Appeal No. 2002-1415
Application No. 09/141,812
that make soluble or volatile compounds with a given chemical residue or
contaminant may be added to enhance the removal of the resist. Any one
of a variety of additives may be selected depending upon the composition
of the resist and the etch process used. Common additives include Ar, He,
SF6, Cl2, CHF3, C2F6, CFC's, N2, N2O, NH3 [ammonia], H2, water vapor, or
the like. For instance, after a polysilicon etch process, using a normal
resist, CF4 is preferably added to the O2 gas in concentrations of 0.2% to
10% in order to enhance resist removal.
Savas at col. 20, ll. 14-34.
We disagree with appellants’ arguments to the extent they may be based on the
view that the number of possible additives for combining with oxygen tends to show
nonobviousness of the specific combination of ammonia and oxygen. See, e.g., Merck
& Co. v. Biocraft Labs., Inc., 874 F.2d 804, 806-07, 10 USPQ2d 1843, 1845-46 (Fed.
Cir. 1989) (claimed combination of two drugs held to have been obvious in view of
reference which disclosed 1200 possible combinations, without highlighting preference
of two that were claimed). Disclosure of “a multitude of effective combinations does not
render any particular formulation less obvious.” Id. at 807, 10 USPQ2d at 1846.
However, we agree with appellants that Savas does not teach that the
combination of oxygen and ammonia is effective for the uses claimed by appellants.
Nonetheless, we disagree that “[e]ach of Appellants’ claims specifically recite
simultaneous use of ammonia and oxygen after etching a via through an insulating
layer to expose metal.” (Brief at 4.)
Instant claim 8, and those depending therefrom, say nothing of exposing “metal.”
However, each of the independent claims requires treatment of a via with a plasma (or
vapor; claim 1) containing ammonia and oxygen. Notwithstanding the examiner’s
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