Ex Parte Seok

Patent Trial and Appeal Board

Nov 1, 2017

13662384 (P.T.A.B. Nov. 1, 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.
IXYS-01318 9734
EXAMINER
HOQUE, MOHAMMAD M
ART UNIT PAPER NUMBER
2817
MAIL DATE DELIVERY MODE
13/662,384 10/26/2012
47713 7590 11/02/2017
IMPERIUM PATENT WORKS
P.O. BOX 607
Pleasanton, CA 94566
Kyoung Wook Seok
11/02/2017 PAPER
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.
PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
BEFORE THE PATENT TRIAL AND APPEAL BOARD
Ex parte KYOUNG WOOK SEOK
Appeal 2017-002115
Application 13/662,3 841
Technology Center 2800
Before MICHAEL P. COLAIANNI, BRIAN D. RANGE, and
SHELDON M. McGEE, Administrative Patent Judges.
RANGE, Administrative Patent Judge.
DECISION ON APPEAL
SUMMARY
Appellant appeals under 35 U.S.C. § 134(a) from the Examiner’s
decision rejecting claim 17. We have jurisdiction. 35 U.S.C. § 6(b).
We REVERSE.
1 Appellant is the Applicant, IXYS Corporation, which according to the brief
is also the real party in interest. Appeal Br. 1.
Appeal 2017-002115
Application 13/662,384
STATEMENT OF THE CASE2
Appellant describes the invention as relating to an Insulated Gate
Bipolar Transistor (IGBT) die structure. Appeal Br. 2. Claim 17,
reproduced below with emphasis added to certain key recitations, is now the
only claim on appeal:
17. An Insulated Gate Bipolar Transistor (IGBT) die structure
comprising:
an IGBT having a gate, an N type source region, a P type
body region, an N type drift layer, and a P type substrate layer,
wherein a first metal terminal is coupled to the N type source
region and to the P type body region, wherein a second metal
terminal is coupled to the gate, and wherein a fourth metal
terminal is coupled to the P type substrate layer; and
means for injecting charge carriers into the N type
drift layer during a turn on time TON of the IGBT by
injecting a current into the IGBT through a third metal
terminal of the IGBT.
Appeal Br. 29—30 (Claims App’x).
REJECTION AND REFERENCES
On appeal, the Examiner maintains the rejection of claim 17 under 35
U.S.C. § 103 as unpatentable over Oh et al., U.S. Patent Publication No.
2011/0062490 Al, Mar. 17, 2011 (hereinafter “Oh”) in view of Baliga, U.S.
Patent No. 4,743,952, May 10, 1988 (hereinafter “Baliga”). Non-Final Act.
12; see also Ans. 6 (withdrawing all other rejections).
2 In this opinion, we refer to the Non-Final Office Action dated March 16,
2016 (“Non-Final Act.”), the Appeal Brief filed April 1, 2016 (“Appeal
Br.”), the Examiner’s Answer dated November 1, 2016 (“Ans.”), and the
Reply Brief filed November 28, 2016 (“Reply Br.”).
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Appeal 2017-002115
Application 13/662,384
ANALYSIS
The Examiner finds that Oh teaches most of the recited elements of
claim 17 but does not teach a “means for injecting charge carriers ... by
injecting a current into the IGBT through a third metal terminal of the
IGBT.” Non-Final Act. 12 (providing citations to Oh). The Examiner finds
that Baliga teaches the “means . . . IGBT” recitation, and the Examiner finds
that shorting electrode 46 corresponds to claim 17 ’s recited third metal
terminal. Id. at 13 (providing citations to Baliga); see also Ans. 5 (“The
office mapped ‘shorting electrode 46’ as the third terminal.”).
Appellant argues no external charge is injected into or drawn from
Baliga’s shorting electrode 46. Appeal Br. 19. The preponderance of the
evidence before us supports Appellant’s position. Baliga’s Figure 1 depicts
shorting electrode 46 and is reproduced below.
Figure 1 is a schematic view in cross-section of a portion of a semiconductor
device in accordance with Baliga’s teachings. Baliga 2:24—26. As depicted
in Figure 1, dielectric film 44 is between the gate electrode 42 and the
shorting electrode 46. See also id. at 3:36-4:2 (explaining that gate
electrode 42 serves to induce an inversion layer in channel region 40). Thus,
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Appeal 2017-002115
Application 13/662,384
current does not flow between gate electrode 42 to shorting electrode 46.
Rather, the purpose of shorting electrode 46 is to complete current path 50 as
depicted in Figure 1. Id. at 3:60—65. Shorting electrode 46 serves to move
current and/or charge within the Baliga semiconductor device; shorting
electrode 46 does not inject current into the device.
The Examiner responds to Appellant’s argument by stating that “the
features upon which applicant relies (i.e., ‘external’ charge is to be injected
into or ‘drawn from’ shorting electrode) are not recited in the rejected
(claim(s)).” Ans. 6. Claim 17, however, requires a “means for injecting
charge carriers into the N type drift layer [i.e., a layer of the IGBT] ... by
injecting a current into the IGBT through a third metal terminal of the
IGBT.” Appeal Br. 30 (Claims App’x) (emphasis added); see also Reply
Br. 7 (arguing that claim 17 requires signal into or out of the IGBT). We do
not sustain the Examiner’s rejection because the Examiner has not
adequately explained why, in Baliga or in the Oh/Baliga combination, it
would have been obvious to a person of ordinary skill in the art to include a
means that injects current into the IGBT through shorting electrode 46 as
depicted in Baliga.
DECISION
For the above reasons, we reverse the Examiner’s rejection of claim
17.
REVERSED
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