User Manual - The University of Texas at Dallas
Contents
1. AUTHORS Roger Robbins Page 21 of 32 VACUUM VACUUM BoA HOLD HOLD VENT VACUUM VACUUM Table IA Vacuum Controller Parameter list OFFS Process Variable Offset 0 PhP ArST Auto Reset Integral Time default 3 TALE Rate Derivaive Time 14sec biAS ManudReset Ba 25 Ct 1 Output 1 Cycle Time 8 sec PhA1 HihAlamt Pressure PhA2 X BHighAlam2 Apt AutoPreTue Disabled PoEn Auto Mancontro Selection Disabled SPr Setpoint Ramping Disabled rP X SPRampRatevadue OFF SP Process Pressure Setpoint Note Key parameters are listed in Red Norm 32 DOCUMENT TITLE ParyleneDepManual 12 10 2014 AUTHORS Roger Robbins Page 22 of 32 Table 2A Vaporizer Controller Parameter list OFFS Process Variable Offset 0 Primary Heater Power PbP ProportionalBand 5 rAt Rate Derivaive Time O3sec biAS Manual Reset Bias 25 Ct 1 Output 1 Cycle Time 8 sec Norm 32 bAL1 X BandAlarm tt PhA1 HighAlamQi 200 PLA1 LowAlam BasePressue PhA2 J hHihAlam2 174C Apt AutoPreTune Disabled PoEn _ Auto Man control Selection Disabled SPr Setpoint Ramping Disabled rPP X SPRampRaevaue OFF SP Process Pressure Setpoint 17502. gem Typical Properties of GALXYL Films GALXYLS GALXYL GALXYL Parylene N Parylene C Parylene D Data recorded following appropriate ASTM methods ypical Physical amp Mechanical Properties ensile strength psi 65 000 10 000 11 000 45 ensile strength MPa 45 o 76 Yield strength psi ield strength MPa Elongation at break 200 Density g cm 1 110 1 289 1 418 Coefficient of friction stai Data compiled and published by V amp P Scientific Inc 9823 Pacific Heights Boulevard Suite T oan Diego CA 92121 http www vp scientific com parylene properties htm DOCUMENT TITLE ParyleneDepManual 12 10 2014 AUTHORS Roger Robbins Page 29 of 32 OO ParylemeType N C D Water absorption 24 hr 0 01 0 019 0 06 0 029 Typical Electrical Properties E strength short time Volts mil at 1 c cian Surface resistivity 23 C 50 RH Ohm cm Typical Barrier Properties N Jo Gas Permeability N N N cm3 mil 100 in2 24hr atm 23 C g mil 100 1n2 24hr 37 C 90 RH 1 mil 1 1000 in 25 4 microns Typical Thermal Properties Melting Temperature C Linear coefficient of expansion 10 5 C 69 3S o o Thermal conductivity 10 4 cal sec cm2 3 C cm DOGUMENT TITLE ParyleneDepManual 12 10 2014 AUTHORS Roger Robbins Page 30 of 32 50 m e wm M nu 166 ED wo x OS C Parylene is a vacuum deposited plastic film used to coat many types of su
3. Vaporizer door open for Parylene Dimer insertion DOCUMENT TITLE ParyleneDepManual 12 10 2014 AUTHORS Roger Robbins Page 10 of 32 e Spread the Dimer with the spatula into a granular layer 1 2 layers thick in the bottom of the AI Boat Do this in order to achieve close thermal linkage to the furnace floor for better control of the process pressure Leave about 1 inch clear space between the door and the start of the Dimer pile For successive runs make sure the Vaporizer temperature drops to less than 40 C before starting the next run f Close the Vaporizer door and latch it g Close the front panel Step 8 Replace the Cold Trap a Remove the SS plate seal from the cold trap hole b Carefully lift the cold trap from its outside mounting and place it in its vacuum system hole Please do not stress the electrical cable or the LN2 line during cold trap handling Make sure that the O ring is clear of any water remnant or parylene debris Also make sure that the cold trap itself has no Parylene debris under its top flange that would lie across the seal and cause a vacuum leak or fly into the vacuum pump at pump down or back into the process chamber during vent Figure 12 Cold trap set on external mount at standby before insertion into vacuum system hole with orange O ring Step 9 Start Vacuum Pump a Switch the vacuum switch to PUMP b Immediately hold down both the Chamber Lid and the Cold Trap against their O rings to
4. to 20 m Torr above the Process Base Pressure to determine the deposition rate for your samples i This is the key parameter that determines the quality of your film Smaller numbers produce better films in general li Default Process Pressure Setpoint value is 12 m Torr b On the Vacuum controller press the Function key Far right key i Use the up or down arrow key to change the Process Pressure Set Point value li Value cannot be less than the Base Process Pressure value PLA1 Default value 8 m Torr ii Value should not be greater than the max pressure achievable with the amount of Parylene in the Vaporizer See Figure C2 in Appendix C C Press the Function key again to exit the setup mode See Figure 3 for definition DOCUMENT TITLE ParyleneDepManual 12 10 2014 AUTHORS Roger Robbins Page 12 of 32 VACUUM HOL VENT VACUUM Figure 13 Setpoint Screen B Process Base Pressure Set point a Setthis parameter to a value just above the actual Process Base Pressure See Process Overview section for definition and example This is a critical value to ensure that the process proceeds to the sublimation step b Use the procedure described in Appendix A to find and set the PLA parameter to the proper value depending on the condition of the vacuum system Values range between 6 and 15 mTorr but don t guess on this parameter if you don t know the Process Base pressure don t change the PLA1 parameter This value has
