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Run Card for cmos150 |
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Step 38.0 |
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Process: Back side etch |
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1. |
Remove PR in O2 plasma (matrix), piranha
clean wafers in sink9 MEMS side (no dip). Dehydrate wafers in oven at 120 C
for >30 min.
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April 30th, 2002 |
vorosl |
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2. |
Etch backside: |
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a) Spin PR on front side, hard bake. I-line resist. |
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b) Dip off oxide (PSG) in 5:1 BHF. |
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c) Etch poly-Si in lam4. |
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d) Final dip in BHF until back dewets. |
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g) Remove PR in O2 plasma, piranha clean wafers in sink9 MEMS side (no dip). |
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Note: only #2, #4, #8, #10 wfrs were back side etched. 10:1 HF was used instead of 5:1 Buffered HF with the corresponding etch time. Always use BHF at this step! |
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Otherwise this could happen:
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