Ex parte Hill

Board of Patent Appeals and Interferences

Aug 10, 2001

08669794 (B.P.A.I. Aug. 10, 2001)

The opinion in support of the decision being entered today was not written for
publication and is not binding precedent of the Board.
Paper No. 15
UNITED STATES PATENT AND TRADEMARK OFFICE
_____________
BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
_____________
Ex parte RODNEY L. HILL
_____________
Appeal No. 1998-2582
Application No. 08/669,794
______________
ON BRIEF
_______________
Before CAROFF, KRATZ and DELMENDO, Administrative Patent
Judges.
CAROFF, Administrative Patent Judge.
DECISION ON APPEAL
This decision on appeal relates to the examiner’s final
rejection of claims 12-17, all the claims now pending in
appellant’s application.
The claims are directed to a method of processing
semiconductor wafers having an exposed aluminum-containing
layer. The method includes the step of rinsing the wafers
Appeal No. 1998-2582
Application No. 08/669,794
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with deionized (DI) water which has been purified by being
subjected to air
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injection followed by degasification to reduce the
concentration of dissolved oxygen (DO) in the water.
Claim 12, the sole independent claim, is representative:
12. A method of processing semiconductor wafers
having an exposed metal layer including aluminum formed
thereon, comprising the steps of:
deionizing water,
prior to use of the deionized water for
processing of the semiconductor wafers, injecting
air into the deionized water, thereby to remove
carbon dioxide from the deionized water;
passing the water with the injected air through
a degasifier unit, thereby reducing a concentration
of oxygen gas that was dissolved in the water due to
the step of injecting air; and
rinsing the semiconductor wafers having the
exposed metal layer with the degasified water,
thereby reducing any etching or pitting of the
exposed metal layer by oxygen gas in the water.
All of the claims on appeal stand rejected for
obviousness under 35 U.S.C. § 103 in view of the admitted
prior art disclosed in appellant’s specification (pages 1-4)
taken in combination with the following prior art reference:
Hirofuji 5,422,013 Jun. 6,
1995
Based upon the record before us, we agree with appellant
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Application No. 08/669,794
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that the examiner has failed to establish a prima facie case
of obviousness. Accordingly, we shall reverse the sole rejection
at issue essentially for the reasons discussed in appellant’s
brief.
Hirofuji relates to a method for purifying water to be
used in a process for manufacturing semiconductor devices. In
Hirofuji, water is passed in sequence through a deaerator, an
oxidation device, an ion eliminating device and a particle
eliminating device.
Appellant acknowledges that it was a well known problem
in the semiconductor field that DI water undesirably etches
aluminum and aluminum alloys. Appellant also acknowledges
that it was common practice to subject DI water to injection
of air to remove dissolved carbon dioxide. Apparently,
appellant was the first to recognize that the problematic
etching of aluminum caused by DI water was not due to the DI
water itself but rather to the DO content of the DI water.
While Hirofuji (col. 1, ll. 25-29) suggests that
reduction of DO content may be desirable, this suggestion does
not arise in the particular context of a purification process
which involves an air injection step, as recited in the
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Application No. 08/669,794
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instant claims, where DO is necessarily present at relatively
high levels. Neither does Hirofuji particularly relate to the
rinsing of semiconductor wafers which have an exposed metal
layer including aluminum, the operational area where the
problem addressed by appellant arises.
Thus, we find there would be no motivation to combine the
teachings of Hirofuji with the admitted prior art in a way
which would render the claimed process obvious within the
purview of 35 U.S.C. § 103.
In a nutshell, the examiner has not given due regard to
the principle that patentability may reside in the discovery
of the source of a problem even though the remedy may be
obvious once the source of the problem is identified. See In
re Sponnoble, 405 F.2d 578, 585, 160 USPQ 237, 243 (CCPA
1969); and Eibel Process Co. v. Minnesota & Ontario Paper Co.,
261 U.S. 45, 67-68, 1923 CD 623, 639-40 (1923).
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Application No. 08/669,794
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For the foregoing reasons, the decision of the examiner
is reversed.
REVERSED
MARC L. CAROFF )
Administrative Patent Judge )
)
)
) BOARD OF PATENT
PETER F. KRATZ ) APPEALS AND
Administrative Patent Judge ) INTERFERENCES
)
)
)
ROMULO H. DELMENDO )
Administrative Patent Judge )
MLC:hh
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Application No. 08/669,794
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