Appeal No. 2002-2244
Application 09/037,586
areas of silica and which may contain some areas of alternative
material such as metal, is chemical mechanical polished, cleaned
with an aqueous ammonium hydroxide solution, and etched with a
mixture of hydrofluoric acid and nitric acid (abstract; col. 2,
lines 25-43). “The aqueous ammonium hydroxide solution
preferably includes citric acid. However, chelating and other
agents may be used in addition to or instead of the citric acid”
(col. 6, lines 33-36). Vines does not disclose the cleaning
solution’s pH or concentration of ammonium hydroxide or citric
acid.
The examiner argues that the concentration of a cleaning
solution is a result effective variable and that, therefore, it
would have been obvious to one of ordinary skill in the art to
determine the optimum concentration of ammonium hydroxide and
citric acid in Vines’ cleaning solution through no more than
routine experimentation (answer, pages 3-4). As for the cleaning
solution pH, the examiner argues that “[d]epending upon the ratio
of the acidic portion of the solution to the basic portion of the
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