Ex Parte Fujimoto et al

Patent Trial and Appeal Board

Sep 28, 2017

12592747 (P.T.A.B. Sep. 28, 2017)

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.
12/592,747 12/01/2009 Tatsuo Fujimoto 52433/1043 6267
2292 7590 10/02/2017
BIRCH STEWART KOLASCH & BIRCH, LLP
8110 Gatehouse Road
Suite 100 East
FALLS CHURCH, VA 22042-1248
EXAMINER
LANGMAN, JONATHAN C
ART UNIT PAPER NUMBER
1784
NOTIFICATION DATE DELIVERY MODE
10/02/2017 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):
mailroom @ bskb. com
PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
BEFORE THE PATENT TRIAL AND APPEAL BOARD
Ex parte TATSUO FUJIMOTO,
NOBORU OHTANI, MASAKAZU KATSUNO,
MASASHINAKABAYASHI, and HIROKATSU YASHIRO
Appeal 2016-007527
Application 12/592,747
Technology Center 1700
Before ADRIENE LEPIANE HANLON, GEORGE C. BEST, and
JEFFREY R. SNAY, Administrative Patent Judges.
BEST, Administrative Patent Judge.
DECISION ON APPEAL
The Examiner finally rejected claims 1-10 and 12-15 of Application
12/592,747 under 35 U.S.C. § 103(a) as obvious. Final Act. (May 7, 2015).
Appellants1 seek reversal of these rejections pursuant to 35 U.S.C. § 134(a).
We have jurisdiction under 35 U.S.C. § 6.
For the reasons set forth below, we reverse.
1 Nippon Steel & Sumitomo Metal Corp. of Japan is identified as the real
party in interest. Appeal Br. 1.
Appeal 2016-007527
Application 12/592,747
BACKGROUND
The ’747 Application describes a low resistivity silicon carbide single
crystal wafer that can be used to fabricate high-performance electronic
devices. Spec. 1.
Claim 1 is representative of the ’747 Application’s claims and is
reproduced below from the Claims Appendix.
1. A low resistivity silicon carbide single crystal
wafer having a specific volume resistance of 0.001 Q cm to
0.012 Q cm, wherein 90% or greater of the entire wafer surface
area over both sides of the wafer has a surface roughness (Ra)
of 1.0 nm or less, wherein the basal plane stacking fault density
in the wafer after high-temperature annealing at 1000 °C to
1800 °C is 30 cm-1 or less.
Appeal Br. Claims App. 1 (emphasis added).
REJECTIONS
On appeal, the Examiner maintains the following rejections:
1. Claims 1, 2, 4-6, 9, 10, 12, 13, and 15 are rejected under 35 U.S.C.
§ 103(a) as unpatentable over the combination of Nakamura,2
Maruyama,3 Kerr,4 and Hirooka.5 Answer 2.
2 US 2007/0243722 Al, published October 18, 2007.
3 US 2008/0032880 Al, published February 7, 2008.
4 US 2008/0261401 Al, published October 23, 2008.
5 US 2004/0134418 Al, published July 15, 2004.
2
Appeal 2016-007527
Application 12/592,747
2. Claims 3, 7, and 8 are rejected under 35 U.S.C. § 103(a) as
unpatentable over the combination of Nakamura, Maruyama, Kerr,
Hirooka, and Shimoida.6 Id. at 8.
3. Claim 14 is rejected under 35 U.S.C. § 103(a) as unpatentable over
the combination of Nakamura, Maruyama, Kerr, Hirooka, and
Simin.7 Id. at 9.
DISCUSSION
Appellants present a single argument for reversal of all three pending
rejections. See Appeal Br. 2-8. This argument focuses upon the limitations
of claim 1, which is the sole independent claim on appeal. Id. at 8 (“For at
least the above reasons, claim 1, as well as any claim which depends
therefrom, are [sic] not obvious over Nakamura, Maruyama, Kerr, Hirooka,
Shimoida, and Simin, either individually or combined, and the rejections
under 35 U.S.C. § 103(a) should be withdrawn.”). Accordingly, we limit
our discussion to the rejection of claim 1.
Appellants argue that the rejection of claim 1 should be reversed
because, inter alia, the Examiner has not established a prima facie case of
obviousness. In particular, “Appellants respectfully note that the Examiner
has not given a reason as to why one skilled in the art would be motivated to
combine the respective constituent elements of the references. Appellants
6 US 2004/0031971 Al, published February 19, 2004.
7 G. Simin et al., 7.5 kW/mm2 current switch using AlGaN/GaNmetal-oxide
semiconductor heterostructure field effect transistors on SiC substrates, 36
Electronics Letts. 2043^14 (2000).
3
Appeal 2016-007527
Application 12/592,747
respectfully submit that the Examiner’s combination is based on hindsight
reconstruction.” Appeal Br. 3.
For the following reasons, we are persuaded by Appellants’ argument
and reverse the rejection of claim 1. In relevant part, claim 1 requires that at
least 90% of the surface area of the wafer be polished on both sides such that
it has a surface roughness of 1.0 nm or less. The Examiner relies upon
Hirooka as describing polishing of a silicon carbide wafer on both sides:
Kerr et al. are silent [as] to which the sides of the wafer
are polished, specifically that both sides undergo the polishing
as claimed.
Hirooka teaches methods of forming flats looking carbide
wafers were one surface is mirror finished ([0058]-[0062]).
Final Act. 5.
The record also teaches that mere:
polishing entails CMP methods, which achieve a roughness of
less than 1 nm ([0055]). Hirooka teaches that[,] while only one
side is mirror polished in their embodiments, . . . the other
surface may also be mirror finished by performing CMP
([0068]).
Thus[,] Hirooka teaches the polishing either one or both
sides of the wafer[] is well known in the art. It would have
been obvious to one of ordinary skill in the art at the time of the
present invention to apply the CMP technique of Kerr et al., to
either one or both sides of the low resistivity SiC wafer of
Nakamura et al., as this is an obvious design choice when CMP
finishing SiC wafers to a roughness of less than 1 nm.
Id. at 5-6.
As the Federal Circuit has explained, “rejections on obviousness
grounds cannot be sustained by mere conclusory statements; instead, there
must be some articulated reasoning with some rational underpinning to
4
Appeal 2016-007527
Application 12/592,747
support the legal conclusion of obviousness.” In re Kahn, 441 F.3d 977, 988
(Fed. Cir. 2006).
In this case, the Examiner has not provided an adequate explanation or
reason for a person of ordinary skill in the art at the time of the invention to
have chosen to polish both sides of the silica and carbide wafer described or
suggested by the combination of Nakamura, Maruyama, and Kerr. Final
Act. 6. The Examiner merely asserts that it is a matter of routine design
choice to choose whether to polish one side or both sides of the wafer. Id.
This argument is not compelling. As Appellants explain, choosing to
polish both sides of a silicon carbide wafer adds extra steps and expenses to
the manufacturing process. The Examiner has not explained why a person
having ordinary skill in the art would be motivated to incur the additional
processing steps and associated cost as a matter of design choice. In the
absence of such an explanation supported by adequate evidence, we
determine that the Examiner has not identified an adequate reason for a
person of ordinary skill in the art to have been motivated to form the silicon
carbide wafer with both sides polished to a very high degree of smoothness.
We, therefore, conclude that the Examiner made improper use of hindsight
reconstruction in arriving at the rejection set forth in the Final Action. Thus,
we reverse the rejection of claim 1.
CONCLUSION
For the reasons set forth above, we reverse the rejection of claims 1-
10 and 12-15 of the ’747 Application.
REVERSED
5