Infineon Technologies AG

Patent Trials and Appeals Board

Jun 2, 2021

2020004218 (P.T.A.B. Jun. 2, 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.
15/817,810 11/20/2017 Markus Zundel 1012-2021 /
2016P51980 US
9336
57579 7590 06/02/2021
MURPHY, BILAK & HOMILLER/INFINEON TECHNOLOGIES
1255 CRESCENT GREEN
SUITE 200
CARY, NC 27518
EXAMINER
WALL, VINCENT
ART UNIT PAPER NUMBER
2822
NOTIFICATION DATE DELIVERY MODE
06/02/2021 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 MARKUS ZUNDEL,
RAINER PELZER,
and MANFRED SCHNEEGANS
__________

Appeal 2020-004218
Application 15/817,810
Technology Center 2800
___________

Before ADRIENE LEPIANE HANLON, JAMES C. HOUSEL, and
JULIA HEANEY, Administrative Patent Judges.

HANLON, Administrative Patent Judge.

DECISION ON APPEAL

A. STATEMENT OF THE CASE
The Appellant1 filed an appeal under 35 U.S.C. § 134(a) from an Examiner’s
decision finally rejecting claims 11–18. Claims 1–10 and 19–23 are also pending
but have been withdrawn from consideration. We have jurisdiction under
35 U.S.C. § 6(b).

1 We use the word “Appellant” to refer to “applicant” as defined in 37 C.F.R.
§ 1.42. The Appellant identifies the real party in interest as Infineon Technologies
AG. Appeal Brief dated February 21, 2020 (“Appeal Br.”), at 2.
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We REVERSE and enter a new ground of rejection under 37 C.F.R. §
41.50(b).
Claim 11, the sole independent claim on appeal, is reproduced below from
the Claims Appendix to the Appeal Brief. The limitation at issue is italicized.
11. A method of processing a power semiconductor device, the
method comprising:
providing a semiconductor body configured to conduct a load
current;
forming a first load terminal electrically connected with the
semiconductor body and configured to couple the load current into
and/or out of the semiconductor body, wherein the first load terminal
comprises a metallization having a frontside and a backside, the
backside interfacing with a surface of the semiconductor body and the
frontside being configured to interface with a wire structure having at
least one wire configured to conduct at least a part of the load current,
wherein forming the first load terminal further comprises:
laterally structuring the frontside of the metallization by
forming at least one local elevation of the metallization so that the
metallization has a local increase of depth in a region of the at least
one local elevation and a lesser, non-zero depth outside the region of
the at least one local elevation, the at least one local elevation having
a height in an extension direction defined by the distance between a
base and a top of the local elevation and, in a first lateral direction
perpendicular to the extension direction, a base width at the base and a
top width at the top, wherein the at least one local elevation is formed
such that the top width amounts to less than 90% of the base width,
wherein there is neither a material barrier within the at least one
local elevation itself nor between the at least one local elevation and a
remaining section of the metallization outside the region of the at
least one local elevation.
Appeal Br. 19.
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On appeal, the Appellant seeks review of the Examiner’s rejection of claims
11–18 under 35 U.S.C. § 112(a) based on the written description requirement.2
B. DISCUSSION
By way of background, the Examiner made the following restriction
requirement in the instant Application.
Group I. Claims 1–10, drawn to a device, classified in H01L24/05.
Group II. Claims 11–23, drawn to a method, classified in H01L24/03.
Office Action dated April 13, 2018 (“Office Act.”), at 2.
With respect to the method, the Examiner also indicated that claim 11 is
generic to the following patentably distinct species disclosed in the Appellant’s
Specification.
Species C1: figures 6–9;
Species C2: figure 10;
Species C3: figure[s] 11–13; and
Species C4: figure 14.
Office Act. 3–4.
The Appellant elected the invention of Group II (method) and Species C1
(Figures 6–9).3 Response dated June 12, 2008 (“Response”). Thus, claims 11–18,
drawn to Species C1, were subsequently examined.
In the rejection under 35 U.S.C. § 112(a) on appeal, the Examiner finds that
the original disclosure does not provide written description support for the

