Ex parte HA et al.

Board of Patent Appeals and Interferences

Feb 27, 2002

08810920 (B.P.A.I. Feb. 27, 2002)

-1-
The opinion in support of the decision being
entered today was not written for publication
in a law journal and is not binding precedent
of the Board.
Paper No. 17
UNITED STATES PATENT AND TRADEMARK OFFICE

BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES

Ex parte JAE HEE HA, DONG HYEN YI
and MYUNG HO YIM

Appeal No. 2000-1848
Application No. 08/810,920

ON BRIEF

Before KIMLIN, KRATZ and PAWLIKOWSKI, Administrative Patent
Judges.
KIMLIN, Administrative Patent Judge.
DECISION ON APPEAL
This is an appeal from the final rejection of claims 1-4,
6-18 and 20, all the claims remaining in the present
application. Claim 1 is illustrative:
1. A method of etching a photoresist layer, comprising
the steps of:
Appeal No. 2000-1848
Application No. 08/810,920
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sequentially forming a layer to be etched and first
photoresist layer on a semiconductor substrate;
sequentially forming an intermediate barrier layer
and second photoresist layer on the first photoresist layer;
patterning the second photoresist layer, and etching
the intermediate barrier layer using the second photoresist
layer patterned as a mask; and
etching the first photoresist layer with a helicon-
type etching apparatus, using only nitrogen gas, using the
patterned intermediate barrier layer as a mask.
The examiner relies upon the following references as
evidence of obviousness:
Higashikawa et al. 4,473,437 Sep. 25, 1984
(Higashikawa)
Katz et al. 5,508,144 Apr. 16, 1996
(Katz)
Appellants' claimed invention is directed to a method of
patterning, via etching, a first photoresist layer through a
patterned intermediate barrier layer. The barrier layer is
patterned by use of a second photoresist layer. Claim 1
recites that the first photoresist layer is etched using only
nitrogen gas with a helicon-type apparatus, whereas claim 11
specifies that the first photoresist layer is patterned by
reactive ion etching in a nitrogen gas atmosphere.
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Application No. 08/810,920
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Appealed claims 1-4, 6-18 and 20 stand rejected under
35 U.S.C. § 103 as being unpatentable over Higashikawa in view
of Katz.
Upon careful consideration of the opposing arguments
presented on appeal, we are in agreement with appellants that
the examiner has failed to establish a prima facie case of
obviousness for the claimed subject matter. Accordingly, we
will not sustain the examiner's rejection.
There is no dispute that Higashikawa discloses a method
of etching a first photoresist layer much like the claimed
method with the exception that Higashikawa does not disclose
the use of a helicon-type etching apparatus for etching with
the nitrogen gas. Since Katz discloses the use of a helicon-
type etching apparatus for patterning a photoresist, the
examiner concludes that it would have been obvious for one of
ordinary skill in the art to use the helicon-type apparatus
disclosed by Katz in the method of Higashikawa.
The flaw in the examiner's reasoning in support of the
legal conclusion of obviousness can be found in the statement
at page 5 of the Answer: "The apparatus of Katz is
functionally equivalent to the apparatus of Higashikawa in
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Application No. 08/810,920
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that both produce a plasma of a gas to etch a substrate." As
urged by appellants, the reactive ion etching process
disclosed in Katz is different than the dry etching process
utilized by Higashikawa. For instance, the reactive ion
etching of Katz is conducted at a low pressure
(1-3 mTorr), whereas the dry etching process of Higashikawa is
performed at relatively high pressures (0.3 Torr). Hence,
since the apparatus and processes of Higashikawa and Katz are
considerably different, it is incumbent upon the examiner to
factually establish that it was known in the art to employ a
helicon-type etching apparatus, or reactive ion etching, in a
process of the type disclosed by Higashikawa which etches the
photoresist in nitrogen gas. This the examiner has not done.
Furthermore, as pointed out by appellants, Katz provides no
teaching or suggestion that the helicon-type etching
apparatus, or reactive ion etching, can be used with an
etching atmosphere of nitrogen. Katz only discloses the use
of oxygen gas as the etching atmosphere. We find no response
by the examiner to appellants' cogent argument that "there is
no suggestion in either reference to use Nitrogen plasma in a
Helicon apparatus to etch a layer, or to use Nitrogen plasma
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Application No. 08/810,920
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in a reactive ion etching process to etch a layer" (page 3 of
Reply Brief, last paragraph).
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Application No. 08/810,920
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In conclusion, based on the foregoing, we are constrained
to reverse the examiner's rejection.
REVERSED
EDWARD C. KIMLIN )
Administrative Patent Judge )
)
)
)
)
PETER F. KRATZ ) BOARD OF PATENT
Administrative Patent Judge ) APPEALS AND
) INTERFERENCES
)
)
)
BEVERLY PAWLIKOWSKI )
Administrative Patent Judge )
ECK:clm
Appeal No. 2000-1848
Application No. 08/810,920
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