Fwd: CMP Challenges
edmyers at stanford.edu
Mon Jun 27 19:34:52 PDT 2011
I want to be more clear about what is going on with the CMP. Right
now the gold contaminated hardware set is not working. This was
reported by a lab member who found a zero polishing rate for this
hardware set. It has also been reported that the clean non-metal
also has a low polishing rate.
I believe these problems related to the membrane assembly. Recently
I purchase membranes from the US distributor. These membranes do not
work with our hardware. Apparently we have an older version of
hardware, which caused the confusion. I am working with the vendor
to get the correct membranes, but I'm afraid they will have to be
shipped from overseas.
In the mean time, I am also trying to address the polish rate
variations between new and used membrane assemblies.
>Date: Tue, 21 Jun 2011 16:22:20 -0700
>To: cmp at snf.stanford.edu
>From: Ed Myers <edmyers at stanford.edu>
>Subject: CMP Challenges
>Over the years I would get occasional reports of polishing rate
>asperities. This may happen more than I'm aware, since often times
>problems or concerns go unreported. During these isolated
>excursions, I was never able to find any correlate to these problems.
>Recently I have changed out a number of our membranes within a sort
>time period. This has resulted in many more reports of polishing
>problems. I feel pretty confident there is a correlation to our
>membrane assemblies and our polishing rate excursions. I am working
>with the US parts supplier and GnP to understand why we are so
>sensitive to the changing of the membranes. We are trying to
>determine if we received incorrect assemblies, if there is a way to
>condition the assemblies or if we need to modernize our wafer heads.
>I will keep you appraised to any findings or developments as they
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