Stepper 2 (AutoStep 200) Operating Procedures

Work In Progress This article is still under construction. It may contain factual errors. Content is subject to change.

Cleaning the back-side of wafer

If the back side of wafer has some resist residue or particulates, this can cause errors in the interpreted best focus point since the wafer surface may be at a different height.

1. Make sure all work surfaces/spin chucks/hot plates are cleaned! Don’t use wipes, instead use cleaned steel surfaces.
2. Spin coat resist following the recipe for spinning/baking specific resist.
3. Check back-side of wafer thoroughly for resist residue/particulates before loading into system!
4. If you see particulates, try to blow off with high N2 flow first, you may need a razor blade to remove stubborn particles.
5. If you see resist residue, do next:
   1. Place wafer upside down in POLOS spinner using non-contact chuck.
   2. Set spin speed to 2000rpm.
   3. Spin wafer, wait until at top speed.
   4. Squirt Acetone on sample back for 3 seconds. Followed by ISO for 3 sec.
   5. Spin Dry while blowing with N2.
6. Load the wafer on chuck and then stage.

Reticle Loading and Unloading

Loading the reticle

 Mask Alignment on this system is automatic. You need to have the square marks on the top and bottom of the mask. These are put on automatically by Photronix and the gds file can be obtained from Brian Thibeault if you use a different vendor. There are 10 reticle box positions on the elevator. Slot 1 is dedicated for a calibration mask. Slots 2-10 are available for your use. Slots will NOT be dedicated for any users.

1. Load the reticle into a box with chrome side down (shown in the figure 1.)
2. Type RMSL on the main computer at the colon prompt.
3. Swing the reticle forks 90 degrees away from the reticle elevator.
4. Pull out knob, insert box in one of the slots (2-10), release knob to hold   box.
5. Make sure the box is sitting properly in place.
6. Hit Enter on the computer and the system will map the reticles.
7. On them main monitor you will get information about the reticle name and the slot# it is loaded (if the reticle does not have a name it will say just NONE)

Unloading the reticle

 At the end of each job you need to unload the mask

1. Type RMSR on the main computer at the colon prompt.
2. Wait for the reticle to be loaded back in the reticle box.
3. Type RMSL on the main computer at the colon prompt.
4. Get your reticle from  the reticle box
5. NOTE: NEVER try to manually unload the reticle (as you would in GCA 6300 Stepper #1). Always use commands.