0 1 1 1 0 250 500 750 1000 cycle Aging conditions e PCT4h 105 C 100 RH 1 22 x 105Pa Temperature cycling test conditions e 40 to 125 C 10 minutes dwell Package e 28 x 28 mm 208 pin QFP 0 5 mm pitch e Lead material Cu Fe Ni 42Alloy e Plating Sn Bi Printed wiring board e Size 125 x 125 xt 1 6 mm e Material FR 4 4 layers e Pad surface treatment Preflux Stencil e Thickness 150 um Solder paste e Sn 3Ag 0 5Cu Reflow soldering temperature leads e 230 245 260 C peak Lead pull test conditions e 45 direction 5 mm minute Note Conforms to the JEITA ED 4702 Mechanical stress test methods for semiconductor surface mounting devices standard Figure 6 4 Lead Pull Strength Page 128 of 140 LEN ESAS R50ZZ0003EJ0500 Rev 5 00 Feb 03 2015 Semiconductor Package Mount Manual 6 Solder Joint Reliability 6 2 Influence of Printed Wiring Board Thickness The reliability results of mounting the same package on printed wiring boards of various thicknesses and then performing temperature cycle testing are shown below In the condition range used this time the temperature cycle life was longer for thinner printed wiring boards This is thought to be due to the fact that in the case of a thick printed wiring board it is more difficult for the board to keep up with the pac
55. 2 mm e Material FR 4 4 layers e Pad surface treatment Stencil e Thickness 130 um Solder paste e Sn 3Ag 0 5Cu Sn 37Pb Temperature cycling test conditions Reflow soldering temperature lead e 40 to 125 C 15 minutes dwell e 230 C for combinations involving only earlier materials 220 C Package Strength conditions e 14 x 14 mm 100 pin QFP 0 5 mm pitch e 45 direction 20 mm minute e Lead materials Cu Fe Ni 42 Alloy Note Conforms to the JEITA ED 4702 Mechanical stress test methods e Lead plating Sn Cu Sn Bi Sn Ni Pd Au for semiconductor surface mounting devices s tandard Sn Cu plating Cu frame i Sn Cu plating Fe Ni 42 Alloy frame 4 12 10 D 7 t 26 2 4 Sn Cu plating Sn 3Ag 0 5Cu paste a 4 e Sn Cu plating Sn 3Ag 0 5Cu paste 3 8 Sn Cu plating Sn 37Pb paste 8 2 Sn Cu plating Sn 37Pb paste S Sn Pb plating Sn 37Pb paste a e Sn Pb plating Sn 37Pb paste 0 L L L 0 500 1000 1500 2000 0 500 1000 1500 2000 cycle cycle 7 Sn Bi plating Cu frame mi Sn Bi plating Fe Ni 42 Alloy frame 12 12 X 10 40 5 5 8 5 8 t t o 6 D 6 a 4 Sn Bi plating Sn 3Ag 0 5Cu paste a 4 Sn Bi plating Sn 3Ag 0 5Cu p
56. 3 Self Alignment Effect er hr TTT TTT TTT E ee ER 56 3 3 Solder y ProCA SSE A TT TTT TTT rr E a a a a AE E aT E a aa aA Ao o po ro 64 3 3 1 Th Temperature Profile Concept 1 4 3 nein a shih utas sukno siai kare Anis ae E a ESEESE io 64 3 3 2 Temperature Profile Conditions dn cess iui a ABSINTO 65 3 3 3 Notes on BGA Package Reflow Soldering 0 0 0 ce eesesscssssccesecseeecseeecsaeeccsaeceesecsevsecnaeeeceecsaseecsaecateaeeneeeas 67 3 3 4 Temperature Distributions in Mixed MOumnting ce eeeeeeccesecscesecseeeeceeeeeceaeceeesecsevsecnaeeecseceaseecsaecatesaeseeegs 68 34 Cleaning Process iat seli ilala i kubon klp pies iia die ees 70 3 4 1 FLUX SClECHOM EET TE ooWe TR TTT TTT TTT TTT S eae 71 3 4 2 Cleaning Fluid Selection monensin irnia those Dini ENVI kk e Lm 71 3 4 3 Selecting the Cleaning Method and Equipment 0 ccesscsssecssesecseeseceseeeessceaeceessecseesecnerseesaeeeesaecatenaeeees 72 3 4 4 Assessment Methods is sss sin um dais Rig l Sesh IN Ra Nn Ra nie Reeds 73 3 5 Inspection Process sistoj havens bade Sete have site dies Ate ave olive Kuba lu os ear eae ene kod 74 3 5 1 Visual Inspection Equipment sse sss Sk pren E peak eda KA sa DAS apne Ada et 75 3 5 2 Misual Inspection MEMS suspensa Sk ls ral ra Banke ete sekta 76 316 RepaliinS andReworkmn5 a seonsi kioo o usar a anI KT masao Ia ro nl Ea i INE o lS ko 78 3 6 1 REPANME shania nis aa kites avi tie haven biti dee eel A
57. 30 240 250 260 270 Melted solder temperature C Figure 4 5 Wetting Time Temperature Dependence Evaluation Results Sn 37Pb solder bath Page 88 of 140 RENESAS e Semiconductor Package Mount Manual 4 Notes on Storage and Mounting 0 40 _ 0 35 wn o 5 0 30 e sn a 0 25 e Sn cu E 0 20 e Ni Pd Au 2 0 15 Sn Pb uu D Sn Bi z 0 10 9 0 05 0 00 210 220 230 240 250 260 270 Melted solder temperature C Figure 4 6 Wetting Time Temperature Dependence Evaluation Results Sn 3Ag 0 5Cu solder bath As shown in figure 4 5 and 4 6 for both of these solders when melted the wetting time increases as the temperature falls and this indicates that the same trend will hold for printed wiring board mounting as well It is thought that using a higher mounting temperature can be effective for acquiring good solder wetting Therefore we recommend taking this into consideration when selecting the optimal soldering conditions While the allowable temperature profile will differ depending on the solder paste used and the electronic components being mounted we recommend setting the temperature to the high end of the possible range 4 1 5 Solderability following High Temperature Storage Table 4 3 and figure 4 7 show the solderability when high temperature baking 150 C is performed for up to 500 hours These results indicate stable solderability with the wetting time remaining unchanged even after 500 hours Table 4 3 Meniscograph Testing
58. 85 mm Location range in the pin thickness direction 2x c MAX 2 x 2 2 x 0 25 0 1 2 0 25 2 Page 38 of 140 RENESAS Oo 9 Semiconductor Package Mount Manual 2 Printed Wiring Board Design 2x 0 60 2 0 60 mm From the results of these calculations the location range in the pin width direction is included in the location range in the pin thickness direction Figure 2 13 shows the location range in the pin width direction 0 50 0 10 KP 0 25 bMAX 0 60 l Center position Center position displaced to the left i iaigplaced to the when b is at its maximum JIRO p right when b is at its maximum Center position displaced when b is at its maximum 0 60 a 2 Location range for pin width b Through hole diameter 2 54 j4 gt i Figure 2 13 Relationship Between Center Position Displacement in the Pin Width Direction and Printed Wiring Board Through Holes R50ZZ0003EJ0500 Rev 5 00 2 AS Page 39 of 140 Feb 03 2015 KENES 2 Printed Wiring Board Design Semiconductor Package Mount Manual 2 3 2 Through Hole Diameter Design The through hole diameter is designed based on the pin location range for the THD Through holes on printed wiring boards are circular in shape and furthermore since the pin thickness has a tolerance the through hole diameter must be designed to be larger by that amount This relationship
59. Conditions Sn 37Pb bath Flux Rosin R Type Sample 208 pin QFP Cu alloy Test temperature 210 C Immersion speed 10 mm s Immersion depth 1 5mm Immersion time 5s Number of leads immersed 10 Number of tests 10 Storage conditions 150 C R50ZZ0003EJ0500 Rev 5 00 a2 AS Page 89 of 140 Feb 03 2015 KENES 4 Notes on Storage and Mounting Semiconductor Package Mount Manual _ 3 0 72 225 8 2 0 o 21 5 e Sn Pb plating 0 100 200 300 400 500 600 150 C high temperature storage time hours Figure 4 7 Results of Wetting Balance Test Table 4 4 and figure 4 8 show the solderability when high temperature baking 150 C is performed for up to 500 hours These results indicate stable solderability with the wetting time remaining unchanged even after 500 hours Table 4 4 Meniscograph Testing Conditions Sn 3Ag 0 5Cu bath Flux Rosin R Type Sample 208 pin QFP Cu alloy Test temperature 245 C Immersion speed 10 mm s Immersion depth 1 5mm Immersion time 5s Number of leads immersed 10 Number of tests 10 Storage conditions 150 C 0 100 200 300 400 500 600 150 C high temperature storage time hours Figure 4 8 Results of Wetting Balance Test 4 1 6 Solderability following Long Term Storage 1 Lead Materials Cu Sn 3Ag 0 5Cu Solder Bath The following shows the results of wettability testing with an Sn 3Ag 0 5Cu sol
60. Cu balls Sn 3Ag 0 5Cu paste e Ball composition Sn 3Ag 0 5Cu _ Printed wiring board Ordinary FR 4 Printed wiring board 10 Sn 37Pb balls Sn 37Pb paste e Size 65 x 58 x t 0 8 mm 5 e Material Ordinary FR 4 halogen free FR 4 e Pad size 60 40 mm 1 e Pad surface processing preflux Solder paste Sn 3Ag 0 5Cu Sn 37Pb Reflow soldering temperature BGA ball 0 1 e Peak 230 C Sn 3Ag 0 5Cu paste 10 100 1000 e Peak 220 C Sn 37Pb paste cycle Mounting form e Double sided mounting Failure definition e 20 nominal resistance increase Figure 6 7 Weibull Plot Influence of Printed Wiring Board Materials 2 6 5 Influence of Printed Wiring Board Pad Structure The results of mounting the same package on printed wiring boards with an NSMD and SMD land structure and then performing temperature cycle testing are shown below For the following conditions range the NSMD structure has a longer temperature cycle life than the SMD structure This is believed to be due to the fact that when the NSMD structure is used the solder connection strength is greater because the pad sides are also soldered On the other hand use of the NSMD structure has the demerit that the neck part of the pad lead out wiring can easily break due to mechanical stress Therefore the land structure must be selected according to the intended application Land Test temper
61. EGA Mounting ke ss or TETTE TTT TTT TTTTEETESTITI 119 5 2 1 Mounting Case FLA sss SSS VA LIIN ANI SEIAS DO 119 522 LGA Probletin Cases seas presi Ee ekus Kra Sbeacteahtulantendbunesapiukeuses soy EE kto ei Skeel 122 523 Notes on Mounting Pad Design for HQFP and HLQFP Mounting e eesisessesisneseesnesieseeseseeneesee nee 124 5 3 1 Mounting Pad Design Example for HLQFP Mounting 0 0 ceeecssesceseccesecseeeeceeeseesecseesecsaeeeessecseeseeners 124 5A Lead Free Solder Mounting Examples inienn inaa E ea E EE EAE E E EAE E E S 125 5 4 1 External Appearance of Pins Plated with Lead Free Solder Lead Type esseeesseseeseesrreeereresrsrsrrrrererrreee 125 5 4 2 Cross Sectional Photographs after Mounting of Pins Plated with Lead Free Solder Lead Type 126 6 3o der oMm RENADIIIY ss sn e l E LT obl ala sa 127 6 1 Influence of Reflow Soldering Temperature esc scesecssesecseesecesseeceseeseesecseesessecseesecseeseesaeeeesaecaseeeaecateaeeneaes 127 6 1 1 Ball type SMD esc sene mu e atid eatin ended ee habe oath anna kml 127 6 1 2 Teead type S MID is ites a Sisia sete Seas tevds ABA A oui Mini A Roel Bec aA acini 128 62 Influence of Printed Wiring Board Thickness eessesesecsseseseceesecsecsecsseeecsaeceeesecseesecnaeecsaeeeeaeeaeeeeeaesaeeseeners 129 6 3 Influence of Printed Wiring Board Materials 1 ccc cesccesceesecesecenecececseeeneeeneeseceseeeseceseceseeeeeeseeeaeecaeenaeeaeeaeeeas 129
62. Electronics shall not be in any way liable for any damages or losses incurred by you or third parties arising from the use of any Renesas Electronics product for which the product is not intended by Renesas Electronics You should use the Renesas Electronics products described in this document within the range specified by Renesas Electronics especially with respect to the maximum rating operating supply voltage range movement power voltage range heat radiation characteristics installation and other product characteristics Renesas Electronics shall have no liability for malfunctions or damages arising out of the use of Renesas Electronics products beyond such specified ranges Although Renesas Electronics endeavors to improve the quality and reliability of its products semiconductor products have specific characteristics such as the occurrence of failure at a certain rate and malfunctions under certain use conditions Further Renesas Electronics products are not subject to radiation resistance design Please be sure to implement safety measures to guard them against the possibility of physical injury and injury or damage caused by fire in the event of the failure of a Renesas Electronics product such as safety design for hardware and software including but not limited to redundancy fire control and malfunction prevention appropriate treatment for aging degradation or any other appropriate measures Because the evaluation of microcomputer software
63. GA packages Note that the printing precision of current printing equipment with image recognition functions is 0 025 to 0 05 mm 2 Printed form of the solder Factors that can influence the printed form include the type of the stencil the surface shape and surface processing on the mounting pads of printed wiring board the printer settings and conditions and the solder paste used In the following however we discuss the type of the stencil used and the printer settings and conditions which are particularly influential on the printed form a wm Stencil types As package lead spacings become finer and finer the cross stencil form of the stencil apertures has come to have a large influence on the acceptability of the printing due to the smaller and smaller sizes of the apertures The stencil which was previously formed by an etching process is made to have a shape curved in the thickness direction in forming As a result solder paste remains in these curved sections during printing and as the number of boards printed increases this remaining paste matter can cause clogging of the apertures This can cause thin areas and the solder paste may work its way around to the back side of the stencil the side that contacts the printed wiring board during print and cause bleeding and smearing To improve these problems stencil with improved etching precision and stencil produced by new methods are now being sold Table 3 4 compares the
64. LGA 0 65 mm pitch package no opens or shorts were recognized with stencil apertures from 0 30 mm to 0 45 mm For the LGA 0 5 mm pitch package no opens or shorts were recognized with stencil apertures from 0 25 mm to 0 35 mm Since the LGA package is difficult to inspect visually we recommend that printing conditions be set based on X ray peel off or other inspections to determine the mounting conditions Page 54 of 140 RENESAS Semiconductor Package Mount Manual 3 Mounting Processes 3 2 Component Mounting Processes 3 2 1 Adhesives In flow soldering processes the SMD packages are usually attached to the printed wiring board with an adhesive The following characteristics must be taken into account when selecting an adhesive 1 Select an adhesive with an adequate adhesive strength 2 Use an appropriate amount of adhesive to prevent both soldering failures and inadequate adhesion In particular each component s standoff distance and weight must be considered 3 The hardening temperature must fall within the storage temperature ranges in the ratings for each of the components In particular a temperature lower than the glass transition temperature around 150 C that some plastic packages have 3 2 2 Component Placement Equipment One critical point in the component placement process is the precision with which the mounted components to be mounted are placed Verify the amount of margin for displaceme
65. Material D Material E Material G Material H Material number Reflow soldering conditions Peak temperature 235 C Solder wetting and Area after reflow R Time below 220 C 35 s i OIA Rue shen ee Atmosphere 1 Air spreading ratio Area after printing S 2 Nitrogen Oxygen density 300 30 ppm After printing fI After reflow BGA wetting defect Head in Pillow i e Board 4700 MVV 12 temen 190 SEA Figure 5 1 Solder Paste Material Wetting and Spreading R50ZZ0003EJ0500 Rev 5 00 2 AS Page 105 of 140 Feb 03 2015 KENES 5 Examples of Mounting and Problems Semiconductor Package Mount Manual 5 1 2 Notes on WLBGA Usage Extreme care is required in handling these products since the chip is not protected by resin 1 Use vacuum tweezers to move these products Use of metal tweezers to handle these products can chip the silicon chip 2 Use extreme care to prevent applying mechanical shocks to these products to prevent chipping or cracking of the silicon chip Chipping or cracking can occur if boards are stacked after mounting 3 These chips must be handled only in environments in which anti static measures have been implemented to prevent damage from static discharge 4 Ifunderfilling is performed after mounting form a fillet of at least 50 of the devices thickness along each side of the device If the fillet is insufficient peeling may occur in the rewiring layers including the silicon chip and resin section
66. Mount Manual 2 Temperature Cycle Characteristics Soldering Paste Temperature C Sn 3Ag 0 5Cu Sn 37Pb Sn 3Ag 0 5Cu Sn 37Pb Sn 3Ag 0 5Cu Sn 37Pb Sn 3Ag 0 5Cu Sn 37Pb Sn 3Ag 0 5Cu Sn 37Pb Sn 3Ag 0 5Cu Sn 37Pb Sn 3Ag 0 5Cu Sn 37Pb Sn 3Ag 0 5Cu Sn 37Pb Sn 3Ag 0 5Cu Sn 37Pb gt 5 S Sl ol ol eolelele elelelelel elaefeleoleo o ol lo o o ol S o o olo Olola oll l O10 D 91H o lD ALO Bed Be Pac in FBGA 0 8 mm Figure 6 3 Thermal Cycle Test Results Using Sn 3Ag 0 5Cu Solder Ball and Sn 37Pb Paste 6 1 2 Lead type SMD The reliability results of mounting a lead type lead free product using Sn 3Ag 0 5Cu solder under various temperatures and then evaluating the lead connection strength after temperature cycle testing are shown below Looking at these results we can see a tendency toward lower strength as the number of temperature cycles is increased regardless of whether the lead material is Cu or Fe Ni 42 Alloy If the lead material is Cu the lead connection strength tends to be somewhat higher at lower soldering temperatures and if the lead material is Fe Ni 42 Alloy it ends to be somewhat higher at higher soldering temperatures Lead material Cu 14 Z 42 E diu 10 8 n 6 e 230 C a e 245 C 8 260 C 0 2 l 0 i i i 0 250 500 750 10
67. Mount Manual 3 Mounting Processes 3 3 2 Temperature Profile Conditions This section discusses the four points required of the temperature profile 1 Peak temperature 1 The component surface temperature must be lower than the stipulated temperature 2 The temperature of the section being soldered must be higher than the melting point of the solder In particular for BGA packages the temperature of the innermost ball or its mounting pad on the printed wiring board which is the place that often has the lowest temperature must exceed the melting point of the solder paste or solder ball 3 The peak temperature must not be excessively high An excessively high peak temperature can increase the warping of the printed wiring board or packages and can result in open or short circuits The peak temperature must be set based on careful verification in advance In particular BGA packages are subject to greater warping than QFP packages and require special care It is also necessary to manage the temperature of the components on the previously mounted side when mounting components on the side mounted later If the components on the previously mounted side reach a high temperature they may peel away due to warping This problem also requires careful verification in advance When setting the peak temperature observe the following two points to set the mounting equipment temperature The temperature of the soldered areas the area under the pins or
