Ex Parte Bowling

Board of Patent Appeals and Interferences

Aug 17, 2004

09466440 (B.P.A.I. Aug. 17, 2004)

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for publication and is not binding precedent of the Board.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. 21
UNITED STATES PATENT AND TRADEMARK OFFICE
____________
BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
____________
Ex parte STEVEN KIRK BOWLING
____________
Appeal No. 2004-1741
Application No. 09/466,440
____________
ON BRIEF
____________
Before CAROFF, KIMLIN, and PAWLIKOWSKI, Administrative Patent
Judges.
CAROFF, Administrative Patent Judge.
DECISION ON APPEAL
This is a decision on appeal from the examiner’s final
rejection of claims 1-26, all the claims pending in appellant’s
application.
The claims on appeal relate to a method for selectively
etching a substrate having a tungsten silicide layer with a plasma
Appeal No. 2004-1741
Application No. 09/466,440
1 The examiner asserts that the copy of the appealed claims
appearing in the Appendix to the brief is correct, the claims
appearing in the Appendix corresponding to the claims as amended
in appellant’s response filed on April 4, 2002 (Paper No. 13).
Although the amendment apparently was not properly entered in the
application file, we will consider the claims as they appear in
the Appendix to the brief. The examiner should make sure the
aforementioned amendment is correctly entered.
2
generated from a mixture of SF6, HBr, He, and a chlorine containing
gas.1
Appellant stipulates that all of the claims stand or fall
together (brief-page 3). Accordingly, we will limit our
consideration to claim 1, the first of four independent claims.
Claim 1 reads as follows:
1. A method for selectively etching a substrate having a tungsten
silicide layer with a resist material on portions of the tungsten
silicide layer, the method comprising:
introducing a process gas comprising SF6, HBr, He, and a
chlorine containing gas onto the substrate, the volumetric flow
ratio of SF6:HBr ranging from about 1:0.95 to about 1:1.85, the
volumetric flow ratio of SF6:He ranging from about 1:3.95 to about
1:7.69; the volumetric flow ratio of SF6:chlorine containing gas
ranging from about 1:0.68 to about 1:1.46; and
generating a plasma to form an etch gas from the process gas,
wherein the etch gas selectively etches the tungsten silicide layer
on the substrate.
The references of record relied upon by the examiner on appeal
are:
Cheung et al. (Cheung) 5,354,417 Oct. 11, 1994
Kun-Yu et al. (Kun-Yu) 6,117,755 Sept. 12, 2000
Appeal No. 2004-1741
Application No. 09/466,440
2A previous rejection under the first paragraph of 35 U.S.C.
§ 112 is no longer maintained in the examiner’s answer and,
therefore, presumably has been withdrawn by the examiner.
3
Claims 1-26 stand rejected under 35 U.S.C. § 103 for
obviousness in view of Cheung taken in combination with Kun-Yu.
Claims 1, 10 and 24 also are rejected under 35 U.S.C. § 103
based upon Cheung alone.2
Based upon the record before us, we agree with the appellant
that the examiner has failed to establish a prima facie case of
obviousness. Accordingly, we reverse the rejections applied by the
examiner.
The examiner’s case fails on two accounts. First of all, the
process gas employed by Cheung does not include all four of the
gases recited in appellant’s claims. The claims require a
combination of SF6, HBr, He, and a chlorine containing gas; whereas,
at most, Cheung employs a combination of SF6, HBr, and an oxygen
containing gas to etch a silicide layer. While Cheung (Table III;
Example 14) does refer to He and chlorine, those two gases are
mentioned, along with HBr, only with reference to a second
“overetch” step for etching an underlying polysilicon layer below
the silicide layer.
Appeal No. 2004-1741
Application No. 09/466,440
4
Second, as noted by appellant, the examiner has not
established that those of ordinary skill in the art would have a
reasonable expectation that a prior art process (Cheung) for
etching a molybdenum silicide layer with a particular combination
of gases could be successfully utilized to etch a tungsten silicide
layer. The fact that molybdenum and tungsten silicide are used
alternatively in the manufacture of semiconductor devices (Kun-Yu)
does not establish an equivalence for the purpose of etching layers
of those materials.
Applying an “obvious to try” standard is not a sufficient
basis for establishing obviousness under 35 U.S.C. § 103. Here,
the examiner has failed to establish, by resort to either objective
evidence or sound technical reasoning, that there would have been a
reasonable expectation of success in applying a particular process
for etching molybdenum silicide to selectively etch a tungsten
silicide layer on a substrate.
For the foregoing reasons, the decision of the examiner is
reversed.
Appeal No. 2004-1741
Application No. 09/466,440
5
REVERSED
MARC L. CAROFF )
Administrative Patent Judge )
)
)
)
) BOARD OF PATENT
EDWARD C. KIMLIN ) APPEALS
Administrative Patent Judge ) AND
) INTERFERENCES
)
)
)
BEVERLY A. PAWLIKOWSKI )
Administrative Patent Judge )
MLC/lp
Appeal No. 2004-1741
Application No. 09/466,440
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CORPORATE PATENT COUNSEL
PHILIPS NORTH AMERICA CORPORATION
580 WHITE PLAINS ROAD