Appeal No. 2002-1992
Application 09/206,170
because it is known to satisfactorily remove surface residue and
contamination” (answer, page 5).
In Grieger’s method, removal of the doped silica is to be
minimized (abstract; col. 12, lines 49-52), whereas in the
Schonauer ‘769 method, a very shallow depth of the surface is
intentionally etched away (col. 3, lines 30-34). The examiner
has not explained, and it is not apparent, why the applied
references would have led one of ordinary skill in the art to
combine these methods.
As for combining the teachings of Chen and Schonauer ‘769,
the teaching in Schonauer ‘769 that his etching solution rapidly
dissolves Ti (col. 4, lines 14-42) is evidence that this etching
solution is not compatible with all metals.5 The examiner has
not provided evidence or technical reasoning which shows that one
of ordinary skill in the art would have reasonably expected the
Schonauer ‘769 etching solution to be compatible with Chen’s
copper wiring. Like Schonauer ‘769 (col. 3, lines 34-38),
Grieger uses a cleaning solution which contains HF (abstract).
5
5 The wiring metal which is disclosed in Schonauer ‘769
(col. 2, lines 14-19) and recited in the claims is tungsten.
11
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