Infineon Technologies AG

Patent Trials and Appeals Board

Sep 10, 2021

2020006296 (P.T.A.B. Sep. 10, 2021)

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.
15/951,918 04/12/2018 Joachim Weyers 1012-2114 /
2016P50732 US
5411
57579 7590 09/10/2021
MURPHY, BILAK & HOMILLER/INFINEON TECHNOLOGIES
1255 CRESCENT GREEN
SUITE 200
CARY, NC 27518
EXAMINER
FAN, BO
ART UNIT PAPER NUMBER
3646
NOTIFICATION DATE DELIVERY MODE
09/10/2021 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):
official@mbhiplaw.com
PTOL-90A (Rev. 04/07)

UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE PATENT TRIAL AND APPEAL BOARD
____________

Ex parte JOACHIM WEYERS, STEFAN GAMERITH, FRANZ HIRLER,
and ANTON MAUDER
____________

Appeal 2020-006296
Application 15/951,918
Technology Center 3600
____________

Before STEFAN STAICOVICI, BENJAMIN D. M. WOOD, and
GEORGE R. HOSKINS, Administrative Patent Judges.

HOSKINS, Administrative Patent Judge.

DECISION ON APPEAL
Pursuant to 35 U.S.C. § 134(a), Appellant1 appeals from the
Examiner’s decision rejecting claims 1–8 and 10–15 in this application.2
We REVERSE.

1 We use the word “Appellant” to refer to “applicant” as defined in
37 C.F.R. § 1.42. The Appeal Brief identifies Infinion Technologies AG as
the real party in interest. Appeal Br. 2.
2 Claim 9 has been deemed allowable, claim 16 has been canceled, and
claims 17–21 have been withdrawn from consideration. See Final Act. 2–3,
9–10; Amend. (Oct. 9, 2019), 5; Appeal Br. 2.
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CLAIMED SUBJECT MATTER
Claim 1 is the sole independent claim on appeal, and it recites:
1. A semiconductor device, comprising:
a silicon carbide semiconductor body having a first surface
and a second surface opposite to the first surface;
a transistor structure in the silicon carbide semiconductor
body;
a trench structure extending from the first surface into the
silicon carbide semiconductor body;
an electrostatic discharge protection structure in the trench
structure and comprising a first terminal region and a second
terminal region;
a source contact structure at the first surface and electrically
connected to source regions of the transistor structure and to the
first terminal region; and
a gate contact structure at the first surface and electrically
connected to a gate electrode of the transistor structure and to
the second terminal region.
Appeal Br. 16 (Claims App.) (emphases added).
REJECTIONS ON APPEAL
Claims 1–4, 7, and 10–15 are rejected under 35 U.S.C. § 102(a)(1) as
anticipated by Weyers (US 2015/0294966 A1, pub. Oct. 15, 2015).
Claims 5, 6, and 8 are rejected under 35 U.S.C. § 103 as unpatentable
over Weyers and Schmenn (US 2015/0243561 A1, pub. Aug. 27, 2105).
OPINION
The Examiner finds Weyers discloses, as recited in claim 1, “a trench
structure extending from the first surface into the . . . body” with “an
electrostatic discharge protection structure in the trench structure.” Final
Act. 3, 10. Appellant challenges this finding. Appeal Br. 4–12. We
conclude this finding is not supported by a preponderance of the evidence.
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A. Weyers Disclosure
Figure 4B of Weyers3 is reproduced below, with our addition of
reference numeral 101:

Figure 4B is a cross-sectional view of semiconductor device 10. Weyers
¶¶ 10, 15.
Figure 4B illustrates “semiconductor body 100 having a first
surface 101 and a second surface 102 opposite to the first surface 101.” Id.
¶¶ 16, 21. We have added reference numeral 101 in Figure 4B, based on the
Weyers disclosure in paragraphs 16 and 21, and the corresponding reference
numeral shown in Figures 1 and 3A. Body 100 includes “semiconductor
well region 140.” Id. ¶¶ 43–44.
Figure 4B also illustrates “a first isolation layer 200 on the first
surface 101” and “a first electrostatic discharge protection structure 310 on