5. to be measured periodically and will vary with time and the condition of the vacuum system If you measure it please write it down in the logbook for the next user Start Process Step 10 Start Process owitch both the Furnace Pyrolizer and Vaporizer switches to ENABLE Leave the Vacuum switch in VACUUM Check to make sure the LN2 source valve is open Press the Green Start Button to start the process after vacuum achieves 20 mT oocmp Step 11 Wait a The process will start and go through its flow but it will take a while You can go away and come back in about 2 hours expecting your process to be complete Green Start button flashing Green b If the run time greatly exceeds the expected time contact tool owner DOCUMENT TITLE ParyleneDepManual 12 10 2014 AUTHORS Roger Robbins Page 13 of 32 Rules of Run Logic 1 If the Process Pressure is below the process base pressure set point Default base pressure set point PLA1 8 m Torr when the Pyrolizer reaches its spec value 690 for parylene C then the deposition process is officially started a If this condition is not met the process will not progress the process will continue indefinitely without ever heating the Vaporizer b If the process pressure never rises to Process Set Point SP but does fall below process base pressure PLA 1 at the end of vaporization then the run will terminate after 5 10 minute delay When the Parylene is tot
6. Both left rotary switches should be disabled Vent the system a Turn the Vacuum rotary switch to Vent b Wait until the pressure gauge stops increasing its readout numbers 912 Torr Remove the lid from the top of the deposition chamber oo0o0p DOCUMENT TITLE ParyleneDepManual 12 10 2014 AUTHORS Roger Robbins Page 16 of 32 a Place the lid upside down on a stable surface 9 Remove the rotary sample tower a Just lift it out of the chamber and set it on a table 10 Load samples onto Rotary sample tower a To get the best uniformity do not place samples close to the edge of the shelves or next to a support post Leave about a centimeter between samples b Center shelf is best location for thickness control 11 Replace Rotary sample tower into the deposition chamber on top of the rotary table a Make sure it is seated flat and centered 12 Replace the chamber lid a Take care that no parylene is trapped between the O ring and its sealing surface 13 Open the Vaporizer Furnace Door behind front panel 14 Carefully Insert the Al Dimer boat with Dimer into the Vaporizer a Spread the Dimer with the spatula into a granular layer 1 2 layers thick in the bottom of the Al Boat but leave about one inch clear space between the door and the start of the Dimer material 15 Close and latch the Vaporizer door 16 Remove the SS plate seal form the cold trap 17 Carefully place the cold trap back into its operating positio
7. IX C PEAK PROCESS PRESSURE VS DIMER MASS sees ese es sesse sessies ses ses ees ees ees ees ees ees asses ses see ees 25 APPENDIX D PARYLENE ADHESION PROMOTION ees esse sesse sees eee eene nennen eee these see eke ee ee Re ee 27 Adhesion Promoter Preparation sees sk ek Ee Ee Ee Ee Se See eek nennen sea ee AE ee Ee ee Gee Re ee Ee ee See sena na 27 PDO WEA OI TO al SIES ae OE N EG GE Ee IMMUNE Ge Ee 27 New Adhesion Promotion System se se ek ER Ee ER ER Ee Ee Ee See Gee eek ea Ee ee eke ee Sea ea esas esas ena 28 APPENDIX E PARYLENE PROPERTIES REFERENCE sees esse sesse sees esse seek ese sees esse sees esse sees eke sesse sesse ees e ee 29 DOCUMENT TITLE ParyleneDepManual 12 10 2014 AUTHORS Roger Robbins Page 2 of 32 SCS Parylene Deposition Tool Manual Roger Robbins 12 10 2010 Update 1 15 2014 C MyDocuments CleanRoomGeneral Equipment ParyleneDepT ool ParyleneDepManual doc Introduction Parylene is a unique polymer consisting of a linear chain of Benzene rings with two Methylene groups replacing 2 Hydrogen atoms on opposite sides of the Benzene ring serving as coupling links for the polymer This film has become known for its imperviousness to water transmission which enables device protection from environmental deterioration via encapsulation and also for its electrical characteristics which are useful for micro electrical circuitry The source material for the deposited film is
8. Note Key parameters are listed in Red No need to adjust parameters on this controller DOCUMENT TITLE ParyleneDepManual 12 10 2014 AUTHORS Roger Robbins Page 23 of 32 Appendix B Film Thickness vs Dimer Mass Open Loop Film Thickness vs Dimer Mass 9 22 2010 EF 100000 y 0 620x 97 F 10000 q E pas 4 1000 _ 2 E x v 0 620 0 9277 t 10 Ma a 10 1 100 1000 10000 X Dimer mass mg Figure B1 Chart of film thickness vs Dimer mass in the Vaporizer A more accurate estimate of the Dimer mass required for a given film thickness can be had by using the equations in the chart and a scientific calculator DOCUMENT TITLE ParyleneDepManual 12 10 2014 AUTHORS Roger Robbins Page 24 of 32 Appendix C Peak Process Pressure vs Dimer Mass Parylene deposition at high rates of deposition create poor parylene films The purpose of showing this graphic relation is to define the maximum process pressure envelope so that the user can set a practical process pressure setpoint to limit the deposition rate to levels consistent with a good film deposition The process setpoint pressure must never be set higher than the curve in Figure C1 To do so would defeat the feedback loop control of the deposition rate This would lead to defective films produced by process runs using the larger dimer masses This graph defines the maximum process pressure that can be achieved with no limit control on the chamber pressure Tha