68. Renesas Electronics product whether in whole or in part Renesas Electronics assumes no responsibility for any losses incurred by you or third parties arising from such alteration modification copy or otherwise misappropriation of Renesas Electronics product Renesas Electronics products are classified according to the following two quality grades Standard and High Quality The recommended applications for each Renesas Electronics product depends on the product s quality grade as indicated below Standard Computers office equipment communications equipment test and measurement equipment audio and visual equipment home electronic appliances machine tools personal electronic equipment and industrial robots etc High Quality Transportation equipment automobiles trains ships etc traffic control systems anti disaster systems anti crime systems and safety equipment etc Renesas Electronics products are neither intended nor authorized for use in products or systems that may pose a direct threat to human life or bodily injury artificial life support devices or systems surgical implantations etc or may cause serious property damages nuclear reactor control systems military equipment etc You must check the quality grade of each Renesas Electronics product before using it in a particular application You may not use any Renesas Electronics product for any application for which it is not intended Renesas
69. Soldering After countermeasures R50ZZ0003EJ0500 Rev 5 00 2 AS Page 123 of 140 Feb 03 2015 KENES 5 Examples of Mounting and Problems Semiconductor Package Mount Manual 5 3 Notes on Mounting Pad Design for HQFP and HLQFP Mounting 5 3 1 Mounting Pad Design Example for HLQFP Mounting For HLQFP packages we recommend solder resist silkscreening or other separate processing to assure an adequate amount of solder for the heat spreader at the corner of the package Figure 5 33 presents a case where separate processing is used Separating these areas with solder resist or other means can prevent solder that reaches the package corner areas from flowing under the package Solder influx under the package in excess of that required can lift the package and adversely affect connection with the lead pins We recommend verifying this for the solder materials and mounting conditions you are actually using Figure 5 33 Photograph of Separation by Solder Resist Figure 5 34 shows the experimental results of the effects of this separation 1 In the evaluation of boards in which land separation was implemented no solder influx under the package was found 2 In the evaluation of boards in which land separation was not implemented solder influx under the package was found Package observed from above Package observed from an angle Corner area lands separated Corner area lands not separated Figure 5 34 Photographs of the Mounted Sta
70. TQFP HLQFP and HTQFP o0 cece eccssesscssecseesecneeeeceseeecssecseesecsevsecsaeeeeaecaeeeeeneeaes Figure 2 4 4 HQFP HLQFP and HTQFP exposed die pad type oe ee eeeecesecssesecseeeeceseeeeseceeesecneesessaeeecaecateeeeaeeats Figure 2 5 5 HQFP HLQFP Exposed back surface heat spreader type eesesesesesscseesececeeeeeecseeeeeaeeeeteeeaeeseeneeeees Figure 2 6 2 J Lead Type Packages MISOL spe o ooo PETE Figure 2 7 PARON een E E p yFTTBBEorr E Figure 2 8 3 Non Lead Type Packages 2 QEN and HQEN ou eeeeecccecccccesssscecsesececeneeeceeseeecseaaececseeeecesseeecseaaeeecenseeceesaeeecsesaeeesseaeeeeesaeeecsesaeeessneeeeneae Figure 2 9 R50ZZ0003EJ0500 Rev 5 00 TENESAS Page 27 of 140 Feb 03 2015 2 Printed Wiring Board Design Semiconductor Package Mount Manual 1 Gull Wing Type Package Dimensions 1 Mounting pad dimensions for SOP MIL standard packages The mounting dimensions are those shown below l2 L B1 B2 b lt be lt e y The constants are all the same for the package widths 1 from type 1 225 mil to type 6 600 mil Package width 1 types Type 1 225 mil 5 72 Type 2 300 mil 7 62 Type 3 375 mil 9 53 Type 4 450 mil 11 43 Type 5 525 mil 13 34 Type 6 600 mil 15 24 e Renesas Package Dimension Examples SOP Type MIL Standard e
71. X ray CT image Cross sectional view Figure 5 11 Example of Solder Ball Failure to Head in Pillow 2 Inferred mechanism for failure to fuse faults Figure 5 12 shows the mechanism for the failure to Head in Pillow When the package or the printed wiring board is heated warping occurs If this warping is large the solder ball and solder paste will be pulled apart the preheating process in the figure If heating continues in this state the solder ball will be subjected to high heat and surface oxidation proceeds rapidly the main heating process At this time although flux seeps out from the solder paste and covers the surface if this flux loses its activity when the warping is reversed during the cooling process even if the solder ball makes contact the flux cannot remove the oxide film from the solder ball surface and a failure to Head in Pillow occurs cooling process Page 110 of 140 RENESAS ee Semiconductor Package Mount Manual 5 Examples of Mounting and Problems Temperature Solder paste side Time Figure 5 12 Assumed Mechanism for the Failure to Head in Pillow 3 Analysis of Failure to Fuse Fault Causes In addition to the cause discussed in the assumed mechanism section several other factors may cause failure to Head in Pillow to occur Figure 5 13 presents a fault tree analysis FTA for package and mounting factors It is thought that failure to Head in Pillow can occur do to individual causes
72. a pin shown above cannot be exceeded regardless of the pin width Therefore when the pin width is narrower than the maximum pin width the tolerance for the pin center position will be larger In the following we present an example based on a 0 5 mm pitch QFP Pin width 0 2 0 05 mm Tolerance zone for the pin center position 0 08 Thus for a 0 5 mm pitch QFP the maximum pin location range will be 0 33 mm 0 165 mm from the true pin center position True center position v Tolerance zone for the pin center position X 0 08 mm 0 04 mm Maximum pin location range pin maximum width tolerance zone for the pin center position 0 25 0 08 0 33 Pin center position tolerance pin position for 0 04 mm tolerance Pin center position tolerance pin position for 0 04 mm tolerance 0 25 mm Pin maximum width true pin location range 0 33 mm Maximum pin location range the maximum allowable range for a pin Figure 2 1 Pin Center Position Tolerance for a 0 5 mm Pitch QFP Page 26 of 140 RENESAS o 9 Semiconductor Package Mount Manual 2 Printed Wiring Board Design 2 1 2 Dimensional Examples for Different Package Types 1 Gull Wing Type Packages Ti SOP MIL standard sa a an heer ee rr ath i skermo oda EE NEE EEAS Figure 2 2 2 TSOP type I type ID SSOP LSSOP TSSOP VSSOP and WSOP 00 eee eee eee eeeeeeeeeeeeeeeeeeees Figure 2 3 3 QFP HQFP LQFP
73. able commercially During printing it is desirable to reduce the squeegee tip pressure and print at a low speed In this case a phenomenon called rolling in which the solder paste is rolled in can be observed 2 Printing gap separation between the printed wiring board and the stencil If the printing gap is too small bleeding can occur and if too large problems such as variations in the form of the printed solder and scattering of solder when separating the work may occur Therefore an appropriate gap must be set More recently contract printing technology in which this printing gap is set to 0 mm appears ready for more widespread adoption However adoption of contact printing requires the use of printing equipment that supports low printing pressures and speed control when separating the screen from the work 3 Printing pressure The actual printing pressure is generally around 5 to 10 g cm Note however that this pressure is the pressure at the tip of the squeegee and can be influenced by the way the squeegee collapses under this pressure Care is therefore required when determining the printing pressure More recently printing equipment that provides a floating squeegee structure to achieve lower and more even printing pressures have become available commercially 4 Squeegee speed During printing a squeegee speed in the range 5 to 50 mm s is used Note however that it is necessary to slow the squeegee speed as much as possib
74. alone is very difficult please evaluate the safety of the final products or systems manufactured by you Please contact a Renesas Electronics sales office for details as to environmental matters such as the environmental compatibility of each Renesas Electronics product Please use Renesas Electronics products in compliance with all applicable laws and regulations that regulate the inclusion or use of controlled substances including without limitation the EU RoHS Directive Renesas Electronics assumes no liability for damages or losses occurring as a result of your noncompliance with applicable laws and regulations Renesas Electronics products and technology may not be used for or incorporated into any products or systems whose manufacture use or sale is prohibited under any applicable domestic or foreign laws or regulations You should not use Renesas Electronics products or technology described in this document for any purpose relating to military applications or use by the military including but not limited to the development of weapons of mass destruction When exporting the Renesas Electronics products or technology described in this document you should comply with the applicable export control laws and regulations and follow the procedures required by such laws and regulations It is the responsibility of the buyer or distributor of Renesas Electronics products who distributes disposes of or otherwise places the product with a third party
75. aning agents and cleaning methods used Clean the work as soon after reflow as possible Wicking Board Mounting pad Phenomenon in which the melted solder is wicked up the sides of the leads The filet between the lead and mounting pad becomes smaller This can easily occur in the VPS method when the work is heated rapidly The lead temperature rises more rapidly than the mounting pad and reaches the solder melting temperature first Use adequate preheating in the VPS method Use an IR reflow furnace for soldering Head in Pillow Package Ball Ss Board Solder Mounting pad R50ZZ0003EJ0500 Rev 5 00 Feb 03 2015 The state in BGA mounting where the outer ball do not fuse correctly to the solder on the mounting pad The amount of solder printed is uneven The melting time is insufficient The pressure used in the mounting equipment is insufficient Pin surface oxidation Insufficient solder paste activation Review the solder printing conditions Review the heating conditions Review the mounting conditions Check the package storage state Page 77 of 140 3 Mounting Processes Semiconductor Package Mount Manual 3 6 Repairing and Reworking This section presents an overview of repairing and reworking component replacement for post soldering defects as well as examples of these operations 3 6 1 Repairing A soldering iron can be used to repair soldering defects for packa
76. aste koj i 2 Sn Bi plating Sn 37Pb paste So Sn Bi plating Sn 37Pb paste 9 Sn Pb plating Sn 37Pb paste 4 Sn Pb plating Sn 37Pb paste 0 I r r 0 l I L 0 500 1000 1500 2000 0 500 1000 1500 2000 cycle cycle 7 Sn plating Cu frame 14 Ni Pd Au plating Cu frame 12 P B g 8 g 7 t o 6 D E 4 9 Sn plating Sn 3Ag 0 5Cu paste E 4 H e Ni Pd Au plating Sn 3Ag 0 5Cu paste Bo 9 Sn plating Sn 37Pb paste e Ni Pd Au plating Sn 37Pb paste Sn Pb plating Sn 37Pb paste Sn Pb plating Sn 37Pb paste 0 0 0 500 1000 1500 2000 0 500 1000 1500 2000 cycle cycle Figure 6 15 Lead Pull Strength R50ZZ0003EJ0500 Rev 5 00 2 AS Page 135 of 140 Feb 03 2015 ENES 6 Solder Joint Reliability Semiconductor Package Mount Manual 6 9 2 BGA Ball Attachment Strength after High Temperature Storage This section presents the results of investigating changes in the ball attachment strength after high temperature storage for earlier Sn 37Pb eutectic solder ball products and lead free Sn 3Ag 0 5Cu ball products These results show that while both types of solder ball show similar reductions at up to 200 hours at 150 C there were no changes in strength after that 10 9 8 OF Z 6 Package 5 l e 15 x 15 mm 240 pin FBGA 0 8 mm pitch 3 e Sn 3Ag 0 5Cu balls e Ball composition Sn 3Ag 0 5Cu Sn 37Pb 2 2 M Sn 37Pb balls
77. at side D A LI Observation direction Line t joining pad surfaces Board Distance from A and B of wi bumps at both ends line segment AB to pad surface Figure 5 15 Example of Failure to Head in Pillow Due to Warping Factor 2 Solder ball surface oxide film Since if packages are left standing for a long period after opening the moisture proof packing oxide film formation on the solder ball will progress and the oxide film become thicker this can be thought to be a cause of the occurrence of failure to Head in Pillow Although we verified that even if the oxide film on the solder balls becomes somewhat thicker due to the preprocessing its influence on solderability is not significant as shown in figure 5 16 if some other factors are combined with this for example if the oxide film on the solder balls grows rapidly during reflow heating or if the BGA package or printed wiring board warps its influence on failure to Head in Pillow may be heightened e Reproducibility evaluation example Solderability of solder ball oxide film thickness and solder paste In this example even for solder balls on which preprocessing has been performed and the surface oxide film has become thicker good bonding was obtained Preprocessing of solder balls Steam aging 93 C 100 16 h Evaluation conditions Oxide film thickness 363 A Solder ball Sn 3Ag 0 5Cu Ball diameter 0 5 mm Solder paste Sn 3Ag 0 5Cu Flux content 11 5 Chlorine content 0
78. aterials For lead type SMD the reliability temp cycle results of mounting conventional Sn Pb plated products and lead free Sn Bi plated products and Ni Pd Au plated products with conventional Sn 37Pb eutectic solder and lead free Sn 3Ag 0 5Cu solder are shown below The combination of the lead free product with the lead free solder yielded temperature cycle characteristics superior to those of the conventional combination and the combination of the conventional product with lead free solder and lead free product with conventional solder yielded inferior results Since the combination of Sn 37Pb solder with lead free solder leads to reduced thermal cycle performance in some cases thorough evaluation in advance is required if mounting materials with differing compositions are selected Weibull Plot F t Lead material Cu Test temperature EEU e Plating Sn Bi Paste Sn 3Ag 0 5Cu Vi e Plating Sn Bi Paste Sn 37Pb gA e Plating Sn Pb Paste Sn 3Ag 0 5Cu AH e Plating Sn Pb Paste Sn 37Pb 10 5 1 0 1 100 1000 10000 100000 cycle Weibull Plot F t Lead material Fe Ni 42 Alloy By e Plating Sn Bi Paste Sn 3Ag 0 5Cu el o e 40 to 125 C 10 minutes dwell Package e 28 x 28 mm 208 pin QFP 0 5 mm pitch daisy chain e Lead material Cu Fe Ni 42Alloy e Plating Sn Bi Sn Pb Ni Pd Au Printed wiring board e Size 125 x 125 x t 1 6 mm e Material FR 4 4 layers e Pad surface treatment Preflux Stencil e
79. ature e 40 to 125 C 10 minutes dwell Package Printed wiring e 13 x 13 mm 225 pin FBGA 0 65 mm pitch daisy chain SMD structure NSMD structure board e Ball composition Sn 37Pb Solder Mask Defined Non Solder Mask Defined Printed wiring board e Size 124 x 130 x t0 8 mm Solder regist F t Weibull Plot Material FR 4 4 layers o e Pad size EE NSMD Cu 0 35 SR 0 45 mm SMD Cu 60 45 SR 0 35 mm e Pad surface treatment Preflux Stencil e Thickness 150 um Aperture 0 35 mm Solder paste e Sn 37Pb Reflow soldering temperature package surface e Max 235 C Failure definition e 20 nominal resistance increase 8 10 5 1 0 1 100 1000 10000 cycle Figure 6 8 Weibull Plot Influence of Printed Wiring Board Pad Structure Page 130 of 140 RENESAS E Seiee Semiconductor Package Mount Manual 6 Solder Joint Reliability 6 6 Single Sided and Double Sided Mounting This section presents the results of thermal cycle testing of double sided mounting with four types of position shifting compared with single sided mounting These results show that type II with 100 overlap in double sided mounting has significantly worse performance in thermal cycling compared to type I single sided mounting Furthermore we found that type V double sided mounting with packages displaced by the size of the package width provides essentially the same performance in thermal cycling as single sided mounting
80. be used to assess the degree of cleaning achieved Cleaning degree assessment methods e Visual assessment e Contact angle and wetting indices e Contaminant extraction concentration measurement method e Optical methods e Molecular spectroscopy methods 2 No clean Assessment Methods When no cleaning is implemented it is important to analyze the flux used In particular the following items must be evaluated e Corrosivity tests e g the copper mirror test e Reactivity tests e g the silver chromate paper test e Insulation resistance tests e g high temperature high humidity bias testing e Aqueous solution resistance measurement e Actual equipment testing reliability testing of the cleaned board as an actual product reliability testing of each individual component Since the assessment standards used for each of the above items will differ with the reliability level required for the application and the specifications the user must determine these standards based on a thorough analysis for each product R50ZZ0003EJ0500 Rev 5 00 2 AS Page 73 of 140 Feb 03 2015 ENES 3 Mounting Processes Semiconductor Package Mount Manual 3 5 Inspection Process Due to increasingly smaller sizes and lighter weights in electronic equipment all aspects related to the electronic components mounted in this equipment are seeing trends towards more minute sizes and higher densities As a result the post soldering visual inspection previ
81. c 0 2 mm 240 C Note 1 The placement load shows spring loading for the mounting nozzles on the SMD placement system Mounting Results Package Dimension Package Displacement Package Displacement Package Displacement 0 05 mm 0 10 mm 0 15 mm LQFP144 20x20 0 5 QFP144 20x20 0 5 0 5 0 5 0 5 Note 2 The mounting displacement of 0 15 mm corresponds to a protrusion amount from the mounting pads by 1 2 the lead width Self alignment Evaluation Photograph Example LQFP144 20x20 0 5 QFP144 20x20 0 5 Displacement 0 15 mm Displacement 0 15 mm Before reflow We verified than adequate self alignment in reflow soldering even for large QFP packages After verifying the solder materials and reflow conditions actually used the mounting conditions should be analyzed carefully R50ZZ0003EJ0500 Rev 5 00 RENESAS Page 63 of 140 Feb 03 2015 3 Mounting Processes Semiconductor Package Mount Manual 3 3 Soldering Processes This section describes full heating soldering processes The conditions required of a soldering process are that the mounted components be connected both electrically and mechanically to the printed wiring board To achieve these conditions it is necessary to meet temperature profile conditions described in a later section A temperature profile indicates in what ways the temperature changes with time inside the soldering equipment for the printed wiring board to which the components are bein
