HMDS工艺简介

Chapter 4.6HMDS(Primeoven and Sink4 HMDS)1.0 1.0TitleHMDS (H exa M ethyl D i S ilazane)2.0 2.0PurposeHexamethyldisilazane (HMDS) is widely used in the semiconductor industry to improve photoresist adhesion to oxides. The HMDS reacts with the oxide surface in a process known as silylation, forming a strong bond to the surface. At the same time free bonds are left which readily react with the photoresist, enhancing the photoresist adhesion.The process works not only on silicon dioxide, but other oxides (e.g., Al203) as well. 3.0 3.0ScopeTwo methods are used to prime wafers prior to the application of photoresist. Wafers are coated with HMDS in the primeoven or in the wet sink. The primeoven is considered the main process with the HMDS bubbler used as a back-up method, if the primeoven is not available.4.0 4.0Applicable Documents4.1 Hardcopy Y. E. S. primeoven manual in the office.4.2 Serial Number: 00244.3 Y. E. S. Primeoven LP-5 Model Number: YES/LP III – M55.0 5.0Definitions & Process Terminology6.0 6.0SafetyDo not allow it to contact your skin and avoid inhalation. HMDS is flammable and reacts with strong oxidizers and reducing agents.7.0 7.0Statistical Process Data7.1 Refer to problem log.8.0 8.0Available Processes & Gases8.1 Hexamethyldisilazane (HMDS)8.2 Nitrogen9.0 9.0Equipment OperationHMDS9.1 Primeoven9.1.1 9.1.1Enable primeoven on the wand.9.1.2 9.1.2Check to see that the following are correct:9.1.2.1 9.1.2.1The temperature setting of 100ºC is displayed by redlight.9.1.2.2 9.1.2.2The Minarik controller displays red light on output 01.9.1.2.3 9.1.2.3Small red light is lit on vacuum gage.9.1.2.4 9.1.2.4Vacuum gage should read 1000 torr.9.1.2.5 9.1.2.5Check to see if the thumbwheel is set to 0.Note:If thumbwheel is not set at 0, turn thumbwheel to zero.9.1.3 9.1.3Open door of primeoven.9.1.4 9.1.4Place Teflon® carrier with wafers into oven.9.1.5 9.1.5Close door.9.1.6 9.1.6Push start button.Note:System should begin pump-down to approx. 10 torr.9.1.7 9.1.7After three (3 ea) pump/N2-purge cycles to 10 torr, followed by apump-down to 1 torr, HMDS is dispensed into chamber.9.1.8 9.1.8Exposure to HMDS vapor produces a monolayer coating in oneminute.9.1.9 9.1.9When the full cycle is completed (length of cycle: approx. 35min.), an audible alarm will sound. It can be silenced by pushing the redreset button.9.1.10 9.1.10Open the door and remove wafer carriers with red rubber heatshield.The optional alternate method for HMDS is the use of the bubbler throughHMDS in the recessed HMDS tank at sink4 in Y1.9.2 9.2SINK4, SINK5 HMDSThe procedure for using the HMDS at sink4 tank is as follows:9.2.1 9.2.1If your wafers were just freshly cleaned, or have been sitting outin the air for a while, you should dehydrate them by placing them in aTylan furnace tube at 750ºC for 5 minutes, or in the convection oven at120ºC for 15 minutes. If they are coming directly out of the furnace, theymay be placed straight into the HMDS tank as soon as they have cooled.9.2.2 9.2.2Place the cassette with your wafers in the HMDS tank in sink 4.The HMDS bubbler is activated by the HMDS timer mounted on the upperfront panel of the sink. Turn the time switch past 5 initially to activate thetime, and then set your desired time. Prime for 1-3 minutes, taking care toreplace the top cover snugly.9.2.3 9.2.3Remove your wafers and spin resist immediately.10.0 10.0Troubleshooting GuidelinesN/A11.0 11.0Figures & SchematicsN/A12.0 12.0Appendices12.1 Program EntryThe Minarik WP-6200 series microprocessor-based controller can drive fouroutputs and has a decision-making capability based on the status of up to five user-programmed inputs. (The fifth input is an added special model for YES.)The system utilizes all four outputs and all five of the inputs. They are:output 0 = cycle complete/abort lightoutput 1 = nitrogen valveoutput 2 = vacuum valveoutput 3 = HMDS valve(Inputs are normally open