9. SCS Parylene Deposition Tool Manual Roger Robbins 12 10 2010 Update 1 15 2014 The University of Texas at Dallas ERIK JONSSON SCHOOL OF ENGINEERING DOCUMENT TITLE ParyleneDepManual 12 10 2014 AUTHORS Roger Robbins Page 1 of 32 SCS Parylene Deposition Tool Manual Roger Robbins 12 10 2010 Update 1 15 2014 Table of Contents PINT ie DUCTION Mer ieee 3 DESCRIPTION EG 3 PROCESS AE ER H 5 OPERATING INSTRUCTIONS ees ds cars ee Ge Ge ed Ge Ge ee EE EG GE Ee Ge GE Ge EP EG de 6 dae lee EE GE EE ON EO EE EE OE Ar EN 6 TOO Mis ee de ale eN OR EE RE RE E 6 Step 1 Clean the Cold Trap iese se se ee RR RR Ge ee ee ee RE enne ee ee RE ee ee ee nea ee Re eek ee Re ee ee ee 6 Step 2 Create a Parylene Dimer BOSE Ee ie EG ee oe ie ie ee GE GE ee N ie GE GE 8 Step 3 Weigh out the Parylene Dimer ies sees ese ee ee ee ee Ee ee ee Ee ee Ee ee Ee ee Ee ee Ee ee ee ee Ee ee ee ee ee ee ee ee ee 8 Stepd Power up the SySEePfEa Es NN RESI PR EG GE ER GEE OG GE RE GR Ge RE GE Re GEE GR Re GEE GE RE EG Ee Ge ee Ge 8 Sas AE EE EE ET ER AA tt se E tesa ees 9 SES OS OAC Sa NN OE EE EE EE EE ER EE EE eS 9 Step 7 meen tie Parviene DIME eo EE EE E DNUS AT Ge G6 EN SE De NUN TU men GU Ee Se DR GR Re EN RU NOSE 10 SECO a Re
10. SLCt Select OPtr DOCUMENT TITLE ParyleneDepManual 12 10 2014 AUTHORS Roger Robbins Page 19 of 32 Step 3 Press the Up Arrow key once Middle right key VACUUM wes PV MAN AT ALM eag SLCt Select SEtP Setpoint Step 4 Press the Function key once The lower display will show ULoc Press up Arrow to increment the unlock code number to 10 Then push the Function Key to accept VACUUM PV MAN AT ALM e Io m HOLD VENT VACUUM ULoc Unlock Code 10 DOCUMENT TITLE ParyleneDepManual 12 10 2014 AUTHORS Roger Robbins Page 20 of 32 Step 5 Use the Function key to scroll through the parameters Use the up and down arrow keys to increment the function values Note the MAN light will come on for this operation VACUUM OL VENT VACUUM EXAMPLE SP Process Pressure Setpoint Value 25 PLA1 Setup Press the Function Key 12 times to find PLA1 Set PLA1 4mTorr above the actual Process Base Pressure value See Figure 3 for definition of Base P Pressure This is the setpoint that defines the beginning of rapid pressure rise as the Dimer starts rapid sublimation Exit Setup Mode otep 1 Depress and hold Function Key and press up Arrow key to return to select mode SLCt SEtP Step 2 Press Down Arrow key to select OPtr Step 3 Press Function key to select the operation mode You are now exited from the setup program DOCUMENT TITLE ParyleneDepManual 12 10 2014
11. a dimer form of the parylene molecule in which two monomers are coupled in parallel by the Methylene ends The dimer is sublimated in a Vaporizer chamber broken into monomer molecules in the Pyrolizer furnace and then deposited as long chain polymers on substrates in the deposition chamber This manual describes how to run our Parylene Deposition tool Specialty coating Systems Model PDS 2010 Labcoter 2 Description The Parylene deposition system consists of a series of connected vacuum chambers that sequentially produce parylene vapor pyrolize it deposit it as a polymer and then capture its effluent The Vaporizer chamber is a horizontal tube at the bottom of the tool behind the front panel It has a hinged door that is held in place by a simple latch This is where an Aluminum foil boat with the Parylene Dimer pellets is loaded into the system The Pyrolizer furnace is a vertical tube connected to the back of the horizontal Vaporizer and is the place that the Dimer vapor is broken into Monomers in preparation for deposition on the substrates in the Deposition Chamber The exhaust is pumped into a LN2 trap by a mechanical oil pump Figure 1 depicts the Parylene chemistry process and the vacuum system schematic DOCUMENT TITLE ParyleneDepManual 12 10 2014 AUTHORS Roger Robbins Page 3 of 32 M EE EE ee EE Ee EA Mili HSEEESDHEUSSESEREIMENMUNIEEE REESE SEDE E EE CE E CE DEC E EM DM Di para xylylene Para xylyl
12. ak Process Pressure mTorr 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 Parylene Dimer Mass mg Figure C2 Expanded scale for Open Loop Max Process Pressure vs Dimer mass showing lower Dimer mass range for easier reading DOCUMENT TITLE ParyleneDepManual 12 10 2014 AUTHORS Roger Robbins Page 26 of 32 Appendix D Parylene Adhesion Promotion Native Parylene has the propensity to peel off of some substrates If you have a strong need to improve the adhesion there is a way to do that This Appendix describes a method of improving the adhesion using a chemical monolayer applied by liquid immersion The adhesion promoter is commonly called Silane A 174 but the chemical name is officially 3 Methacryloxypropyltrimethoxysilane C10H2005Si This is a liquid that needs to be mixed with IPA and DI water in a specific ratio and then sit for at least 2 hours to fully react before immersing the samples in it Adhesion Promoter Preparation The steps to prepare the adhesion promoter follow 1 Mix equal parts of Cleanroom IPA and DI water in a beaker in a solvent hood 2 Add 05 1 part in 200 by volume of the Silane A 174 to the beaker 3 Stir the mixture for about 30 seconds and let it stand for at least 2 hours to fully react NOTE The shelf life of the solution is 24 hours so mix only the amount that will be used during that time Discard this solution after you have finished preparing all you samples It can be poured in
