Problem cmp SNF 2012-03-03 14:58:56: head 1 pressure bad, or gapping bad

cmcg at cmcg at
Sat Mar 3 14:58:56 PST 2012

After conditioning the tool as usual, I noticed the bladder on the wafer chuck was very weak, and did not inflate for deflate very well. I removed the head and attempted to remount it. This seemed to improve the suction slightly. After chucking a wafer and lowering down the head to begin polishing, the machine made a loud grinding noise as if it was pushing down on the polishing pad with great force. I immediately stopped the machine, and attempted to regap. I'm not sure if I did this properly, but when I tried it again there was no grinding sound. The pressure for the bladder was still very weak, and it didn't feel as if the wafer was being held very well. After polishing a test wafer with polysi on oxide for 8min, I removed the wafer and measured a polishing rate of 32A/min. Nominal polishing rate for polysi is close to 2000A/min.

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