Ex parte Sandaresan

Board of Patent Appeals and Interferences

Nov 8, 1999

08350504 (B.P.A.I. Nov. 8, 1999)

Application for patent filed December 6, 1994. Accord-1
ing to appellant, the application is a continuation of Appli-
cation 08/254,286, filed June 6, 1994, abandoned; which is a
continuation of Application 07/752,863, filed August 30, 1991,
abandoned.
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(2) is not binding precedent of the Board.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. 29
UNITED STATES PATENT AND TRADEMARK OFFICE
_____________
BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
_____________
Ex parte RAVISHANKAR SANDARESAN
_____________
Appeal No. 1997-0515
Application 08/350,5041
______________
ON BRIEF
_______________
Before JERRY SMITH, BARRETT and FLEMING, Administrative Patent
Judges.
FLEMING, Administrative Patent Judge.
DECISION ON APPEAL
Appeal No. 1997-0515
Application 08/350,504
2
This is a decision on appeal from the final rejec-
tion of claims 10 and 14 through 16, all the claims pending in
the present application. Claims 1 through 9 were withdrawn as
directed to a non-elected invention. Claims 11 through 13
have been cancelled.
The invention relates to a transistor suitable for
use in integrated circuits having small feature sizes. In
particular, Appellant discloses on page 8 of the specification
that figure 4 shows the invention. Figure 4 shows a structure
having a moderately doped region 14 and an epitaxial layer 16
used to form a self-aligned, lightly doped drain (LDD) struc-
ture. Sidewall oxide regions 26 are then formed alongside the
gate electrode 20 followed by implant of the heavily doped
source/drain regions 28.
Independent claim 10 is reproduced as follows:
10. An integrated circuit device, comprising:
a substrate having a doped region therein, said
doped region having a first doping level;
an epitaxial silicon region overlying the doped
substrate region, said epitaxial silicon region having a
second doping level that is less than said first doping level;
Appeal No. 1997-0515
Application 08/350,504
3
a gate insulating layer and gate electrode overlying
the epitaxial silicon region, wherein a channel region is
formed under the gate electrode in said epitaxial silicon
region;
sidewall insulating regions disposed alongside said
gate electrode;
lightly doped source/drain regions in said epitaxial
silicon region and said substrate underneath said sidewall
insulating regions and adjacent the channel region;
highly doped source/drain regions in said doped
substrate region and said epitaxial silicon region adjacent
the lightly doped source/drain regions, each of said highly
doped source/drain regions extending from an upper surface of
said epitaxial silicon region into said doped substrate re-
gion; and
a threshold adjust impurity region within the chan-
nel region.
The Examiner relies on the following references:
Kotani et al. (Kotani) 4,242,691 Dec. 30, 1980
Shibata et al. (Shibata) 4,939,386 July 3, 1990
Nakada et al. (Nakada) 60-235471 Nov. 22, 1985
(Japanese Kokai)
Claims 10 and 14 through 16 stand rejected under
35 U.S.C. § 103 as being unpatentable over Kotani in view of
Nakada and Shibata.
Appeal No. 1997-0515
Application 08/350,504
Appellant filed an appeal brief on June 3, 1996. Appel-2
lant filed a reply brief on October 29, 1996. The Examiner
mailed a communication on August 12, 1998 stating that the
reply brief has been entered and considered.
4
Rather than reiterate the arguments of Appellant and
the Examiner, reference is made to the briefs and answer for2
the respective details thereof.
OPINION
We will not sustain the rejection of claims 10 and
14 through 16 under 35 U.S.C. § 103.
The Examiner has failed to set forth a prima facie
case. It is the burden of the Examiner to establish why one
having ordinary skill in the art would have been led to the
claimed invention by the express teachings or suggestions
found in the prior art, or by implications contained in such
teachings or suggestions. In re Sernaker, 702 F.2d 989, 995,
217 USPQ 1, 6 (Fed. Cir. 1983). "Additionally, when determin-
ing obviousness, the claimed invention should be considered as
a whole; there is no legally recognizable 'heart' of the
invention." Para-Ordnance Mfg. v. SGS Importers Int'l, Inc.,
Appeal No. 1997-0515
Application 08/350,504
5
73 F.3d 1085, 1087, 37 USPQ2d 1237, 1239 (Fed. Cir. 1995),
cert. denied, 519 U.S. 822 (1996) citing W. L. Gore & Assoc.,
Inc. v. Garlock, Inc., 721 F.2d 1540, 1548, 220 USPQ 303, 309
(Fed. Cir. 1983), cert. denied, 469 U.S. 851 (1984).
On pages 4 and 5 of the brief, Appellant argues that
the three references cited against claim 10 teach alternative
approaches to minimizing the short channel effect. These
alternative approaches are taught as alternatives and cannot
be
combined to result in the claim structure. Appellant argues
that the Examiner has selected various features of these
references out of context to find the claim structure through
hindsight
reconstruction. Appellant argues that there would have been
no incentive to combine the references to produce the claim
structure.
The Federal Circuit states that "[t]he mere fact
that the prior art may be modified in the manner suggested by
the Examiner does not make the modification obvious unless the
Appeal No. 1997-0515
Application 08/350,504
6
prior art suggested the desirability of the modification." In
re Fritch, 972 F.2d 1260, 1266 n.14, 23 USPQ2d 1780, 1783-84
n.14 (Fed. Cir. 1992), citing In re Gordon, 733 F.2d 900, 902,
221 USPQ 1125, 1127 (Fed. Cir. 1984). "Obviousness may not be
established using hindsight or in view of the teachings or
suggestions of the inventor." Para-Ordnance Mfg., 73 F.3d at
1087, 37 USPQ2d at 1239, citing W. L. Gore, 721 F.2d at 1551,
1553, 220 USPQ at 311, 312-313.
Upon our review of the references relied upon by
the Examiner, we fail to find any suggestion or reason to form
the Nakada lightly doped epitaxial layer 3 and the Shibata
sidewalls 13 in the Kotani structure. We note that Kotani
actually teaches a distinct substrate 10 which has a doping
level lower than the epitaxial layer 20. Furthermore, we note
that Appellant claims a substrate having a first doping level
in an
epitaxial silicon region overlying the doped substrate region
having a second doping level that is less than the first
doping level. We fail to find that Nakada or Shibata would
Appeal No. 1997-0515
Application 08/350,504
7
suggest to those skilled in the art to modify Kotani's sub-
strate 10 doping level and the epitaxial layer 20's doping
level. Furthermore, we fail to find that there is any sugges-
tion or teaching to modify Kotani to provide additional
epitaxial layers as suggested by the Examiner. Finally, we
fail to find that there is any suggestion in Shibata to use
the silicon oxide film for sidewalls in Kotani's structure.
We have not sustained the rejection of claims 10 and
14 through 16 under 35 U.S.C. § 103. Accordingly, the
Examiner's decision is reversed.
REVERSED
JERRY SMITH )
Administrative Patent Judge )
)
)
) BOARD OF
PATENT
LEE E. BARRETT ) APPEALS AND
Administrative Patent Judge )
INTERFERENCES
)
)
)
MICHAEL R. FLEMING )
Administrative Patent Judge )
Appeal No. 1997-0515
Application 08/350,504
8
MRF:psb
Appeal No. 1997-0515
Application 08/350,504
9
Richard K. Robinson
SGS-Thomson Microelectronics Inc.
1310 Electronics Drive
MS 2346
Carrollton, TX 75006