Appeal No. 2001-0482
Application No. 09/186,078
burden is, therefore, upon Appellants to come forward with evidence or arguments which
persuasively rebut the Examiner’s prima facie case of obviousness. Arguments which Appellants
could have made but elected not to make in the Briefs have not been considered in this decision
(note 37 CFR § 1.192).
Appellants’ arguments in response (Brief, pages 15 and 16; Reply brief, page 4) focus on the
contention that the Examiner has not established that the combination of Rho and Gardner would
necessarily result in a semiconductor structure in which the gate oxide layer has thickness at the
trench edges equal to or greater than the remainder of the gate oxide layer. After careful review of
the Gardner reference, relied on by the Examiner to provide a teaching of the formation of a gate
oxide layer with increased thickness over impurity enhanced areas at trench edges, we are in
agreement with the Examiner’s position as articulated in the Answer. Our interpretation of the
disclosure of Gardner coincides with that of the Examiner, i.e., a clear suggestion exists (column 7,
lines 63-65, column 8, lines 14-18, and Figure 14) that the formation of a gate oxide over trench
edge regions containing implanted impurities would result in increased oxide growth over these
regions. In our view, the skilled artisan, considering the collective teachings of the Rho and
Gardner references, would have been motivated and found it obvious to combine the gate oxide
formation teachings of Gardner with Rho to thereby arrive at Appellants’ claimed invention.
We also find to be unpersuasive Appellants’ contention (Brief, page 16) that Gardner grows
a multi-thickness gate oxide layer by implanting impurities at right angles, in contrast to the acute
angle implantation as claimed. In our view, Appellants’ arguments focus on the individual
9
Page: Previous 1 2 3 4 5 6 7 8 9 10 11 12 13 Next
Last modified: November 3, 2007