Appeal No. 2000-1587
Application 09/055,254
PECVD,” as asserted by the Examiner.
Turning now to Wolf 2, we find that the step of baking
the SOG in a low temperature and immediately in a high
temperature after it is spun relates to a step of basic SOG
process that prevents cracking (page 232). The reference is,
however, silent with regard to the step of baking the SOG
subsequent to its partial etch back in order to form a
protection mask in the large area over the shallow trench.
Additionally, the reference teaches that the resist etch rate
is sensitive to the cure cycle, whereas the etch rate of the
SOG, used in lieu of the resist, is less variable with bake
temperature (wolf 2, page 227). Thus, Wolf 2 teaches reduced
variation in etch rate when the SOG is cured, which is
different from the claimed partially etching back of the SOG
and curing its residue over the shallow trench in the large
area that serves as a protection mask.
The Court states that "[t]he mere fact that the
prior art may be modified in the manner suggested by the
Examiner does not make the modification obvious unless the
prior art suggested the desirability of the modification." In
re Fritch, 972 F.2d 1260, 1266 n.14, 23 USPQ2d 1780, 1783-84
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