Ex parte Ikeda

Board of Patent Appeals and Interferences

Feb 27, 1998

07873150 (B.P.A.I. Feb. 27, 1998)

Application for patent filed April 24, 1992.1
-1-
THIS OPINION WAS NOT WRITTEN FOR PUBLICATION
The opinion in support of the decision being entered
today (1) was not written for publication in a law
journal and (2) is not binding precedent of the Board.
Paper No. 18
UNITED STATES PATENT AND TRADEMARK OFFICE
________________
BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
________________
Ex parte RIKIO IKEDA
________________
Appeal No. 95-0589
Application 07/873,1501
________________
HEARD: February 6, 1998
________________
Before CAROFF, KIMLIN and JOHN D. SMITH, Administrative Patent
Judges.
KIMLIN, Administrative Patent Judge.
DECISION ON APPEAL
This is an appeal from the final rejection of claims 1-11,
all the claims in the present application. Claim 1 is
illustrative:
Appeal No. 95-0589
Application 07/873,150
-2-
1. A method of manufacturing a phase-shifting mask having a
light shielding portion, a light permeation portion and a phase-
shifting portion on a transparent substrate, wherein the method
comprises:
forming a negative resist layer over the entire surface of
the transparent substrate formed with a light shielding material
pattern,
applying exposure through the rearface of the transparent
substrate and development to leave the negative resist layer on
the light permeation portion,
etching back said negative resist layer to form a sub-space
between the negative resist layer and the light shielding portion
and using said negative resist layer as a phase-shifting portion.
The examiner relies upon the following reference as evidence
of obviousness:
Okamoto 5,045,417 Sept. 3, 1991
Appellant's claimed invention is directed to a method of
making a phase-shifting mask. The mask comprises a light
shielding portion and a light permeation portion on a transparent
substrate. According to appellant, a "basic feature" of the
claimed photolithographic method is exposing the resist through
the rear surface of the substrate, wherein light shielding
portions on the substrate are used as the exposure mask (page 7
of appellant's principal Brief, last sentence).
Appealed claims 1-11 stand rejected under 35 U.S.C. § 103 as
being unpatentable over Okamoto.
Appeal No. 95-0589
Application 07/873,150
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Upon thorough review of the opposing arguments presented by
appellant and the examiner, we agree with appellant 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.
It is well settled that the initial burden of establishing a
basis for denying patentability to a claimed invention rests upon
the examiner. In re Fine, 837 F.2d 1071, 1074, 5 USPQ2d 1596,
1598 (Fed. Cir. 1988). In rejecting claims under 35 U.S.C.
§ 103, it is incumbent upon the examiner to establish a factual
basis to support the legal conclusion of obviousness. Id. at
1074, 5 USPQ2d at 1598; In re Warner, 379 F.2d 1011, 1017, 154
USPQ 173, 178 (CCPA 1967). In so doing, the examiner is required
to provide a reason why one having ordinary skill in the art
would have been led to modify a prior art reference to arrive at
the claimed invention. The requisite motivation must stem from
some teaching, suggestion or inference in the prior art as a
whole or from knowledge generally available to one having
ordinary skill in the art. Uniroyal, Inc. v. Rudkin-Wiley Corp.,
837 F.2d 1044, 1050-52, 5 USPQ2d 1434, 1438-40 (Fed. Cir. 1988).
In the present case, the examiner concedes that although
Okamoto discloses a phase-shifting mask having a sub-space
between the light shielding portion and the phase-shifting
Appeal No. 95-0589
Application 07/873,150
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portion, the reference does not disclose the claimed method for
obtaining the mask. However, the examiner concludes "[i]t would
have been obvious to one of ordinary skill in the art to use any
art-recognized mask manufacturing method to produce sub-space
regions because of the expected results of such resist exposure
and etching methods being used to produce a known phase-shifting
mask" (page 3 of Answer, emphasis added).
The fundamental error in the examiner's rejection is that no
factual evidence is relied upon to establish the obviousness of
the specifically claimed method steps. Undoubtedly, each of the
claimed steps, individually, was known in the photolithographic
arts at the time of filing the present invention. However, that
each individual step was known is not sufficient to establish a
prima facie case of obviousness for the particularly claimed
manipulative steps of forming a phase-shifting mask. Stated
otherwise, the examiner has presented no evidence that it was
known in the art to manufacture a phase-shifting mask by the
claimed photolithographic steps. For instance, the processes
disclosed by Okamoto and the Nitayama publication for forming
phase-shifting masks are different than the claimed method,
although they include known photolithographic steps.
Appeal No. 95-0589
Application 07/873,150
-5-
In conclusion, based on the insufficient prior art evidence
presented by the examiner, we are constrained to reverse the
examiner's rejection.
REVERSED
MARC L. CAROFF )
Administrative Patent Judge )
)
)
)
EDWARD C. KIMLIN ) BOARD OF PATENT
Administrative Patent Judge ) APPEALS AND
) INTERFERENCES
)
)
JOHN D. SMITH )
Administrative Patent Judge )
Appeal No. 95-0589
Application 07/873,150
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