Appeal 2007-2490
Application 09/846,255
Examiner’s prima facie case of obviousness of that claim based on the
collective teachings of the cited references.
Nevertheless, we find that Verhaverbeke’s teaching of continuously
flowing process gas in a semiconductor etching process would have been
reasonably combinable with Mehta’s etching method. Although
Verhaverbeke discusses static and dynamic modes3 in the context of
traditional HF vapor etching techniques using HF and water vapors
(Verhaverbeke, col. 2, ll. 1-12; col. 3, ll. 7-28), the reference hardly discards
the dynamic mode in favor of the static mode as Appellants seem to suggest.
As the Examiner indicates, Verhaverbeke actually claims performing the
etching process in both the static and dynamic modes in different claims
respectively (Verhaverbeke, col. 8, ll. 23-38 (claims 11 and 12)).
We recognize that Verhaverbeke’s sole example uses the static mode
(Verhaverbeke, col. 5, l. 55 - col. 6, l. 30). But merely describing a single
exemplary procedure using the static mode in the Specification hardly
teaches away from using the dynamic mode. On the contrary, Verhaverbeke
clearly recognizes the significance of each technique (static and dynamic) by
claiming each technique separately. By merely comparing claims 11 and 12
in Verhaverbeke, the skilled artisan would readily ascertain that static and
dynamic modes are equally significant in the recited etching process -- and
therefore interchangeable.
3 Verhaverbeke indicates that “[i]n the static mode, the reactor is filled with
a process gas up to a certain pressure and then the reactor is isolated for
some time. Subsequently, the reactor is evacuated and the etch cycle can be
repeated for a number of times. In the dynamic mode, a continuous flow of
process gas is fed into the reactor which is maintained at a constant
pressure” (Verhaverbeke, col. 3, ll. 22-28).
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