13. ally sublimated the Process pressure must fall below the process base pressure set point for the process to end normally Normal ending is a 5 minute delay after the Process pressure falls below the base pressure set point to allow the vaporizer to heat up and be sure the Parylene dimer is all vaporized a If the process pressure does not fall below the base pressure set point the system will continue for 30 minutes and then time out and shut down all heaters b If Process Pressure falls below baseline pressure but the Vaporizer temperature is below 174 C End of Run Trigger will not trip and Run will continue until the Vaporizer Temperature rises above 174 C or 30 minute time out applies When the Process Pressure rapidly drops because the furnace has run out of dimer the Furnace temperature will ramp up to 184 C for a few minutes to ensure that the Dimer is gone from the Furnace End Process Step 12 End of Process a oo When the Green PROCESS START STOP button flashes green the process is over Press the flashing Green button Turn off the LN2 delivery valve on the Dewar owitch the Pyrolizer and Vaporizer knobs to DISABLE Let the system cool until the Vaporizer temperature is less than 90 C to prevent harmful gases from escaping and affecting nearby people including yOu Step 13 Vent System a Switch the Vacuum switch from PUMP to VENT D C Wait until the vacuum gauge numbers quit rising Immediately lif
14. bstrates These coatings provide excellent corrosion resistance barrier properties and exhibit superior dielectric protection Some items already benefiting from Parylene conformal coating include Accelerometers Bobbins Capacitors Catheters Circuit boards Coils Ferrite Cores Dis Drive Components POPPED Heat Exchangers Components Hybrids Keypads Flow Meter Components a E AR SE DOCUMENT TITLE ParyleneDepManual 12 10 2014 AUTHORS Roger Robbins Page 31 of 32 Understanding Parylene Parylene unlike other polymeric materials is not manufactured or sold as a polymer but rather is produced by vapor phase deposition and polymer ization of para xylylene or its substituted deriva tives A highly crystalline straight chain compound paryleneas a vacuum deposited plastic has the unique quality of coating in a completely uniform manner Unlike dip or spray coatings condensation coating does not run off or sag is pinhole free will not bridge so that holes can be jacketed evenly will conformally coat over edges points and internal areas With parylene the object to be coated remains at or near room temperature eliminating all risk of thermal damage Masking can be used if desired on areas not to be coated Parylene is extremely resistant to chemical at tack exceptionally low in trace metal contamination has superior dielectric strength 5000 volts mil at mil a very low dissipation factor excellent mechani ca
15. ene Poly para xylylene Dimer Monomer Polymer 150 C sl OC 2C 90 C 0001 Tor VAPORIZE PYROLYZE POLYMERIZE DEPOSIT Vaporizer Pyrolysis Furnace i o Deposition Chamber Cold Trap Vacuum Pump Figure 1 Parylene chemistry process concept and vacuum system schematic For the Parylene C chemistry the vaporization temperature is 175 C and in our system the cold trap is chilled by Liquid Nitrogen at 77 deg K or 196 C 77 273 196 C Figure 2 Elements of the Parylene Deposition vacuum system 1 175 C Vaporizer 2 690 C Pyrolizer Furnace 3 Vaporizer Door 4 Deposition chamber 5 Cold Trap 6 Vacuum Pump DOCUMENT TITLE ParyleneDepManual 12 10 2014 AUTHORS Roger Robbins Page 4 of 32 Process Overview The Parylene Deposition process step seguence can be described visually by observing the process parameter timing chart shown in Figure 3 After the Dimer is installed in the Vaporizer chamber and samples are in the sample chamber and a vacuum is established in the system the process is started by enabling all heaters and pushing the start button Figure 3 shows the process temperatures and deposition chamber vacuum pressures as time proceeds through the process When the green start button is pushed the Pyrolizer and vacuum gauge temperatures are ramped up to operating levels As the Pyrolizer furnace temperature increases the Vaporizer chamber also heats up a small amount by thermal co
16. er time Step 16 Finish Logbook Entry a b Finish Logbook entry Take your samples and run DOCUMENT TITLE ParyleneDepManual 12 10 2014 AUTHORS Roger Robbins Page 15 of 32 Consolidated Operating Instructions Step by Step Operation This section is a brief reminder of the operating procedure order for those who have been trained and just need a reminder guide 1 2 3 8 ochedule the Parylene tool using the UTD Cleanroom schedule calendar Fill out the logbook Clean the cold trap Put on a second pair of gloves over the first pair simplifies glove change Scrape off the thick Parylene deposit with a knife blade Clean the remaining deposits with a Soft Scrub pad Rinse the cold trap with Micro90 2 in DI Water Wipe lightly with a lint free cloth leaving the trap slightly moist Change gloves after this operation to prevent tool or clean room contamination from electrostatic Parylene particles i e Pull of the second pair of gloves Create a Parylene Dimer Boat out of Aluminum foil a Cut foil into a rectangle about 3 5 x 6 inches b Curl the foil around the cylindrical former to form a boat Weigh out the Parylene Dimer according to the film thickness required using the Ohaus Balance Use a thin folded piece of weighing paper on the balance a Use a weighing paper to transport the Dimer to the Aluminum boat Power up the system if needed a Release the red emergency button b Press the power button c
