Ex Parte Chakravarthi et al

Patent Trial and Appeal Board

Jun 28, 2016

11693552 (P.T.A.B. Jun. 28, 2016)

UNITED STA TES p A TENT AND TRADEMARK OFFICE
APPLICATION NO. FILING DATE
111693,552 0312912007
23494 7590 06/30/2016
TEXAS INSTRUMENTS IN CORPORA TED
P 0 BOX 655474, MIS 3999
DALLAS, TX 75265
FIRST NAMED INVENTOR
Srinivasan Chakravarthi
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.
TI-62914 9476
EXAMINER
SEVEN, EVREN
ART UNIT PAPER NUMBER
2812
NOTIFICATION DATE DELIVERY MODE
06/30/2016 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):
uspto@ti.com
PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
BEFORE THE PATENT TRIAL AND APPEAL BOARD
Ex parte SRINIVASAN CHAKRA VARTHI, PERIANNAN
CHAKRA VARTHI, and JOHAN WEIJTMANS
Appeal2016-006072
Application 11/693,552
Technology Center 2800
Before MICHAEL P. COLAIANNI, JULIA HEANEY, and
JEFFREY R. SNAY Administrative Patent Judges.
HEANEY, Administrative Patent Judge.
DECISION ON APPEAL
Appellants 1 request review pursuant to 35 U.S.C. § 134(a) of a
decision of the Examiner rejecting claims 1, 3-23, and 37-39 of Application
11/693,552. We have jurisdiction under 35 U.S.C. § 6(b ). We affirm.
BACKGROUND
The subject matter on appeal relates to a PMOS transistor of an
integrated circuit. Br. 1.
1 Appellants identify the real party in interest as Texas Instruments, Inc. Br.
3.
Appeal2016-006072
Application 11/693,552
Claim 1, reproduced below from the Claims Appendix of the Appeal
Brief, is illustrative of the subject matter on appeal:
1. A method of making a PMOS transistor, comprising:
providing a semiconductor substrate having a PMOS transistor
gate stack, source/drain extensions, and recess etched active
reg10ns;
depositing in-situ boron and carbon doped epitaxial SiGe into
said recess etched active regions; and
forming source/drain regions within said semiconductor
substrate.
REFERENCES
The Examiner relied upon the following prior art in rejecting the
claims on appeal:
Otto et al. us 5,643,638 Jul. 1, 1997
("Otto")
Cheng et al. US 2005/0112817 Al May 26, 2005
("Cheng")
Warn! et al. US 2007 /0093033 Al Anr. 2. 2007 . ----o - - ---- - -_._- - - - 7 - - - -
("Wang")
Chong et al. US 2007 /0235802 Al Oct. 11, 2007
("Chong '802 ")
Chong et al. US 2007/0132038 Al Jun. 14,2007
("Chong '038")
Enicks US 2007 /0262295 Al Nov. 15, 2007
("Enicks")
Cook et al. US 2008/0124878 Al May 29, 2008
("Cook")
THE REJECTIONS
1. Claims 1and6 are rejected under 35 U.S.C. § 102(b) as
anticipated by Cheng.
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2. Claim 3 is rejected under 35 U.S.C. § 103(a) as unpatentable over
Cheng in view of Chong '802.
3. Claims 4 and 5 are rejected under 35 U.S.C. § 103(a) as
unpatentable over Cheng in view of Chong '038.
4. Claim 7 is rejected under 35 U.S.C. § 103(a) as unpatentable over
Cheng in view of Enicks.
5. Claims 8-11 are rejected under 35 U.S.C. § 103(a) as unpatentable
over Cheng in view of Cook.
6. Claims 12-17 are rejected under 35 U.S.C. § 103(a) as
unpatentable over Cheng in view of Wang.
7. Claims 18-23, 38, and 39 are rejected under 35 U.S.C. § 103(a) as
unpatentable over Cheng in view of Wang and Cook.
8. Claim 37 is rejected under 35 U.S.C. § 103(a) as unpatentable over
Cheng in view of Chong '802 and Otto.
