Ex Parte Hsu

Patent Trial and Appeal Board

May 25, 2016

13278285 (P.T.A.B. May. 25, 2016)

UNITED STA TES p A TENT AND TRADEMARK OFFICE
APPLICATION NO. FILING DATE
13/278,285 10/21/2011
107476 7590 05/27/2016
Eschweiler & Associates, LLC
629 Euclid A venue, Suite 1000
National City Bank Building
Cleveland, OH 44114
FIRST NAMED INVENTOR
Kai-Shiung Hsu
UNITED STATES DEPARTMENT OF COMMERCE
United States Patent and Trademark Office
Address: COMMISSIONER FOR PATENTS
P.O. Box 1450
Alexandria, Virginia 22313-1450
www .uspto.gov
ATTORNEY DOCKET NO. CONFIRMATION NO.
TSMCP109US 7115
EXAMINER
PHAM, THANHHA S
ART UNIT PAPER NUMBER
2819
NOTIFICATION DATE DELIVERY MODE
05/27/2016 ELECTRONIC
Please find below and/or attached an Office communication concerning this application or proceeding.
The time period for reply, if any, is set in the attached communication.
Notice of the Office communication was sent electronically on above-indicated "Notification Date" to the
following e-mail address( es):
docketing@eschweilerlaw.com
PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
BEFORE THE PATENT TRIAL AND APPEAL BOARD
Ex parte KAI-SHIUNG HSU1
Appeal2014-008589
Application 13/278,285
Technology Center 2800
Before DEBRA K. STEPHENS, JASON V. MORGAN, and
DAVID J. CUTITTA II, Administrative Patent Judges.
CUTITTA, Administrative Patent Judge.
DECISION ON APPEAL
This is an appeal under 35 U.S.C. § 134(a) from the Examiner's
decision rejecting claims 1, 4--14, 17, 18, 20, and 25. We have jurisdiction
over this appeal under 35 U.S.C. § 6(b).
We AFFIRM.2
1 According to Appellant, the real party in interest is Taiwan Semiconductor
Manufacturing Co., Ltd. See Appeal Brief 1.
2 Throughout this Opinion, we refer to: (1) Appellant's Specification filed
October 21, 2011 (Spec.), (2) the Final Rejection (Final Act.) mailed July 5,
2013, (3) the Appeal Brief (Appeal Br.) filed March 7, 2014, and (4) the
Examiner's Answer (Ans.) mailed June 5, 2014.
Appeal2014-008589
Application 13/278,285
BACKGROUND
According to Appellant, the application relates to an improved
manufacturing method for field effect transistors having strain-induced
channel regions. Spec. 2. The method seeks to improve downward scaling
limits and semiconductor device performance by introducing a silicon
germanium layer into the strain inducing layer. Id. Claims 1, 8, and 18 are
independent claims. Claim 1 is representative and is reproduced below with
disputed limitations emphasized:
1. A method comprising:
providing a p-type body region in a semiconductor substrate,
the p-type body region corresponding to a n-type field effect
transistor structure;
providing a gate electrode of the n-type field effect transistor
structure over a channel region in the p-type body region,
wherein a gate dielectric is disposed between the gate electrode
and the channel region to electrically isolate the gate electrode
from the channel region;
forming n-type source and drain regions for then-type field
effect transistor structure in the semiconductor substrate about
opposing sides of the gate electrode;
providing a strain inducing layer over the n-type field effect
transistor structure, wherein the strain inducing layer does not
extend over a neighboring p-type field effect transistor structure
on the semiconductor substrate and wherein the strain inducing
layer comprises a silicon germanium layer; and
performing a treatment of the strain inducing layer to induce
strain into a channel region of then-type field effect transistor
structure.
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Appeal2014-008589
Application 13/278,285
REFERENCES
The prior art relied upon by the Examiner in rejecting the claims on
appeal:
Chao et al. (hereinafter
"Chao")
Pi din
Owada et al. (hereinafter
"Owada")
US 2006/0267106 Al
US 2010/0012992 Al
US 2010/0012991 Al
REJECTIONS
Nov. 30, 2006
Jan. 21, 2010
Jan. 21, 2010
Claims 1, 4, 6-14, 17, 18, and 25 are rejected under 35 U.S.C.
§ 103(a) as being unpatentable over Pidin in view of Chao.
Claims 5 and 20 are rejected under 35 U.S.C. § 103(a) as being
unpatentable over Pidin in view of Chao and further in view of Owada.
Our review in this appeal is limited only to the above rejections and
issues raised by the Examiner and Appellant. \Ve have not considered other
possible issues that have not been raised by Appellant or the Examiner and
which are therefore not before us.
DISCUSSION
After review of Appellant's arguments and the Examiner's findings
and reasoning, we determine that the Appellant has not identified reversible
error in the Examiner's rejection.
Accordingly, we affirm the rejection for reasons set forth by the
Examiner in the Final Action and the Answer. See generally, Final Act. 3-
6; Ans. 2-3. We add the following for emphasis and completeness.
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Appeal2014-008589
Application 13/278,285
The Examiner relies on Pidin's nitride film layer 3 to suggest the
strain inducing layer while relying on Chao to teach "the strain inducing
layer comprises a silicon-germanium layer," as claimed. Specifically, the
Examiner finds Chao "teaches that the silicon-germanium layer and silicon
nitride layer are equivalent layers for using the strain inducing layer." Final
Act. 3 citing Chao i-f 3 9.
Appellant argues that Pidin teaches away from the proposed
combination. Appellant, however, has not shown that Pidin criticizes,
discredits, or otherwise discourages modifying a reference to arrive at the
claimed invention, for the reasons set forth below. See In re Fulton, 391
F.3d 1195, 1201 (Fed. Cir. 2004).
Appellant further argues that the proposed combination would
frustrate a primary purpose of Pidin. Appeal Br. 4. Specifically, Appellant
contends that a central concept in Pidin is that the Ni-Pt silicide region 17
and nitride strain inducing layer 3 collectively form an interface that allows