17. lstrength very high surface and volume resistivities and other superior electrical properties that remain virtually constant with changes in temperature Parylene can simultaneously coat many small parts of varving configurations In current commer cial applications parylene is deposited in thicknesses ranging from a few thousand angstroms to about 75 microns depending on the function the parylene film has to perform Parts so small that they cannot be seen by the naked eye can be conformaly coated to thicknesses that can be controlled generally to plus or minus 1055 This provides physical barrier proper ties equal to or better than the 2 6 mil thickness of epoxies silicones urethanes or other conventional coatings which generally require multiple applica tions to eliminate pinholes Parvlene requires no catalysts or solvents thus eliminating environmental concerns Because of very low coefficients of static and dynamic friction that are virtually the same parylene can serve as a dry film lubricant which aids greatly in devices such as miniature servo mo tors where starting torque can be a problem arviene N is poly para xylylene which exhibits all of the above characteristics in addition to the ability to be used at temperatures exceeding 220 degrees C in the absence of oxygen Parylene is poly monochoro para xylylene and is the most widely used member of this unique poly mer series due to its excellent barrier
18. n a Make sure that all the Parylene flakes from cold trap cleaning are removed from base of flange region 18 Turn the Vacuum switch to pump and hold down the deposition Chamber Lid and the Cold Trap to help the vacuum pump produce a vacuum in the system 19 Wait until the vacuum pressure drops to minimum lt 20 m Torr a Should take about 5 to 10 minutes b If it stalls clean the O rings and try again Call staff if this fails 20 Open the LN liquid valve to fill the cold trap with LN2 21 Enable the Furnace Pyrolizer Chamber Gauge and Vaporizer switches a Vacuum Switch should remain on Vacuum 22 Press the Green Start Switch when the vacuum gets below base pressure Default Base Pressure PLA1 8 m Torr 23 Long delay while process runs 2 5 hrs depending on volume of dimer 24 Ending the Process Run a When the Green Start lamp flashes the run is over Press Green button b Turn off the LN2 Valve c Disable the Pyrolizer Furnace and Vaporizer via the 2 switches on the front panel d Let the system cool until the Vaporizer temperature is less than 90 C 25 Vent the system by switching the switch from Pump to Vent a Allow system pressure to rise to atmosphere b Immediately remove the cold trap and set it in the holding ring c Place SS plate over cold trap to prevent anything from falling in 26 Remove the Chamber Lid and set on a firm surface upside down 27 Lift out the rotary
19. nduction causing the Dimer to outgas adsorbed vapor and the deposition chamber pressure rises a little from the Base Vacuum Pump Pressure to the Process Base pressure Just before the Pyrolizer furnace rises to its set point the Vaporizer furnace is turned on As the Vaporizer temperature reaches about 90 C the Dimer begins to sublimate in earnest and the process pressure begins to rise rapidly until it reaches its set point Even though there is a small overshoot in the process pressure the temperature of the Vaporizer is adjusted on feedback instructions from the pressure gauge to stabilize the pressure at the Process Set Point Note the gradual temperature rise in the Vaporizer is required to maintain the process pressure as the dimer is used up This process pressure is maintained at the Process Set Point Pressure by the Vaporizer temperature until all the Dimer source material is vaporized Then the process pressure drops rapidly back through the Process Base Pressure in spite of the Vaporizer temperature rise After about 5 minutes of maintaining Vaporizer temperatures to be sure all the Dimer is vaporized the system shuts down all the heaters and begins to cool At this point the green Start button flashes to note the end of the process However the system cannot be opened until the Vaporizer temperature drops below 90 C to prevent harmful gases from reaching the user Parylene Process Parameter Tuning X220 800 Optimized feedback pa
20. place ie Gl TE so m 11 Step 9 Seles Vacuum PUNIO KAR AT ERR 11 SCE ODeraung Paramelels sesse EG ie ee ee GO EG EE RR EG EG GE Ge Ge N FUR ee ei 12 OS saan ER N EE E EO N OE 13 Step 10 Start PIOESSS P Satie eles De anata a a Duta Datta 13 SOMAR EE NE EE TE een rene mre re rn ren nr nmr rn rere 13 PCS hun LONG idee Ed de n ee ie AG EG ED EG GE Ge Ee Ge DE EE Ee 14 ERO PIOGESS ue cite ee ER ER EO GE MM De oe NEP SRM MEE NER Ge oi Ge errr 14 Step P End Of Proeess ee A EG Ter er Eq rer er DPI dE 14 SEED 13 VED E SEEN soes ive DEE ee EE ee ee ee EE er eee eee eee ee eee eee eee ee 14 Step 14 Retrieve Samiples ie e erra m RR RR EE NERA SERERE RXEREER visa Ge NG N ee Ge GR Ge ee RS 15 VE TOO TE P m 15 Step 15 Pump down SVSUCIM siese N ED EG Ge EI ro Ee Ge oe 15 step 6 Fidel OEDOOR ENE oie oe DE ee ve dee gee ee ee oe ee ee ee Ge ee RERUM 15 CONSOLIDATED OPERATING INSTRUCTIONS ese see se se see se ee Se AA Se ee Se AA Re AA Se AA Re esse sea esse ee ee sese ee ee ee ee 16 Step by Step Io oio eed Ed DE ee Ee oe ie De Ge oo Ee ee ee ee N N Ee 16 APPENDIX A PROCESS CONTROL PARAMETERS 4 eee eee ees ees ses ses ses ses eN EER EER EER EER EER EER Ee asso Re 19 ge iim ET OE N EE RE OE EE EE AO EE EG 19 El SEUD E EE ates ia e tals ER GE OE GE EE N Ge IE Ge Ee 21 APPENDIX B FILM THICKNESS VS DIMER MASS esse ERR Re GR Ee Ge ee es EE Ge ee ee Ge Ge GN Gee Ge ed Go de seed 24 APPEND
