Ex Parte Buie et al

Board of Patent Appeals and Interferences

May 12, 2006

10024958 (B.P.A.I. May. 12, 2006)

The opinion in support of the decision being entered today was not
written for publication and is not binding precedent of the Board.

UNITED STATES PATENT AND TRADEMARK OFFICE
__________
BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
__________
Ex parte MELISA BUIE, BRIGITTE STOEHR and GUENTHER RUHL
__________
Appeal No. 2006-1320
Application No. 10/024,958
__________
ON BRIEF
__________
Before KIMLIN, WALTZ and FRANKLIN, Administrative Patent Judges.
KIMLIN, Administrative Patent Judge.
DECISION ON APPEAL
This is an appeal from the final rejection of claims 1-24.
Claim 1 is illustrative:
1. A method for processing a photolithographic
reticle, comprising:
positioning the reticle on a support member in a
processing chamber, wherein the reticle comprises a metal
photomask layer formed on a silicon based substrate and a
patterned resist material deposited on the metal photomask
layer;
Appeal No. 2006-1320
Application No. 10/024,958
2
introducing a processing gas comprising carbon
monoxide and chlorine gas into the processing chamber,
wherein the carbon monoxide and chlorine gas have a molar
ratio between about 1:9 and about 9:1; and
delivering power to the processing chamber to generate
a plasma and remove exposed portions of the metal photomask
layer.
The examiner relies upon the following references as
evidence of obviousness:
Meyer et al. (Meyer) 4,600,686 Jul. 15, 1986
Yasuzato et al. (Yasuzato) 5,750,290 May 12, 1998
Kornblit et al. (Kornblit) 5,948,570 Sep. 7, 1999
Demmin et al. (Demmin) 6,635,185 Oct. 21, 2003
(filed: Dec. 31, 1997)
Appellants’ claimed invention is directed to a method for
processing photolithographic reticles. The method entails plasma
etching exposed portions of a metal photomask layer, such as
chromium, with a processing gas comprising carbon monoxide and
chlorine gas.
Appealed claims 1-24 stand rejected under 35 U.S.C.
§ 103(a) as being unpatentable over Kornblit in view of Meyer,
Yasuzato and Demmin.
Appellants have not presented separate substantive arguments
for the dependent claims on appeal. Accordingly, the dependent
claims stand or fall together with the independent claims upon
which they depend, namely, claims 1, 13 and 20.
Appeal No. 2006-1320
Application No. 10/024,958
3
We have thoroughly reviewed each of appellants’ arguments
for patentability. However, we are in complete agreement with
the examiner that the claimed subject matter would have been
obvious to one of ordinary skill in the art within the meaning of
Section 103 in view of the applied prior art. Accordingly, we
will sustain the examiner’s rejection for essentially those
reasons expressed in the answer.
There is no dispute that Kornblit, like appellants,
discloses a method of plasma etching a chromium layer that can be
used for reticles by utilizing a gaseous mixture of oxygen,
chlorine and nitrogen. As appreciated by the examiner, Kornblit
does not teach the use of the presently claimed carbon monoxide
in the gaseous etching mixture. However, Kornblit expressly
teaches that other gases may be added to the etchant gas mixture
(column 4, lines 38 et seq.). Meyer, on the other hand,
discloses the plasma etching of a chromium photomask by using a
gaseous mixture of carbon monoxide and chlorine-containing gas,
with the carbon monoxide being a carrier gas. Accordingly, we
find that it would have been obvious for one of ordinary skill in
the art to select carbon monoxide as one of the “other gases” of
Kornblit to serve as a carrier gas. We note that Kornblit
Appeal No. 2006-1320
Application No. 10/024,958
1We note that the Demmin reference is not necessary for our conclusion
of obviousness of the claimed subject matter.
4
teaches noble gases as examples of the “other gases,” and Meyer
teaches carbon monoxide as an equivalent of noble gas argon as a
carrier gas. While appellants stress that Meyer teaches the use
of carbon monoxide in combination with carbon tetrachloride, we
agree with the examiner that Yasuzato clearly teaches the
equivalence of chlorine gas and carbon tetrachloride as an
etchant for chromium (column 2, lines 12-14).1
Appellants contend that “the critical use of nitrogen
specifically in combination with chlorine and oxygen in Kornblit
teaches away from the use [sic, of] other compounds, such as
carbon monoxide recited in claims 1-24" (page 11 of principal
brief, penultimate paragraph). However, as explained above,
Kornblit expressly teaches the use of other gases in the etchant
mixture. Appellants have not explained why it would have been
nonobvious for one of ordinary skill in the art to use carbon
monoxide as a carrier gas in the etchant mixture of Kornblit.
Manifestly, the examiner’s finding of obviousness does not
require the elimination of nitrogen from the etchant mixture of
Appeal No. 2006-1320
Application No. 10/024,958
5
Kornblit, and the “comprising” language of the appealed claims
does not preclude the use of nitrogen in the etchant mixture.
Regarding the operating parameters recited in the
independent claims, such as molar ratio between carbon monoxide
and chlorine gas and chamber pressure, appellants have not
demonstrated, let alone asserted, any criticality with respect to
these parameters. It is well settled that where patentability is
predicated upon a change in a condition of a prior art
composition or process, such as a change in concentration,
temperature, pressure or the like, the burden is on the applicant
to establish with objective evidence that the change is critical,
i.e., it leads to a new, unexcepted result. In re Woodruff, 919
F.2d 1575, 1578, 16 USPQ2d 1934, 1936 (Fed. Cir. 1990); In re
Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955).
As a final point, we note that appellants base no argument
upon objective evidence of nonobviousness, such as unexpected
results, which would serve to rebut the inference of obviousness
established by the examiner.
Appeal No. 2006-1320
Application No. 10/024,958
6
In conclusion, based on the foregoing, the examiner’s
decision rejecting the appealed claims is affirmed.
No time period for taking any subsequent action in
connection with this appeal may be extended under 37 CFR
§ 1.136(a).
AFFIRMED
EDWARD C. KIMLIN )
Administrative Patent Judge )
)
)
) BOARD OF PATENT
THOMAS A. WALTZ ) APPEALS AND
Administrative Patent Judge ) INTERFERENCES
)
)
)
BEVERLY A. FRANKLIN )
Administrative Patent Judge )
ECK:hh
Appeal No. 2006-1330
Application No. 10/024,958
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