Stepper 2 (AutoStep 200) Operating Procedures

Cleaning the back-sides of wafers

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/Unloading

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