21. properties Parylene offers significantly lower permeability to moisture and gases such as nitrogen oxygen carbon dioxide hydrogen sulfide sulfur dioxide and chlo rine while retaining excellent electrical properties Parylene Coating Process Dimer Loaded into System i gt DIMER 150 C Vaporization 1mm Ha 650 C arylene is not produced or sold as a polymer It is not practical to melt extrude mold or calender as with thermoplastics Nor can it be applied from solvent systems Actually many of the advantages found in parylene coatings unlike epoxies ure thanes or silicones are a direct result of the coating deposition process DOCUMENT TITLE ParyleneDepManual AUTHORS Roger Robbins lim MONOMER Pyrolysis 0 5mm Ha li POLYMER Ambient Temp Polymerization 0 1mm Ha Fixtured Rotating Substrates in Deposition CH I E X Jl Vacuum Pump The parylene process isarelatively simple vacuum application system that starts with a dimer which is placed in a vacuum system and converted to reactive vapor of the monomer When passed over room temperature objects this vapor will rapidly coat them with a polvmer note illustrations The end result is an almost impervious uniform finish 12 10 2014 Page 32 of 32
22. rameters 3100 mg Parylene Adjust Proportional Feedback Pb P to 0 5 Process Base Dime Pressure Definition PLAT param 7 00 12 mTorr P Setpoint 600 b mtorr Base gies EE ZN Pb P 0 5 m dil 200 ArST 3 00 400 ee SP 12 mTorr 300 foe M Temperature C Vacuum mTorr Base Vac Pump Pressure 100 or 0 5 0 00 0 28 0 57 1 26 1 55 2 24 2 52 Time hh mm Parylene Dimer on floor of Figure 3 Parylene deposition parameter timing chart Note the definition of Process Base Pressure Process Base Pressure Setpoint Parameter PLA1 must be set just above this value DOCUMENT TITLE ParyleneDepManual 12 10 2014 AUTHORS Roger Robbins Page 5 of 32 Operating Instructions Logbook This tool requires time reservation on the UTD Cleanroom Scheduler The scheduler is found at http 10 110 49 95 cleanroom but it requires a password to access create your own password when you first create an account In addition each tool in the scheduler list requires permission to access given only after proper training A normal time reservation would be about 3 hours max but the run time is somewhat dependent on the amount of Parylene to be deposited There is a paper logbook at the tool which must be filled out Tool Preparations Before the tool can be operated there are some preliminary steps required to prepare the system and material for the run Normally the starting configuration for a ne
23. reduce air leaks so that the vacuum pump can start making a vacuum in the system DOCUMENT TITLE ParyleneDepManual 12 10 2014 AUTHORS Roger Robbins Page 11 of 32 c When the numbers on the vacuum gauge begin dropping you can release your pressure on the lid and cold trap d In about 10 min the vacuum pressure should reach a minimum lt 20 m Torr Open the LN2 valve on the LN2 tank to start the cold trap operation The vacuum indicator should drop to 5 m Torr At ultimate vacuum pump performance the vacuum pressure can drop to an indicated 4 mTorr e Wait until the vacuum system achieves base vacuum pump pressure will not pump down further and write the number in the logbook This value is important to know it denotes the condition of the vacuum system and indicates when it needs service a The actual Base Vacuum Pump pressure must be less than the Process Base Vacuum Set Point in the Vacuum controller for the system to even start your process b If the actual Process Base Pressure observed on the Vacuum Gauge is higher than the base pressure set point call appropriate staff for service c Chamber pressure must achieve a value below the Process Set Point Pressure for normal operation For thicker runs the Process Set Point Pressure PLA1 must be increased to 5 mTorr above the Process Base Pressure Set Operating Parameters A Process Pressure Set point a Setthis parameter to a value in the range of 5
24. sample tower and set on a table 28 Remove your samples 29 Place the rotary sample tower back into the deposition chamber 30 Replace the Chamber lid a Make sure the O ring and sealing surfaces are clear of parylene DOCUMENT TITLE ParyleneDepManual 12 10 2014 AUTHORS Roger Robbins Page 17 of 32 31 Pump down the system a Turn the Vacuum switch to Vacuum b Atthe same time hold down the Chamber lid and the cold trap sealing plate c When the vacuum gauge begins to drop to lower pressure release your pressure on the lid and cold trap plate d When the pressure drops to base lt 100 m Torr switch the vacuum switch to Hold to prevent vacuum pump oil from migrating back into system 32 Finish the logbook entry 33 Take your samples and run away DOCUMENT TITLE ParyleneDepManual 12 10 2014 AUTHORS Roger Robbins Page 18 of 32 Appendix A Process Control Parameters Process control parameters are set in the four process controllers on the front panel of the Parylene deposition tool The first exposition describes the procedure of accessing the control parameters in the controller software The process control parameters are listed in two tables later in this Appendix Figure 1A Parylene Deposition tool front panel Enter Setup Mode otep 1 Depress and hold the Function Key Far right key Step 2 Depress the Up Arrow Key Middle right key Photo below shows resulting readout me BYao HOLD VENT VACUUM
