Ex parte Ferla et al.

Board of Patent Appeals and Interferences

Jul 24, 2001

08811363 (B.P.A.I. Jul. 24, 2001)

1
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and is not binding precedent of the Board.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. 16
UNITED STATES PATENT AND TRADEMARK OFFICE
_____________
BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
_____________
Ex parte GIUSEPPE FERLA and FERRUCCIO FRISINA
_____________
Appeal No. 1999-2578
Application No. 08/811,363
______________
ON BRIEF
_______________
Before KRASS, JERRY SMITH and LALL, Administrative Patent Judges.
KRASS, Administrative Patent Judge.
DECISION ON APPEAL
This is a decision on appeal from the final rejection of claims 19-34.
The invention is directed to a high density power device. More particularly, a
process is disclosed which is said to allow higher scales of integration in power
MOSFETS. The process for manufacturing such power MOSFETS includes an
implantation mask for the source regions which coincides with the implantation mask
Appeal No. 1999-2578
Application No. 08/811,363
2
for the channel regions and for the deep body regions of elementary functional units. This
is made possible by implanting dopant along directions tilted at angles ranging from 0 to
60 degrees with respect to a direction orthogonal to the surface of the material wherein the
dopant is to be implanted. Consequently, the tolerance on the dimension of the source
regions is not determined by the mask alignment rules, but substantially by the tolerance of
thicknesses of three layers (gate oxide, polysilicon oxide, insulating oxide), which is at
least one order of magnitude lower. Therefore, the dimension of the source region is more
finely controlled and narrower elementary functional units can be formed.
Representative independent claim 19 is reproduced as follows:
19. A high-density MOS-technology power device integrated structure
comprising a plurality of elementary functional units formed in a
semiconductor material layer of a first conductivity type covered by a
conductive insulated gate layer sandwiched between two insulating layers,
wherein each elementary functional unit comprises:
an elongated window formed in said insulated gate layer and in said
two insulating layers, having two elongated edges and two short edges, said
edges being sealed by insulating material sidewall spacers;
a heavily doped elongated deep body region of a second conductivity
type formed in the semiconductor material layer and substantially aligned
with the edges of the window;
two elongated channel regions of the second conductivity type
formed in said semiconductor material layer and extending along the
elongated edges of said window; and
two elongated source regions of the first conductivity type formed in
Appeal No. 1999-2578
Application No. 08/811,363
3
the deep body region along said elongated edges of the window so as not to
extend under the insulated gate layer.
The examiner relies on the following reference:
Korman et al. [Korman] 5,119.153 Jun 02, 1992
Claims 19-34 stand rejected under 35 U.S.C. § 112, first paragraph, as relying on
an inadequate written description. In particular, the examiner contends that there is no
written description, i.e. no support in the originally filed disclosure, for “so as not to extend
under the insulated gate layer” in claim 19, and for “not under the gate electrode structure”
in claim 28.
Claims 19-34 stand further rejected under 35 U.S.C. § 103 as unpatentable over
Korman.
Reference is made to the brief and the answer for the respective positions of
appellants and the examiner.
OPINION
In accordance with appellants’ grouping of the claims, at page 7 of the brief, all
claims will stand or fall together.
We turn our attention first to the rejection of all the claims under 35 U.S.C.
§ 112, first paragraph. It is the examiner’s position that in accordance with instant Figure 5
and page 8 of the specification, source regions are formed by dopants
Appeal No. 1999-2578
Application No. 08/811,363
4
implanted at an angle of 60 degrees. The examiner contends that at this angle, “it appears
that source regions are extended below the gate layer although the drawings do not clearly
show the extended portion under the gate layer. Note that the specification is completely
silent whether the source region is extended under the gate layer or not” [answer-page 4].
Within the confines of the written description requirement of 35 U.S.C. § 112, all that
must be shown is that an applicant had possession of the claimed subject matter at the
time of originally filing the patent application. Vas-Cath Inc. v. Mahurkar, 935 F.2d 1555,
1563, 1564, 19 USPQ2d 1111, 1117 (Fed. Cir. 1991).
