User Manual - The University of Texas at Dallas
Contents
1. they are pre set by Staff Figure 1 Ultratech Mask Washer showing the user interface features The microprocessor high pressure water pump and carbon Dioxide carbonator bottle is contained in the lower compartment Note that an identical mass mask must be mounted opposite to your mask to be cleaned otherwise the rotor will be out of balance and a vibration sensor will stop the program Normally a dummy mask is available at the machine for counterbalancing TITLE UltraTech Mask Washer Operation Page 4 of 10 Document Number SU2008 L 001 3 31 2008 Author Roger Robbins Tool Operation To operate the system follow the steps below 1 Open the upper chamber door using the Door Open button on the left side of the panel Figure 2 Figure 2 Note the Door Open black button at the bottom of the big button panel Push the Door Open button and aid the door with your other hand to unlatch it Lower the door and mount your mask 2 Mount your mask in the appropriate size holding slot AND insure that there is a mask with the exact same mass in the opposite holding slot That means that the counter balance mask thickness must be the same thickness as your mask to be washed otherwise the machine will vibrate excessively and shut down After mounting the masks close the door by pulling it to the top until it latches Figure 3 Mask Mounting Place an edge of the mask in the inner spring loaded edge clip black rectangle a2. photoresist or other material blotches it might be prudent to wash these blemishes with TITLE UltraTech Mask Washer Operation Page 3 of 10 Document Number SU2008 L 001 3 31 2008 Author Roger Robbins a solvent that will chemically dissolve the defects and then execute a mask wash procedure Machine Description The mask washer is shown in Figure 1 with descriptive labels The upper chamber is the cleaning station while behind closed doors in the lower section reside the high pressure water pump the carbonization canister and the electronics that control the system The soapy water is contained in a canister behind the wall that can be seen at the lower right in the photo It is pressurized and delivers the soapy water when the controller opens the water valve This canister can run dry after a number of soapy wash cycles If no suds are formed during the soapy wash program call a staff member to check and refill the soapy water canister We use a special soap compatible with the contamination free requirements of semiconductor processing Mask Cleaning chamber High Pressure Wash Arm Rotating Mask Cleaner Disc Mounted Mask for cleaning Note the identical mass counterbalance mask opposite the mask to be cleaned red arrow Oscillating Soapy Brush arm Soapy water Canister Programming Panel with Start Stop buttons Buttons Off On Door Open RPM speed monitor Knobs under the plastic panel must not be turned
3. rotation drying cycle The term electrically conducting De ionized water means that ordinary DI water has been treated with CO carbonated to reduce the resistivity of the water without having undesirable metal ions doing the conducting It turned out that in the initial mask cleaning development high pressure and high speed DI water rushing across the surface of the photomask created corona discharges at corners of the metal features on the mask because of the insulating nature of the water These corona discharges caused lightning bolt type etching of the metal patterns destroying the fidelity of the mask Therefore the carbonization of the water was instituted to defeat the destruction mechanism We have implemented this feature in our mask washer We also implemented a soapy water wash in program 1 to dislodge insidiously stuck particles via surfactant reduction of the DI water surface tension This program activates another oscillating arm having rotating brushes to lightly brush the mask while soapy water is fed to the brush through a piping system in the arm This arm travels back and forth across the mask while the mask rotor is rotating at low speed After the soap process is completed the microprocessor calls the high pressure water jet program to do the final rinse Note however that the cleaning process is intended to remove particles not chemically attached stains blotches of resist etc If your mask is contaminated with
4. UltraTech Mask Washer Operation Roger Robbins 3 31 2008 The University of Texas at Dallas Erik Jonsson Engineering School of Engineering TITLE UltraTech Mask Washer Operation Page 1 of 10 Document Number SU2008 L 001 3 31 2008 Author Roger Robbins UltraTech Mask Washer Operation Roger Robbins 3 31 2008 C MyDocuments CleanRoomGeneral Equipment MaskWasher UltraTechMaskWasherOperation doc Table of Contents UltraTech Mask Washer Operation 3 ilgero es 3 eren er 3 Cleaning een alvi tua adie 3 Machine DeSCHpllalu uode ta Rn tob beni UEM ES 4 Tool OperatiO Hr M 5 Comments on Effectiveness of 6 CON GIUISION e rr 7 PAD UCI MEME 8 Programming Insti aus casi casita rr tte bEk ea mrt d uec eet entr gems ratb pe rbIIE 8 Instruction RU MEE ccs 8 lp sl Ly mic I H e 8 T 9 Appendix gt NE o 10 TITLE UltraTech Mask Washer Operation Page 2 of 10 Document Number SU2008 L 001 3 31 2008 Author Roger Ro
5. bbins UltraTech Mask Washer Operation Roger Robbins 3 31 2008 C MyDocuments CleanRoomGeneral Equipment MaskWasher UltraTechMaskWasherOperation doc Introduction The UltraTech Model 605 mask Washer circa 1987 donated to UTD by our friends at Texas Instruments is a microprocessor controlled double sided Mask Cleaner The system uses high pressure DI water with pressure up to 2500 psi in a very small diameter jet to dislodge and wash off particles stuck to the surface of photomasks of 4x4 or 5x5 inch sizes The programming consists of two pre programmed sequences which allow the user to push the start button and walk away and in 5 to 7 minutes come back and fetch their newly cleaned mask Program 0 is a simple pressurized water clean and Program 1 includes a soapy brush wash cycle and final rinse with the program 0 high pressure wash routine Tool Description Cleaning Concepts The mask washer is designed to wash both sides of the mask at the same time with front and backside high pressure jets of electrically conducting DI water program 0 The mask is mounted on a large rotating disc as shown in Figure 1 The large disc rotates and the water jet arms oscillate across the mask surface according to the programmed instructions At the conclusion of the washing cycle the water jet arms continue oscillating but now a jet of drying N is directed at the mask from the arms to aid in water shedding during the high speed
6. ch Enable Disable Soap Dispense ON OFF Water Dispense ON OFF Chamber rinse Optional Exhaust Blower ON OFF Spray arm Park Brush arm Park Spare not used TITLE Ultratech Mask Washer Operation Document Number SU2008 L 001 Author Roger Robbins Page 9 of 10 3 31 2008 Appendix B Active Mask Cleaning Program Listing UltraTech Corp Mask Washer Program Title Mask Washer Program 0 amp 1 Date 10 5 2005 Programming Sheet ourPPUT INPUTS Nl RET EE EIER TET ECL CIR RE ER EET EA ET A opo xiHedutiStart o 9 Txt 1 I 1 Testinputs amp StartifOK faf oj 1 x ik kha xL TT iki kT TT Tt 2 H P Water Clean Cyce 3 5 p Ik kk TI ki ToT TT ki TTT tt h 3 s Tl epp 4 Park SprayArm _ 8 Tip Pii ITI s SlowDown 4 jx e PITI xi PET LI LLLLLLIEI 6 Finish v ox t L xk TT P T T LLLLLEI Loop c qan queque piii sqq yp o 0 S eee eee ee eee ae Ege LL LL LLLELL LIII II IL LI LII LI LLL TL OL LLL LLLLLLI S W Step Advance ime Count on off inputs in on mode Program Number Prog Start Branch to Step Spindle on Low Speed Spindle High Speed Blow Off Brush Rotation Door Latch Enable Soap at Brush Water at Brush Chambe
7. nditions defined by modifiers 5 Hold kill Temporarily stops the program from executing but turns OFF activated outputs Outputs based on various conditions defined by modifiers 6 Hold at End Temporarily stops the program execution at the end of a step based on various conditions defined by modifiers 7 Branch at End Causes the program flow to branch to some other step of the program from the end of the current step based on conditions defined by modifiers 8 Branch During Causes the program flow to branch to some other step during execution of the current step based on conditions defined by modifiers 9 Hold at Start Causes the program execution to temporarily stop at the beginning of the current step based on modifiers Used at the beginning to wait for the user to push START Input Port Assignment Function Door Sensor Spray Arm Sweep Count Brush Arm Sweep Count Spray Arm Home Brush Arm Home Spare AUTO MANUAL Mode Switch Spare o 47 TITLE Ultratech Mask Washer Operation Document Number SU2008 L 001 Page 8 of 10 3 31 2008 Author Roger Robbins Output Port Assignment Function Spindle Low Speed ON OFF Spindle High Speed ON OFF Brush Arm ON OFF Ceiling Blow Off ON OFF Spray Arm ON OFF N2 Blow off ON OFF Brush rotation Motor ON OFF olol olasi co ro High pressure Pump ON OFF Door Lat