25. sion for ease in cleanup e After this operation your Cleanroom gloves will most likely be coated with lots of small Parylene particles it is highly recommended that you change gloves at this point to prevent tracking electrostatic particles into other parts of the tool or clean room There should be some clean gloves on the parylene table somewhere but if not bring some with you from the smock room a Optionally you can put on a second pair of gloves over the first pair before starting the cleanup clean the cold trap and then pull off the outer pair Now you have a clean pair already on without having trouble pulling new gloves onto sticky sweaty hands DOCUMENT TITLE ParyleneDepManual 12 10 2014 AUTHORS Roger Robbins Page 7 of 32 Step 2 Create a Parylene Dimer Boat a Obtain Al foil and cut a rectangular patch of foil about 3 5 x 6 inches for the boat b Curl the patch of AI foil around the former tube to shape it for insertion into the Vaporizer Furnace Smooth out the wrinkles with your hand to improve the thermal link between the Vaporizer wall and the Parylene itself This simple act will improve the performance of the thermal control Figure 7 Curl a patch of Al foil around the former cylinder with the bright side against the former tube Step 3 Weigh out the Parylene Dimer a Weigh out the Parylene Dimer according to the film thickness required using the Ohaus Balance Appendix B has a chart of Dimer mass vs ac
26. t is for this graph the pressure set point value is set so high that the pressure cannot be limited by the chamber pressure feed back control limiting the Vaporizer furnace temperature and thus the sublimation rate of the Parylene The graph in Figure C1 shows the maximimum chamber pressure achieved as the Vaporizer furnace heats to its max value 175 C in this case as a function of the amount of parylene dimer in the vaporizer This pressure is established by the evaporation rate of the dimer set by the maximum vaporizer temperature and balanced with the pumping rate of the vacuum system The process pressure falloff at low dimer mass occurs because the dimer is depleted before the vaporizer can achieve its set maximum temperature Peak Process Pressure vs Parylene Dimer Mass non EF Peak Process Pressure mTorr 2000 10000 15000 20000 253000 30000 Parylene Dimer Mass mg Figure C1 Graph of peak process pressure vs parylene dimer mass The accuracy of this curve depends on the vacuum system being leakless and the vacuum pump being in good condition with a proper base pressure capability NOTE This graph was established with Vaporizer Temperature set point of 175 C Peak Pressure curve will be different for different values of this Vaporizer temperature SCS Instruction manual DOCUMENT TITLE ParyleneDepManual 12 10 2014 AUTHORS Roger Robbins Page 25 of 32 Peak Process Pressure vs Parylene Dimer Mass si KR Pe
27. t the cold trap out of its hole and fit it into the external holder ring over the side of the tool Be careful not to stress the wires or LN2 line The immediacy of this action prevents moisture from condensing on the cold trap and entering the vacuum system If water gets into the vacuum system the pump will have a hard time achieving base pressure for the next run It can also foster an HCI acid attack of the cold trap weld joints DOCUMENT TITLE ParyleneDepManual 12 10 2014 AUTHORS Roger Robbins Page 14 of 32 d Place the SS plate over the cold trap hole to prevent anything from falling into it Step 14 Retrieve Samples a D C d e f Idle Tool Lift the chamber lid and set it on the table upside down The lid is heavy Lift the rotary sample table out of the deposition chamber and set it on the table also Hemove your samples Return the sample table to the deposition chamber Make sure that the lid and lid O ring are free of parylene debris and return the lid to its chamber seat Hemove the spent Aluminum Dimer Boat foil from the Vaporizer Furnace Step 15 Pump down System a b C Turn the Vacuum switch to VACUUM Hold down the SS plate over the Cold Trap hole and the Deposition lid until the vacuum gauge shows that the system is pumping down When the pressure drops below something like 100 m Torr turn the Vacuum knob to HOLD This prevents vacuum pump oil from migrating back into the system ov
28. to the solvent sink Please drain the sink and rinse with IPA after discarding SAFETY ISSUES Avoid breathing vapors or contact with skin or eyes Affects lungs edema Skin irritation Central Nervous system depression asphyxiation and eyes irritation Do not remove mixture from the solvent hood to apply coating to samples Application to Samples 1 Submerge your samples in the solution for 15 30 minutes 2 Remove the parts and allow them to air dry for 15 30 minutes 3 Submerge your dried parts in IPA for 15 30 seconds Agitate the samples during soak 4 Blow dry the samples with a N gun 5 After coating all samples discard solution in the solvent sink oamples should be coated with parylene within 30 hours max of applying Silane A 174 Taken from the Specialty Coating Systems PDS 2010 LABCOTER 2 Operator s Manual New AdPro Poly Adhesion promoter for low surface energy polymeric substrates www scscoatings com DOCUMENT TITLE ParyleneDepManual 12 10 2014 AUTHORS Roger Robbins Page 27 of 32 New Adhesion Promotion System Specialty Coating Systems Inc has recently announced a new adhesion promotion system that enables parylene to adhere very tightly to low surface energy surfaces such as polyimide Kapton and other such materials Further information can be obtained directly from SCS at their web site www scscoatings com or the corporate phone number 317 244 1200 DOCUMENT TITLE Par