DISCUSSION
Rejection 1
Appellants argue that Cheng does not teach a method that includes
"depositing in-situ boron and carbon doped epitaxial SiGe into the recess
etched active regions and also forming source/drain regions" as required by
claim 1,2 but rather describes "'deeper source and drain doped regions 528B
are formed' only in 'the semiconductor device 501b."' Br. 11-12 (citing
2 Appellants do not present substantively distinct argument for dependent
claim 6.
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Application 11/693,552
Cheng i-f 81). 3 We are not persuaded that Appellants identify reversible error
in the rejection. As the Examiner correctly finds, Cheng Figs. 5a-5i show a
method of making a PMOS transistor including growing epitaxial
source/drain regions such as 520a and deep implant source/drain regions.
Ans. 2-3. Although the deep implant source/drain regions are unnumbered
in Fig. 5e, they are also shown in Cheng Fig. 4 and described in i-f 68 as
"heavily doped source and drain regions 428a ... formed in the substrate
402." Appellants do not reply to this finding; no reply brief was filed.
Accordingly, we affirm the anticipation rejection of claims 1 and 6.
Rejection 2
Claim 3 depends from claim 1 and recites the additional limitation
that "said boron and carbon doped epitaxial SiGe has a graded boron
concentration." Claims App 'x. Appellants mischaracterize claim 3,
however, by arguing that it requires both the source/drain regions and the in-
situ boron and carbon doped epitaxial SiGe have a graded boron
concentration. Br. 14. ivforeover, Appellants do not respond to the
Examiner's determination that Chong '802 provides motivation for a person
of ordinary skill in the art to include a graded boron concentration in
epitaxial SiGe. Ans. 5, citing Chong '802 i-f 94. Accordingly, we affirm the
obviousness rejection of claim 3.
Rejection 3
Claims 4 and 5 depend from claim 1 and recite additional steps of
implanting additional boron dopants into the boron and carbon doped
3 We are not persuaded by Appellants' argument that Cheng teaches away
from the claimed invention, because that argument is not germane to an
anticipation rejection.
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Application 11/693,552
epitaxial SiGe, and annealing the semiconductor substrate. Appellants'
argument that Chong '03 8 does not teach an additional boron implant or
annealing the substrate is not persuasive. Br. 15-16. Moreover, Appellants
do not respond to the Examiner's determination that Chong '038 provides
motivation for one of ordinary skill in the art to include additional boron
implants after in-situ doping of the source/drain regions and further,
explicitly teaches annealing. Ans. 5, citing Chong '038 i-fi-144, 67, and 69.
Accordingly, we affirm the obviousness rejection of claims 4 and 5.
Rejection 4
Claim 7 depends from claim 1 and additionally recites that the boron
and carbon doped epitaxial is deposited by a R TCVD process. Appellants
argue that Enicks does not teach RTCVD, and further that Enicks teaches
away from source/drain extensions, a PMOS transistor gate stack, and recess
etched active regions. Br. 18-19. Appellants' argument is not persuasive of
reversible error, in that they do not address the Examiner's finding that
Enicks teaches various types of CVD for depos1tmg a Si Ge layer. Ans. 5-6.
Further, the argument that Enicks teaches away is not persuasive because
Enicks' lack of teaching is not a teaching away. See In re Fulton, 391 F.3d
1195, 1201 (Fed. Cir. 2004) (prior art does not teach away from claimed
subject matter merely by disclosing a different solution to a similar problem
unless the prior art also criticizes, discredits, or otherwise discourages the
solution claimed). Moreover, Appellants' arguments against the references
individually cannot overcome a rejection based on a combination of the
references. In re Keller, 642 F.2d 413, 426 (CCPA 1981). Accordingly, we
affirm the obviousness rejection of claim 7.
Rejection 5
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Claims 8-11 depend from claim 1 and additionally recite various
dopant concentration ranges in the SiGe region. Appellants present
argument for claim 8 and repeat that argument for claims 9-11. Br. 19-26.