82. c principle of convection reflow soldering is that an atmosphere air or N2 heated by a heater is circulated within a furnace and heat is transmitted to the work by convection heating to perform the soldering The result of this process is that an even temperature distribution is achieved after a fixed time even if there are differences in thermal capacities between the board and components Convection reflow hot air soldering has the following characteristics 1 Advantages Superlative temperature evenness compared to IR methods IR reflow The temperature is not significantly affected by the objects being heated Comparatively low thermal stress 2 Disadvantages The soldering time tends to be longer than that for IR reflow Heated air Heater Fan Straightening vanes _ Pere ae alata mimt a COn alalatai mt a nimiam imt mte fe Figure 1 10 Convection Reflow Method Example 4 Combined Convection IR Method Convection IR Reflow In this method convection and IR heating are combined to decrease the soldering time which is a disadvantage of the previous method convection reflow aaa N Tel aa NaN a aa at Tah alal la Figure 1 11 Convection Reflow Method Example R50ZZ0003EJ0500 Rev 5 00 2 AS Page 9 of 140 Feb 03 2015 KENES 1 Overview of Soldering Technology Semiconductor Package Mount Manual 5 Flow Wave Soldering Method In this method solder melted i
83. cess This section presents notes on solder mounting and examples of problems in solder mounting based on the BGA mounting case 5 1 1 Notes on Lead Free Solder Mounting Differences in the wetting and spreading characteristics of the various lead free solder Sn 3Ag 0 5Cu materials on copper plates have been recognized Materials that result in an area smaller than the area printed with the solder paste are also seen occasionally when reflow is performed in air Furthermore materials with differences in wetting and spreading have also been recognized when reflow is performed in a nitrogen atmosphere See figure 5 1 To acquire stable solder wetting characteristics careful selection of the solder materials and optimization of the reflow process conditions are required 7 7 T 7 t T Solder wetting and spreading ratio on a copper plate i i i 7 i i i i i i i i i i i i i i i i i i i i i i i i i i i i i i i i i i i i i i i i i i i i i 4 i i i i i i i i i 1 T i i _ Air rrogen Ar Kr Air Nitrogen Air i Nitrogen Air Nitrogen Air Nitrogen A Nitrogen BGA wetting None Nore None None None None None None None None None defect ratio i i i Material Halogen free Halogen free Halogen free T Halogen free T specifications soft residue soft residue soft residue soft residue LOW halogen soft residue soft residue Material cata og Material 1 Material 2
84. ckages Table 4 6 Storage Condition Examples Condition Temperature 5 to 30 C Humidity Under 70 RH Time 168 hours The time from the point the packaging is opened until mounting the last device has completed Page 92 of 140 RENESAS e Semiconductor Package Mount Manual 4 Notes on Storage and Mounting Note however that individual products may have product specific stipulations Thus all products must be stored only after verifying the conditions stipulated in the delivery specifications documents Figure 4 13 presents examples of moisture absorption characteristics for plastic packages of different thicknesses Plastic thickness w 1 5mm 2 0mm 2 7mm o DS 3 7mm Oo a Absorption ratio weight 10 50 100 500 1000 Absorption time hours Figure 4 13 Examples of Plastic Package Moisture Absorption Characteristics 4 2 3 Baking Before soldering perform the baking operation described below 1 Cases Where Baking Is Required e If the 30 spot on the indicator card packed together with the product at moisture proof packaging time has turned pink e If the stipulated storage conditions after opening the moisture proof packaging have been exceeded 2 Baking Conditions Baking must be implemented so as to meet the following conditions Note however that individual products may have product specific stipulations Therefore the baking drying processing must be implemented only after v
85. craping during the electrical test process following lead plating the solderability should not suffer Package QFP144 20x20 0 5 Plating composition Sn Mounting Solder paste composition Sn 3Ag 0 5Cu reflow temperature peak 214 9 C Condition Plating Thin plating Normal plating Thick plating Thickness Ave 5 um Ave 10 um Ave 17 um Before mounting After mounting Figure 4 4 Plating Thickness and Solderability R50ZZ0003EJ0500 Rev 5 00 2 AS Page 87 of 140 Feb 03 2015 KENES 4 Notes on Storage and Mounting Semiconductor Package Mount Manual 4 1 4 Wetting Time Temperature Dependence This section presents an example of evaluation of the temperature dependence of wetting time When mounting electronic components on a printed wiring board insufficient wetting may occur due to insufficient heating during mounting Figures 4 5 and 4 6 show the results of investigating the temperature dependence of the wetting time listed in table 4 2 Test Conditions Table 4 2 Meniscograph Test Conditions Flux Rosin R Type Sample 100 pin LQFP Cu alloy Test temperature See figures 4 5 and 4 6 Immersion speed 15 mm s Immersion depth 0 15 mm Immersion time 5s Number of leads immersed 1 Number of tests 5 Storage conditions 100 C 100 4 hours 0 40 _ 0 35 3 0 30 S 7 Sn e 0 25 e Sn cu 0 20 Ni Pd Au 2 0 15 F e Sn Pb o Sn Bi 2 0 10 o 0 05 210 220 2
86. ct For details consult a Renesas Electronics sales representative Products mounted on the board Table 4 222 Heat Resistance Conditions Partial Heating Maximum temperature 300 C or below temperature of pins Time 3 s or less per one side Rosin flux with minimal chlorine content chlorine percentage mass 0 2 or less Note The peak temperature is 300 or 350 C depending on the product For details consult a Renesas Electronics sales representative R50ZZ0003EJ0500 Rev 5 00 2 AS Page 101 of 140 Feb 03 2015 KENES 4 Notes on Storage and Mounting Semiconductor Package Mount Manual 4 3 3 Soldering Temperature The reflow soldering temperature must be managed so that the package body temperature remains under its heat resistance temperature The ideal temperature conditions are those such that the package contacts and pins enter the recommended temperature range for the solder paste used Since the preheating temperature and time and the main soldering temperature and time will differ depending on the composition of the solder used and the characteristics of the flux these must be verified in advance Note that the composition of the package contacts and pins involves processing with multiple metallic compositions as discussed in section 4 3 4 Therefore the melting temperature of the platings used on the package contacts and pins must also be taken into consideration Process condition settings such that the sol
87. currence may increase in these cases a After first reflow During second reflow After second reflow Warping Figure 5 22 Assumed Ball Drop Occurrence Mechanism R50ZZ0003EJ0500 Rev 5 00 2 AS Page 117 of 140 Feb 03 2015 KENES 5 Examples of Mounting and Problems Semiconductor Package Mount Manual 3 Workarounds Consider the following methods as workarounds to prevent the ball drop phenomenon from occurring 1 Avoid remelting after mounting Only perform one reflow soldering operation on packages for which ball drop occurs i e mount such packages during the second reflow operation Also avoid performing reflow soldering again during repairs 2 Reflow atmosphere If atmospheric reflow is used switch to N2 nitrogen reflow soldering which provides improved solderability 3 Prevent moisture absorption When multiple reflow operations are performed store packages and printed wiring boards so that they do not absorb moisture from the first reflow operation until the last reflow operation 4 Reduce the reflow temperature For packages for which multiple reflow operations are performed reduce the reflow temperature for the second and later reflow operations to the low end of the acceptable range Page 118 of 140 RENESAS EOAR Semiconductor Package Mount Manual 5 Examples of Mounting and Problems 5 2 LGA Mounting Process This section presents notes on solder mounting and examples of problems in solder mounting based on the
88. d reflow or VPS and that the molten solder temperature is indicated if the soldering method is wave soldering Table 4 10 Maximum Temperature Symbol Maximum Temperature Baking time The recommended baking time is indicated by using two numerical digits shown in the table below Table 4 11 Baking Time Symbol Baking Time Baking unnecessary 0 hours 10 hours min 72 hours max 20 hours min 72 hours max 36 hours min 72 hours max Page 96 of 140 RENESAS e Semiconductor Package Mount Manual 4 Notes on Storage and Mounting Number of storage days after opening moisture proof packaging dry pack The number of days during which the product can be stored after the moisture proof packaging dry pack has been opened is indicated by the symbols shown in the table below Table 4 12 Number of Storage Days After Opening Moisture proof Packaging Dry Pack Symbol Number of Days 1 day 24 hours max 2 days 48 hours max 3 days 72 hours max 7 days 168 hours max Not limited Number of times of mounting The number of times the product can be mounted is indicated by the symbols shown in the table below Table 4 113 Number of Times of Mounting Symbol Number of Times 1 2 times max 3 times max Remark The above symbol codes apply to the products that can be soldered by means of a total heating method Some of Renesas E
89. d wiring board and components being cleaned do not contact the ultrasonic actuator Please refer to the reliability handbook for more information on conditions for ultrasonic cleaning 2 Water quality and effluent handling for rinse cleaning When terpene based or semi aqueous cleaning agents are used a water cleaning phase is introduced as a post clean rinse cleaning operation Here a careful analyses of the water quality during the water cleaning itself and of the water quality of the effluents must be performed 3 Safety precautions when using flammable solvents The explosion prevention safety measures in cleaning equipment must be analyzed thoroughly when using alcohol terpene based solvents semi aqueous solvents petroleum base solvents or other flammable solvent due to the danger of fire Page 72 of 140 LEN ESAS aa ko Semiconductor Package Mount Manual 3 Mounting Processes 2 Cleaning With Water When water cleaning is used generally the cleaning itself is implemented as a shower This is followed by draining and then drying When water cleaning including shower cleaning methods is implemented the washing conditions such as the spray pressure and the nozzle angles the drying method and the drying conditions require careful study Also the waste water must be processed to conform to all national and local laws and regulations 3 4 4 Assessment Methods 1 Assessing the Cleaning Effect The following methods can
90. der bath for devices that use an Cu alloy as the lead material after long term storage under differing storage environments These results show that even after storage for two years under differing packing conditions there is almost no change in the wetting time and that the solder wetting characteristics remain good Page 90 of 140 RENESAS e Semiconductor Package Mount Manual 4 Notes on Storage and Mounting Table 4 5 Meniscograph Testing Conditions Sn 3Ag 0 5Cu bath Flux Rosin R Type Sample 208 pin QFP Cu Alloy Test temperature 245 C Immersion speed 10 mm s Immersion depth 1 5mm Immersion time 10s Number of leads immersed 10 Number of tests 10 Storage conditions 25 5 C and 50 30 RH I 2 Moistureproof packing dry pack Cu Alloy frame 8 O 9 oO E D o First 6months 1 year 2 years quater Storage time Figure 4 9 Results of Wetting Balance Test T 6 Moistureproof packing dry pack Cu Alloy frame 8 O e oO E dD O First 6months 1 year 2 years quater Storage time Figure 4 10 Results of Wetting Balance Test T Moistureproof packing dry pack Cu Alloy frame 8 O 2 o E D o ru 6months 1 year 2 years e Storage time Figure 4 11 Results of Wetting Balance Test R50ZZ0003EJ0500 Rev 5 00 ztENESAS Page 91 of 140 Feb 03 2015 4 Notes on Storage and Mounting Semiconductor Package Mount Manual 4 2 Package Storage Cond
91. der residue and projections cause the stencil to not closely adhere to the substrate during solder paste printing leading to improper solder paste supply Moreover when the solder resist peels all the way to an adjacent through hole the solder paste printed on the pad gets sucked to the through hole during reflow which may cause improper connection Figure 3 16 shows examples of cleaning work defects a Left over solder b Projection c Peeling solder resist Figure 3 16 Examples of Cleaning Work Defects 3 Supplying Solder Paste Solder supply during rework is done using specialized jigs and tools Examples for wide spacing and narrow spacing between parts are described below Relatively wide spacing between parts As shown in figure 3 17 fix the partial stencil on the printed wiring board using tape and print the solder paste with a squeegee figure 3 18 Figure 3 17 Partial Stencil Attached R50ZZ0003EJ0500 Rev 5 00 a2 AS Page 81 of 140 Feb 03 2015 ENES 3 Mounting Processes Semiconductor Package Mount Manual Figure 3 18 Solder Paste Printed on Partial Stencil Narrow spacing between parts If the spacing between parts is too narrow to attach a simple partial stencil there is also the method of supplying solder paste on the BGA balls as shown in figure 3 19 The procedure is shown below 1 Fix the package with a jig etc figure 3 20 2 Fix the partial stencil to cover the package as shown figure 3
92. der used for mounting and the package contact metal and pin plating metal fuse together are ideal Also note that the soldering atmosphere nitrogen atmosphere is an item that has a large effect and influence on the soldering time and temperature and must be taken into consideration when analyzing the process condition settings Up to the package heat resistance temperature surface temperature Renesas Recommended temperature range for the solder paste soldering position temperature Solder manufacturer Temperature C Above the fusing temperature for the solder and the package s ball metal or lead plating metal oq Preheating Main heating Time seconds Figure 4 222 Soldering Temperature Page 102 of 140 RENESAS eee Semiconductor Package Mount Manual 4 Notes on Storage and Mounting 4 3 4 Package Contact and Pin Plating Metal Compositions The table below lists common contact and pin plating compositions and their melting points We recommend taking these values into consideration when selecting the solder paste and when setting the reflow temperature profile in particular consider setting the soldering conditions to be higher than the melting temperature of the contact material Table 4 23 Contact and Pin Plating Compositions and Melting Temperatures Package Pins Contact and Pin Plating Composition Melting Temperature Ball pins e g BGA Sn 37Pb 183 C Sn 3Ag 0 5Cu 217 to 220 C
93. dn Bhd Unit 1207 Block B Menara Amcorp Amcorp Trade Centre No 18 Jin Persiaran Barat 46050 Petaling Jaya Selangor Darul Ehsan Malaysia Tel 60 3 7955 9390 Fax 60 3 7955 9510 Renesas Electronics India Pvt Ltd No 777C 100 Feet Road HAL II Stage Indiranagar Bangalore India Tel 91 80 67208700 Fax 91 80 67208777 Renesas Electronics Korea Co Ltd 12F 234 Teheran ro Gangnam Gu Seoul 135 080 Korea Tel 82 2 558 3737 Fax 82 2 558 5141 2015 Renesas Electronics Corporation All rights reserved Colophon 4 0 Semiconductor Package Mount Manual TENESAS Renesas Electronics Corporation R50ZZ0003EJ0500
94. during reflow to assure the required amounts of solder for the contact land areas that correspond to the heat spreader corner sections Figure 2 6 HQFP and HLQFP Exposed back surface heat spreader type Examples Page 32 of 140 RENESAS ees Semiconductor Package Mount Manual 2 Printed Wiring Board Design 2 J Lead Type Package Dimensions 1 Mounting pad dimensions for SOJ packages The mounting dimensions are those shown below e Renesas Dimension Example SOJ Unit mm e 1 27 l 1 20 l2 2 00 b2 0 75 Note Reference values based on the former EIAJ ED 7406 standard Figure 2 7 SOJ Example R50ZZ0003EJ0500 Rev 5 00 2 AS Page 33 of 140 Feb 03 2015 KENES 2 Printed Wiring Board Design Semiconductor Package Mount Manual 2 Mounting pad dimensions for QFJ packages The mounting dimensions are those shown below 1E OF 1D i b2 e Renesas Dimension Example QFJ Unit mm 1 27 l 1 20 E di 7 200 b2 0 75 Note Reference values based on the former EIAJ ED 7407 standard Figure 2 8 QFJ Example Page 34 of 140 LE NESAS aaa Semiconductor Package Mount Manual 2 Printed Wiring Board Design 3 Non Lead Type Package Dimensions 1 Mounting pad dimensions for QFN and HQEN packages The mounting dimensions are those shown below Punch Ty
95. e 5 9 shows a good solder joint formation example for a BGA package when the BGA package joint process is viewed with a high temperature observation unit In this example when the main heating above the melting point phase is entered and the solder paste fuses the solder starts to wet move up the balls and when all the balls have fused the device starts to sink To acquire good joining it is important to set the time above the melting point appropriately so that the devices adequately sink into the solder In this example about 20 seconds is required for the package to sink adequately 0 8 mm pitch TFPBGA Printed wiring board FR 4 t 1 0 mm Observed point Sn Ag Cu ball Solder paste Sn Ag Cu Temperature C Eia 160 160 190 190 220 220 235 Displayed temperature measurement point 60 120 30 20 Ne verd Printed wiring board 200 C 220 C 235 C Room temperature Figure 5 9 Good BGA Joint Formation Process 1 Problem Case 1 Insufficient heating Figure 5 10 shows a problem case that is due to insufficient heating in the BGA package joint formation process This is an example of changing the heating conditions and observing the joint external appearance and cross section If the peak temperature is low and the time above the melting point is short either the solder paste and solder ball may not melt and thus not fuse together condition 1 or even if they do melt the shape of the solder joint may be poo
96. e Mount Manual 3 THD Lead Type SMD Flow Soldering Adhesive application Adhesive Printed wiring board J Lead type SMD Chip component Mounting of component l Heat Adhesive ee hardening THD Board reversal and component mounting insertion a l Figure 1 18 THD Lead Type SMD Flow Soldering Page 22 of 140 LE NESAS E e e Semiconductor Package Mount Manual 1 Overview of Soldering Technology Flux application Spray nozzle a Flow soldering Melted solder Solder port Visual check Appearance inspection camera lt Figure 1 18 THD Lead Type SMD Flow Soldering cont R50ZZ0003EJ0500 Rev 5 00 TENESAS Page 23 of 140 Feb 03 2015 1 Overview of Soldering Technology Semiconductor Package Mount Manual Page 24 of 140 LE NESAS EA Ea Aso pro Semiconductor Package Mount Manual 2 Printed Wiring Board Design 2 Printed Wiring Board Design 2 1 Lead Type SMDs In designing the mounting pads for a printed wiring board that mounts lead type SMD packages it is important to take the shape of the leads into consideration Also note that care is required since there may be subtle differences in pin shapes even between devices with the same package name The parameters regulating the mount pad dimensions are as follows e Cleanliness a e Soldering strength B1 e Pattern precision and ease of visual inspection B2 e Solder bridge tolerance y The allowable margins for whic
