Appeal No. 94-1889
Application 07/890,003
transmitting region of the mask, and that this is a teaching
directly away from providing phase-shifting portions on opposite
surfaces of the transparent substrate (brief, page 5).
In order for a prima facie case of obviousness to be
established, the teachings from the prior art itself must appear
to have suggested the claimed subject matter to one of ordinary
skill in the art. See In re Rinehart, 531 F.2d 1048, 1051, 189
USPQ 143, 147 (CCPA 1976). The mere fact that the prior art
could be modified as proposed by the examiner is not sufficient
to establish a prima facie case of obviousness. See In re
Fritsch, 972 F.2d 1260, 1266, 23 USPQ2d 1780, 1783 (Fed. Cir.
1992). The examiner must explain why the prior art would have
suggested to one of ordinary skill in the art the desirability of
the modification. Id. at 1266, 23 USPQ2d at 1783-84.
In the present case, the examiner asserts that a teaching of
placing phase-shifting material on either side of a substrate,
together with Athe expected and predictable results of the
optical properties of such phase shifting masks@, would have
suggested, to one of ordinary skill in the art, placing phase-
shifting material on both sides of the substrate (answer, page
3). The examiner does not explain, and it is not apparent to us,
what Aexpected and predictable results of the optical properties@
4
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