Paul S. Ho et al.

Patent Trials and Appeals Board

Dec 20, 2019

15040025 - (D) (P.T.A.B. Dec. 20, 2019)

UNITED STATES PATENT AND TRADEMARK OFFICE
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
APPLICATION NO. FILING DATE FIRST NAMED INVENTOR ATTORNEY DOCKET NO. CONFIRMATION NO.
15/040,025 02/10/2016 Paul S. Ho 065715.0483 8229
31625 7590 12/20/2019
Baker Botts L.L.P.
98 San Jacinto Blvd
Suite 1500
Austin, TX 78701
EXAMINER
LEE, JAE
ART UNIT PAPER NUMBER
2899
NOTIFICATION DATE DELIVERY MODE
12/20/2019 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):
crystle.garbade@bakerbotts.com
juli.tran@bakerbotts.com
tracy.engberg@bakerbotts.com
PTOL-90A (Rev. 04/07)

UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE PATENT TRIAL AND APPEAL BOARD
____________

Ex parte PAUL S. HO
and ZHUOJIE WU

Appeal 2019-000036
Application 15/040,025
Technology Center 2800
____________

Before GEORGE C. BEST, DONNA M. PRAISS, and LILAN REN,
Administrative Patent Judges.

PRAISS, Administrative Patent Judge.

DECISION ON APPEAL1

Pursuant to 35 U.S.C. § 134(a), Appellant appeals from the
Examiner’s decision to reject claims 1, 4–22, and 31.2 We have jurisdiction
under 35 U.S.C. § 6(b).
We AFFIRM.

1 In this Decision, we refer to the Specification filed Feb. 10, 2016 (“Spec.”),
the Non-Final Office Action dated Oct. 26, 2017 (“Non-Final Act.”), the
Appeal Brief filed Mar. 26, 2018 (“Appeal Br.”), and the Examiner’s
Answer dated July 31, 2018 (“Ans.”).
2 We use the word “Appellant” to refer to “applicant” as defined in
37 C.F.R. § 1.42. Board of Regents, The University of Texas System is
identified as the real party in interest. Appeal Br. 3.
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STATEMENT OF THE CASE
The invention relates to methods of fabricating silicon nanowires.
Spec. 1:4. According to the Specification, silicon nanowires show promise
for use in applications such as nanoelectronics, opto-electronics,
electromechanical devices, energy conversion and storage, biological and
chemical sensors, and drug delivery devices. Id. at 1:13–16. The
Specification states that there is a need for a cost-effective process for
fabricating large quantities of silicon nanowires, particularly those with a
width of 100 nm or less. Id. at 1:17–19.
Sole independent claim 1, reproduced below, is illustrative of the
subject matter on appeal (disputed limitation italicized).
1. A method of fabricating a silicon nanowire having a
width of 100 nm or less comprising:
depositing a metal film on a silicon-containing layer;
treating the metal film using a wet process to produce an
interconnected metal network having gaps on the silicon-
containing layer;
etching the silicon-containing layer with a metal-assisted
etching process in which an etching solution and the inter-
connected metal network etch silicon of the silicon-containing
layer, leaving unetched silicon of the silicon-containing layer in
the gaps of the interconnected metal network to form a silicon
nanowire having a width of 100 nm or less by controlling the
width of the silicon nanowire through controlling the width of
the gaps and the silicon nanowire having a length that is
controlled by controlling the duration of etching.
Appeal Br. 13 (Claims Appendix).
ANALYSIS
We review the appealed rejections for error based upon the issues
Appellant identifies, and in light of the arguments and evidence produced
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thereon. Ex parte Frye, 94 USPQ2d 1072, 1075 (BPAI 2010) (precedential)
(cited with approval in In re Jung, 637 F.3d 1356, 1365 (Fed. Cir. 2011)
(“[I]t has long been the Board’s practice to require an applicant to identify
the alleged error in the examiner’s rejections.”)). After considering the
argued claim in light of the case law presented in this Appeal and each of
Appellant’s arguments, we are not persuaded of reversible error in the
appealed rejections.
The Examiner rejects claims 1, 4–22, and 31 as follows. Non-Final
Act. 3–9.
Claims Rejected 35 U.S.C. § Reference(s)/Basis
1, 4–7, 10–17, 19, 20,
31 103 Yu,
3 Lin4
21, 22 103 Yu, Lin, Banerjee5
7, 18 103 Yu, Lin, Xu6
8, 9 103 Yu, Lin, Liu7
Appellant separately argues the rejection of independent claim 1.
Appeal Br. 3–9. In view of the lack of arguments directed to the remaining
claims and the subsidiary rejections, claims 4–7, 10–16, 19, 20, 31 stand or
fall with claim 1, and we will apply Appellant’s arguments to the remaining
rejections of claims 7–9, 18, 21, and 22. See 37 C.F.R. § 41.37(c)(1)(iv).
Rejection over Yu and Lin (Claims 1, 4–7, 10–17, 19, 20, 31)
Appellant contends that the Examiner erred in rejecting claim 1 over
the combined teachings of Yu and Lin because neither Yu nor Lin alone or