97. e oe a aerate 38 2 3 1 THI Pin Location Range sn pus EE EE E E E E E 38 2 3 2 Through Hole Diameter Design erii irnrie o salerese inivesi e eraras eir e E Giras EEEE ENEE TE EnEn 40 2 3 3 Through Hole Diameter Dimensional Design for Printed Wiring Boards Design Ranges 40 24 Discrete Devices ainsi hain he ae eee aig eae 41 2 Board Pis kILTI T ooho Jhio err TTT TTTETTTTTETTE TIDE 41 2 5 1 Preventing Mounting Pad Oxidation 0 0 ees cesesscneeeecnseeecsseceeesccseesecnaescesaecaessceaecasesecseesecnaeeeesaeeseeneeseeegs 42 2 5 2 Printed Wiring Board Warping assess nasca Arh Pss Arties theaters Ash Bus kores vos ka Seo Anes hide Mase dusk 43 2 5 3 Solder J int Reliability siie seroterapio tintin ania KS ESI ROJ 43 3 Mounting PLOCESSES sa pn E UA la AAA 45 3 1 Solder Supply Processe isisszs ui i I NA A l AW o iro nese 45 3 1 1 solder Paste inrer nE E E E l keo AS NS IS e 45 3 1 2 Solder Paste Printing Processes i c s c tesccsgeicerdesadescebevensas tapes eases VE OUN SL 48 3 1 3 Amount of Solder Paste Supplied ee cieecseeccsseeecsseceeesecseesecseesecsaecaeeecsaecasesecsevsecnaeeeesaeceeesecaeeseenaeseeegs 50 3 2 Component Mounting Processes ssssssscsessscsseeecesecssesecseesccsaeeccsaecaseecsaecaeesecseesecsasecesaecatesecseesaecaesaesseseeenaeeeeegs 55 3 2 1 Adhesives TET TETTE TITT TITT TTT TTT TTTTTTTTETTEY TEL 55 3 2 2 Component Placement BquIpment ss aston A aia nga E E AAE E E a aaa 55 3 2
98. ed and RA Rosin Activated Table 3 1 lists their features R50ZZ0003EJ0500 Rev 5 00 LEN ESAS Page 45 of 140 Feb 03 2015 3 Mounting Processes Semiconductor Package Mount Manual Table 3 1 Flux Types and Features Flux Type Features Type R ROL Type These are non activated fluxes They are noncorrosive non activated Rosin Rosin Low activity levels Type RMA ROM Type These are weakly activated fluxes They are noncorrosive They provide superior solderability Rosin Mildly Activated compared to type R fluxes Rosin Moderate activity levels Type RA ROH Type These are strongly activated fluxes While they provide superior solderability compared to Rosin Activated Rosin type R and RMA fluxes they are more strongly corrosive High activity levels Solder Powder Size Range Sn 3Ag 0 5Cu Solder Powder Sn 37Pb Solder Powder Type 2 0 075 mm to 0 045mm Type 3 0 045 mm to 0 020mm Type 4 0 038 mm to 0 020mm Type 5 0 025 mm to 0 010mm Figure 3 1 SEM Photographs of Solder Particles in Solder Paste Page 46 of 140 LEN ESAS EL kj Semiconductor Package Mount Manual 3 Mounting Processes Table 3 2 Solder Powder Size for Solder Paste and Corresponding Lead Pitches e Lead type packages QFP SOP and similar packages Solder Powder Lead Pitch mm Size Range 0 80 0 65 0 075 to 0 045 mm 0 045 to 0 020 mm 0 038 to 0 020 mm 0 025 to 0 010 mm So
99. eflow temperature profile There are cases when failure to fuse faults occur if the time above the melting point is short If the time above the melting point is made longer as shown in figure 5 20 it is possible that the failure to Head in Pillow occurrence ratio may be reduced Thus keeping the time above the melting point as long as possible is effective Rate of occurrence of non bonding Number of unmelted bumps Total number of bumps Preprocessing Preprocessing Baking 125 C 10 h Baking 125 C 10 h Moisture absorbed 85 C 85 120h 20 Moisture absorbed 85 C 85 154h seo s Fos gs i e i 1 0 0 Peak temperature Time at 220 C or higher 135mm 484pin P BGA D17mM305pin P FBGA Figure 5 20 Time Above Melting Point and Failure to Head in Pillow Occurrence Ratio Page 116 of 140 TEN ESAS R50ZZ0003EJ0500 Rev 5 00 Feb 03 2015 Semiconductor Package Mount Manual 5 Examples of Mounting and Problems 3 Fault Example 3 Solder Joints Separation Ball Drop 1 Solder joints separation ball drop The characteristics of the solder joints separation ball drop fault are that the area where the solder ball contacts the BGA land or the pad on the mounting board appears rounded on inspection of the cross section of the solder joint area and appears as though the ball is falling There is also a tendency for this fault to occur in the balls in the inner periphery of the ball array Figure 5 21 shows an example of the ball drop
100. ems Void reduction idio shift mounting used seto Mounting void area ratio 0 6 Figure 5 30 X Ray Inspection After countermeasure 2 2 Problem Case 2 Solder failure to join faults In evaluating the mounting of an 11 x 11 mm 192 pin FLGA package with a 0 65 mm pitch solder failure to join faults occurred We increased the stencil aperture diameter from 0 35 mm to 0 43 mm and increased the amount of solder printed The result was that solder failure to join faults no longer occurred and we acquired good solderability The FLGA package does not have solder balls and compared to the BGA package the total amount of solder used is smaller As a result as the package size increases it becomes more sensitive to package and printed wiring board warping By increasing the amount of solder it becomes easier for the solder to follow the warping 1 Before countermeasures Package land structure dimensions NSMD structure copper pad diameter 0 35 mm SR aperture diameter 0 45 mm Stencil aperture diameter 0 35 mm thickness 100 um Package side Although joints are created there is no solder on the sides of the land Board side Figure 5 31 Cross Section After Soldering Before countermeasures 2 After countermeasures Stencil aperture diameter 0 43 mm thickness 100 um Package side Solder joints are formed on the sides of the land Board side Figure 5 32 Cross Section After
101. era i y h Ay LED illumination D Optical EO Image sensor obstruction MD A Lasi el Laser JM Photodetector a scanning Wee Micro focus X ray X ray O Assessment possible A Some assessments possible x Not supported A value of 0 1 mm for lead flatness which is particularly important for soldering quality is standard for fine lead pitch packages Technological advances that can promote improved quality in lead flatness are strongly desired 2 Paste Printing State Visual Inspection Equipment This is equipment that is intended to prevent soldering defects excess or deficient solder bridges in advance by inspecting the solder printed form volume displacements paste height bridges droop unevenness and other aspects for the solder paste for fine lead pitch packages There are currently two methods used step illumination and laser scanning R50ZZ0003EJ0500 Rev 5 00 2 AS Page 75 of 140 Feb 03 2015 ENES 3 Mounting Processes Semiconductor Package Mount Manual 3 5 2 Visual Inspection ltems Items such as those listed in table 3 9 are tested with a visual inspection of the solder areas For reference purposes in resolving issues we also list causes of defects and measures to resolve the problem Table 3 9 Defect Item Solder not melting Solder powder remains Mounting pad a Board Phenomenon The state where solder powder remains
102. erifying the conditions stipulated in the delivery specifications documents Use heat resistant trays during the baking process Heat resistant trays will be marked either HEAT PROOF or with their heat resistance temperature Verify this marking before using any tray for this processing Table 4 7 Baking Condition Examples PO Baking Temperature Baking Time Repeated Baking Thin form packages with 125 5 C 4 to 24 hours No more than 96 hours total a mounting height of 1 2 mm or less All other packages 125 5 C 16 to 24 hours No more than 96 hours total 4 2 4 Reflow Cycles Do not perform more than three reflow operations Note however that individual products may have product specific stipulations Therefore verify the conditions stipulated in the delivery specifications documents and only apply a number of cycles equal to or less than the number stipulated in those specifications Furthermore the number of reflow cycles used must be set based on a comprehensive verification that no other problems can occur R50ZZ0003EJ0500 Rev 5 00 a2 AS Page 93 of 140 Feb 03 2015 KENES 4 Notes on Storage and Mounting Semiconductor Package Mount Manual 4 3 Soldering Temperature Profiles The soldering temperature profile used must be set based on careful consideration of the heat resistance and solderability of the parts used 4 3 1 Heat Resistance Profiles Compared to the previously used eutectic solders the lead free solders
103. ermal expansion of the front and back sides of the board e Provide a warping prevention structure during reflow during cooling e Use a printed wiring board clamping jig and forcibly prevent warping while performing reflow soldering e Use a heat resistant glass epoxy board Since the type and thickness of the board used influences board warping we recommend carefully analyzing the board specifications including consulting with the board manufacturer and thoroughly checking all aspects based on this evaluation 2 5 3 Solder Joint Reliability Minimizing the difference in coefficients of thermal expansion between the printed wiring board and the packages used must be considered to assure solder joint reliability For example when ceramic packages are surface mounted consider using a ceramic board with an essentially identical coefficient of thermal expansion Also when mounting miniature thin packages in which the ratio of the area occupied by the silicon chip itself is high such as the TSOP VFQN and S WFBGA packages increased solder joint lifetimes can be expected if you select a board with a coefficient of thermal expansion that is as close to that of the package as possible to reduce the apparent coefficient of thermal expansion of the packages overall Such boards include FR 5 equivalent boards that have a high glass transition temperature Tg and a small coefficient of thermal expansion R50ZZ0003EJ0500 Rev 5 00 2 AS Page 43 of
104. ev 5 00 a2 AS Page 51 of 140 Feb 03 2015 ENES 3 Mounting Processes Semiconductor Package Mount Manual 3 Mounting Evaluation Data for Representative Packages This section presents the results of mountability evaluations performed for representative packages with solder paste printing thickness and printing diameter as parameters Solder Paste Supply Amount vs Mountability P VQFN This section presents an example of evaluation of solder paste supply amount and mountability for the P VQEN package Evaluation Sample Package Dimension Mounting Pads Stencil Solder Paste Lead Plating 0 10 mm thickness P VQFN48 7x7 0 5 0 75 x 0 25 mm 0 75 x 0 25 mm Sn 3Ag 0 5Cu Mounting Conditions Package Dimension Placement Load The Push Distance at Placement Reflow Temperature P VQFN48 7x7 0 5 300 g ic 0 20 mm 250 C Air reflow Note The placement load shows spring loading for the mounting nozzles on the SMD placement system Mounting Results Solder Printing 0 20 x 0 20 mm 0 25 x 0 35 mm 0 25 x 0 55 mm 0 25 x 0 75 mm 0 25 x 0 95 mm stencil aperture Mounting Results opens and shorts Solder Printing 0 30 x 0 30 mm 0 30 x 0 35 mm 0 30 x 0 55 mm 0 30 x 0 75 mm 0 30 x 0 95 mm stencil aperture Mounting Results opens and shorts Visual Examples Solder Printing Stencil Aperture Dimensions 0 20 x 0 20 mm 0 25 x 0 75 mm 0 30 x 0 95 mm Solder printing appearance Post reflow X
105. ever if the board and packages are easily warped the aperture diameter is enlarged to about 1 2 times the package land diameter 4 Solder Paste e Sn 3Ag 0 5Cu solder particle diameter 20 to 36 um Flux No wash RMA type Use a solder paste with good printability 5 Package Recognition and Placement e Placement equipment Multifunction mounter with visual recognition Shape recognition is used for package recognition Since the land shapes are not the same shape recognition can be used as the FLGA recognition method 6 Reflow Soldering Conditions e Reflow soldering after preprocessing 125 C 10 hours bake package moisture absorption for 168 hours at 30 C 70 RH Reflow soldering at 240 C once only 300 250 200 Temperature C a o 0 60 120 180 240 300 Time seconds Figure 5 25 Reflow Soldering Temperature Profile Reflow soldering is performed under the device stipulated heat resistance temperature profile and within the recommended usage temperature conditions for the solder paste used Page 120 of 140 RENESAS eee Semiconductor Package Mount Manual 5 Examples of Mounting and Problems 7 Verification After Soldering p Void Void Although voids can be seen these do not affect mounting reliability Figure 5 26 X Ray After Soldering o o Figure 5 27 Cross Section After Soldering R50ZZ0003EJ0500 Rev 5 00 2 AS Page 121 of 140 Feb 03 2015 KENES 5 Examples of Moun
106. g Solder ball failure to Head in Pillow Small mounting margin Further increased danger of mounting problem factors Causes increasing the danger of failure Warping or expansion of devices and Ki at room Variations in the amount and height of solder printed Lowered solder characteristics tacking flux activity Increased danger of For example mounting problem factors characteristics For example e Lowered solder characteristics tacking flux activity during heating heating Increased danger of package problem factors lt For example gt e Large package warping during heating lt For example gt e Large package warping during heating on ball surface Figure 5 14 Failure to Head in Pillow Causes and the Mounting Margin Next we present examples of methods for resolving this problem Factor 1 BGA package printed wiring board warping e Lowered solder tacking flux activity e Large board warping e Insufficient main Further increased danger of package problem factors e Growth of oxide film Warping occurs when a BGA package or printed wiring board is heated When the amount of warping is large or when the directions of warping are opposite the spacing at the solder joints increases the solder ball and solder paste become separated and failure to Head in Pillow may occur Page 112
107. g Temperature Profiless 4 5 30 caeesd pitas se lee ea eee a a en eens 94 4 3 1 Heat Resistance Profiles anen o a a a unin a a a aie eO a rE 94 4 3 2 Heat Resistance Temperature Profile Symbols 0 cc cecesseecesecsseseceeeecseeeceaeceeesecsevseceaeeeesaecaeesecaeeaeesesseeeas 95 4 3 3 Soldering Temperature sn id aap a ee ey Ia 102 4 3 4 Package Contact and Pin Plating Metal Compositions ccecesssecsseeseeseesecseeseceeeseceaeeecaecaeesecneverenaeeees 103 4 3 5 Notes on Solder Shorts and Opens s sssevi scie p ees eroto Gota osoessonto Sa seris Est TE E ETTR EERO EEE e ebsos pla SS E RE sE iot 103 44 Temperature Conditions on Second Reflow cceceesssscssssecsseeseesecseesccsessccsaeeeeaecseesecseeseesaeeesseseaseeeeaecateaeeneeees 104 4 5 Mechanical Strength of Soldered Sections After MOUntINg ce ceeeeseeeceseeeeesecseesecseesecsaeeecsaecetsecseeseenaeneeees 104 5 Examples of Mounting and Problems cccccssccssssssesssscessascsenancsensecessacceenccesnacesenscsessecsesneees 105 5 1 BGA Mounting Process A ek E enon pO canes sheds Bone adel ON STO 105 5 1 1 Notes on Lead Free Solder Mounting serenita n E E E E E RAE 105 5 1 2 Notes on WEBGA Usane sss no VANAN I OR E N 106 5 1 3 Mounting Example WLBGA 22 4 sce atin ota Se nah enna ata ena athens 106 5 1 4 Examples of Problems in BGA Mounting cceeesescsseecssecseesecsesecsaeeecsaecseesecsevsecsaseecsaecaeesessesseeeeenees 109 5 2
108. g attached 3 3 1 The Temperature Profile Concept A temperature profile must meet the following two conditions e The temperature setting required for soldering Failure to meet this condition can result in problems such as poor solder wetting solder shorting weak solder joints and failure to melt the solder e The temperature setting required to prevent diminution of component quality Failure to meet this condition can result in problems such as package cracking and separation between chip and package The specific conditions settings for a temperature profile to meet the above conditions are the following e Peak temperature e Solder melting time the time the product is held at a temperature above the solder melting point e The preheating time and temperature e The temperature gradient When selecting reflow equipment we strongly recommend looking into equipment that allows each zone to be completely isolated and the temperatures set independently as shown in figure 3 4 Cross Sectional View of the Reflow Equipment Exhaust E vo i Sample temperature profile Peak temperature Heating I I Rising Steady temperature temperature I l 200 150 I IPreheating time Temperature C 100 i l l 50 I Temperature slope 0 Time Figure 3 4 Relationship between the Reflow Equipment and the Temperature Profile Page 64 of 140 RENESAS Semiconductor Package
109. ges that have leads that extend beyond the package periphery The soldering iron temperature and usage must be set so that the package surface temperature does not exceed its maximum allowable temperature Note that there are products for which the soldering iron usage conditions are stipulated Contact your Renesas sales representative for details Note that soldering iron repair for packages such as BGA LGA and QEN that have pins underneath the package is not possible For packages that previously could not be repaired using a soldering iron we suggest reworking component replacement using the equipment shown in figure 3 10 SOP or QFP CSP or BGA Board Chip capacitor Figure 3 10 Example of Equipment for Reworking BGA LGA and QFN Packages The following items must be observed when performing the repairs described above These items also apply to reworking e The influence of the heating on adjacent pins must be minimized e Since the heating conditions will differ due to differences in the heat capacities of the printed wiring board board thickness number of layers and mounted components used Therefore the conditions must be set to correspond to the actual product and its mounted components e Reusing mounted components after repair or reworking requires verification with the manufacturer of each component Note Renesas quality guarantees do not apply to components that have been removed during package reworking compone
110. h are determined by the pattern design philosophy and the device s application Below we describe the design method for the printed wiring board mounting pad dimensions and pin position precision based on package drawings R50ZZ0003EJ0500 Rev 5 00 2 AS Page 25 of 140 Feb 03 2015 KENES 2 Printed Wiring Board Design Semiconductor Package Mount Manual 2 1 1 Pin Location Range for Lead Type SMDs The package pin positions pin location range which are critical when designing the mounting pads on a printed wiring board are stipulated in terms of the tolerances for the pin widths and the pin center positions in the package drawing For the pin center position tolerance the maximum material condition can be expressed as follows Oo X0 e Symbol This symbol expresses the positional tolerance e Symbol x This symbol expresses the tolerance zone for the pin center position e Symbol This symbol expresses the maximum material condition That is the tolerance zone range for the pin center position allowed when the pin width is maximum The true pin location range is the range from the true center position to the maximum pin width However since the pin center position also has a tolerance the maximum pin location range is the sum of the maximum pin width and the pin center position tolerance zone The maximum material condition expresses the fact that the maximum pin location range the maximum allowable range for
