Ex Parte Ohtani

Board of Patent Appeals and Interferences

Jul 29, 2003

08995368 (B.P.A.I. Jul. 29, 2003)

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written for publication and is not binding precedent of the Board.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. 34
UNITED STATES PATENT AND TRADEMARK OFFICE
____________
BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
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Ex parte HISASHI OHTANI
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Appeal No. 2003-0751
Application No. 08/995,368
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HEARD: July 15, 2003
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Before PAK, WARREN and KRATZ, Administrative Patent Judges.
KRATZ, Administrative Patent Judge.
DECISION ON APPEAL
This is a decision on appeal from the examiner's refusal to
allow claims 15-17, 24 and 25. Claims 2, 4, 18, 19 and 21-23
have been indicated as allowable by the examiner. Claims 5-14,
which are all of the remaining claims pending in this
application, stand withdrawn from further consideration by the
examiner as drawn to a non-elected invention.
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Application No. 08/995,368
Page 2
BACKGROUND
Appellant's invention relates to a method of manufacturing a
semiconductor device wherein a polishing step is performed on a
substrate surface. Subsequently, an amorphous silicon
semiconductor film is formed thereon. The latter film formation
step is followed by crystallization and patterning steps. The
polishing step is carried out such that the root mean square of
the substrate surface roughness is smaller than the semiconductor
film thickness. An understanding of the invention can be derived
from a reading of exemplary claim 15, which is reproduced below.
15. A method of manufacturing a semiconductor device
comprising the steps of:
polishing a surface over a substrate;
forming an insulating film comprising silicon oxide
over the polished substrate;
forming a semiconductor film comprising amorphous
silicon over said insulating film;
crystallizing the semiconductor film by heating; and
patterning the crystallized semiconductor film to form
an active layer,
wherein the surface over said substrate is polished so
that a root mean square of a surface roughness of said
surfaces is smaller than a thickness of the semiconductor
film and a density of projection on said surface is 100
pieces/cm2 or less.
The prior art references of record relied upon by the
examiner in rejecting the appealed claims are:
Zhang et al. (Zhang) 5,403,772 Apr. 04, 1995
Appeal No. 2003-0751
Application No. 08/995,368
Page 3
Ohtani et al. (Ohtani) 5,923,962 Jul. 13, 1999
Claims 15-17 stand rejected under 35 U.S.C. § 103(a) as
being unpatentable over Zhang. Claims 24 and 25 stand rejected
under 35 U.S.C. § 103(a) as being unpatentable over Zhang in view
of Ohtani.
We refer to the brief and reply brief and to the answer for
a complete exposition of the opposing viewpoints expressed by
appellant and the examiner concerning the issues before us on
this appeal.
OPINION
Upon careful review of the respective positions advanced by
appellant and the examiner with respect to the rejections that
are before us for review, we find ourselves in agreement with
appellant’s position in that the examiner has failed to carry the
burden of establishing a prima facie case of obviousness with
respect to either of the stated rejections. See In re Oetiker,
977 F.2d 1443, 1445, 24 USPQ2d 1443, 1444 (Fed. Cir. 1992); In re
Piasecki, 745 F.2d 1468, 1471-1472, 223 USPQ 785, 787-788 (Fed.
Cir. 1984). Accordingly, we will not sustain the examiner's
rejections.
Appeal No. 2003-0751
Application No. 08/995,368
Page 4
In an attempt at establishing the obviousness of the claimed
method, the examiner asserts that “it is well within the ordinary
skill of the art to polish the substrate to a high degree of
smoothness” and that “it would have been obvious to one of
ordinary skill in the art to determine through routine
experimentation the optimum, operable surface roughness and
thickness in the Zhang et al reference in order to create a
uniform crystallized silicon layer” (answer, page 3).
However, the examiner has not established where either of
the applied references describe or suggest a substrate polishing
step prior to the formation of an amorphous silicon film on the
surface, let alone a polishing step conducted so as to achieve
the surface roughness as here claimed as a preliminary step in
forming a semiconductor device. Polishing may be a generally
known step as examiner as acknowleged by appellant. However,
the examiner has not established that the here claimed polishing
step, conducted as part of a semiconductor manufacturing method
in the manner and to the extent as set forth in the appealed
claims would have been obvious to one of ordinary skill in the
art based on the evidence put forward by the examiner.
Concerning this matter, it is well settled that the mere
fact that the prior art may be modified to reflect features of
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Application No. 08/995,368
Page 5
the claimed invention does not make the modification obvious
unless the desirability of such modification is suggested by the
applied prior art. See In re Fritch, 972 F.2d 1260, 1266, 23
USPQ2d 1780, 1784 (Fed. Cir. 1992). Accordingly, on this record,
the rejections fail for lack of a sufficient factual basis upon
which to reach a conclusion of obviousness. In re Fine, 837 F.2d
1071, 1073-74, 5 USPQ2d 1596, 1598 (Fed. Cir. 1988).
CONCLUSION
On this record, the decision of the examiner to reject
claims 15-17 under 35 U.S.C. § 103(a) as being unpatentable over
Zhang and to reject claims 24 and 25 under 35 U.S.C. § 103(a) as
being unpatentable over Zhang in view of Ohtani is reversed.
REVERSED
CHUNG K. PAK )
Administrative Patent Judge )
)
)
)
) BOARD OF PATENT
CHARLES F. WARREN ) APPEALS
Administrative Patent Judge ) AND
) INTERFERENCES
)
)
Appeal No. 2003-0751
Application No. 08/995,368
Page 6
)
PETER F. KRATZ )
Administrative Patent Judge )
Appeal No. 2003-0751
Application No. 08/995,368
Page 7
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