Ex parte WEI

Board of Patent Appeals and Interferences

Jan 21, 1998

07769185 (B.P.A.I. Jan. 21, 1998)

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(2) is not binding precedent of the Board.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. 31
UNITED STATES PATENT AND TRADEMARK OFFICE
_______________
BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
_______________
Ex parte CHE-CHIA WEI
_______________
Appeal No. 95-2928
Application 07/769,1851
_______________
HEARD: Jan. 13, 1998
_______________
Before KRASS, JERRY SMITH, and FLEMING, Administrative
Patent Judges.
KRASS, Administrative Patent Judge.
DECISION ON APPEAL
This is a decision on appeal from the final
rejection of claims 18 through 38. Claims 1 through 17
stand withdrawn as being directed to a nonelected
invention.
The invention pertains to improvements in integrated
circuit FET structures. More particularly, the invention
employs HALO and LDD diffusions near the transistor
Appeal No. 95-2928
Application No. 07/769,185
2
channels, where they perform their useful function of
solving the hot electron effect problem, as was known in
the prior art. Additionally, however, the HALO implant
is excluded from other portions of the active regions
such that junction capacitances are lowered in those
regions, resulting in faster switching speed.
Representative independent claim 18 is reproduced as
follows:
18. A field effect transistor for an integrated
circuit device, comprising:
a substrate region having a first conductivity type;
a gate electrode over said substrate region;
lightly doped drain regions in said substrate region
adjacent said gate electrode, said lightly doped drain
regions having a second conductivity type;
heavily doped source/drain regions having the second
conductivity type in said substrate region adjacent said
lightly doped drain regions; and
halo regions having the first conductivity type
within said substrate region adjacent said gate electrode
and extending a relatively short distance into said
source/drain regions, wherein those portions of said
source/drain regions which are spaced further from said
gate electrode than the relatively short distance do not
contain the first conductivity type dopant used to form
the halo regions.
The examiner relies on the following references:
Liou et al. (Liou) 4,771,014 Sep. 13, 1988
Bergonzoni 4,968,639 Nov. 6, 1990

1 Application for patent filed September 30, 1991.
Appeal No. 95-2928
Application No. 07/769,185
3
Lineback, J.R., “Triple Diffusion Doubles RAM Speed”,
Electronics, pp. 54, 61, (1983).
Claims 18 through 38 stand rejected under 35 U.S.C.
' 103. As evidence of obviousness, the examiner cites
Bergonzoni and Liou in view of Lineback.2
Reference is made to the briefs and answer for the
respective positions of appellant and the examiner.
OPINION
We have carefully considered the evidence before us,
including, inter alia, the arguments of appellant and the
examiner, the declarations of Dr. James Cunningham and
the applied references and we conclude therefrom that the
instant claimed subject matter would not have been

2 Because of a reference to a patent to Cham in the
examiner’s communication of February 9, 1995 (Paper No.
18), appellant questioned, in the supplemental reply
brief of March 9, 1995 (Paper No. 20) whether a new
ground of rejection , relying on Cham, was possibly being
applied. However, the examiner made clear, in Paper No.
22, of April 17, 1995, that no new ground of rejection is
made and that Cham was referenced only to show that
masked implants were known in the art even though, in the
examiner’s view, “the method of masked implantation used
as evidence by Appellant in the Declaration and the Reply
Brief is not at issue here, only the structure claimed”
[Paper No. 18]. Accordingly, Cham is not relied upon by
Appeal No. 95-2928
Application No. 07/769,185
4
obvious, within the meaning of 35 U.S.C. ' 103, based on
such evidence.
Taking independent claim 18 as exemplary
(independent claims 23 and 31 include similar, but not
exact, language), the limitation of particular interest
herein is
wherein those portions of said source/drain
regions which are spaced further from said gate
electrode than the relatively short distance do
not contain the first conductivity type dopant
used to form the halo regions.
Both parties agree that neither of the Bergonzoni or
Liou references discloses or suggests that the halo
regions should be formed only in the area adjacent the
gate electrode since the halo region 13’ in Bergonzoni
appears to underlie all portions of n+ drain region 31
and LDD region 19’ while, in Liou, nothing appears to
suggest that the halo region be restricted to the gate
electrode area.
The examiner relies on Lineback, specifically the
figure at the top right on page 54, to show that it was
known to establish a halo region, shown with conductivity
p around the gate electrode region while the remainder of
the source and drain regions, heavily doped n+ regions,