111. he radiative efficiency for IR heating differs with the structural materials and the shape of the components temperature differences arise due to differences between the packages devices IR reflow soldering has the following characteristics 1 Advantages Superlative running costs and ease of maintenance Short soldering times 2 Disadvantages The pin temperature increase depends strongly on the package size Itis difficult to raise the temperature of areas in shadows where the IR radiation does hit As aresult of the above two phenomena it is easy for differences in temperature to arise in the printed wiring board and components places being soldered As a result it is necessary to set process conditions based on the places that are the most difficult to heat and there is a tendency for large thermal stresses to be applied to packages IR heater IR rays radiative heating Figure 1 8 IR Method Example R50ZZ0003EJ0500 Rev 5 00 a2 AS Page 7 of 140 Feb 03 2015 KENES 1 Overview of Soldering Technology Semiconductor Package Mount Manual 2 VPS Vapor Phase Soldering Method In this method a special inert liquid is heated by a heater and the product to be soldered is immersed in the saturated vapor atmosphere acquired by the boiling of that liquid and the vapor that contacts the product releases its latent heat of vaporation as it condenses This results in highly efficient and even soldering of the
112. hod wetting balance method EIAJ ET 7401 Figure 4 1 shows a meniscograph curve indicating the measurement mechanism The shorter the wetting time B to E in figure 4 1 the better the solderability Wetting time B to E Maximum value of buoyancy WB Figure 4 1 Meniscograph Curve by Solder Equilibration Method Wetting time measurement examples obtained using the solder equilibration method for different plating materials are shown below 1 Evaluation Results for Sn 37Pb Solder Bus Solder Temperature 230 C 3 0 Fe Ni Alloy Cu Alloy 2 5 wn o le 8 20 OD e 16 o 1 0 o Sn Bi Sn Cu Sn Pb Sn Bi Sn Cu Sn Pb Ni Pd Au Sn Figure 4 2 Wetting Time Measurement Results Sn 37Pb Solder Bath Page 86 of 140 RENESAS PUA PE 509 Semiconductor Package Mount Manual 4 Notes on Storage and Mounting 2 Evaluation Results for Sn 3Ag 0 5Cu Solder Bus Solder Temperature 245 C 3 0 Fe Ni Alloy Cu Alloy o 2 5 n koj Cc 8 20 OD e 16 o 1 0 o th Sn Bi Sn Cu Sn Pb Sn Bi Sn Cu Sn Pb Ni Pd Au Sn Figure 4 3 Wetting Time Measurement Results Sn 3Ag 0 5Cu Solder Bath 4 1 3 Plating Thickness Next mounting evaluation examples of a case in which the lead plating thickness is reduced are introduced Satisfactory solderability was obtained even in the case of reduced plating thickness as shown in figure 4 4 Even if the plating thickness is reduced in areas as a result of contact friction s
113. igure 3 13 shows an example of attachment of a sensor during temperature measurement Center of temperature Hot air measurement location 5 Surface of center part of package Thermocouple Temperature Center of temperature measurement locations measurement location 1 2 3 4 Figure 3 13 Example of Sensor Attachment during Temperature Measurement Figure 3 14 shows an example of the BGA having been removed and the solder remaining in pinholder shapes If the temperature is low pad peeling may occur so caution is required Figure 3 14 Trace After BGA Removal Printed Wiring Board Side If the printed wiring board is large it is important to avoid bending of the printed material due to selective heating so a bending prevention tool must be placed on the bottom of the printed wiring board and a bottom heater installed to allow heating of the entire printed wiring board in order to raise work efficiency Page 80 of 140 RENESAS Semiconductor Package Mount Manual 3 Mounting Processes 2 Removing Solder Pad Cleaning Neatly remove the solder that remains on the pad using a solder sucker soldering iron solder wick etc after applying flux Figure 3 15 shows the pad states following cleaning using these various methods a Solder sucker b Soldering iron c Solder wick Figure 3 15 Pad States Following Cleaning Pad cleaning must be performed with care Leftover sol
114. ing after soldering Non Temperature humidity 85 C 85 Applied voltage 50 V Judgment criterion of failure Defective when 100 KQ or less Figure 6 17 Ion Migration Evaluation Board Page 138 of 140 RENESAS ee Semiconductor Package Mount Manual 7 Appendix 7 Appendix 7 1 Characteristics of Constituent Materials 7 1 1 Thermal Expansion Coefficients of Constituent Materials The thermal expansion coefficients linear expansion coefficients for the materials used to configure packages are shown below Bonding wire f Au Cu Chip Si External plating Internal plating Ag Interposer glass epoxy polyimide solder Lead frame Solder ball Die attachment material Fe Ni Cu Conductive layer Cu Sn Pb Sn Ag Cu Interposer rua 1Sn 3Ag 0 5Cu Linear expansion Printed wiring board 57 Sn 37Pb coefficient ppm K 1 10 Li 100 2 4 6 8 kot 20r 40 60 80 Au Ag 1 DI Si Fe Ni i cu Mold resin Figure 7 1 Thermal Expansion Coefficients of Constituent Materials R50ZZ0003EJ0500 Rev 5 00 2 AS Page 139 of 140 Feb 03 2015 ENES 7 Appendix Semiconductor Package Mount Manual Page 140 of 140 LEN ESAS L oe Semiconductor Package Mount Manual Publication Date Rev 1 00 November 24 2010 Rev 5 00 February 3 2015 Published by Renesas Electronics Corporation LENESAS SALES OFFICES Renesas Electronics Corporation hitp Awww renesas com Refer to http www
115. ing costs high phase e No temperature control system is required e Equipment costs high soldering e The heating temperature can be made lower and the time shorter e Minimal oxidation and contamination of soldered sections Flow e Running costs low e Temperature variations large soldering e Processing times short e Handling diverse packages such as fine lead pitch wave e Thermal stress low THD packages is difficult soldering e Thermal stress high SMD R50ZZ0003EJ0500 Rev 5 00 2 AS Page 3 of 140 Feb 03 2015 KENES 1 Overview of Soldering Technology Semiconductor Package Mount Manual 1 1 3 Partial Heat Methods 1 Soldering Iron Method In this method the package leads are soldered to the mounting pads on the printed wiring board using a soldering iron and wire solder The thermal capacity of the soldering iron used must be determined based on the size and shapes of the places to be soldered and the melting point of the solder Care is required since increasing the temperature more than necessary can lead to degradation due to exceeding heat tolerances for example peeling of the mounting pads from the printed wiring board Since the actual temperatures of the places soldered depend on the heating capacity of the soldering iron the heat source and the thermal capacities of the package and mounting board it is necessary to take these issues into account by for example measuring thermal characteristics before starting
116. ing loading for the mounting nozzles on the SMD placement system Mounting Results Solder Materials TSOP Displacement TSOP Displacement TSOP Displacement protruding by 1 3 protruding by 1 2 protruding by 2 3 Sn 37Pb solder 0 20 0 20 0 20 Sn 3Ag 0 5Cu solder 0 20 0 20 0 20 Visual Examples TSOP Displacement Protruding by 2 3 of The Lead Width displacement 0 1 mm Sn Pb Solder 220 C air reflow Sn Ag Cu Solder 240 C air reflow Before reflow After reflow We were able to verify self alignment for the TSOP type II package even in the example where the device protruded by 2 3 of the lead width mounting displacement 0 1 mm After verifying the solder materials and reflow conditions actually used the mounting conditions should be analyzed carefully Page 58 of 140 RENESAS 3 Semiconductor Package Mount Manual 3 Mounting Processes Self Alignment P VQFN This section presents a sample evaluation for the self alignment effect for the P VQFN package Evaluation Sample Package Dimension Mounting Pads Stencil Solder Paste Lead Plating 0 10 mm thickness P VQFN48 7x7 0 5 0 30 x 0 75 mm 0 30 x 0 75 mm Sn 3Ag 0 5Cu Mounting Conditions Package Dimension Placement Load The Push Distance at Reflow Temperature Placement P VQFN48 7x7 0 5 300 g ic 250 C Air reflow Note The placement load shows spring loading for the mounting nozzles on the SMD placement system Mounting Re
117. is shown in figure 2 14 and the radius of the holes in the printed wiring board that takes the pin thickness into account can be calculated as shown below r Ja2 bMAX 2 cMAX 2 4 0 25 2 0 60 2 0 35 2 0 46 mm Therefore the diameter of through holes in the printed wiring board is given by 6 2 x r 2 x 0 46 0 92 mm Figure 2 14 Relationship Between the Pin Position Displacement Considering Pin Thickness and the Printed Wiring Board Through Hole Diameter If the through hole diameter on the printed wiring board is at least 0 92 mm then the pins can be inserted without problem The ends of pins on DIP packages usually have a tapered shape with a taper ratio of 0 2 0 5 Therefore printed wiring boards with through holes with a diameter smaller than 0 92 mm namely 0 8 mm minimum are used Defective soldering may occur during flow mounting or other processes if the through hole diameter is too large When designing actual mounting pads a comprehensive review is required for all soldering conditions including the desired pin joint strength package printed wiring board precision mechanical precision of equipment in which the board will be used and the performance of the soldering equipment 2 3 3 Through Hole Diameter Dimensional Design for Printed Wiring Boards Design Ranges Table 2 2 Through Hole Diameter Examples Pin row spacing e mil w am em ee Through hole diameter
118. itions When a package adsorbs moisture the expansion on vaporization of this moisture due to the heat applied during reflow soldering can cause separation or cracking within the package A plastic package absorbs moisture even when it is stored at room temperature If the package is subjected to heat stress of soldering the reliability of the device may be degraded or delamination or cracks may occur inside the package Since this separation or cracking can cause open circuits in the wiring within the package or degradation of device reliability we strongly recommend that such packages only be used under the conditions stipulated in the items below Figure 4 12 Package Crack See the Renesas Reliability Handbook for the detailed mechanisms reasons for occurrence methods for avoidance and other information on package cracking during reflow soldering 4 2 1 Storage Before Opening Moisture Proof Packing Before opening moisture proof packing semiconductor devices must be stored at a temperature in the range 5 to 35 C and at a humidity under 85 RH Note however that individual products may have product specific stipulations Thus all products must be stored only after verifying the conditions stipulated in the delivery specifications documents 4 2 2 Storage After Opening Moisture Proof Packing After opening moisture proof packing semiconductor devices must be stored under the following conditions to prevent moisture absorption by the pa
119. kage s thermal expansion and contraction which results in greater thermal stress on the solder joints Weibull Plot F t aa Board thickness e t1 2mm BAe e t1 6mm 10 5 1 0 1 100 1000 1000 cycle Test temperature e 40 to 125 C 10 minutes dwell Package e 16 x 16 mm 224 pin FPBGA 0 8 mm pitch daisy chain e Ball composition Sn 3Ag 0 5Cu Printed wiring board e Size 124 x 130 x t 1 2 mm t 1 6 mm e Material FR 4 4 layers e Pad size Cu 90 4 SR 00 55 mm e Pad surface treatment Preflux Stencil e Thickness 150 um e Aperture 60 4 mm Solder paste e Sn 3Ag 0 5Cu Reflow soldering temperature package surface e Max 260 C Failure definition e 20 nominal resistance increase Figure 6 5 Weibull Plot Influence of Printed Wiring Board Thickness 6 3 Influence of Printed Wiring Board Materials 1 This section presents the results of thermal cycle testing with the same packages mounted for printed wiring boards made from different materials These results show that within the following condition ranges the FR 4 printed wiring board material has a longer thermal cycle life than CEM3 We think that this is because it is difficult for the differences in thermal contraction of the printed wiring board to follow the thermal expansion of the packages and the stress on the solder joints is larger Weibull Plot F t 999 ERA ie 10 5 1 0 1 1 10 100 1000 Test temperature e 40 t
120. kli Sutro deer eaten Aone die Seis aa 78 3 6 2 Re working iis m ee asa ane me p en ie pn pp pm p p pn p e eth 79 4 Notes on Storage and MOUNIE s sesan a cadseeeetace 85 41 SOlderabIlty is si enter ko ead on i I e e ot nio VA peta Ia leo 85 4 1 1 Platine Composition aree aria ar e E e O EAE E E a r E nei asl aeons vod 85 4 1 2 Solderability Evaluation Method sisine soina ie te EAN i e EEPE eE Ea EE aVR SEE 86 4 1 3 Plating THICKNESS yess 22 tten eere e E a EA connec E ose sete te ad nea EErEE vs ESS NEE TE ieee aoc EEE 87 4 1 4 Wetting Time Temperature Dependence ee eeeecssseeessecsseecseeescssesecsaeceessecseescesecaeeseenesseenaeeeesuecaeenaeeeeegs 88 4 1 5 Solderability following High Temperature Storage es eeesecssesscseeseceseeecesecaeesecnevseenaeeeesaecaeesecnereenaeeees 89 4 1 6 Solderability following Long Term Storage 0 0 0 ceseesceseecssecseeecneeeccsseeecssecaeesecneeseesaeenesaecaeesecnesseenaeeees 90 42 Package Storage Ge illo EET TTT TTT TET TTT TITT TTT doled Seer dei 92 4 2 1 Storage Before Opening Moisture Proof Packing cc eescssssecseesecseesecseeeceseceeesecseeecsaeeeeaecaeesesaesaeeeeenees 92 4 2 2 Storage After Opening Moisture Proof Packing cesesecssssecseesecneeeecsseeeessecseesecneseesaeeecaecaeesecnesaeesaeenes 92 4 2 3 lIr m aiMonsp epopea or preme me pep e pn p em p E Em Mate em Eo 93 4 2 4 Reflow Cycle Separe ista ees pr buo kvar kinn alee ee ee er 93 4 3 Solderin
121. l 6 Solder Joint Reliability 6 Solder Joint Reliability 6 1 Influence of Reflow Soldering Temperature 6 1 1 Ball type SMD The results of mounting a lead free BGA package using Sn 3Ag 0 5Cu solder melting point 217 C to 220 C and Sn 37Pb eutectic solder melting point 183 C under various temperatures visually checking the solder joint and performing temperature cycle testing are shown below If the BGA balls used for mounting are Sn 3Ag 0 5Cu and the solder paste is Sn 37Pb eutectic solder the solder paste will not completely fuse beneath the solder ball melting point Moreover during temperature cycle testing after mounting if the reflow soldering temperature was low the result will be that the temperature cycle life is short Therefore to obtain sufficient solder joint reliability it is necessary to set the temperature to the solder ball or solder paste melting point whichever is higher a taking into consideration temperature variations during the mounting process 1 Solder Joint Package side Board side Reflow soldering 220 C 225 C 230 C temperature Figure 6 1 Sn 3Ag 0 5Cu Balls Sn 3Ag 0 5Cu Paste Package side Board side Reflow soldering temperature Package side Board side Reflow soldering 220 C 235 C temperature Figure 6 2 Sn 3Ag 0 5Cu Balls Sn 37Pb Paste R50ZZ0003EJ0500 Rev 5 00 LEN ESAS Page 127 of 140 Feb 03 2015 6 Solder Joint Reliability Semiconductor Package
122. l height to arise if solidified balls and melted balls occur adjacent to each other As a result as the cooling slope increases the height differentials also increase and at the same time warping of the printed wiring board and open circuit defects may occur Therefore the cooling slope conditions must be set by careful a priori verification Page 66 of 140 RENESAS Semiconductor Package Mount Manual 3 Mounting Processes 3 3 3 Notes on BGA Package Reflow Soldering Variations in the package internal temperature are of concern when reflow soldering packages such as BGA and LGA packages that have soldered sections underneath the package These temperature variations however can be minimized by making the preheat time in the soldering temperature profile as long as possible Below we present the results of an evaluation of FCBGA package temperature variations when components with a variety of heat capacities are contact mounted with an FCGBA package and the influence on solderability of those variations Components with a variety of heat capacities Printed wiring 5 235 g 230 Poara Direction of board D e 225 D flow in the reflow 5 equipment w 220 8 215 gt a amp 210 gt 2 A c Package 205 ted 1681 pin FCBGA 200 e 195 1 2 3 Temperature measurement point Temperature measurement point board surface these are near solder balls Heat capacity of Max temperature Min tempe
123. le so that the solder paste rolling occurs R50ZZ0003EJ0500 Rev 5 00 a2 AS Page 49 of 140 Feb 03 2015 ENES 3 Mounting Processes Semiconductor Package Mount Manual 5 Screen removal speed The shear elastic force that occurs between the solder paste and the stencil after printing at screen separation can be suppressed by controlling the speed of screen removal and the solder paste s ease of screen removal characteristics can be improved We think that the necessity of applying this technology will continue to increase in the future to support ever finer package pin spacings Area where shear elastic force occurs n Diieelon okskearelasi iame Stencil Solder paste Figure 3 2 Shear Elastic Force Occurring Between Stencil and Solder Paste 3 1 3 Amount of Solder Paste Supplied 1 Supply amount of solder paste that supports gull wing mounting After using the following simplified method for working out the amount of solder paste required considering the optimal shape of the solder after reflow calculate the required amount precisely Mounting pad Figure 3 3 Exploded Block Diagram of the Soldered Sections Page 50 of 140 RENESAS Semiconductor Package Mount Manual 3 Mounting Processes The optimal solder amount can be determined by calculating the solder volume for each block in the exploded block diagram of the soldered sections shown in figure 3 3 A to D Amount of solder in all blocks optimal solder amount
124. leaning after component mounting e The corrosion resistance insulation resistance migration and other properties of the flux used e The required reliability level of the end product e The environment in which the end product will be used e The required quality under visual inspection e The ability of the visual inspection to detect defects e The necessity of in circuit testing 2 Flux Cleaning If you determine that cleaning is required after evaluating the above necessity of cleaning conditions there are four items that must be studied to determine the cleaning process the flux used the cleaning fluids the cleaning method and the cleaning equipment Table 3 6 lists these items together to provide an overview Table3 6 Cleaning Process Selection Examples Cleaning fluid Cleaning method selection Cleaning equipment selection Rosin flux Petroleum based Immersion cleaning Use or not of Inline or batch cleaning agents ultrasonic cleaning Terpene based cleaning agents Shower cleaning including rinse cleaning Semi aqueous Shower cleaning including rinse cleaning or cleaning agents immersion cleaning Water soluble flux Water Shower cleaning or immersion cleaning Water neutralizer Shower cleaning or immersion cleaning including the use of neutralizers In the following we discuss the above four items and ways of deciding on the cleaning method Page 70 of 140 RENESAS