for a highly selective etch to easily remove the nitride layer 3 without
damaging/over-etching the underlying Ni-Pt silicide region 17. Appeal Br.
5---6. Appellant, however, provides no citation to Pidin or other evidence
specifically supporting the assertion that collectively forming an interface
that allows for a highly selective etch to easily remove the nitride layer is "a
central concept" or ''primary purpose" in Pidin. Appeal Br. 5; see also
Appeal Br. 4, 6-7.
Furthermore, even if the proposed combination were to result in a less
selective etch, this would still fail to discredit the "improv[ ed] electron and
hole mobility" obtained from the claimed solution. See Spec. 1, 11. 11-15.
"The fact that the motivating benefit comes at the expense of another benefit
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Appeal2014-008589
Application 13/278,285
... should not nullify its use as a basis to modify the disclosure of one
reference with the teachings of another. Instead, the benefits, both lost and
gained, should be weighed against one another." Winner Int'! Royalty
Corp. v. Wang, 202 F.3d 1340, 1349 n.8 (Fed. Cir. 2000). Here, Appellant
provides insufficient evidence that the alleged expense of a less selective
etch outweighs the "improve[ d] electron and hole mobility" obtained from
the claimed solution. Spec. 1, 11. 11-15.
In support of the assertion that the proposed combination would result
in a less selective etch, Appellant sets forth evidence that "silicon
germanium is more than 33% more difficult to remove than silicon nitride."
Appeal Br. 7. Appellant then concludes that this could cause difficulty in
removing the silicon germanium ("alternatively SiGe") layer and "this
difficulty in removing the SiGe layer would equate to a longer and/or more
abrasive etch, which could cause damage to the underlying Ni-Pt silicide
layer 17 and ultimately result in a non-ohmic contact.'' Id., emphasis added.
We find this conclusion hypothetical and not completely supported by
the evidence. For example, as found by the Examiner:
The argument is not persuasive since etch selectivity and
etching rate of different materials can be adjusted or varied
based on different etch chemistry ( etchants) and/ or condition of
etching (temperature or flow rate ... ). As such, it is not
reasonable to use Williams et al and Oehrlien et al to show
SiGe is more difficult to remove than a silicon nitride layer in
the process of Pidin since the etch chemistry of Pidin
(CHF3/Ar/02 etchant) to remove the nitride strain-inducing
layer is different than the etch chemistry of William et al and
Oehrlien et al (CF4) to remove silicon nitride and silicon
germamum.
Answer 3.
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Appeal2014-008589
Application 13/278,285
Appellant further argues an ordinarily skilled artisan would not have
been motivated to modify Pidin as suggested, absent impermissible
hindsight because the proposed modification would alter the interface
between Pidin's nitride layer 3 and the underlying Ni-Pt silicide region 17,
possibly lowering the etch selectivity between nitride layer 3 and Ni-Pt
silicide 17 and thereby making the Ni-Pt silicide more susceptible to
damage/overetching. Id. at 6.
We are not persuaded by Appellant's argument, for the reasons
provided supra, and because the Examiner has provided reasoning with
rational underpinnings, namely, "it would have been obvious for those
skilled in the art, in view of Chao et al, to use the strain inducing layer which
comprises the silicon-germanium layer in the process of Pidin to provide
appropriate stress as being needed for improving device performance." Final
Act. 3; see also In re Kahn, 441 F.3d 977, 988 (Fed. Cir. 2006)
("[R ]ejections on obviousness grounds [require] some articulated reasoning
with some rational underpinning to support the legal conclusion of
obviousness") (cited with approval in KSR Int 'l Co. v. Teleflex Inc., 550 U.S.
398, 418 (2007).
Thus, Appellant has not proffered sufficient evidence or argument to
persuade us that Pidin teaches away from the invention as recited in claim 1
and that an ordinarily skilled artisan would not have had a reason to combine
the teachings and suggestion of Pidin and Chao absent impermissible
hindsight.
Therefore, on this record, Appellant has not identified reversible error
in the Examiner's determination that one of ordinary skill in the art,
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Application 13/278,285
furnished with the disclosures of Pidin and Chao, would have been led to the
subject matter of claim 1 within the meaning 35 U.S.C. § 103(a).
We accordingly sustain the Examiner's§ 103(a) rejection of claim 1
as unpatentable over Pidin and Chao.
With respect to the rejection of independent claims 8 and 18,
Appellant relies on the arguments presented above in response to the
rejection of claim 1. Appeal Br. 4--8. Accordingly, for the same reasons as
discussed above, we also sustain the rejection of independent claims 8 and
18 under 35 U.S.C. § 103(a) as being obvious over Pidin and Chao.
Appellant does not make any other substantive argument regarding
the rejection of dependent claims 4, 6, 7, 9-14, 17 and 25. See Appeal Br.
4--8. Therefore, we likewise sustain the rejections of these dependent
claims.
DECISION
We affirm the Examiner;s decision rejecting claims 1, 4, 6-14, 17, 18,
and 25 under 35 U.S.C. § 103(a) as being unpatentable over Pidin in view of
Chao.
We affirm the Examiner's decision rejecting claims 5 and 20 under 35
U.S.C. § 103(a) as being unpatentable over Pidin in view of Chao and
further in view of Owada.
No time period for taking any subsequent action in connection with
this appeal may be extended under 37 C.F.R. § 1.136(a)(l )(iv).
AFFIRMED
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