residue on wafer

Christopher McGuinness cmcg at
Fri May 9 18:52:26 PDT 2008

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?

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: <>

More information about the teos2 mailing list