8. one Comments on Effectiveness of Cleaning Photomasks in industrial settings are usually pristinely clean and only need to be cleaned if they pick up a few particles However in the UTD Clean Room have noted that masks become contaminated with fingerprints resist splotches scratches tape glue and an amazing array of different contaminates This machine is primarily designed to remove particles If you note that you have these non particle type contaminants there is no harm in manually removing them with acetone and a gentle wipe with a swab and a subsequent rinse with Acetone and or IPA A final cleanup in the mask washer would TITLE UltraTech Mask Washer Operation Page 6 of 10 Document Number SU2008 L 001 3 31 2008 Author Roger Robbins then be more practical Neither soap nor high pressure water will remove photoresist that has dried on the mask Acetone will Another practical issue is that if the soap brushes have not been used for a long time they will leave dried specks of soap on the mask during the first several soap wash cycles Therefore you may want to run a couple of soap wash cycles on a pair of dummy masks before cleaning your mask with the soap process Conclusion This manual has described the basic operating procedures for the normal user Detailed programming will be described in another document Normal users do not need to program the system The Appendices record for reference programming logic and data c
9. ontained in the currently active programs TITLE UltraTech Mask Washer Operation Page 7 of 10 Document Number SU2008 L 001 3 31 2008 Author Roger Robbins Appendix A Programming Instruction In the Program Mode the numeric right hand touch keys allow the programmer to enter instruction input output and step identifier numbers and the value of time or count parameters Any numeric value to be entered must be preceded by the pressing of one of the command keys on the left hand touch key area For the convenience of the programmer each numeric touch key has its corresponding instruction label printed on it This appendix lists the input and output number assignments as a reference to the program in Appendix B Programming will be documented in another document Instruction List No Instruction Brief Definition 0 NO OP Causes the Controller to bypass the step in which it appears 1 Set Loop This instruction must be used with either Loop Back or the Event Counter to set the Counter number of repetitions of a sequence of operations 2 Loop Back Must be preceded by a Set Loop Counter instruction Loop Back causes the program to go back to the step preceding the one specified by this instruction 3 Event Count Counts electrical transitions from OFF to ON states for all inputs independently 4 Hold with Temporarily stops the program from executing but keeps activated outputs turn ON Outputs based on various co
10. r Rinse Park Spray Arm Park Brush Arm Alarm Enable Spray Arm at Center Brush Arm at Center Spray Arm at Home Brush Arm at Home Change Enable LI I LI LT EE TT 4 7 x Hold unti Stat 9 Txt 1 8 Tetlmus amp StatifOK 1 x lx KI xxi ki TT kek h 9 SoapyBrushSweep 3 3 fk x ki kh ki TT tt kT 10 DiBrushSweep 3 4 ik Pk kt xi kK gt gt t tt kt tt ty h ti ParkBrush Jsf Tt kT kT eT ei xi i PIT T TTT TT PITIT h 12 PressureWash 3 3 x ik ke TT kK Pet 13 SpinDryN2 P ep Pii PITI PP 14 Park SprayArm 8 ip Pii PITI ik kT TPP tT tT kT TT TT h 15 SlowDown xf 12 tT tT kT TT TTT kT te Finish xf is FP kT b ET eT TT ET TE ET TT kT CU EG eee eee eee eae Df hes eee eee eee RRR Program Author Roger Robbins x indicates that the input or output is active TITLE UltraTech Mask Washer Operation Page 10 of 10 Document Number SU2008 L 001 3 31 2008 Author Roger Robbins
11. t the left of the mask in the photo Push the mask to compress the spring and then seat the opposite edge in the fixed clip at the right side of the mask in the photo Make sure the top and bottom edges of the mask are seated properly in the support tabs Check the counterbalance mask seating TITLE UltraTech Mask Washer Operation Page 5 of 10 Document Number SU2008 L 001 3 31 2008 Author Roger Robbins 3 Select the desired program 0 for high pressure water cleaning or 1 for soap scrub and high pressure water cleaning Figure 4 Key should be in Auto mode for operation Program Number indicator Program Start Button Program Number Selector Number pad for program selection entry Enter Key to accept program selection Figure 4 Programming keyboard For program 0 select Go to Program on the keypad select 0 on the keypad and then hit Enter to accept the selection If O already appears in the PROG LED indicator you do not have to go through the select steps Note the two keypads Left group and Right group important in programming 4 To start the program hit the Program Start button on the left side of the keypad 5 Wait Program 0 takes about 5 5 minutes and Program 1 takes about 7 min 6 When the program stops the rotating drum completely push the Door Open button lower the door and remove your mask 7 Close the door when you are d
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