kimsangb at stanford.edu
Fri Apr 10 12:33:34 PDT 2009
Do you know during which CMP step your wafer gets broken? In my case, most of my broken wafers actaully got broken when it is picked back up again by the head after it is done polishing. If that is the case for you, you can avoid that by turning off the vacuum pump during your polish so that the wafer is not picked up.
----- Original Message -----
From: "Chong Xie" <chongxie at stanford.edu>
To: cmp at snf.stanford.edu
Sent: Friday, April 10, 2009 10:58:58 AM GMT -08:00 US/Canada Pacific
Subject: Wafer broken
Dear CMP users,
The CMP broke most of my wafers (3 out of 4) last time I use it. Chucking was all right, but the wafers were broken during polishing. I was just using the normal setting:
Polishing pressure: 200gm/cm2
Retainer pressure: 300gm/cm2
My wafers have 2 um deep trenches on them. I thought that might be the reason, but the same conditions worked for me all right before.
I was wondering whether I could tune any of these parameters. Dose anyone have similar problems before?
Any input is appreciated, and thanks in advance.
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