29. tual film thickness produced for Parylene C Use a thin folded piece of weighing paper on the balance so that you can transfer the dimer to the AI boat b If you spill any parylene Dimer please clean it up immediately Do not leave any Dimer in the balance ever It will damage the balance over time Figure 8 Weigh out the desired mass of Parylene Dimer onto a weighing paper or Al Boat Step 4 Power up the system a Power up the system if needed Normally it is always on a Release the red EMERGENCY STOP button b Press the MAIN POWER button DOCUMENT TITLE ParyleneDepManual 12 10 2014 AUTHORS Roger Robbins Page 8 of 32 c Switch the Furnace vacuum gauge and the Vaporizer rotary switches to DISABLED and the Vacuum should be set at HOLD l A Figure 9 Front panel switches and buttons and process controller readouts Red numbers top are actual readings Green numbers bottom are set point values Step 5 Vent a Turn the Vacuum rotary switch to VENT b Wait until the pressure gauge stops increasing its readout numbers 912 vacuum units at atmosphere Step 6 Load Samples a Lift the Deposition Chamber lid by the handles and set it upside down on a table The lid is heavy b Lift the rotary sample table out of the chamber and set it on the table c Load your samples onto the shelves Note that there will be some uniformity differences between samples on different shelves a To reduce non
30. uniformity do not place your samples close to the rim of the rotary table shelf or close to the shelf support posts b Deposition rates are calibrated for the center shelf Robbins Roger SCS Parylene Deposition Uniformity http www utdallas edu rarO119300 Parylene ParyleneDepUniformity pdf 9 3 2010 DOCUMENT TITLE ParyleneDepManual 12 10 2014 AUTHORS Roger Robbins Page 9 of 32 Figure 10 Rotary sample table sitting on the rotating platform in the bottom of the deposition chamber Outer edges of samples close to the edge of the rotary sample shelves receive slightly more film thickness than positions more interior to the shelves Also note the color differences of the samples on different shelves This color difference represents film thickness variation Deposition Chamber removed to show sample tower d Return the rotary sample tower to the deposition chamber and set it on the rotating platform making sure that the rotary table is seated flat and centered e Replace the chamber lid Make sure that the O ring and the sealing surfaces are clear of any parylene film that may have fallen across the seal Step 7 Insert the Parylene Dimer a Open the front cabinet door of the tool b Open the Vaporizer Door c Remove the old Aluminum dimer Boat from the furnace d Insert the new parylene Dimer boat with the Dimer mass prepared earlier F amp Hu I l f M a pe M i Ee 4 T B Figure 11
31. w run would have the system under vacuum with the cold trap outside and the cold trap flange sealed with a SS plate to hold vacuum with the vacuum switch in HOLD As is routine in the clean room please fill out the logbook before starting any operation on any tool Step 1 Clean the Cold Trap a Scrape off the thick waste parylene using a knife blade Usually the thick film will flake off fairly easy Figure 4 Scraping cold trap to remove Parylene deposits before starting run b Clean off the remaining deposits using a Soft Scrub pad Ask Staff for replacement pads when they become unusable DOCUMENT TITLE ParyleneDepManual 12 10 2014 AUTHORS Roger Robbins Page 6 of 32 Figure 5 Soft Scrub cold trap to remove thin films of Parylene c Deposit waste scrapings in the lined trash can usually placed under the cold trap to catch the droppings d Spray a thin coat of Micro 90 2 solution onto the cold trap and then gently wipe off excess with a lint free cloth This solution reduces the adhesion of Parylene to the cold trap and makes cleanup much easier It also removes parylene flakes still clinging to the cold trap Make sure that you clean off all particles especially at the top of the cold trap so they will not fly back into the vacuum pump during pump down or fly up into the process chamber during vent Figure 6 Spraying cold trap with Micro 90 296 DI H20 and wiping excess liquid off to reduce future Parylene adhe
32. yleneDepManual 12 10 2014 AUTHORS Roger Robbins Page 28 of 32 Appendix E Parylene Properties Reference Parylene coatings are completely conformal of uniform thickness and pinhole free This is achieved by a unique vapor deposition polymerization process The advantage of this process is that the coating forms from a gaseous monomer without an intermediate liquid stage As a result component configurations with sharp edges points flat surfaces crevices or exposed internal surfaces are coated uniformly without voids Properties High reliability Suitable for military or commercial applications Light weight Compared to other coatings Stress free coatings Sensitive circuitry unchanged by coating Low coefficient of friction Use as a dry film lubricant Transparency Thin films can be of optical quality Out gassing Virtually none Outstanding barrier Very low permeability to moisture and gases Fungus and bacteria resistance Excellent Mechanical High tensile and yield strength Truly conformal Uniform thickness on all surfaces Wide temperature range From 200 C to 200 C Radiation resistance Suitable for space applications Bio compatible Inertness invaluable for medical applications Particle retention Upgrades electronic and mechanical devices Solvent resistance Insoluble in common solvents Acid and base resistance Resists attack from exposure Electrical breakdown Extremely high dielectric strength i
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