125. lectronic s SMDs however cannot be soldered by a total heating method and a code partial heating indicating that these products must be soldered by a partial heating method is used for such products 3 Heat Resistance Temperature Profile In the following we show the various soldering method temperature profiles marked by these symbols a IR reflow 220 C IR20 The table below lists the soldering heat resistance conditions IR20 for IR reflow Table 4 114 Heat Resistance Conditions IR20 Maximum temperature package s surface temperature 220 C or below Time at maximum temperature 10 sor less Time of temperature higher than 183 C 60 s or less Preheating time at 1209C to 1609C 60 to 90s Maximum chlorine content of rosin flux percentage mass 0 2 or less R50ZZ0003EJ0500 Rev 5 00 Feb 03 2015 TENESAS Page 97 of 140 4 Notes on Storage and Mounting Preheating 160 C 120 C Semiconductor Package Mount Manual Main heating to10s 60 to 90s Package surface temperature C 220 C max 183 C Time seconds Figure 4 16 Infrared Reflow Temperature Profile IR20 b IR reflow 230 C IR30 The table below lists the soldering heat resistance conditions IR30 for IR reflow Table 4 15 Heat Resistance Conditions IR30 Maximum temperature package s surface temperature 230 C or below Time at maximum temperature 10 s
126. m or smaller are commonly used better results can be obtained for fine pitch packages such as 0 5 mm or finer pitch QFP and 0 8 mm and finer pitch BGA packages by using a material with a fine particle size of 40 um or smaller and a narrow viscosity distribution Note however that there is concern that with solder powders with finer particle sizes capillary ball formation due to surface oxidation may occur and that solder wettability may be affected This means that special care is required when using this type of solder powder b Flux Flux is used for the following reasons in soldering processes Removal of oxidized matter from components and pattern surfaces Preventing reoxidation during soldering Reducing the surface tension of the molten solder That is it is used to improve solderability The four components of the fluxes used to assist soldering are tackifiers thixotropic agents solvents and activating agents These are used for the following purposes Tackifier resins Component mountability metal cleaning reoxidation prevention Thixotropic agents Preventing separation of solder powder and flux and droop prevention Activating agents Metal cleaning Solvents Forming the paste There are three main types of flux rosin fluxes alloy resin fluxes and water soluble fluxes In addition rosin fluxes are classified into three types by their degree of activation R non activated Rosin RMA Rosin Mildly Activat
127. m temperature e Baking time e Number of storage days after the moisture proof packaging dry pack has been opened e Number of times the product can be mounted These symbol codes are used in combination as shown in the example in figure 4 15 below 1 Heating conditions for each 2 Package moisture absorption control 3 Number of times mounting ear method Soldering method E Baking ime kind m Number of eTA Esau of times MIO MEMO E asing Ume eTA after opening of Esau Example p ape n 1 IR tt 35 r 40 li 7 tt 3 l l I i li I tamo hy tamo ato E l E Number of times of mounting 3 times Number of storage days after opening 7 days Baking time 10 hours Peak temperature 235 C Soldering method Infrared reflow Figure 4 15 Soldering Heat Resistance Condition Symbols and Example R50ZZ0003EJ0500 Rev 5 00 2 AS Page 95 of 140 Feb 03 2015 KENES 4 Notes on Storage and Mounting Semiconductor Package Mount Manual 2 Symbol Definitions Soldering method The soldering method is indicated by a code consisting of two letters of the alphabet shown in the table below Table 4 9 Soldering Method Symbol Soldering Method Infrared reflow VPS Wave soldering Maximum temperature The peak temperature is indicated by the lower two digits of the specified peak temperature Note that the package surface temperature is indicated if the recommended soldering method is infrare
128. n by Packase Type s si3 nuns acs n a nasaun dap aa 11 1 1 6 Solder Mounting Processes eo esuo IT ENS OVAS NSD anise adeno 12 1 1 7 Basic Mounting Processes ccsccescssscessceseceseeesecscecseeeseceseesneeseeeseesseensecaeceaeceaecasecaeecaeeeaeseneeeeeeeeeeerenerensees 12 1 1 8 Single sided Solderin ssu ns Bedi a eee eee AG oe A oe inte slices Ln elek 13 1 1 9 Double sided Soldering ss 2 4 te0 u TTT ul Rete bed acne TITT TTITTEETIT PESI 17 2 Printed WirimgBoaro LG SI Mae ASE KTA ANIO 25 2 1 Lead Type SMDS ETT a rear REE Ee sE TTT TTT TITT SEa EET EESE TR REESS 25 2 1 1 Pin Location Range for Lead Type SMDS ssssesesesssrstsreerereesrststttetetssesertetsstststeteststsseststttstserseststeeretetse 26 2 1 2 Dimensional Examples for Different Package Types cccccescessssesceeecesecesecaecenecaeecaeeeseeeneeeeeeeeeeereneensees 27 2 2 Ball Type SMD Including LGA Packages ceecesccsssscsseeecesecseesecseesecsaeccsaeceessecsessecnessecsaeeeesaecateecsaecateseeneats 36 2 2 1 Pin Positions Areas for Ball Type SMD Packages ceessssssscseesecesesecseceeesecseesecnaeeecsaecasesecaesseenaeseeeas 36 222 Mounting Pad Design for BGA and LGA Packages cc ceeecseescsseseceseeeeeseceeesecnesseceecneeseesaeeeesaecateseeneaes 37 2 2 3 Mounting Pad Dimensions Design Range scsescssssecssecseeecseesecuaeeccsaecetesecsessecnaeeeesaecaeesecaeeseeneeseeeas 37 o EN IDI E E eisai ean e
129. n a tank flows onto the work to perform the soldering The printed wiring board is immersed in the flowing melted solder This method has the following characteristics 1 Advantages Itis superb for mass production soldering can be completed in a few seconds 2 Disadvantages Itis difficult to use with diverse package types especially ball type SMD packages and narrow lead pitch SMD packages THD Flowing solder second wave Chip component Flowing solder first wave Lead type SMD Melted solder Melted solder Figure 1 12 Flow Wave Soldering Method Example Page 10 of 140 TEN ESAS EA Ea Aso pro Semiconductor Package Mount Manual 1 Overview of Soldering Technology 1 1 5 Adaptation by Package Types Available soldering methods due to package type An example where soldering methods are classified by package is shown below Select the soldering method best suited to your application by taking into consideration the advantages and disadvantages of each soldering method as well as the heat resistance of the parts Table 122 Soldering Method Applicability by Package Type Soldering Method MFPAK HQFP DPAK S SMPAK HLQFP and CMPAC HTQFP other SMFPAK HSOP discrete TSOP 6 HTSOP packages LDPAK S HTSSOP 4 HSOF HQFN RPspP Soldering iron x Hot air O Laser x Pulse heater IR convection and combined reflow VPS Wave soldering
130. nd level 1 for products that are not moistureproof packed Contact your Renesas sales representative for MSL ratings for individual products Note however that temperature measurements are made at the top surface of package body After opening the moisture proof packing products must be stored in an environment where temperature and humidity are less than 30 C and 70 RH respectively Note however that individual products may have product specific stipulations Therefore always verify the storage conditions stipulated in the delivery specifications documents for each individual product used 3 The reflow conditions for the larger and thicker HQFP packages that have a size of over 28 mm and have a built in heat sink are as follows peak temperature 240 C maximum main heating 235 C for 10 s maximum time at over 220 C 30 to 50 s preheating 150 to 180 C for 90 30 s 4 Some products have the conditions marked on them with a symbol See section 4 3 2 for details on these conditions 4 3 2 Heat Resistance Temperature Profile Symbols Certain heat resistance temperature profiles stipulated for individual products are indicated using symbols This section describes these temperature profiles and their symbols 1 Description Method The individual product soldering conditions indicated with symbols consist of the five items described below The profile is stipulated by the combination of these symbols e Soldering method e Maximu
131. nition is used for package recognition Both ball recognition and shape recognition can be supported as the recognition method 6 Reflow Soldering Conditions e Reflow soldering after preprocessing 125 C 10 hours bake package moisture absorption for 168 hours at 30 C 70 RH Reflow soldering at 260 C x 3 times 280 p 260 240 Temperature C p o fe Values indicate the PKG surface temperature 0 L 4 4 a L 4 Ti L L J 0 20 40 60 80 100 120 140 160 180 200 220 240 Time sec Figure 5 6 Reflow Soldering Temperature Profile While the preprocessing was performed in this evaluation the bake operation is not required since this package is dry packing free product Although this evaluation used mounting at 260 C in mass production mounting should be performed within the recommended usage temperature conditions range for the solder paste actually used 7 Mountability Verification n 108 No particular abnormality Figure 5 7 Post Mounting X Ray Page 108 of 140 RENESAS ee Semiconductor Package Mount Manual 5 Examples of Mounting and Problems Resin portion 4 0 198 0 202rhm 0 170 0 177mm E Figure 5 8 Post Mounting Cross Section 5 1 4 Examples of Problems in BGA Mounting When preventing the occurrence of mounting problems and when resolving or improving such problems it is important to know the behavior of the solder joint during reflow heating Figur
132. nsideration the advantages and disadvantages of each soldering method as well as the heat resistance of the SMD Page 2 of 140 RENESAS SE ee Semiconductor Package Mount Manual 1 Overview of Soldering Technology 1 1 2 Features of the Different Soldering Methods Table 1 1 lists the features of each method Furthermore sections 1 1 3 and 1 1 4 discuss the partial heating methods and the total heating methods Table 1 1 Soldering Method Features Soldering Heating Method Features Type Method Strengths Weaknesses Partial Soldering Thermal stress low e Temperature variations large Local iron method e Running costs high Heating Hot air Thermal stress low e Temperature variations large method e Running costs high Laser e Thermal stress low e Not appropriate for mass production method e Post soldering is possible long processing times e All pins and all components must be heated Pulse e Thermal stress low e Not appropriate for mass production heating e Post soldering is possible long processing times method e All pins and all components must be heated Total Infrared e Running costs low e Temperature variations large Heating method e Processing times short e Thermal stress high IR reflow e Simple structures e Itis difficult to heat components that are in shadows e Temperature variations arise due to component shapes and colors for near IR Convection e Temperature variations medium e Thermal
133. nt is provided by the component self aligning effect A mounting precision that falls within that range is required In particular high precision placement equipment is required for fine pitch packages with a lead pitch of 0 5 mm or under Table 3 5 lists the features of the different types of component placement equipment Table 3 5 Component Placement Equipment Features High Speed Type Multifunction Type Tact time Chip components 0 1 to 0 15 seconds Chip components 0 3 to 0 6 seconds QFP and similar packages 0 9 to 4 0 seconds Precision Chip components 0 1 to 0 15 mm Chip components 0 05 to 0 15 mm QFP and similar packages 0 05 to 0 10 mm Component forms Tape components only Tray tape tube Precision Mechanical centering image recognition Chip components Image recognition QFP and similar packages Image recognition The five items listed below are the important points when selecting this equipment e Price that is commensurate with the performance mounting precision and speed e Support for multi product low volume production e Understanding the basic performance positioning repeatability resolution e Connection with upstream and downstream equipment electrical and mechanical e The manufacturer s service system R50ZZ0003EJ0500 Rev 5 00 2 AS Page 55 of 140 Feb 03 2015 ENES 3 Mounting Processes Semiconductor Package Mount Manual The following three points are particularl
134. nt replacement Therefore we strongly recommend that component reuse be avoided if at all possible Page 78 of 140 RENESAS Semiconductor Package Mount Manual 3 Mounting Processes 3 6 2 Reworking When a package is replaced and a new package mounted due to functional defects in the original product this can be performed using the local heating methods described in the previous section for repairing Note that since quality guarantees do not apply to products that have been removed in reworking we strongly recommend that component reuse be avoided if at all possible The flowcharts shown below are examples of reworking procedures The rework method SMD type THD type etc differs according to the device package shape figures 3 11 and 3 12 e Be v w v ps e w Figure 3 11 SMD Type Rework Process Figure 3 12 THD Type Rework Process In the following pages we describe the process steps using the BGA package as an example R50ZZ0003EJ0500 Rev 5 00 RENESAS Page 79 of 140 Feb 03 2015 7 3 Mounting Processes Semiconductor Package Mount Manual 1 Removing Package In the case of BGA and CSP the solder joint is located on the bottom of the package so the solder is melted by heating up the entire package while it is covered using specialized equipment jigs and tools The temperature conditions at this time should minimize temperature variations within the package and non melted solder joints must be avoided F
135. nt system Mounting Results Solder Materials TSOP Displacement TSOP Displacement TSOP Displacement protruding by 1 3 protruding by 1 2 protruding by 2 3 Sn 37Pb solder 0 20 0 20 0 20 Sn 3Ag 0 5Cu solder 0 20 0 20 0 20 Visual Examples TSOP Displacement Protruding by 2 3 of The Lead Width displacement 0 1 mm Sn Pb Solder 220 C air reflow Sn Ag Cu Solder 240 C air reflow Before reflow After reflow We were able to verify self alignment for the TSOP type I package even in the example where the device protruded by 2 3 of the lead width mounting displacement 0 1 mm After verifying the solder materials and reflow conditions actually used the mounting conditions should be analyzed carefully R50ZZ0003EJ0500 Rev 5 00 RENESAS Page 57 of 140 Feb 03 2015 3 Mounting Processes Semiconductor Package Mount Manual Self Alignment TSOP type II This section presents a sample evaluation for the self alignment effect for the TSOP type II package Evaluation Sample Package Dimension Mounting Pads Stencil Solder Paste Lead Plating 0 10 mm thickness P TSOP 2 52 8 89x10 79 0 40 0 90 x 0 20 mm 0 90 x 0 20 mm Sn 37Pb Sn Cu Sn 3Ag 0 5Cu Mounting Conditions Package Dimension Placement The Push Distance at Reflow Temperature Load Placement P TSOP 2 52 8 89x10 79 0 40 300 g ic 0 20 mm Sn 37Pb 220 C Air reflow Sn 3Ag 0 5Cu 240 C Air reflow Note The placement load shows spr
136. nting printing area and thickness Change the printing method Capillary balls Lead oe ete o oL e ee e e Mounting pad Capillary balls Mounting pad X Capillary balls Capillary balls are present around mounting pads or components Solder grains capillary balls are present on the surface of the reflow processed solder Solder paste was printed beyond the mounting pads Solder paste smeared beyond the mounting pads Solder paste stuck to the back side of the stencil transferred to the work Insufficient heating temperature time Excessive preheating Degradation of the solder paste Print somewhat smaller than the mounting pad size Switch to a solder paste with minimal droop Clean the stencil Review the reflow profile Verify the solder paste storage method Page 76 of 140 TENESAS R50ZZ0003EJ0500 Rev 5 00 Feb 03 2015 Semiconductor Package Mount Manual Defect Item Uneven amount of solder There is a difference in the amount of solder ks __ Phenomenon The amount of solder on the soldered areas differs The solder paste printability release properties are poor The printing conditions are inappropriate 3 Mounting Processes Resolution Measure Switch to a solder paste with good printability Review the printing conditions Component positional displacement Mounting pad paste Lead Soldering was performed wi
137. nting LGA Displacement X Displacement X Visual X ray Visual X ray Visual X ray Visual X ray Inspection Inspection Inspection Inspection Inspection Inspection Inspection Inspection Notes 1 Solder unevenness 2 Pitch displacement Inspection Examples X ray LGA Displacement 0 2 mm Solder Printing Solder Printing Solder Printing Displacement 0 05 mm Displacement 0 10 mm Displacement 0 15 mm solder unevenness Pitch displacemen Post reflow X ray photographs The result of verifying self alignment in a 0 65 mm pitch LGA package was that there were no problems if the solder printing and LGA mounting both had displacements of no more than 0 15 mm Since it is difficult to judge soldering visually with LGA packages it may be necessary to verify mounting with X ray or other inspection techniques in advance R50ZZ0003EJ0500 Rev 5 00 a2 AS Page 61 of 140 Feb 03 2015 ENES 3 Mounting Processes Semiconductor Package Mount Manual Self Alignment LGA 0 5 mm pitch This section presents a sample evaluation for the self alignment effect for the LGA 0 5 mm pitch package Evaluation Sample Package Dimension Mounting Pads Stencil Solder Paste Terminal Plating 0 10 mm thickness Mounting Conditions Package Dimension Placement Load The Push Distance at Reflow Temperature Placement LFLGA304 13x13 0 5 180 g ic 250 C Air reflow N
138. o 125 C 10 minutes dwell Package e 12 x 12 mm 100 pin LQFP 0 8 mm pitch e Sn Bi plating Printed wiring board e Size 124 x 130 x 1 6 mm Materials 4 layer FR 4 and 2 layer CEM3 e Pad size 0 25 x 1 7 mm e Pad surface processing preflux e Stencil e Thickness 150 um Aperture 0 25 x 1 7 mm Solder paste e Sn 3Ag 0 5Cu Reflow soldering temperature package surface e Peak 250 C Single reflow operation Mounting form e Single sided mounting Failure definition e 20 nominal resistance increase Figure 6 6 Weibull Plot Influence of Printed Wiring Board Materials 1 R50ZZ0003EJ0500 Rev 5 00 Feb 03 2015 TENESAS Page 129 of 140 6 Solder Joint Reliability Semiconductor Package Mount Manual 6 4 Influence of Printed Wiring Board Materials 2 This section presents the results of thermal cycle testing with FBGA packages mounted on boards made from ordinary FR 4 and halogen free FR 4 materials These result show that within the following condition ranges there were essentially no meaningful differences due to the difference in materials F t Weibull Pls Test temperature o o ay e Printed wiring board Ordinary FR 4 e 25 to 125 C 10 minutes dwell H Sn 3Ag 0 5Cu balls Sn 3Ag 0 5Cu paste Package S e Printed wiring board Halogen free FR 4 e 15 x 15 mm 240 pin FBGA 0 8 mm pitch Sn 3Ag 0 5