the examiner and will not be considered by us in the
Appeal No. 95-2928
Application No. 07/769,185
5
do not contain any of the p-conductivity type dopant used
to form the halo regions.
Appellant disputes the examiner’s interpretation of
Lineback and contends, via arguments and the Cunningham
declarations, that there is no suggestion in Lineback
that the dopants which make up the halo regions would be
excluded from the rest of the source/drain area and that
there is no suggestion anywhere in Lineback that a masked
halo or LDD implant, which would exclude such diffusions
from most of the source/drain area, should be used.
Appellant further contends [page 4, principal brief] that
the Lineback drawing does not show the extent of the halo
diffusion inside the n+ source/drain area “because the n+
diffusion is deeper and heavier and would swamp the
dopant” of the halo diffusion.
We see no problem making the combination of Lineback
with the teachings of Bergonzoni and Liou, the motivation
being provided by the advantages taught by Lineback for
his structure, even if the purpose was not for
appellant’s purpose. The problem we do find, however, is
that even if we combine the teachings of these
references, the combination does not result in the

decision herein.
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Application No. 07/769,185
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claimed subject matter because Lineback does not clearly
suggest that the further spaced apart portions of the
source/drain regions do not contain the first
conductivity type dopant used to form the halo regions.
The instant claims are drawn to structure, rather
than to a method of fabricating the structure and, so,
normally, we would not be concerned with a mask
implantation step which results in the claimed structure
where the step apparently forms no part of the claim and
the prior art apparently discloses the same structure.
Determination of patentability in “product-by-process”
claims is based on the product itself, even though the
claims may be limited and defined by a process, and thus
the product in such claims is unpatentable if it is the
same as, or obvious from, a product of the prior art,
even if the prior product was made by a different
process. In re Thorpe, 777 F.2d 695, 697, 227 USPQ 964,
966 (Fed. Cir. 1985).
However, the claims before us recite a specific
characteristic of the structure, i.e., that the portions
of the source/drain regions which are spaced further from
the gate electrode do not contain the first conductivity
type dopant used to form the halo regions. This
Appeal No. 95-2928
Application No. 07/769,185
7
characteristic is brought about because of the masking
implantation steps of the process of making the claimed
structure. If the structure of Lineback can be shown to
possess this characteristic, even if not brought about
through a similar process, then we would agree with the
examiner as to the obviousness of the claimed subject
matter.
While, at first blush, the structure of Lineback
appears to show the claimed limitation, since no p-
conductivity type dopant is shown within the heavily
doped n+ regions constituting the source/drain regions,
in our view, appellant has made a cogent case, through
argument and the Cunningham declarations, for the
proposition that it was conventional not to mask the halo
or LDD implants. If it was conventional not to so mask
these implants, then, in the absence of a specific
teaching to the contrary by Lineback, it would appear
reasonable to us, on weighing the arguments of appellant
and the examiner, that Lineback did not
contemplate making the disclosed structure in any manner
other than the conventional manner, i.e., without masking
the halo and LDD implants.
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Application No. 07/769,185
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Accordingly, while the examiner has presented a
well-written answer, clearly setting forth a not
unreasonable rationale for a finding of obviousness,
since the examiner has pointed to nothing but the general
drawing in Lineback to suggest that Lineback’s structure
has the claimed property of certain portions of the
source/drain regions not containing the first
conductivity type dopant used to form the halo regions
and there is nothing in Lineback’s descriptive portion to
indicate that the structure was formed in any particular
manner which would have necessarily resulted in a
structure having the claimed characteristics, on balance,
we find ourselves in agreement with appellant that the
claimed subject matter would not have been obvious within
the meaning of 35 U.S.C. ' 103.
Appeal No. 95-2928
Application No. 07/769,185
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The examiner’s decision rejecting claims 18 through
38 under 35 U.S.C. ' 103 is reversed.
REVERSED
Errol A. Krass )
Administrative Patent Judge )
)
)
)
Jerry Smith ) BOARD OF
PATENT
Administrative Patent Judge ) APPEALS AND
) INTERFERENCES
)
)
Michael R. Fleming )
Administrative Patent Judge )
Appeal No. 95-2928
Application No. 07/769,185
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Richard K. Robinson
SGS-Thomson Microelectronics, Inc.
1310 Electronics Dr.
Carrollton, TX 75006