circuits, activating will close circuit.)input A = start switchinput B = vacuum gauge, pressure greater than setpoint 1input C = thumbwheel switch set at 2 or 3input D = vacuum gauge, pressure greater than setpoint 2input E = thumbwheel switch set at 1 or 3The suggested program examines the status of user set interlocks. Theseinterlocks are the Granville=Phillips vacuum gauge setpoints. In the stepswhere the interlocks are examined, we are looking to see if the unit hasreached a sufficient vacuum or pressure. If the interlock is not satisfied, itmeans there is a major system leak, a defective pump, or an insufficientvacuum or pressure. If these interlocks are not satisfied, the process will abort to user pre-programmed subroutines where the "cycle complete" light flashesrapidly and the system is back-filled with nitrogen until the reset button ispushed.Note:The abort cycles should be allowed to continue until the system has reached atmospheric pressure, as indicated by the ability to open thedoor, before pressing RESET.In the case of the pre-HMDS vacuum cycle, if there is insufficient vacuum, itwill be useless to continue, since there will not be enough of a vacuum tovaporize HMDS. The setpoints control the decision making process ofwhether to continue the process or not. The proper setpoints are in the control of the process engineer. Suggestions are 100-Torr for setpoint #1, and10-Torr for setpoint #2.12.2 Re-Install ProgramRecheck the system in the following manner:Insert key and turn to horizontal position.Confirm that the system is ready for operation:►►oil in the pump►►pump exhaust connected and on►►pump on►►vacuum line connected►►nitrogen lines connected►►sufficient nitrogen pressure►►cabinet exhaust on►►system power on►►HMDS in flask►►temperature controller setpoints selected and stable►►vacuum gauge setpoints selected12.2.1 12.2.1If the display of the microprocessor is off, press the greenON button. The display should read RESET. If not, push the RESET(RST) button.12.2.2 12.2.2Press the yellow program (PGM) button. You are now in theprogram entry mode. This is possible only if the microprocessor waspreviously in the reset mode. The display should now read the firststep 01 and a function, some data and the outputs to be activated.12.2.3 12.2.3Press the grey function (FUNC) button with up indicator once.You will see the function display change. Continue pressing and thedisplay will march through all seven of the available functions. Bypressing the FUNC with down indicator you can reverse the direction.12.2.4 12.2.4Set the function display to M 99:59. This means that you areprogramming in minutes and seconds. Using the DATA yellowbuttons set the time to 02:00 (02 mins, 00 secs).12.2.5 12.2.5Push the orange OUTPU T button #2 (O2). This instructs themicroprocessor to open the vacuum valve. (Step #1 is notprogrammed as 2 minutes of output 2 in the actual process.) TheOUTPUT buttons both write and erase. If you push an OUTPUTbutton when the LED indicator above is on, it will turn the LED off(erase the output ON command).12.2.6 12.2.6Push the STEP button with the up indicator once. Thedisplay now reads step 02. If you pushed the STEP button too manytimes you can go backwards using STEP with the down indicator.Push either grey FUNC button until you get to the IF _> _ statement(> = GOTO). Using the yellow DATA buttons set the display to read IFB> 30. This means on input B (insufficient vacuum) go to step 30(abort cycle). (An input for the micro is a switch closure to ground). Ifthe vacuum gauge reads a pressure above the setpoint, the gauge'srelay closes. If the vacuum gauge reads below the setpoint (highervacuum) the relay contacts are open and no input signal is present.12.2.7 12.2.7Using these instructions as a guideline, complete programentry as follows:Program Priming Cycle Inputs Activated0 1 2 3 4+1 minute10 seconds1 minutePlace vacuum in flaskNot