From cmcg at stanford.edu Fri May 9 18:52:26 2008 From: cmcg at stanford.edu (Christopher McGuinness) Date: Fri, 9 May 2008 18:52:26 -0700 Subject: residue on wafer Message-ID: <393d7fe80805091852s5f44e3d9je80f5daaca9852d9@mail.gmail.com> Hi all, I have recently noticed an odd residue on my wafers. It looks like a big animal sneezed on them. I am suspicious that this came from either the CMP or the TEOS tubes, and was wondering if anyone noticed anything similar in the past. My observations are as follows: CMP: typically leaves a slight hint of slurry residue if not cleaned properly afterwards. At this point I am fairly confident in my cleaning procedure, and have not had a problem with this on the last batch of wafers I ran, so i'm somewhat doubtful this is the culprit. TEOS: Tube ran out of TEOS during an earlier deposition. I ran several tests after this point, and reran the wafers to finish the oxide deposition. At this point I do recall noticing a slight hint of something, but it was not obvious enough to cause alarm. After etching into this layer the residue was more apparent, and after depositing a layer of poly on top of this it was very apparent. I have included a picture (as best of one as Uli and I could get). Anyone see anything like this before, or think this will cause serious problems? Any ideas of what it could be? Thanks, Chris McGuinness -------------- next part -------------- An HTML attachment was scrubbed... URL: -------------- next part -------------- A non-text attachment was scrubbed... Name: P1000140.JPG Type: image/jpeg Size: 2978571 bytes Desc: not available URL: From cmcg at stanford.edu Sat May 31 12:19:19 2008 From: cmcg at stanford.edu (Christopher McGuinness) Date: Sat, 31 May 2008 12:19:19 -0700 Subject: teos2 dep rate? Message-ID: <393d7fe80805311219q3625d0afv436adcd80c368a32@mail.gmail.com> Has anyone noticed inconsistent dep rate from teos 2? I typically measure 35-40A/min, averaged across the wafer and across the tube. Occasionally I have noticed this value dropping to tens of A/min and up to 55A/min. The symptoms seem to be low chamber pressure in some cases, and teos2 gas running low in others. I am curious if other people have noticed similarly unpredictable behavior, and if this is a concern or not. It is very important for me to achieve controllable oxide layer thicknesses, so is important to me. Any thoughts on how to improve the consistency? Thanks, Chris -------------- next part -------------- An HTML attachment was scrubbed... URL: