Appeal No. 1998-2916
Application No. 08/606,975
full step coverage of the plasma deposited material in a
contact hole is contemplated. We are convinced that the
skilled artisan, seeking guidance as to the proper halogenated
gas to H flow ratio to achieve maximum coverage would be led
2
to the teachings of Sandhu which suggests the proper flow
ratio range of 0.1 to 0.5 of metal source gas to reactive gas
(e.g. TiCl to H ) to achieve the desired full coverage result.4 2
It is not necessary
that the references be combined for the same reasons as
Appellant. The fact that Appellant has recognized another
advantage which would flow naturally from the suggestions of
the prior art, i.e. prevention of contact hole grain growth of
Ti, cannot be the basis for patentability when the differences
would otherwise be obvious. Ex parte Obiaya, 227 USPQ 58, 60
(Bd. Pat. App. & Inter. 1985).
Appellant further contends that none of the prior art,
particularly Sandhu, teaches or suggests the particular
claimed halogenated product to H flow ratio of 0.4 or
2
greater. We do not find such argument to be persuasive. It
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