wbdiff for Ge clean?

Jim McVittie mcvittie at snf.stanford.edu
Thu Oct 14 12:43:47 PDT 2004


HF tanks are the most critical part of our cleaning process since we often
finish with a HF dip. If the HF tank is comtaminated it can undo everything
that was done previously to remove metals. We recently had a problem in our
in the Diff Clean bench and I suspect it was a contaminated HF tank. In
particlar, an elevated Cr level was found on cleaned wafer which had been
given a final HF dip. After getting these results, I had Nancy give the HF
tank an HCl clean. It probably would be wise to clean our HF tanks (at
least on the cleaning bench) on a regular basis. We should run anpther test
on our cleaning. With this mind and knowing that Ge wafers often have high
surface metal levels, I really do not want Ge cleaning to be done on the
diff clean bench.

I propose that we let him use one of the HF tanks on the non-metal bench
and that he gives the tanks a HCl clean after in the finished.


Mary Tang wrote:

> Hello SpecMat'ers --
> I think this is a question for Jim & Mike....   The wbsilicide bench
> moves next week and the maintenance guys are allocating two weeks for
> re-installation and County inspection approval.  Abhijit Pethe has been
> using the HF tank for cleaning his Ge wafers.  Would it be possible for
> him to use one of the wbdiff HF tanks for his process while the
> wbsilicide bench is unavailable?  Is it possible to put in some sort of
> precautionary measures (i.e. changing out acid) to reassure other users
> that contamination is not an issue?
> Can we get an answer soon?  (The bench goes down on Monday.)
> Thanks,
> Mary
> --
> Mary X. Tang, Ph.D.
> Stanford Nanofabrication Facility
> CIS Room 136, Mail Code 4070
> Stanford, CA  94305
> (650)723-9980
> mtang at stanford.edu
> http://snf.stanford.edu
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