139. oefficients of Constituent Materials sseeeeeeeseeeeeeseeesrereereresstsrrrerrereessesrerrerereee 139 RENESAS Semiconductor Package Mount Manual Renzo a eV Feb 03 2015 1 Overview of Soldering Technology The electronics industry is seeing ever strong demands for increasing functionality and smaller and thinner form factors in end products At the same time there are continuing demands for lower costs and these demands are only expected to get stronger with time The technologies used for mounting devices packages are critical for responding to these demands and a wide range of techniques and processes have been studied and applied As an example figure 1 1 shows the technologies required in typical solder mounting This chapter presents an overview of solder mounting methods and equipment and processes Design Printed wiring Conductor pattern design board design including mounting pad design Printed wiring boards Main components Surface mounting device ICs SMD Peripheral and chip components Parts and materials Solder paste pre solder materials Supplementary Flux adhesives materials rt Cleansers Solder mounting technologies Solder printing equipment Component placement equipment Equipment Soldering equipment Cleaning equipment Other equipment e g solder inspection and reworking equipment Solder supply processes Component placement
140. of 140 Problem case warping cause and inferred failure to Head in Pillow Figure 5 15 shows the result of studying the warping in mounting defect products where failure to Head in Pillow occurred In this example concave warping can be seen in both the BGA package and the printed wiring board in the BGA package mounting area Here failure to fuse faults occur at the places where the warping separation between the BGA package and the printed wiring board is the largest at the center of the D side Workarounds 1 BGA package and printed wiring board storage Warping becomes larger when BGA packages and printed wiring boards absorb moisture If moisture absorption occurs bake these item under the stipulated conditions Printed wiring board and the mounting layout Since warping can be promoted by the printed wiring board materials structure wiring shape and mounting layout verify the warping behavior at room temperature and when heated If there is large warping when heated consider implementing a warp prevention jig TENESAS R50ZZ0003EJ0500 Rev 5 00 Feb 03 2015 Semiconductor Package Mount Manual 5 Examples of Mounting and Problems Observation direction Warping moasurement method 35mm 544pin P BGA Package warping o Line segment pang pad Distance from line segment surfaces C and D of bumps CD to pad surface at both ends Unbonded bump Device Observation direction Printed wiring boar Bump 12
141. older ball removed from device Observing reflow heating Nae Donny Room temperature 210 C 217 C 218 Note The temperatures indicated above indicate the stage temperature that is the temperature on the back of the printed wiring board and differ slightly from the temperatures of the soldered part Figure 5 17 Joint Formed by Reduced Activity Solder Paste Page 114 of 140 RENESAS e Semiconductor Package Mount Manual 5 Examples of Mounting and Problems e Workarounds 1 Verify the solder paste storage conditions Verify that you are observing all usage notes provided by the manufacturer of the solder paste used in the storage environment and storage conditions 2 Review the reflow temperature profile Verify that the process conditions are within the recommended conditions for the solder paste used at the BGA package solder joints 3 Change the reflow atmosphere Reflow heating in a nitrogen atmosphere has a large effect in preventing solder ball surface oxidation 4 Change the solder paste used Figure 5 18 shows a case where we implemented a failure to fuse reproducibility evaluation under identical conditions for twenty types of solder paste that can be easily purchased in Japan Here we saw a difference of about a factor of 20 between the solder paste with the low failure to Head in Pillow occurrence ratio solder paste type 1 and the solder paste with the high failure to Head in Pillow occurrence ratio type 20 That is the
142. ote The placement load shows spring loading for the mounting nozzles on the SMD placement system Mounting Results We evaluated solder printing displacements and LGA displacements as reverse direction displacements Solder Printing LGA Displacement X Displacement X Inspection Examples X ray LGA Displacement 0 15 mm Solder Printing Displacement 0 05 mm Solder Printing Displacement 0 10 mm Post reflow X ray photographs The result of verifying self alignment in a 0 5 mm pitch LGA package was that there were no problems if the solder printing and LGA mounting both had displacements of no more than 0 1 mm Since it is difficult to judge soldering visually with LGA packages it may be necessary to verify mounting with X ray or other inspection techniques in advance Page 62 of 140 RENESAS needy 3 Semiconductor Package Mount Manual 3 Mounting Processes Self Alignment LQFP and QFP This section presents sample evaluations for the self alignment effect for the LQFP and QFP packages Evaluation Sample Package Dimension Mounting Pads Stencil Solder Paste Lead plating 0 10 mm thickness LQFP144 20x20 0 5 0 3 x 1 3mm 0 25 x 1 5 mm Sn 3Ag 0 5Cu QFP144 20x20 0 5 0 3 x 1 3 mm 0 25 x 1 5mm Sn 3Ag 0 5Cu Mounting Conditions Package Dimension Placement Load The Push Distance at Placement Reflow Temperature LQFP144 20x20 0 5 180 g ic 0 2 mm 240 C QFP144 20x20 0 5 180 g i
143. ously carried out by direct visual inspection has become difficult Also due to the need to reduce the assembly costs for electronic equipment there are increasing trends to push for the automation of the above mentioned post soldering visual inspection In this section we discuss the items that require study when introducing post soldering visual inspection equipment Defects in soldering lead type SMD packages include solder balls wicking no solder connection and short circuits These defects can be inspected for visually or with optical inspection equipment While defects in soldering BGA CSP and similar packages include no solder connection and short circuits since these are in places under the package that cannot be seen they cannot be inspected with optical inspection equipment Although transmission X ray equipment can detect short circuit defects it cannot detect no solder connection defects To resolve this problem there are 3D inspection methods for visual inspection of places that cannot be seen such as locations under packages The tomography synthesis method and the laminography method which uses a scanning X ray beam are such methods Currently the equipment for the methods listed in table 3 7 is commercially available as post soldering visual inspection equipment Table3 7 Visual Inspection Equipment Inspection Method Details of the Inspection Method Optical systems Integrated laser sensor rotating scan method Color
144. p2 0 20 to 0 40 ISU 0 20 to 0 40 Y 0 30 lt 0 25 0 20 Note Reference values based on the former EIAJ ED 7402 standard Figure 2 3 TSOP type I type ID SSOP LSSOP TSSOP VSSOP and WSOP Examples R50ZZ0003EJ0500 Rev 5 00 2 AS Page 29 of 140 Feb 03 2015 KENES 2 Printed Wiring Board Design Semiconductor Package Mount Manual 3 Mounting dimensions for QFP HQFP LQFP TQFP HLQFP and HTQFP packages The mounting dimensions are those shown below He or Hp l2 L B1 B2 b lt bz lt e y e Renesas Package Dimension Examples QFP and HQFP Products with built in heat spreaders Unit mm bars 1 00 0 80 0 65 oso ff a 0 30 0 10 to 0 30 lt Bi 0 50 0 20 to 0 40 Be 0 20 to 0 40 lt Y 0 30 g 0 25 0 20 e Renesas Package Dimension Examples LQFP TQFP HLQFP and THQFP Products with built in heat spreaders Unit mm E 0 0 80 0 65 0 50 a 0 10 to 0 30 Ba 0 20 to 0 40 p2 0 20 to 0 40 LIU lt e Y 0 30 lt 0 25 Note Reference values based on the former EIAJ ED 7404 standard Figure 2 4 QFP HQFP LQFP TQFP and HTQFP Examples Page 30 of 140 RENESAS EN 0900 Fo DI Semiconductor Package Mount Manual 2 Printed Wiring Board Design 4 Mounting pad dimensions for QFP HQFP HLQFP and HTQFP exposed die pad type package
145. pads on the printed wiring board is poor the position is automatically corrected during reflow The self alignment strength of the different mounted components can be determined using the following equation Whether or not a self alignment effect can be acquired can be inferred by comparing the self alignment strength and the weight of the component itself Self alignment strength y x L x n y Surface tension of the solder L Contact length of a package pin and the solder circumference n Number of pins Note The solder surface tension for Sn 3Ag 0 5Cu solder is 558 mN m For reference purposes in the following pages we introduce the results of evaluating representative Renesas packages for this self alignment effect Page 56 of 140 RENESAS Semiconductor Package Mount Manual 3 Mounting Processes Self Alignment TSOP type I This section presents a sample evaluation for the self alignment effect for the TSOP type I package Evaluation Sample Package Dimension Mounting Pads Stencil Solder Paste Lead Plating 0 10 mm thickness P TSOP 1 48 12x18 4 0 50 0 90 x 0 20 mm 0 90 x 0 20 mm Sn 37Pb Sn Cu Sn 3Ag 0 5Cu Mounting Conditions Package Dimension Placement Load The Push Distance at Reflow Temperature Placement P TSOP 1 48 12x18 4 0 5 300 g ic 0 20 mm Sn 37Pb 220 C Air reflow Sn 3Ag 0 5Cu 240 C Air reflow Note The placement load shows spring loading for the mounting nozzles on the SMD placeme
146. pe Saw Type z pi 2 b lt b2 lt e y 1 forwos otwos o0o1002 e When die pads are soldered the mounting lands are designed to have the same size as the exposed die pad size e Avoid mounting leads that are exposed at the package corners die pad hanging leads on the printed wiring board e If required the corner land B1 dimension should be analyzed further Figure 2 9 QFN and HQFN Examples R50ZZ0003EJ0500 Rev 5 00 a2 AS Page 35 of 140 Feb 03 2015 KENES 2 Printed Wiring Board Design Semiconductor Package Mount Manual 2 2 Ball Type SMD Including LGA Packages 2 2 1 Pin Positions Areas for Ball Type SMD Packages Since unlike the lead type SMD packages the pin shape for ball type SMD packages is a circle or sphere Therefore the pin width and pin center position tolerances are expressed as diameters 0 In the following we present an example of a 0 5 mm pitch FBGA package Pin width 90 30 0 05 mm Pin center position tolerance zone Thus for a 0 5 mm pitch FBGA package the maximum pin location range will be 0 40 mm from the true pin center position True center position Tolerance zone for the pin center position X 90 05 mm 0 025 mm o Pin position tolerance pin position for 0 025 mm tolerance Pin position tolerance pin position for 0 025 mm tolerance
147. perature 250 C or below Time at maximum temperature 10 s or less Time of temperature higher than 220 C 60 s or less Preheating time at 1609C to 1809C 60to 120s Maximum chlorine content of rosin flux percentage mass 160 C 0 2 or less Main heating to10s 60 to 120s Preheating Package surface temperature C 250 C max 220 C Time seconds Figure 4 19 Infrared Reflow Temperature Profile IR50 e IR reflow 260 C IR60 The table below lists the soldering heat resistance conditions IR60 for IR reflow Table 4 18 Heat Resistance Conditions IR60 Maximum temperature package s surface temperature 260 C or below Time at maximum temperature 10 s or less Time of temperature higher than 220 C 60 s or less Preheating time at 1609C to 1809C 60to 120s Maximum chlorine content of rosin flux percentage mass 0 2 or less R50ZZ0003EJ0500 Rev 5 00 Feb 03 2015 TENESAS Page 99 of 140 4 Notes on Storage and Mounting 160 C Semiconductor Package Mount Manual Main heating to10s 260 C max 220 C 60 to 120s Preheating Package surface temperature C Time seconds Figure 4 20 Infrared Reflow Temperature Profile IR60 f VPS reflow VPS The table below lists the soldering heat resistance conditions VPS for VPS reflow Table 4 19 Heat Resistance Conditions VPS
148. product Figure 1 9 shows the structure of the equipment used in this method This equipment consists of the first vapor phase used for the batch reflow soldering a preheater cooling and a second vapor phase to prevent splashing of the liquid from the first vapor phase Vapor phase soldering has the following characteristics 1 Advantages The efficiency with which heat is transmitted to the work is extremely high and the whole work is heated evenly regardless of the shapes of the components Since the latent heat of vaporation is used the temperature can be controlled precisely Since soldering is performed in an inert atmosphere there is minimal oxidation or contamination of the soldered sections As aresult of the above features the heating conditions can be kept low and the processing times can be short As a result the thermal stress applied to the packages is minimal 2 Disadvantages High running costs Page 8 of 140 Conveyor Second cooling coil First cooling coil Heater Figure 1 9 Vapor Phase Soldering Method Example LE NESAS R50ZZ0003EJ0500 Rev 5 00 Feb 03 2015 Semiconductor Package Mount Manual 1 Overview of Soldering Technology 3 Convection Reflow Method Air or N2 Reflow This is a method that resolves the problems of uneven heating of the printed wiring board and components in IR reflow and of high running costs of VPS see section 1 1 4 2 The basi
149. r and the standoff may remain excessive condition 2 As the peak temperature becomes higher and the time above the melting point becomes longer the solder joint shape improves condition 3 and with appropriate conditions set a good solder joint shape is acquired condition 4 R50ZZ0003EJ0500 Rev 5 00 2 AS Page 109 of 140 Feb 03 2015 KENES 5 Examples of Mounting and Problems Semiconductor Package Mount Manual 0 8 mm pitch T FBGA Mounting board FR4 t 1 0 mm Sn Ag Cu ball Solder paste Sn Ag Cu Observed point cross section N Temperature measurement point Device side Device side Condition 1 Condition 2 Condition 3 Condition 4 Peak temp 214 C Peak temp 218 C Peak temp 222 C Peak temp 238 C 220 C or higher 0 sec 220 C or higher 0 sec 220 C orhigher 6sec 220 C or higher 34 sec Figure 5 10 Heating Conditions and Solder Joint State 2 Problem Case 2 Head in Pillow 1 What does it mean for the Head in Pillow When mounting BGA packages a phenomenon in which the solder paste and solder ball do not fuse together may occur as shown in figure 5 11 In this failure to Head in Pillow the solder ball and the solder paste are in a state where they are not fused Even in this state however the joint may be electrically conductive in initial post mounting testing Device 1 27 mm pitch PBGA Solder ball composition Sn 3Ag 0 5Cu Solder paste composition Sn 3Ag 0 5Cu X ray view
150. r reason for another structure The NSMD structure improves the thermal cycle characteristics more than SMD However for the NSMD structure it is easy for wire breakage due to mechanical stress to occur in the areas where the leads intersect with the SR aperture area Therefore a teardrop shape is used and the lead width in those areas is made as wide as possible Although the via holes are provided near the pads if connection routing is difficult it may be necessary to use a pad on via arrangement Either non electrolytic Ni Au flash plating or a heat resistant preflux is used for the pad surface processing 3 Stencil Specifications e Aperture diameter 0 28 mm thickness 120 um D TE Ho we ee ats E E o L ON E E E OEO oj Sow ow 4 amp ume b I DON o Y a FO y FON IO ON a y amp Figure 5 5 External Appearance after Solder Printing The stencil aperture diameter is made to match the board pad diameter There should be no problems in mountability if the stencil thickness is 100 um 4 Solder Paste e Sn 3Ag 0 5Cu solder particle diameter 15 to 25 um Flux No wash RMA type Use a solder paste with good printability R50ZZ0003EJ0500 Rev 5 00 2 AS Page 107 of 140 Feb 03 2015 KENES 5 Examples of Mounting and Problems Semiconductor Package Mount Manual 5 Package Recognition and Placement e Placement equipment Multifunction mounter with visual recognition Shape recog
151. rature Soldering failure mode adjacent component for 1 to 3 for 1 to 3 Open Bridge Other a 220 C 215 C 0 5 0 5 0 5 b 225 C 215 C 0 5 0 5 0 5 c 2209C 2059C 0 5 0 5 0 5 d 2259C 2059C 0 5 0 5 0 5 e 2259C 200 C 0 5 0 5 1 5 Note Voids occur in the solder ball Figure 3 7 BGA Solderability when Other Components are Mounted Nearby The result of the above evaluation is that we verified that temperature differences occurred in adjacent sections due to the influence of the heat capacity of nearby components We also verified that voids and other defects can occur inside solder balls if the temperature does not rise adequately We strongly recommend that our customers carefully consider the placement and heat capacities of components on the printed wiring board when designing their reflow process R50ZZ0003EJ0500 Rev 5 00 2 AS Page 67 of 140 Feb 03 2015 ENES 3 Mounting Processes Semiconductor Package Mount Manual 3 3 4 Temperature Distributions in Mixed Mounting 1 Influence of the size of an adjacent package For a given package being mounted the larger the size an adjacent has the larger will be the temperature differences within that package See the figure below Thus this point also requires care when setting up a temperature profile Temperature Measurement Conditions Package for temperature measurement Package for temperature Adjacent package measurement with different sizes
152. s The mounting dimensions are those shown below Note For exposed die pad products where the die pad is soldered to the board the mounting pad dimensions are l2 L B1 B2 equivalent to the size of the exposed die pad E2 x Dz b lt bz lt e y e Renesas Package Dimension Examples HQFP Exposed Die Pad Products Constant 1 00 0 80 0 65 0 50 a 0 30 0 10 to 0 30 Ba 0 50 lt 0 20 to 0 40 p2 0 20 to 0 40 lt 1 lt E Y 0 30 lt lt 0 25 Renesas Package Dimension Examples HLQFP and HTQFP Exposed Die Pad Products IN 0 80 0 65 0 50 a 0 10 to 0 30 lt Bi 0 20 to 0 40 E p2 0 20 to 0 40 lt PEI Y 0 30 0 25 Note Reference values based on the former EIAJ ED 7404 standard Figure 2 5 HQFP HLQFP and HTQFP Examples R50ZZ0003EJ0500 Rev 5 00 2 AS Page 31 of 140 Feb 03 2015 KENES 2 Printed Wiring Board Design Semiconductor Package Mount Manual 5 Mounting dimensions for HQFP and HLQFP Exposed back surface heat spreader type packages Mounting pad dimensions The mounting pad dimensions are designed as shown below PRQP0064JB A PLQPOO80KD A 18 0 15 0 14 0 18 0 PLQPO100KD A Note We recommend setting up silk screen or solder resist features on the board to prevent solder escape
153. s MSL moisture sensitivity levels Renesas as a principle stipulates level 3 for moisture proof packed products and level 1 for products that are not moisture proof packed Figure 4 14 shows the IPC JEDEC J STD 020D stipulated reflow conditions for Renesas products and table 4 8 lists the peak temperatures for package volumes and thicknesses 30s max 6 C s max 60 to 150s 60 to 150s 60 to 120s 60 to 120s Package surface temperature C Time seconds a Thin Small volume package Package surface temperature C Time seconds b Larger and thicker packages such as QFJ or 28 mm or larger QFP packages Figure 4 14 Reflow Heat Resistance Temperature Profiles for IPC JEDEC Standards Table 4 8 Thickness Reflow Peak Temperatures for IPC JEDEC Standards Volume Under 350 mm Under 1 6 mm 350 mm to 2000 mm Over 2000 mm 1 6 mm to 2 5 mm 2 5 mm or thicker Notes 1 Profiles for individual products are shown in the delivery documents Either check the delivery documents or contact your Renesas sales representative for details Page 94 of 140 R50ZZ0003EJ0500 Rev 5 00 RENESAS Feb 03 2015 Semiconductor Package Mount Manual 4 Notes on Storage and Mounting 2 For prior to processing moisturization conditions verified as MSL moisture sensitivity level ratings Renesas as a principle stipulates level 3 for moisture proof packed products a
154. stress in handling in the post mounting board process In such cases improvements in both the temperature profile and the mechanical stress should be investigated 3 Preheating time Of soldering defects that occur in the soldering process two of concern are the wicking phenomenon in which solder is drawn up the package leads and the chip standing phenomenon which can be seen for miniature chip components Both of these defects are due to temperature unevenness during reflow Especially for high density printed wiring boards in which large numbers of components are mounted on a single board the rate at which the temperature rises can differ due to the size of each component as shown in figure 3 5 A preheating stage is required to prevent these sorts of temperature differences Inversely however solder paste wetting characteristics can be degraded by excessive preheating Therefore the preheating conditions must be set in advance based on a thorough evaluation R50ZZ0003EJ0500 Rev 5 00 2 AS Page 65 of 140 Feb 03 2015 ENES 3 Mounting Processes Semiconductor Package Mount Manual Small components Large components Temperature Time Figure 3 5 Temperature Rise Examples for Different Components Preheating area Sa S pepo Set temperature Temperature components Time Figure 3 6 Temperature Equalization by Preheating Example The reflow equipment temperature and conveyor speed must be adjusted so
155. sults Solder Printing QFN Displacement X Displacement X Visual Visual Visual Visual Visual Examples QFN Displacement 0 00 mm QFN Displacement 0 15 mm Visual Inspection X ray Inspection Visual Inspection X ray Inspection Mounting Mounting 5 displacement displacement During 10 00 mm 40 15 mm QFN er Printing a Printing mounting displacement L gt Varens D Solder printing Boke Bo Be AT displacement z 0 15 mm While the P VQFN package has superlative self alignment if there are large solder printing and mounting displacements it is possible for solder unevenness to occur even if visual inspection reveals self alignment to have succeeded It may be necessary to verify mounting with X ray or other inspection techniques in advance R50ZZ0003EJ0500 Rev 5 00 RENESAS Page 59 of 140 Feb 03 2015 3 Mounting Processes Semiconductor Package Mount Manual Self Alignment FBGA This section presents a sample evaluation for the self alignment effect for the FBGA package Evaluation Sample Package Dimension Mounting Pads Stencil Solder Paste 0 10 mm thickness FBGA240 15x15 0 8 60 40 mm 60 40 mm Sn 37Pb Sn 37Pb Sn 3Ag 0 5Cu Sn 3Ag 0 5Cu Mounting Conditions Package Dimension Placement Load The Push Distance at Reflow Temperature Placement FBGA240 15x15 0 8 300 g ic 0 20 mm Sn 37Pb 220 C Air reflow Sn 3Ag 0 5Cu 240 C Air
156. tance increase R50ZZ0003EJ0500 Rev 5 00 a2 AS Page 83 of 140 Feb 03 2015 ENES 3 Mounting Processes Semiconductor Package Mount Manual Page 84 of 140 RENESAS Semiconductor Package Mount Manual 4 Notes on Storage and Mounting 4 Notes on Storage and Mounting 4 1 Solderability Depending on their fabrication process history the surface of external leads of lead type SMD may oxidize molding residue may appear during mold resin sealing and impurities may adhere Such conditions may cause the leads to corrode and thus cause soldering defects during the process of soldering parts onto the printed wiring board or during the socket mounting process mechanical joint defects or poor electric conduction Therefore in addition to removing the oxidized film on the surface of external leads and protecting the lead material it is necessary to implement surface treatment so as to facilitate soldering and socket mounting 4 1 1 Plating Composition Renesas Electronics device lead exterior plating specifications are as follows Table 4 1 Pin Plating Compositions Po Previous Plating Materials Lead Free Plating Materials R50ZZ0003EJ0500 Rev 5 00 2 AS Page 85 of 140 Feb 03 2015 KENES 4 Notes on Storage and Mounting Semiconductor Package Mount Manual 4 1 2 Solderability Evaluation Method One of the solderability evaluation method is the quantitative measurement method known as solder equilibration met
157. te Page 124 of 140 RENESAS eer Semiconductor Package Mount Manual 5 Examples of Mounting and Problems 5 4 Lead Free Solder Mounting Examples 5 4 1 External Appearance of Pins Plated with Lead Free Solder Lead Type The external appearance when mounted of pins plated with lead free solder may differ depending on the plating method used It is therefore advisable to conduct mounting tests for confirmation Figure 5 35 shows examples of the external appearance of the pins after mounting Sn Pb solder Lead free solder Sn Pb plating Sn plating x D koj Qa v a Zz Sn Bi plating Sn Cu plating Note 1 Pre applied plating Figure 5 35 Examples Showing External Appearance when Mounted of Pins Plated with Lead Free Solder R50ZZ0003EJ0500 Rev 5 00 a2 AS Page 125 of 140 Feb 03 2015 KENES 5 Examples of Mounting and Problems Semiconductor Package Mount Manual 5 4 2 Cross Sectional Photographs after Mounting of Pins Plated with Lead Free Solder Lead Type Figure 5 36 shows cross sectional photographs after mounting of pins plated with lead free solder Sn Pb solder Lead free solder Sn Pb plating Sn plating Sn Bi plating Ni Pd Au plating peu p Sn Cu plating Note 1 Pre applied plating Figure 5 36 Examples of Cross Sectional Photographs after Mounting of Pins Plated with Lead Free Solder Page 126 of 140 RENESAS PUA e Semiconductor Package Mount Manua
158. th components displaced from their correct positions Components were mounted displaced Insufficiently adhesive solder paste Insufficient pressure at component mounting Floating by the flux Abnormal component dimensions Review the positions where components are mounted Use a solder paste that has higher adhesiveness Review the component mounting conditions Reduce the amount of flux in the solder paste Verify the component dimensions Floating components Lead ye Mounting pad Solder There is no solder on the pin and it has lifted Positional displacement in printing or mounting The amount of solder paste printed is uneven Insufficient melting time Deformation of QFP or similar package pins There are discrepancies in the solder melting time Insufficient pressure in the mounting equipment Print so that there is no positional displacement Reduce the amount of flux in the solder paste Use packages with pins with less deformation Review the printing conditions Make the thickness of the solder paste printed thicker Review the heating conditions Inadequate cleaning Mounting pad _ ea Residues After cleaning flux residues or white powder residues are present The flux used has poor cleaning characteristics Inappropriate cleaning agents methods Work left standing for extended periods after reflow Use a solder paste with better cleaning characteristics Review the cle
159. that the variations in temperature between the printed wiring board and the components is minimized see figure 3 6 during the preheating time for the temperature profile as mentioned in section 3 3 1 Furthermore it is thought that capillary ball formation and insufficient wetting during soldering which are defects during soldering are due to problems with the preheating conditions during the reflow process The following items must be considered as preheating conditions during reflow to improve the above problems The preheat temperature and time must be set so that the volatile components in the solder paste are adequately volatilized The preheat temperature and time must be set so that the activation abilities of the activation agents in the solder paste are maximized The preheat temperature and time must be set so that the activation agents in the solder paste are not degraded 4 Temperature slope An excessively steep temperature slope can cause packages to crack For current reflow soldering equipment we recommend considering temperature slopes in the range 1 to 3 C second Also the shininess of the solder surface can usually be improved by reducing the cooling speed Since temperature distributions can be larger within large BGA packages the solder balls may not all solidify at the same time Since the solder ball volume shrinks on solidification it expands on melting it is possible for differences in solder bal
160. ting and Problems Semiconductor Package Mount Manual 5 2 2 LGA Problem Cases 1 Problem Case 1 Solder Void The LGA package has a tendency for voids to form more easily than with BGA packages It is thought that since there are no solder balls the printed solder directly contacts the package lands and that as a result it is more difficult for air or gas to escape As countermeasures using a void reduction solder paste or displacing the package mounting position by about 30 of the pin pitch in the XY direction Our results were that by using both methods the mounting void area ratio was reduced from about 4 9 to about 0 6 Evaluation conditions e Package 7 x 7 mm 48 pin FLGA 0 8 mm pitch e Copper pad diameter 0 45 mm SR aperture diameter 0 55 mm e Board pad structure and size NSMD structure copper pad diameter 0 45 mm SR aperture diameter 0 55 mm e Printing solder paste Sn 3Ag 0 5Cu e Stencil thickness 150 um 1 Before countermeasures Normal paste no shift mounting Void area ratio total void area total solder area x 100 Void Mounting void area ratio 4 9 Figure 5 28 X Ray Inspection Before countermeasures 2 After countermeasures Normal paste shift mounting used Void area ratio total void area total solder area x 100 Figure 5 29 X Ray Inspection After countermeasure 1 Page 122 of 140 RENESAS eer Semiconductor Package Mount Manual 5 Examples of Mounting and Probl
161. ult in degraded thermal cycle and mechanical shock performance thorough evaluation in advance is required if mounting materials with differing compositions are selected 1 Resistance to Thermal Cycling Weibull Plot de e Sn 3Ag 0 5Cu balls Sn 3Ag 0 5Cu paste do H e Sn 3Ag 0 5Cu balls Sn 37Pb paste oy H Sn 37Pb balls Sn 3Ag 0 5Cu paste SI e Sn 37Pb balls Sn 37Pb paste o 0 1 10 100 1000 10000 cycle Weibull Plot F t 0 ELA e Sn 3Ag 0 5Cu balls Sn 3Ag 0 5Cu paste 0 e Sn 3Ag 0 5Cu balls Sn 37Pb paste BAe e Sn 37Pb balls Sn 37Pb paste jo 1090 590 1 0 1 100 1000 10000 cycle Test temperature e 25 to 125 C 10 minutes dwell Package e 13 x 13 mm 175 pin FBGA 0 8 mm pitch daisy chain e Ball composition Sn 3Ag 0 5Cu Sn 37Pb Printed wiring board e Size 65 x 65 x t0 8 mm e Material FR 4 4 layers e Pad NSMD Cu 60 32 mm SR 0 52 mm e Pad surface treatment Preflux Stencil e Thickness 130 um e Aperture 60 32 mm Solder paste e Sn 3Ag 0 5Cu Sn 37Pb Reflow soldering temperature lead e Sn 3Ag 0 5Cu paste Max 230 C e Sn 37Pb paste Max 220 C Failure definition e 20 nominal resistance increase Test temperature e 40 to 125 C 10 minutes dwell Package e 15 x 15 mm 176 pin FBGA 0 8 mm pitch daisy chain e Ball composition Sn 3Ag 0 5Cu Sn 37Pb Solder paste e Sn 3Ag 0 5Cu Sn 37Pb Reflow soldering temperature lead e Sn 3Ag 0 5Cu paste Max 2509C e Sn 37Pb paste Max 235
162. urce Senju Metal Industry Co Ltd e Bump and land type packages BGA LGA and similar packages Solder Powder Land Pitch mm Size Range 0 80 0 65 0 075 to 0 045 mm O 0 045 to 0 020 mm 0 038 to 0 020 mm 0 025 to 0 010 mm Source Senju Metal Industry Co Ltd 2 Required Characteristics This section discusses the characteristics required in solder pastes a Before reflow Minimal changes with time since manufacture Good printability and applicability characteristics Minimal changes with time after application A long retention time for adhesion characteristics and loss of shape does not occur The solder powder must not separate from the flux The surface must not harden after solder paste manufacture Minimal droop and bleeding b After reflow Good solderability Minimal occurrence of capillary balls Good cleanability characteristics so that no flux residues remain If flux residues do occur reliability must be maintained 3 Notes on Selection When selecting a solder paste keep the following points in mind from the standpoints of printability solder bridges and solder balls and cleanability a Printability Normally a solder powder particle size of 1 4 to 1 5 or less of the metal stencil aperture is selected If the viscosity is too high stencil separability is degraded and cracking crazing can occur If it is too low bleeding or print drooping may occur Generally
163. w soldering 2 SMD flow soldering 3 SMD reflow soldering e Double sided mounting 1 SMD reflow soldering THD SMD flow soldering 2 SMD reflow soldering SMD reflow soldering 3 THD SMD flow soldering Figures 1 13 to 1 18 on the following pages present simplified views of these processes In mixed mounting in which multiple packages of differing types are mounted on the same printed wiring board the ability to withstand heating of the different devices must be taken into consideration when determining the optimal mounting process Page 12 of 140 RENESAS Fon zonglonao e 599 Semiconductor Package Mount Manual 1 1 8 Single sided Soldering 1 Flow Soldering of THD THD Printed wiring board Flux Spray nozzle l Flow soldering Melted solder 1 Overview of Soldering Technology Inseration of component Flux application Solder port Visual check Appearance inspection camera Figure 1 13 THD Flow Soldering R50ZZ0003EJ0500 Rev 5 00 LE NESAS Feb 03 2015 Page 13 of 140 1 Overview of Soldering Technology Semiconductor Package Mount Manual 2 Flow Soldering of SMD Adhesive application Adhesive Printed wiring board Lead type SMD Mounting of component S S Heat S S Adhesive Mermal hardening Flux Flux Spray noze application gt GA Figure 1 14 SMD Flow Soldering Page 14 of 140 TENESAS R50ZZ0003EJ0500 Rev 5 00 Feb 03 2015 Semiconductor
164. wiring board e Stability and safety e Wastewater handling for terpene based solvents alkali rosin cleaners and other fluids 2 Water soluble Flux Cleaning Fluids Consider using soft water or deionized water for cleaning water soluble fluxes Hard water and other fluids with high hardness contain calcium magnesium and iron ions and these can form insoluble salts in the water These can form scaling on the heating elements in the cleaning tanks plug up spray nozzles and cause other problems When water cleaning is used neutralizers may be adopted as auxiliary agents Since these contain surfactants we recommend consulting with the cleaning equipment manufacturer on the possible effects of these surfactants 3 4 3 Selecting the Cleaning Method and Equipment 1 Cleaning Using Organic Solvent Based Cleaning Fluids The following are the main cleaning methods e Vapor cleaning e Immersion cleaning including ultrasonic cleaning e Shower cleaning Generally a combination of cleaning methods in which one is vapor cleaning is used 1 Product damage during ultrasonic cleaning If ultrasound is to be used in conjunction with immersion cleaning users must verify in advance whether or not this can damage the mounted components Applying ultrasound should be avoided for hermetically sealed structures with an inner cavity type devices such as ceramic packages since it can result in wire breakage Also assure that the printe
165. work Also soldering irons with temperature adjustments should be used if at all possible Solder Soldering iron Figure 1 2 Soldering Iron Method 2 Hot Air Soldering This method solders the SMD by heating air or N2 gas with a heater and flowing hot gas from a nozzle onto the joint on the PWB The temperature is adjusted by adjusting the heat source and or the flow of gas Air Figure 1133 Hot Air Method Page 4 of 140 RENESAS a Semiconductor Package Mount Manual 1 Overview of Soldering Technology 3 Laser Method In this method devices are soldered by heating with a laser beam The temperature is adjusted by adjusting the intensity of the laser output and by changing the heating time Laser beam Heat Solder Figure 1 4 Laser Method 4 Pulse Heating Method In this method the Joule heating that occurs due to a current pulse in the tool is used for soldering The temperature is adjusted by adjusting the amount of current and the time for which the current is applied Pulse heating tool Pulse current Joule heating Figure 1 5 Pulse Heating Method R50ZZ0003EJ0500 Rev 5 00 2 AS Page 5 of 140 Feb 03 2015 ENES 1 Overview of Soldering Technology Semiconductor Package Mount Manual 1 1 4 Total Heating Methods Total heating methods include infrared methods VPS vapor phase soldering and convection methods These methods differ in the path over which heat is applied as
166. y important when selecting equipment for mounting packages such as TSOP and QFP that either have a fine pitch of 0 5 mm or under or packages such as BGA and LGA that have a pin arrangement with an area array form e The equipment must be able to recognize the printed wiring board pattern and must be able recognize packages the ability to recognize the electrodes area array pin electrodes for packages such as BGA and LGA e The equipment mounting precision must be 0 1 mm or better For 0 4 mm and narrower lead pitches 0 05 mm is required e Zaxis the direction of the component thickness control must be possible There are now many companies that manufacture component mounting equipment and the functions provided by each manufacturer s equipment differs somewhat In particular for the image recognition method used to recognize components there is now a trend of switching from separate recognition of the lead areas to recognizing all leads in a single operation to reduce the recognition time As we have stressed in the above selection of the component mounting equipment used in the component mounting process is extremely important and we strongly recommend you acquire as much information as possible from the equipment manufacturers when selecting the equipment 3 2 3 Self Alignment Effect There is an effect called the self alignment effect in which even if the positioning precision of the mounted package pins and the mounting

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