Appeal 2007-2490
Application 09/846,255
STATEMENT OF THE CASE
Appellants invented a cleaning process for selectively removing an
unnecessary film from a semiconductor substrate surface, yet leaving
another necessary film intact. Specifically, a mixed gas comprising
anhydrous hydrogen fluoride (HF) gas and a heated inert gas is continuously
brought into contact with the surface of the substrate. As a result, the
unnecessary low-density film can be removed without impairing the
necessary high-density film beyond a tolerance.1 Claim 1 is illustrative with
the key limitation in dispute emphasized:
1. A process for cleaning a surface of a substrate, said surface
carrying thereon a high-density film and a low-density film
lower in density than said high-density film in combination,
which comprises continuously bringing a mixed gas
comprising anhydrous hydrogen fluoride gas and a heated
inert gas into contact with said surface of said substrate such
that at least a portion of said low-density film is removed
without impairing said high-density film beyond a tolerance,
wherein the mixed gas does not contain steam.
[Emphasis added.]
The Examiner relies on the following prior art references to show
unpatentability:
Mehta US 5,635,102 Jun. 3, 1997
Verhaverbeke US 5,922,624 Jul. 13, 1999
Claims 1-3 and 5-14 stand rejected under 35 U.S.C. § 103(a) as
unpatentable over Mehta and Verhaverbeke.
1 See generally Abstract; Specification 1:4-12 and 10:3-12.
2
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