Appeal No. 2001-2540
Application No. 09/240,395
Our review of the instant case finds that the examiner has
established a prima facie case of obviousness since Lur teaches a
gate stack structure essentially as recited in instant claim 1
but for the claimed metal boride layer; Lur teaching, instead,
that a metal nitride layer and a metal boride layer were known to
be used as a diffusion barrier layer. The examiner then, again
quite reasonably, in our view, concludes that it would have been
obvious to use a transition metal boride layer as the diffusion
barrier in Lur, based on the teaching of Thomas.
The burden then passed to appellants to overcome the
examiner’s prima facie case by objective evidence and/or
convincing argument.
We have reviewed appellants’ arguments and find that such
arguments are, indeed, sufficient to overcome the examiner’s
prima facie case of obviousness and, so, we will not sustain the
rejection of claims 1-21 under 35 U.S.C. 103.
Although Thomas does not teach the use of a transition metal
boride layer as a barrier layer within a gate stack, its teaching
of both metal nitrides and borides as diffusion barriers would
have led the artisan to use a metal boride as an equally obvious
substitute for the titanium nitride employed by Lur as the
diffusion barrier layer.
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