Appeal No. 2006-1320
Application No. 10/024,958
We have thoroughly reviewed each of appellants’ arguments
for patentability. However, we are in complete agreement with
the examiner that the claimed subject matter would have been
obvious to one of ordinary skill in the art within the meaning of
Section 103 in view of the applied prior art. Accordingly, we
will sustain the examiner’s rejection for essentially those
reasons expressed in the answer.
There is no dispute that Kornblit, like appellants,
discloses a method of plasma etching a chromium layer that can be
used for reticles by utilizing a gaseous mixture of oxygen,
chlorine and nitrogen. As appreciated by the examiner, Kornblit
does not teach the use of the presently claimed carbon monoxide
in the gaseous etching mixture. However, Kornblit expressly
teaches that other gases may be added to the etchant gas mixture
(column 4, lines 38 et seq.). Meyer, on the other hand,
discloses the plasma etching of a chromium photomask by using a
gaseous mixture of carbon monoxide and chlorine-containing gas,
with the carbon monoxide being a carrier gas. Accordingly, we
find that it would have been obvious for one of ordinary skill in
the art to select carbon monoxide as one of the “other gases” of
Kornblit to serve as a carrier gas. We note that Kornblit
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