2 The Examiner withdrew the obviousness rejection of claims 11–18 based on the
combination of Kelberlau, Hackenberger, and Lin. Examiner’s Answer dated
March 20, 2020 (“Ans.”), at 3.
3 The Appellant contends that Figure 10, identified by the Examiner as Species C2,
should be part of Species C1. Response.
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following limitation recited in claim 11: “wherein there is neither a material
barrier within the at least one local elevation itself nor between the at least one
local elevation and a remaining section of the metallization outside the region of
the at least one local elevation.” Final Act. 3.4
More specifically, the Examiner finds that the original disclosure provides
written description support for the limitation at issue with respect to non-elected
Species C3 (Figures 11–13), but does not provide written description support for
the limitation at issue with respect to elected Species C1 (Figures 6–9). Ans. 7.
1. Claim 11
Figure 11 (Species C3), reproduced below, illustrates a method of
processing a power semiconductor device according to the Appellant’s invention.

4 Final Office Action dated July 23, 2019.
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Appellant’s Figure 11 depicts three steps of a method
of processing a power semiconductor device
according to the Appellant’s invention.
The method includes the following steps:
Step 21: forming a conductive layer 111 on the top surface 101 of a
semiconductor body by means of carrying out a first electroplating processing
step. Spec. ¶ 80.
Step 22: providing a first mask 31 on top of the conductive layer 111,
wherein the first mask includes at least one first mask element 311 that spatially
confines at least one first opening 312. Spec. ¶ 80.
Step 23: carrying out a second electroplating processing step to fill the at
least one first opening 312 with a conductive material, thereby forming at least one
local elevation 112. Spec. ¶ 80.
The Appellant discloses that
the first and the second electroplating processing steps are carried out
with the same material such that there is no material barrier between
the local elevation 112 and the remaining section of the metallization
111. For example, the same bath is used for carrying out the first and
the second electroplating processing steps.
Spec. ¶ 81.
Similarly, paragraphs 82–83 of the Specification and Figure 12 (Species
C3), disclose another method of processing a power semiconductor device,
wherein at least one local elevation 112 is formed using a two-step filling process
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(i.e., steps 23 and 27) that may be carried out by a “respective electroplating
process step.” The Appellant discloses that
said electroplating processing steps can be carried out with the same
material, e.g., by using the same bath, such that there is neither a
material barrier within the local elevation 112 itself nor between the
local elevation 112 and the remaining section of the metallization 111.
Spec. ¶ 83.
The Appellant argues that paragraphs 81 and 83 of the Specification
“provide direct, literal support” for the claim limitation at issue, and the Examiner
“agrees that ¶¶ 0081 and 83 support the negative limitation in regards to non-
elected Species C3, figures 11–13.” Appeal Br. 17 (emphasis omitted); Ans. 7.
Therefore, the rejection of claim 11 under 35 U.S.C. § 112(a) is not sustained.
2. New ground of rejection
Claim 12 depends from claim 11 and recites that the laterally structuring
step recited in claim 11 includes an etch processing step rather than the
electroplating steps described in Species C3 (Figures 11–13). Claims 13–18
depend either directly or indirectly from claim 12.
Claim 12 is reproduced below from the Claims Appendix to the Appeal
Brief.
12. The method of claim 11, wherein laterally structuring the
frontside of the metallization comprises:
forming a conductive layer on top of the surface;
providing a first mask on top of the conductive layer, the first
mask including at least one first mask element;
carrying out a first etch processing step to back-thin the
conductive layer in sections not covered by the at least one first mask
element, wherein the back-thinning of the conductive layer spatially
confines the at least one local elevation, and wherein the back-
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thinning has a first lateral overlap with the at least one first mask
element that amounts to at least 1 µm.
Appeal Br. 20.
Figure 6, reproduced below, illustrates the Appellant’s etching process.