3 US 2015/0041937 A1, published Feb. 12, 2015.
4 US 2013/0143407 A1, published June 6, 2013.
5 US 2012/0326075 A1, published Dec. 27, 2012.
6 US 2013/0309563 A1, published Nov. 21, 2013.
7 US 2014/0335411 A1, published Nov. 13, 2014.
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in combination discloses a “wet process” for producing an interconnected
metal network having gaps on the silicon-containing layer as required by the
claim. Appeal Br. 8–11. According to Appellant, the Specification discloses
a “wet process” for removing metal and in contrast to a “separate and
distinct metal-assisted etching process, which uses a wet ‘etching solution,’
[that] works with the metal to ‘etch silicon’ under the metal.” Id. at 8
(emphasis omitted) (citing Spec. 5:22).
Appellant argues that Yu uses a lithography process to form a pattern
in the metal rather than an etching solution. Id. (citing Yu ¶ 35). Appellant
distinguishes Lin’s wet-etching solutions as (1) not similar to the “wet
process” solution described in Appellant’s Specification and (2) introduced
only after a metal pattern has already been formed. Id. at 9 (citing Lin ¶¶ 6,
8; Spec. 4:7–5:9). Appellant asserts that Lin discloses exactly the same type
of process as Yu in which metal is patterned using lithography or another
non-wet process, followed by a wet-etching process, such as metal-assisted
etching. Id. at 10.
The Examiner responds that Lin is cited to show the benefits that wet
etching provides, namely its low cost. Ans. 3. The Examiner finds that wet
etching of metal is notoriously well-known within the etching technology
and such wet etching techniques have been performed on metal layers to
form desired patterns. Id. The Examiner finds that Yu’s disclosure that metal
mask 212A in Figure 3A can be obtained “using various lithography
techniques” suggests forming patterns using either dry or wet etching
techniques. Id. (citing Yu ¶ 36). The Examiner further finds that Yu teaches
applying a wet photoresist using a deposition method such as spin coating or
spray coating, which are both considered a “wet process” because
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fluids/solvents are involved to treat the metal film layer. Id. (citing Yu
¶ 36).
Appellant does not dispute the Examiner’s finding (Ans. 3) that Yu’s
disclosure of a spin coating or spray coating to apply a wet photoresist to
treat the metal film layer is a lithography technique and also a wet process.
The cited record in this Appeal supports the Examiner’s findings. Yu
discloses forming an array pattern in the metal thin film using lithographic
techniques that involve solvents and etching with a suitable etchant. Yu
¶¶ 36, 39. We are not persuaded that the Examiner erred in finding that Yu’s
“various lithography techniques” for forming a metal network having gaps
include a “wet process” as claim 1 requires. Yu ¶ 36. The Examiner’s
reliance on Lin for teaching the cost benefit of wet etching over dry etching
provides a reasoned basis for selecting a wet process from among the
lithographic techniques taught by Yu. Ans. 3; Lin ¶ 6. Thus, the
preponderance of the evidence in this appeal record supports the Examiner’s
conclusion that the claimed subject matter would have been obvious in view
of Yu and Lin. Accordingly, we sustain the Examiner’s rejection of claim 1
as well as the rejection of claims 4–7, 10–17, 19, 20, and 31 over the
combination of Yu and Lin for essentially those reasons expressed in the
Answer, including the Response to Argument section.
Rejections over Yu and Lin in combination with Banerjee, Xu, or Liu
Appellant requests reversal of all rejections under 35 U.S.C. § 103.
Appeal Br. 11. Because we are not persuaded of error in the Examiner’s
rejection of sole independent claim 1 for the reasons discussed above, we
likewise affirm the rejections of dependent claims 7–9, 18, 21, and 22 in the
absence of arguments directed to the dependent claims.
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For these reasons and those the Examiner provides, we uphold the
Examiner’s rejections of claims 1, 4–22, and 31 under 35 U.S.C. § 103 as
obvious over the cited prior art references.
No time period for taking any subsequent action in connection with
this appeal may be extended under 37 C.F.R. § 1.136(a)(1)(iv).
CONCLUSION
In summary:
Claims
Rejected 35 U.S.C. § Reference(s)/Basis  Affirmed Reversed
1, 4–7, 10–
17, 19, 20, 31 103 Yu, Lin
1, 4–7, 10–
17, 19, 20,
31

21, 22 103 Yu, Lin, Banerjee 21, 22
7, 18 103 Yu, Lin, Xu 7, 18
8, 9 103 Yu, Lin, Liu 8, 9
Overall
Outcome
1, 4–22, 31
AFFIRMED