Ex Parte Ahmed et al

Board of Patent Appeals and Interferences

Feb 7, 2008

10602061 (B.P.A.I. Feb. 7, 2008)

UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
____________

Ex parte SHIBLY S. AHMED,
HAIHONG WANG,
and BIN YU
____________

Appeal 2007-4186
Application 10/602,061
Technology Center 1700
____________

Decided: February 7, 2008
____________

Before CHARLES F. WARREN, CATHERINE Q. TIMM, and
LINDA M. GAUDETTE, Administrative Patent Judges.

TIMM, Administrative Patent Judge.

DECISION ON APPEAL
Appellants appeal under 35 U.S.C. § 134(a) from the Examiner’s
decision rejecting claims 11-15 and 21-29. We have jurisdiction under
35 U.S.C. § 6(b).
We AFFIRM.

Appeal 2007- 4186
Application 10/602,061

I. BACKGROUND
The invention relates to a method of manufacturing a semiconductor
device, specifically, a double-gate device (Specification ¶ 0001). Claim 11
is illustrative of the subject matter on appeal:
11. A method of manufacturing a semiconductor device, comprising:

forming a fin structure on an insulating layer, the fin structure
including a first side surface, a second surface, and a top surface and having
a thickness ranging from about 300 Å to about 1500 Å;

forming source and drain regions at ends of the fin structure;

depositing a gate material over the fin structure to a thickness ranging
from about 300 Å to about 1500 Å, the gate material surrounding the top
surface and the first and second side surfaces;

etching the gate material to form a first gate electrode and a second
gate electrode on opposite sides of the fin; and

planarizing the deposited gate material proximate to the fin.

Appellants request review of the sole rejection maintained by the
Examiner, namely, the rejection of claims 11-15 and 21-29 under 35 U.S.C.
§ 103(a) over Mathew (US 2003/0151077 A1 published Aug. 14, 2003) in
view of Gambino (US 6,689,650 B2 issued Feb. 10, 2004).1

1 Appellants request review of the rejection of claim 11 even though this
claim is not listed in the Examiner’s statement of rejection. As Appellants
treat this claim as rejected and both Appellants and the Examiner respond to
arguments directed to that claim (Br. 5-10; Ans. 5-7), we include claim 11 in
our review of the rejection.
2
Appeal 2007- 4186
Application 10/602,061

II. DISCUSSION
There is no dispute that Mathew describes a method of manufacturing
a semiconductor device including forming the fin structure, gate material
layer, and other layers required by the claims. Nor is there any dispute that
while Mathew describes forming the same structures and layers of materials
as claimed, Mathew is silent as to the thicknesses of those various structures
and layers.
The Examiner determines that:
[i]t would have been obvious to one of ordinary skill in the art
at the time of the invention to form the gate dielectric or gate
material to the thickness range claimed, to form a working
semiconductor device, since it has been held that where the
general conditions of a claim are disclosed in prior art,
discovering the optimum or working ranges involves only
routine skill in the art. In re Aller, 105 USPQ 233.

(Ans. 4).
Appellants contend that because Mathew does not disclose any
working ranges or values associated with the thicknesses of the variously
disclosed structures and layers, Mathew cannot be fairly construed to
suggest forming those structures and layers to the claimed thicknesses absent
impermissible hindsight (see, e.g., Br. 9).
While Appellants argue various claims separately, the arguments are
such that the issue arising for claims 11, 13-15, 21, 23-26, and 28-29 is
essentially the same for all these claims: Given that Mathew describes
forming a semiconductor device having the fin structure and layers required
by the claims at issue, would it have been within the capabilities of one of
ordinary skill in the art to have performed the experimentation necessary to
3
Appeal 2007- 4186
Application 10/602,061

determine the optimum or workable thicknesses for the fin structure and
layers such that that artisan could form a working semiconductor device?
We answer that question in the affirmative.
“[A] prior art reference must be ‘considered together with the
knowledge of one of ordinary skill in the pertinent art.’” In re Paulsen,
30 F.3d 1475, 1480 (Fed. Cir. 1994). In an obviousness analysis, the proper
focus is on evidence of what was known before the time of invention, and
the analysis must not unduly constrain the breath of knowledge available to
one of ordinary skill in the art. In re Translogic Tech., 504 F.3d 1249, 1260
(Fed. Cir. 2007). An improvement in the art is obvious if “it is likely the
product not of innovation but of ordinary skill and common sense.” KSR
Int’l v. Teleflex Inc., 127 S. Ct. 1727, 1742 (2007). Optimization of a
variable which is recognized in the prior art to be a result effective variable
would ordinarily be within the skill in the art. In re Boesch, 617 F.2d 272,
276 (CCPA 1980); see also In re Aller, 220 F.2d 454, 456 (CCPA 1955)
(“where the general conditions of a claim are disclosed in the prior art, it is
not inventive to discover the optimum or workable ranges by routine
experimentation.”).
In the present case, Mathew describes forming a semiconductor
device having the fin structure and layers required by Appellants’ claims.
The structure and layers have the same functions as those of Appellants’
device. It follows that the fin structure and layers must have some thickness,
although the thickness is not disclosed in the reference. In order to make
and use the semiconductor device, one of ordinary skill in the art would
necessarily have to perform routine experimentation or otherwise determine,
based on common knowledge in the art, the workable or optimal thicknesses
4
Appeal 2007- 4186
Application 10/602,061

