Laboratory for Advanced Materials Processing

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WARNING:

Procedure:

Startup:

1. Open the main N2 tank. Both the main valve and the regulator valve must be opened. The regulator pressure should read around 75psi.
2. Open the N2 valve for the MA6 (located on the wall next to the eye wash).
3. Open the vacuum valve for the MA6 (located next to the N2 valve).
4. Switch on the vacuum pump.
5. Check that the MA6 gauges read as follows:

       pressure = 4bar (1st guage)
       N2 pressure = 2bar (4th gauge) 
       vacuum <= -0.8bar (5th gauge)
   

6. Switch on the MA6 main power toggle button.
7. Turn on the power supply for the exposure lamp. The system should display "rdy" indicating that the lamp is ready to be fired.
8. When the lamp power supply reads "rdy", press START to commence the lamp ignition process. The lamp requires approximately 3 minutes to warm up to normal operating temperature, at which point the display will change to display the idle power level (475W).
9. The red light above "CI2" should be lit, indicating that the #2 constant-intensity channel is selected. The normal intensity setting for channel #2 is 3 mW/cm2. If either CI1 or CP is selected, press the CI2 button to select the #2 channel.k

   Mask Loading:

10. The MA6 should start in the LOAD position. If not, press LOAD to move the alignment stage to the wafer-load/exposure position. Note the improper shutdown in the login book.
11. Make sure the aluminum contact lever is in the non-contact (down) position.
12. Make sure the separation lever is in the separation position.
13. Press ALIGN to move the alignment stage to the alignment position.
14. Loosen the two silver screws on the side of the mask holder, and slowly pull the mask holder out. The alignment optics will raise as soon as the holder begins to slide.
15. Place the holder upside-down on the black table area of the MA6. Place the mask onto the bottom of the holder, with the mask pattern facing away from the holder, and the mask oriented so that it will line up properly with the wafer.
16. Press VAC. MASK to turn on vacuum to the mask holder. The mask should now be fixed onto the holder. Check the vacuum contact by nudging the mask with your wafer tweezers.
17. Replace the mask holder into the slot, and gently tighten the set screws to keep the holder in place. The set screws should be only lightly tightened!

    Wafer Alignment:

18. Press LOAD to move the alignment stage to the load/exposure position.
19. Slide out the wafer chuck from underneath the mask holder.
20. Place your wafer face-up on the chuck, with the main flat against the two forwrad pins, and the minor flat against the left-hand pin.
21. Press VAC. WAFER to clamp the wafer to the chuck. Check the vacuum contact by nudging the wafer with your tweezers.
22. Slide the wafer chuck back into its rearmost position.
23. Perform wedge error compensation:

       1. Move the separation lever into contact position.  The green SEPARATION
          light should go out, and the blue KONTACT light should illuminate.
       2. Use the contact lever to bring the wafer into contact with the
          mask, until the yellow MASK WAFER PARALLEL light is illuminated.
       3. Move the separation lever back into separation position.  Both the
          SEPARATION and MASK WAFER PARALLEL lights should be illuminated.
    

24. Press ALIGN to move the alignment stage to the alignment position.
25. Double-check that the separation lever is in the separation position.
26. Use the arrow keys to align the microscope to the mask. Use the FAST key for more rapid motion of the microscope objectives. Position the objectives so that both left and right alignment marks are visible.
27. Use the X, Y, and THETA micrometers to align the wafer to the mask.
28. Bring the separation lever into the contact position, and re-check alignment. (If using vacuum contact, press VAC. CHAMBER to check alignment)

    Exposure:

29. Choose exposure mode:

        ST = standard hard contact (moderate resolution)
        HP = vacuum contact (highest resolution)
        ST + SOFT CONT = soft contact (low resolution)
    

    ST mode is recommended for normal use to avoid damaging your mask, while acheiving 1um or better resoution.
30. Ensure that N2 PURGE is NOT illuminated. This is used for negative resist patterning only, and is not needed for standard positive resist.
31. Set exposure time using the dial gauge, in increments of 0.01 times the selected unit (s=sec, m=min, or h=hour). Make sure the proper unit is selected for your exposure needs (the "s" setting is standard, with a maximum exposure time of 99.99 sec).
32. Double-check that the lamp power supply reads 475W for the idle power.
33. When the alignment is acceptable and all settings are chosen, press EXPOSE. The alignment stage will automatically move under the lamp output and be exposed.
34. After exposure, remove your wafer and repeat the alignment procedure for subsequent wafers.

    Shutdown:

35. While in the load position, remove your wafer.
36. Press ALIGN to move the alignment stage to the alignment position.
37. Make sure the separation lever is in the separation position
38. Make sure the contact lever is not engaged.
39. Remove your mask.
40. Press LOAD to move the alignment stage to the load position.
41. Turn off the exposure lamp power supply.
42. Toggle off main power button on MA6.
43. Turn off vacuum pump (if nobody else is using vacuum).
44. Wait 2 minutes to allow the exposure bulb to cool down.
45. Turn off main tank N2 valve and regulator valve at the N2 tank (if nobody else is using N2).
46. Close N2 valve for MA6 (on wall).
47. Close vacuum valve for MA6 (on wall).
48. Log out of the MA6 log book. Enter any relevant comments about the system.