Appeal No. 1998-2884
Application No. 08/495,960
We further find unpersuasive Appellant’s argument that it
would not be obvious to modify the applied prior art to add
conductive layers since such are undesirable in a trench
isolation structure. In our view, there is no need to modify
the trench isolation structure of Iranmanesh to add upper and
lower conductive layers since the conductive polysilicon
layers 50 and 70 are already in place. The Examiner’s
modification of Iranmanesh extends only to the addition of
Okada’s teachings related to the use of the dual mask layers,
trench cap, and well
structure features. Appellant has not argued the obviousness
of adding the dual mask layers of Okada to Iranmanesh.
Further, in our view, Appellant’s arguments related to the
trench cap and well structure are unconvincing since a clear
teaching exists in Okada for employing such features in an
isolation structure.
For the above reasons, it is our opinion that, since the
Examiner’s prima facie case of obviousness has not been
rebutted by any convincing arguments from Appellant, the
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