Appeal No. 2005-0339
Application No. 09/376,039
planarizing a surface is far more difficult, time consuming and
expensive than performing CMP to simply reduce the height of
peaks to a substantially uniform level" (page 13 of principal
brief, first full sentence), we find that one of ordinary skill
in the art would have found it obvious to avoid polishing the FSG
layer all the way down to the conductive layer in order to save
the known added cost. We are confident that it would have been
within the skill of one of ordinary skill in the art to resort to
a cost/benefit analysis in determining how much of the FSG layer
to remove during the polishing operation. Moreover, we agree
with the examiner that the claims on appeal do not preclude the
complete planarization of the peaks to the height of the
conductive layer. The claim language "to reduce the height of
the peaks to a substantially uniform height" includes reducing
the height of the peaks to zero.
While we agree with appellants that it is not proper for the
examiner to consider FSG layers 203 and 204 of Usami as a single
FSG layer, we nevertheless conclude, for the reasons expressed
above, that the claimed method would have been obvious to one of
ordinary skill in the art.
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