Ex Parte Inoue

Board of Patent Appeals and Interferences

May 31, 2005

10095053 (B.P.A.I. May. 31, 2005)

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written for publication and is not binding precedent of the Board.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 MASAO INOUE
_____________
Appeal No. 2005-1065
Application No. 10/095,053
______________
ON BRIEF
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Before CAROFF, PAK and KRATZ, Administrative Patent Judges.
CAROFF, Administrative Patent Judge.
DECISION ON APPEAL
This decision on appeal relates to appellant’s claims 1-5
which have been thrice-rejected by the examiner. Claims 6-8, all
the other claims in appellant’s involved application, stand
withdrawn from consideration pursuant to the provisions of 37 CFR
§ 1.142(b) and, thus, are not before us.
The claims on appeal are directed to a method of
manufacturing a semiconductor device whereby a gate oxide film is
formed on the surface of a semiconductor substrate. According to
Appeal No. 2005-1065
Application No. 10/095,053
1We note in passing that appellant’s brief and reply brief
erroneously state that it is the oxidation preventive film,
rather that the gate oxide film, which is subject to thinning.
This is clearly not the case, as thoroughly discussed in
appellant’s specification.
2
appellant’s specification (p. 2, l. 24-p. 3, l. 22), the claimed
method provides a gate oxide film of uniform thickness where the
thickness directly above an oxidation preventive film at the top
edge of a trench structure is of the same order as the thickness
of the gate oxide film at other locations along the surface of
the semiconductor substrate. This is said to solve a so-called
“thinning” problem experienced in the prior art.1
Appellant’s brief (page 4) stipulates that the appealed
claims stand or fall together with independent claim 1.
Accordingly, we shall limit our consideration to claim 1 which
reads as follows:
1. A method of manufacturing a semiconductor device
comprising:
a step of forming a trench at a main surface of a
semiconductor substrate;
the step of forming an oxidation preventive film along
an inner wall of said trench;
the step of forming a filling layer so as to fill said
trench; and
Appeal No. 2005-1065
Application No. 10/095,053
3
the step of applying an high oxidation capability on
said main surface of a semiconductor substrate in an
atmosphere in which radicals of at least one kind of
hydrogen radicals and oxygen radicals are generated to
thereby form a gate oxide film on said main surface of a
semiconductor substrate and to oxidize an upper surface of
the oxidation preventive film such that oxidizing speeds on
the oxidation preventive film and the semiconductor
substrate are substantially the same as each other.
The prior art references relied upon by the examiner are:
Admitted Prior Art on pages 1-2 of the instant application.
Toru 10-313114 Nov. 24, 1998
(Published Japanese Patent Application)
Atkins et al. (Atkins), Chemical Principles, pp. 71-2 (W.H.
Freeman and Co., 1999).
Wolf, Silicon Processing For The VLSI Era, Vol. 3: The Submicron
Mosfet, p. 334 (Sunset Beach, CA, Lattice Press, 1995).
All of the appealed claims stand rejected for obviousness
under 35 U.S.C. § 103(a).
To support the rejection of claims 1-2 and 5, the examiner
relies upon the admitted prior art in view of Toru and Atkins.
Claims 3-4 stand rejected on the same basis with additional
reliance upon Wolf.
Based upon the record before us, we find that the examiner
has failed to establish a prima facie case of obviousness.
Accordingly, we shall reverse each of the rejections at issue.
Appeal No. 2005-1065
Application No. 10/095,053
4
As we see it, the examiner’s position is predicated upon the
doctrine of inherency. To wit, in accordance with the examiner’s
reasoning, the conventional technique for forming a gate oxide
film by oxidation involves use of oxygen gas (acknowledged prior
art), and Atkins teaches that oxygen, either in its atomic or
molecular form, is considered to be a radical; more specifically
a biradical. Thus, as stated in the examiner’s answer (pages 10-
11), since the materials and manipulative steps involved in
appellant’s claimed invention appear to be identical to those
embodied in the prior art, the same result must necessarily
occur. That is to say, when the prior art technique is
performed, the upper surface of the oxidation preventive film and
the semiconductor substrate must be oxidized at substantially
the same speed, as in appellant’s invention.
The examiner’s rationale is in line with the body of case
law on inherency exemplified by In re Best, 652 F.2d 1252, 1255,
195 USPQ 430, 433-34 (CCPA 1977). Although there is great force
of logic in the examiner’s position, we nevertheless find that
there is no question of inherency here.
Appeal No. 2005-1065
Application No. 10/095,053
5
In our opinion, claim 1 must be read in light of the
specification (p. 7, ll. 4-13) to give meaning and vitality to
the expression “applying an high oxidation capability.” In so
doing, we take the expression to mean:
. . . [H]ydrogen gas and oxygen gas are separately
introduced into a reaction vessel accommodating wafers to
react with each other directly above the wafers and thereby
generate hydrogen radicals and oxygen radicals, which
generates oxidation with a high capability. [Underlining
added for emphasis.]
Clearly, when the claim language is so interpreted, there is
no question of inherency since neither the admitted prior art
alone, or in combination with any of the other cited references,
teaches or suggests generating hydrogen radicals and oxygen
radicals by separately introducing hydrogen gas and oxygen gas
into a reaction vessel to react with each other directly above
wafers in the vessel to obtain a gate oxide film of uniform
thickness, viz., to oxidize the upper surface of a oxidation
preventive film and the upper surface of a semiconductor
substrate at substantially the same speed.
Appeal No. 2005-1065
Application No. 10/095,053
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In fact, according to appellant’s specification (p. 2, ll.
12-16), in the prior art the oxidation necessary to form a gate
oxide film is effected by introducing hydrogen gas and oxygen gas
into a reaction vessel accommodating wafers after the gases react
with each other, or introducing only oxygen gas into the vessel.
For the foregoing reasons, the decision of the examiner is
reversed.
REVERSED
MARC L. CAROFF )
Administrative Patent Judge )
)
)
) BOARD OF PATENT
CHUNG K. PAK ) APPEALS AND
Administrative Patent Judge ) INTERFERENCES
)
)
)
PETER F. KRATZ )
Administrative Patent Judge )
MLC:hh
Appeal No. 2005-1065
Application No. 10/095,053
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