Therefore, we need only address claim 8. The Examiner finds that Cook
teaches dopant concentration in the source/drain region of a recessed and
epitaxially refilled MOSFET directly affect strain on the channel region, and
therefore is a result effective variable, for which there is a motivation to
optimize. Ans. 6, citing In re Aller, 220 F.2d 454, 456 (CCPA 1955).
Appellants do not respond to that finding or present evidence that the
claimed concentration ranges are critical. Br. 19-26. Moreover, Appellants'
arguments against the references individually, and that Cook teaches away,
are not persuasive for the same reasons as discussed under Rejection 4.
Accordingly, we affirm the obviousness rejection of claims 8-11.
Rejection 6
Appellants present argument for independent claim 12 and repeat that
argument for dependent claims 13-17. Br. 27-35. Therefore, we need only
address claim 12.
The Examiner finds that Cheng discloses all of the steps of claim 12,
except for forming epitaxial SiGe coupled to carbon-doped epitaxial SiGe,
and that Wang teaches in Fig. 1 C forming an additional epitaxial Si Ge 22B
on carbon-doped epitaxial Si Ge 22A coupled to recess etched active regions
20. Non-Final Act. mailed September 2, 2015 at 6. The Examiner
determines that it would have been obvious to a person of ordinary skill to
include Wang's bi-layer structure in Cheng's process, with a reasonable
expectation of success, in order to alleviate the surface roughness of the
recesses formed by etching. Id. at 6-7. The Examiner further acknowledges
that Chang and Wang disagree as to when in the process source/ drain
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extensions are formed, but determines that because claim 12 is silent with
regard to the sequence of steps, Cheng and Wang do not teach away. Ans. 9.
Appellants' arguments that are directed at the references individually
and argue that Cheng teaches away are not persuasive, for the same reasons
as discussed under Rejection 4. Appellants' further arguments against the
combination of Cheng and Wang are based on reading into claim 12 a
required sequence of steps, e.g., recessing etched active regions only after
forming source/drain extensions. Br. 29-30. Appellants do not respond to
the Examiner's determination that claim 12 is silent with regard to the
sequence of steps; no reply brief was filed. Accordingly, Appellants'
arguments are not persuasive of reversible error and we affirm the rejection
of claims 12-17.
Rejection 7
Claims 18-23 depend from claim 12 and additionally recite various
dopant concentration ranges in the SiGe region. Similarly to Rejection 5 as
discussed above, the Examiner finds that Cook teaches that the recited
dopant concentration is a result effective variable. Ans. 10. Appellants do
not respond to that finding or present evidence that the claimed
concentration ranges are critical. Br. 36-43. Moreover, Appellants'
arguments against the references individually, and that Cook teaches away
from the claimed subject matter in general, are not persuasive for the same
reasons as discussed under Rejection 4.
As to claims 38-39, Appellants repeat their arguments against the
rejection of claim 12. We do not find those arguments persuasive, for the
reasons discussed above for claim 12.
Accordingly, we affirm the obviousness rejection of claims 18-23 and
38-39.
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Rejection 8
Appellants argue against the rejection of claim 37 by repeating their
argument against the rejection of claim 12. Br. 46-48. We do not find those
arguments persuasive, for the reasons discussed above for claim 12.
Appellants further argue conclusorily that neither Cheng, Chong '802, nor
Otto teach that deposition of boron is delayed during a first portion of the
step of depositing boron and carbon doped epitaxial SiGe into the recess
etched active regions. Br. 46. The Examiner finds, however, that Otto
explicitly teaches starting a gradient from zero concentration, which implies
that the dopant gas must be turned off at the beginning, i.e., delayed. Non-
Final Act. 8. Appellants do not respond to that finding. Accordingly, we
affirm the obviousness rejection of claim 37.
SUMMARY
We affirm the rejections of claims 1, 3-23, and 37-39.
}~o time period for talcing any subsequent action in connection vvith
this appeal may be extended under 37 C.F.R. § 1.136(a).
AFFIRMED
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