Appellant’s Figure 6 depicts four steps of a method
of processing a power semiconductor device
according to the Appellant’s invention.
The method includes the following steps:
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Step 21: forming a conductive layer 111 on the top surface 101 of a
semiconductor body. Spec. ¶ 71.
Step 22: providing a first mask 31 on top of the conductive layer 111,
wherein the first mask includes at least one first mask element 311. Spec. ¶ 71.
Step 24: carrying out a first etch processing step so as to back-thin the
conductive layer 111 in sections not covered by the at least one first mask element
311, wherein the created back-thinning 113 spatially confines the at least one local
elevation 112. Spec. ¶ 71.
The original disclosure does not include a description corresponding to
paragraphs 81 and 83 in the Specification for the species disclosed in Figures 6–9
(elected Species C1).
The Examiner finds that the disclosed etching process depicted in Figures 6–
9 (elected Species C1) does not provide written description support for the claim
limitation at issue “because no material is added to Species C1 as it is added by
electroplating in Species C3.” Ans. 7 (emphasis added).
Based on the foregoing, it is unclear whether the claim limitation at issue
limits the claimed method or the device formed by the claimed method. The
Appellant discloses that the “electroplating processing steps are carried out with
the same material such that there is no material barrier between the local elevation
112 and the remaining section of the metallization 111.” Spec. ¶ 81 (emphasis
added). Thus, it appears that the negative limitation at issue limits the device
formed by the claimed method. However, the Examiner interprets the limitation as
a step in the claimed method. See Ans. 7 (contending that Appellant is “attempting
to mix a process step[] (e.g. a negative limitation) between embodiments” (i.e.,
between Species C3 and C1)).
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Moreover it is unclear on this record what conditions are necessary to satisfy
the negative claim limitation at issue apart from the local elevation(s) and the
remaining metallization section being the same material.5 Contributing to the
confusion of the scope of claim 11 (and claims 12–18 which depend from claim
11) is the absence of any definition or description of a “material barrier” in the
original disclosure.
Based on the foregoing, we conclude that the following negative limitation
recited in claim 11 is indefinite:
wherein there is neither a material barrier within the at least one local
elevation itself nor between the at least one local elevation and a
remaining section of the metallization outside the region of the at least
one local elevation.
Appeal Br. 19. Therefore, we enter a new ground of rejection of claims 11–18
under 35 U.S.C. § 112(b) based on indefiniteness.
3. Claims 12–18
As discussed above, the negative limitation recited in claim 11 is indefinite.
Therefore, it is unclear whether the original disclosure provides written description
support for the method of claims 12–18, directed to elected Species C1, where the
local elevation(s) and the remaining metallization section of the resulting device
appear to be the same material.
We decline to engage in assumptions as to the scope of claims 12–18, which
either directly or indirectly depend from claim 11, in considering whether the
Appellant has identified a reversible error in the written description rejection on

5 See Appeal Br. 11 (arguing, in response to the withdrawn obviousness rejection,
that “any local elevation formed using Hackenberger’s isotropic structuring will
necessarily have a material barrier both within the local elevation and between the
local elevation and the remaining section of the metallization . . . outside the local
elevation” (emphasis omitted)).
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appeal. For that reason, the rejection of claims 12–18 under 35 U.S.C. § 112(a),
based on the written description requirement, is not sustained. See In re Steele,
305 F.2d 859, 862–63 (CCPA 1962) (reversing obviousness rejection because it
was based on speculation as to the meaning of claim terms and assumptions as to
claim scope). It should be understood that our decision is based solely on the
indefiniteness of the claimed subject matter and not on the merits of the written
description rejection on appeal.
C. DECISION
The Examiner’s decision is reversed. Additionally, a new ground of
rejection under 37 C.F.R. § 41.50(b) is entered.
In summary:

Claims
Rejected
35
U.S.C. §
Reference(s)/Basis Affirmed Reversed6 New
Ground
11–18 112(a) Written description 11–18
11–18 112(b) Indefiniteness 11–18
Overall
Outcome
11–18

This decision contains a new ground of rejection pursuant to 37 C.F.R.
§ 41.50(b). 37 C.F.R. § 41.50(b) provides, “A new ground of rejection pursuant to
this paragraph shall not be considered final for judicial review.”
37 C.F.R. § 41.50(b) also provides that the Appellant, WITHIN TWO
MONTHS FROM THE DATE OF THE DECISION, must exercise one of the

6 As explained above, our reversal of the written description rejection on appeal is
based solely on the indefiniteness of the claimed subject matter and not on the
merits of the written description rejection.
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following two options with respect to the new ground of rejection to avoid
termination of the appeal as to the rejected claims:
(1) Reopen prosecution. Submit an appropriate amendment of
the claims so rejected or new Evidence relating to the claims so
rejected, or both, and have the matter reconsidered by the examiner, in
which event the prosecution will be remanded to the examiner. . . .
(2) Request rehearing. Request that the proceeding be reheard
under §41.52 by the Board upon the same Record. . . .
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).

REVERSED; 37 C.F.R. § 41.50(b)