which would allow the structures and layers to perform their designated
functions. The fact that Mathew does not disclose the thicknesses of these
structures and layers, supports, rather than detracts from, the Examiner’s
findings and conclusion of obviousness: The omission leads to a
presumption that these thicknesses were readily determinable through
routine experimentation, i.e., it was within the capabilities of those of
ordinary skill in the semiconductor art. The reference does, after all, speak
to those of skill in the art.
It is well settled that the question is not whether the reference
discloses a range for the variable at issue, but whether determining the range
to use was within the capabilities of one of ordinary skill in the art. See In re
Huang, 100 F.3d 135, 139 (Fed. Cir. 1996) (“This court and its predecessors
have long held, however, that even though applicant's modification results in
great improvement and utility over the prior art, it may still not be patentable
if the modification was within the capabilities of one skilled in the art, unless
the claimed ranges 'produce a new and unexpected result which is different
in kind and not merely in degree from the results of the prior art.'" quoting In
re Aller, 220 F.2d 454, 456 (CCPA 1955) and citing In re Woodruff, 919
F.2d 1575, 1578 (Fed. Cir. 1990)).
Appellants further contend that the claimed ranges enable the method
to achieve particular advantages with respect to manufacturing a
semiconductor device, such as advantages associated with good short
channel behavior, citing paragraph 40 of the Specification (Br. 9). However,
we agree with the Examiner that the Specification fails to provide evidence
that good short channel behavior arises due to the use of the claimed
thickness ranges (Ans. 6). Nor do Appellants provide evidence that the
5
Appeal 2007- 4186
Application 10/602,061

“good short channel behavior” would have been unexpected by those of
ordinary skill in the art. “[A]ny superior property must be unexpected to be
considered as evidence of non-obviousness.” Pfizer, Inc. v. Apotex, Inc.,
480 F.3d 1348, 1371 (Fed. Cir. 2007).
Appellants have neither shown that the experimentation for
determining the necessary thicknesses was beyond the capabilities of the
ordinary artisan, nor shown that they obtain an unexpected result.
In the absence of evidence to the contrary, we determine that the
evidence supports the Examiner’s determination that it would have been
within the capabilities of one of ordinary skill in the art to have performed
the experimentation necessary to determine the optimum or workable
thicknesses for the fin structure and layers such that that artisan could form a
working semiconductor device.
The totality of the evidence weighs in favor of a conclusion of
obviousness.
With respect to claims 11, 22, and 27, Appellants also contend that the
motivation relied upon for combining the teachings of Mathew and Gambino
does not satisfy the requirements of 35 U.S.C. § 103(a) because the alleged
motivation is merely a conclusory statement providing an alleged benefit.
There is no dispute that Mathew describes forming source and drain
regions at the ends of the fin structure as claimed (e.g., claim 11). The
Examiner relies upon Gambino for its teaching of annealing to activate
source/drain regions. According to the Examiner, “it would have been
obvious to one of ordinary skill in the art at the time of the invention to
combine Gambino with Matthew, because the annealing activates the
source/drain regions of the device.” (Ans. 4).
6
Appeal 2007- 4186
Application 10/602,061

The issue that arises is: Have Appellants shown that the evidence
fails to adequately support the Examiner’s finding of a reason to combine
annealing with a process of forming a semiconductor device as taught by
Mathew?
As a first matter, we note that claim 11 is not limited to the annealing
step. Therefore, the issue is irrelevant with regard to this claim.
The issue is relevant with regard to claims 12, 22, and 27, however.
For these claims, we answer the question in the negative.
Gambino explicitly states that annealing the doped regions forms
activated source/drain diffusion regions (Gambino, col. 6, l. 67 to col. 7, l.
4). Gambino, therefore, provides sufficient evidence supporting the
Examiner’s finding of a reason to combine.

III. DECISION
The Examiner’s decision is affirmed.

IV. TIME PERIOD FOR RESPONSE
No time period for taking any subsequent action in connection with
this appeal maybe extended under 37 C.F.R. § 1.136(a)(1)(iv).

AFFIRMED

PL Initials
sld

7
Appeal 2007- 4186
Application 10/602,061

HARRITY SNYDER LLP
11350 RANDON HIILLS ROAD
SUITE 600
FAIRFAX, VA 22030
8