usedNoneE onlyC onlyE and C12.3 Process ProgramsSTEP FUNC DATA OUTPUT COMMENTS 01 IF A> 03 Does not permit programming of Micro,02 GOTO 01 Because it is in a constant RUN mode when the key-lock is closed…Once START is pressed (input A), the process goes to Step 03.03 IF C> 05 Checking for Program 3 to replace vacuum in flask… (Inputs C and E must be closed.)04 GOTO 0605 IF E> 65 If so, go to 65 … Program 306 L = 0003 3 loops of 7/907 M 03:30 O2 3-1/2 min vacuum08 IF B> 30 Low vacuum alert/abort, go to 3009 M 03:00 O1 3 min of HOT nitrogen back-fill10 IF B> 12 If sufficient nitrogen back-fill pressure, go to 1211 GOTO 35 Low N2 pressure alarm/abort, go to 3512 L> 07 Loop back to 0713 M 04:00 O2 4 min vacuum pump down14 IF D> 40 High vacuum alarm/abort (not reaching 10 Torr)15 IF C> 60 Input C only, go to 60 … Program 216 IF E> 55 Input E only, go to 55 … Program 117 L = 0060 60 loops of … Program 018 S 0100 O3 … 1 second of priming19 IF D> 45 O3 Priming cycle alarm/abort (pressure exceeds 10 Torr)20 L> 18 O3 Loop back to 1821 M 01:30 O2 1-1/2 min vacuum (final steps: To remove HMDS vapors and backfill22 M 01:30 O1 1 min nitrogen23 M 02:30 O2 2-1/2 min vacuum24 M 04:00 O1 4 min nitrogen25 M 10:00 O0 10 min complete light/sound alert …PROCESS DONE26 GOTO 00 RESET27 GOTO 0028 GOTO 0029 GOTO 0030 S 00.10 O1 0.1 sec nitrogen back-fill FLASHING31 S 00.10 O0, O1Complete light and nitrogen LIGHT32 GOTO 30 O1 ABORT from 08, low vacuum process33 GOTO 0034 GOTO 0035 S 00.10 O1 FLASHING36 S 00.10 O0, O1 LIGHT37 GOTO 35 O1 ABORT from 11, low nitrogen backfill pressure38 GOTO 0039 GOTO 0040 S 00.01 O1 FLASHING41 S 00.10 O0, O1 LIGHT42 GOTO 40 O1 ABORT from 14, high vacuum process43 GOTO 0044 GOTO 0045 M 00:30 O246 M 00:30 O147 M 00:30 O248 M 02:30 O149 S 00.10 O1 FLASHING50 S 00.10 O0, O1 LIGHT51 GOTO 49 O1 ABORT from 19, primer application52 GOTO 0053 GOTO 0054 GOTO 0055 L = 0010 Program 1, 10 loops of …56 GOTO 1857 GOTO 0058 GOTO 0059 GOTO 0060 L = 0060 Program 2, 60 loops of …61 GOTO 1862 GOTO 0063 GOTO 0064 GOTO 0065 M 00:30 O2 Program 3 places a vacuum in the flask after it is filled.66 M 00:30 O1 Before evacuating the flask, air is purged from the chamber.67 M 01:30 O268 M 00:30 O2, O369 GOTO 22Note:The duration of each vacuum and nitrogen step has been determinedfor the YES-5 chamber size. Modifications will be necessary at thevacuum steps for use with the YES-3. When the FUNCTION, DATAand OUTPUT LINES are blank in the program, enter GOTO on theFUNCTION line, 00 on the DATA line and leave the OUTPUT lineblank. Step 70 to 79 reads IF0000. The program will go to RESETafter step 79.12.3.1 12.3.1After you have re-entered the program, press RESET (RST).Now go into the programming mode again and step through toconfirm that the program was properly entered. Make sure the correctoutput is activated at the right step.Example:07 M 01:30 O208 IF B> 3009 M 03:00 O110 IF B> 1211 GOTO 3512 L> 07 After the 1-1/2 min of vacuum, the program checks Input B. If the chamber pressure is below setpoint I, there is sufficient vacuum and Step 08 is skipped.After 3 min of nitrogen backfill, setpoint1 is checked again. The pressure should be greater and so the program carries out Step 10 and goes to 12, which loops back to 07. If there was insufficient N2 pressure to backfill the chamber, Step 10 is skipped and Step 11 says to go to Step 35 (abort).Note:If an abort does occur, note the step the abort jumps to. This indicateswhere the problem is.12.3.2 12.3.2When satisfied with the re-programming operation, pressRESET (RST), turn key to vertical position, remove key and you areready to start HMDS coating cycle.Teflon® is a registered trademark of DuPont.Rev. 00 – 5/05, M. Kushner, S. ParsaRev. 01 – 2/06, K. Chan – Changed initial vacuum time on step 7. Added programmingcommands and clarify programming procedures. Added process,gas and general primeoven information on this revision also.。