It is clear to us, from original pages 8-9 and Figures 5-8 of the instant disclosure,
that there are implantations at four different angles, A1-A4, with the implantation angles A1
and A2 directed to implantation of N-type dopants which are not meant to penetrate under
the gate layer, and implantation angles A3 and A4 directed to implantation of dopants
which are meant to penetrate under edges 17 of windows 15. These are two
different processes meant to achieve different results, but as far as the instant independent
claims are concerned, there is clear support for the recitations of source regions formed
“so as not to extend under the insulated gate layer” (claim 19) or formed “not under the
gate electrode structure” (claim 28). We agree with appellants’ explanation at page 8 of
the brief and we adopt such explanation as our own in reversing the rejection of claims 19-
34 under 35 U.S.C. § 112, first paragraph.
Appeal No. 1999-2578
Application No. 08/811,363
5
We turn, now, to the rejection of claims 19-34 under 35 U.S.C. § 103 as
unpatentable over Korman.
At the outset, we note that while the statement of rejection relies only on the Korman
reference, the examiner appears to rely, at least in part, on U.S. Patent No. 5,606,191 to
Wang. See the examiner’s reference to Figure 15 of Wang, at page 6 of the answer, in
responding to appellants’ arguments. We will not consider the Wang reference since there
would appear to be no excuse for not including Wang in the statement of rejection if the
examiner intended to rely on this reference as a basis for the rejection. In re Hoch, 428
F.2d 1341, 1342, 166 USPQ 406, 407 (CCPA 1970).
The examiner’s position is that Korman discloses a power MOSFET (Figure 1)
having a conductive insulated gate layer 132, an elongated window having two elongated
edges and two short edges, side wall spacers 142, heavily doped elongated
deep body regions 119, two elongated channel regions under the gate layer and two
elongated source regions 120. The examiner baldly concludes therefrom, that it “would
have been obvious that Korman teaches the claimed device” [answer-page 5].
Interestingly enough, the examiner points to no difference between the disclosure of
Korman and the instant claimed subject matter. While an anticipatory reference is also
proper under 35 U.S.C. § 103, as anticipation is the epitome of
Appeal No. 1999-2578
Application No. 08/811,363
6
obviousness, one wonders why the examiner did not apply the rejection, based on
35 U.S.C. § 102 if the examiner truly believes that there are no differences between the
instant claimed subject matter and that disclosed by Korman.
Unfortunately, in the answer, the examiner never comes to grips with the specific
claimed limitations relating to the source regions formed “so as not to extend under the
insulated gate layer” (claim 19) and formed “not under the gate electrode structure” (claim
28). Clearly, in Korman, source regions 120 (Figure 1) do extend under the insulated gate
electrode 131. The source regions in Korman do not appear to be aligned as in the instant
claimed invention and the examiner has pointed to nothing in Korman to suggest that the
artisan would have been led to align the source regions with the gate electrode structure.
The reason the examiner ignores the claim limitations relating to the source region
being “not under the gate electrode structure” may be because, in the examiner’s view,
there is no support for these limitations. We note the statement of the examiner’s rationale
for the rejection, at page 4 of the answer: the claims are rejected “insofar as understood.”
If the claims were not fully understood, the examiner should have considered a rejection
based on the second paragraph of 35 U.S.C. § 112. But if a prior art rejection is to be
applied to the claims, that rejection should address each
and every claim limitation, ignoring no limitation because it is not understood or because
there is allegedly no support for it.
Appeal No. 1999-2578
Application No. 08/811,363
7
We will not sustain the rejection of claims 19-34 under 35 U.S.C. § 103 since the
examiner has not addressed each and every claim limitation and, hence, has failed to
establish a prima facie case of obviousness with regard to the instant claimed subject
matter.
We have not sustained the rejection of claims 19-34 under either 35 U.S.C.
§ 112, first paragraph, or 35 U.S.C. § 103.
Accordingly, the examiner’s decision is reversed.
REVERSED
ERROL A. KRASS )
Administrative Patent Judge )
)
)
)
) BOARD OF PATENT
JERRY SMITH ) APPEALS
Administrative Patent Judge ) AND
) INTERFERENCES
)
)
)
PARSHOTAM S. LALL )
Administrative Patent Judge )
eak/vsh
Appeal No. 1999-2578
Application No. 08/811,363
8
JAMES H. MORRIS
WOLF, GREENFIELD & SACKS
600 ATLANTIC AVENUE
BOSTON, MA 02210