3 Weyers has three inventors in common with the application on appeal:
Joachim Weyers, Franz Hirler, and Anton Mauder. Some aspects of
Appellant’s Specification are substantially identical to Weyers’ disclosure.
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the first isolation layer 200.” Id. ¶¶ 16, 21 (emphases added). Further, a
“second electrostatic discharge protection structure 320 may be formed
together with the first electrostatic discharge protection structure 310 on the
first isolation layer 200.” Id. ¶ 24 (emphasis added). Structures 310 and 320
include terminals 312, 314, 322, and 324, and polysilicon layer 300
comprising regions 316, 318, 326, and 328 of alternating conductivity. Id.
¶¶ 16, 24, 28.
B. The Examiner’s Findings
The Examiner finds Figure 4B of Weyers discloses “a trench
structure (comprising the trenches formed adjacent to and around the ESD
structures 310, 320) extending from the first surface into the silicon carbide
semiconductor body 100.” Final Act. 3 (emphases added). The Examiner
also finds ESD structures 310 and 320 are “in the trench structure.” Id.
In support, the Examiner concludes “Applicant’s recited claim
language of ‘trench’ and ‘extend’ are broad terms.” Id. at 10. The Examiner
finds ESD structures 310 and 320 “are formed in/around
3l4/316/312/326/324, which surround the ESD and extend from the
respective surfaces to the body 100 without directly contacting or
penetrating the recited elements.” Id. Further: “the term ‘extend’ does not
necessarily connote a direct contact as it merely conveys ‘spread/stretch
forth.’” Id. Moreover: “[T]he trench ‘structure’ as currently recited is a
generic trench structure that is not necessarily limited to a single and
continuously formed trench, but rather, may include, for instance, a series of
discretely formed trenches.” Adv. Act. (Continuation Sheet).
The Examiner also cites Figure 4B as showing “multiple trenches
adjacent to and around the ESD 310/320, including, for example, trench
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Application 15/951,918

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structure 140, which is within the semiconductor body 100.” Adv. Act.
(Continuation Sheet). Thus, the Examiner’s view is that, even if claim 1 is
interpreted narrowly to “connote[] an extension into the body [100]” by ESD
structures 310 and 320, “such an interpretation is met by [Weyers Figure 4B]
as at least the trench portion 140 adjacent to and around the ESD 310/320 of
[Weyers] extend from the surface into the body.” Id.
C. Appellant’s Argument
Appellant argues the Examiner errs in construing claim 1 to permit
[1] the trench structure to be formed in components other than the
semiconductor body, and [2] the electrostatic discharge protection structure
not to be in such a trench structure. Appeal Br. 4–5 (summary of pertinent
disclosures in Specification), 5–11 (claim construction argument). In
Appellant’s view, “[t]he express language of claim 1 clearly requires
confinement of the trench structure to the silicon carbide semiconductor
body.” Id. at 5–6.
Appellant then argues that Figure 4B of Weyers does not disclose that
ESD structures 310 and 320 are in a trench structure extending from a first
surface of body 100 into body 100, as is required by claim 1. Appeal Br.
6–7, 10–11. In Appellant’s view, ESD structures 310 and 320 instead are
“formed above first surface 101” of body 100, with isolation layer 200
disposed between the ESD structures and the body. Id. at 6 (emphasis by
Appellant).
D. The Examiner’s Answer
In response to Appellant’s claim construction argument, the Answer
focuses on the phrase “from the first surface” in claim 1. Ans. 9. The
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Examiner determines “no specific starting point is necessarily connoted by
‘from the first surface’ in the absence of specifying a direct extension from
said surface.” Id. (emphasis by Examiner). The Examiner also determines
no other language in claim 1 requires the electrostatic discharge protection
structure to extend directly from, or in a direct manner with respect to, any
other structure such as the trench structure. Id. at 9–10.
As to the Weyers disclosure, the Examiner reiterates that ESD
structures 310 and 320 “are formed in/around 314/316/312/326/324, which
surround the ESD and extend from the respective surfaces to the body 100
without directly contacting or penetrating the recited elements.” Id. at 9–10.
The Examiner also finds semiconductor well region 140 is “a ditch-like
structure that is formed adjacent to and around the ESD 310/320 that extends
from the surface into the body.” Id. at 11.
E. Analysis and Conclusion
As to claim construction, claim 1 recites a “body having a first
surface,” and “a trench structure extending from the first surface into the . . .
body.” Appeal Br. 16 (Claims App.) (emphases added). Claim 1 then
recites “an electrostatic discharge protection structure in the trench
structure.” Id. (emphasis added). These limitations require the trench
structure to extend “from the first surface,” that is, starting at the first surface
and extending into the body, and the ESD structure to be in the trench
structure. Based on the plain language of claim 1, the Examiner errs by
construing the claim to permit the trench structure to be found in a
component other than the body, and to permit the ESD structure to be
located entirely outside of the trench structure. The claim, instead, requires
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the trench structure to extend “into” the body, and the electrostatic discharge
protection structure to be “in” the trench structure.
The Examiner’s construction also is not consistent with Appellant’s
Specification. See, e.g., In re Am. Acad. of Sci. Tech Ctr., 367 F.3d 1359,
1364 (Fed. Cir. 2004) (during prosecution, claims are given the broadest
reasonable construction that is consistent with Appellant’s Specification).
Appellant’s Figure 3A is reproduced below, with circles added to certain
references:

Figure 3A is a cross-sectional view of semiconductor device 10. See Spec.
¶¶ 12, 41. The Specification describes Figure 3A as illustrating
semiconductor body 100 having first surface 101, and “[a] trench structure T
extends from the first surface 101 into the semiconductor body.” Spec.
¶¶ 35, 43 (emphases added). Also, “[a]n electrostatic discharge protection
structure 310 is accommodated in the trench structure T.” Id. (emphasis
added).
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Appellant’s Figure 3B is reproduced below, with circles added to
certain references:

Figure 3B is a cross-sectional view of a semiconductor device. See Spec.
¶¶ 13, 64. The Specification describes Figure 3B as illustrating
semiconductor body 100 having first surface 101, and “electrostatic
discharge protection structure 310 is formed on the dielectric layer 200,
which is formed on the first surface 101.” Id. ¶ 64 (emphases added).
“Thus, the electrostatic discharge protection structure 310 is not
accommodated within the trench structure T, as depicted in FIG. 3A, but
formed over” body 100. Id. (emphases added). Also, “further electrical
shielding may be provided by the well region 140” in body 100. Id. Thus,
Appellant’s Specification differentiates between structures 310 located “in”
a trench structure of body 100 (as shown in Figure 3A), versus
structures 310 located “over” body 100 (as shown in Figure 3B). The
Examiner’s claim construction overlooks this express distinction in
Appellant’s Specification. See, e.g., Appeal Br. 8–9; Reply Br. 2.
Next, applying our claim construction to Figure 4B of Weyers
(reproduced above), we find the discharge protection structures 310 and 320
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shown there are not located in a trench structure of body 100, but rather are
located over body 100. In particular, Weyers’ structures 310 and 320 are
located on isolation layer 200 which is located on first surface 101 of
body 100, and Weyers’ structures 310 and 320 are not in semiconductor well
region 140 of body 100.
We therefore do not sustain the rejection of claim 1 and its dependent
claims 2–4, 7, and 10–15 as anticipated by Weyers. The Examiner’s
reliance on Schmenn in relation to dependent claims 5, 6, and 8 does not
cure the deficiency of Weyers (see Final Act. 7–9), so we likewise do not
sustain the obviousness rejection of those claims.
SUMMARY OF DECISION
In summary, we reverse the Examiner’s decision to reject claims 1–8
and 10–15, as set forth in this table:
Claim(s)
Rejected
35 U.S.C. § Reference(s) Affirmed Reversed
1–4, 7,
10–15
102(a)(1) Weyers 1–4, 7,
10–15
5, 6, 8 103 Weyers,
Schmenn
5, 6, 8
Overall
Outcome
1–8,
10–15
REVERSED