Ex Parte Ganitzer et al

Patent Trials and Appeals Board

Jan 31, 2019

14171839 - (D) (P.T.A.B. Jan. 31, 2019)

UNITED STA TES p A TENT AND TRADEMARK OFFICE
APPLICATION NO. FILING DATE
14/171,839 02/04/2014
81722 7590 02/04/2019
Viering, Jentschura & Partner mbB - Inf
c/o
444 Brickell A venue
Suite 51270
Miami, FL 33131
FIRST NAMED INVENTOR
Paul Ganitzer
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
ATTORNEY DOCKET NO. CONFIRMATION NO.
P54552US 3607
EXAMINER
JONES, ERIC W
ART UNIT PAPER NUMBER
2892
NOTIFICATION DATE DELIVERY MODE
02/04/2019 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):
patint@vjp.de
vjp-us@vjp.de
PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
BEFORE THE PATENT TRIAL AND APPEAL BOARD
Ex parte PAUL GANITZER, ARNO ZECHMANN,
and MICHAEL JACOB
Appeal2018-000058
Application 14/171,839
Technology Center 2800
Before ADRIENE LEPIANE HANLON, TERRY J. OWENS, and
MONTE T. SQUIRE, Administrative Patent Judges.
SQUIRE, Administrative Patent Judge.
DECISION ON APPEAL 1
Appellant2 appeals under 35 U.S.C. § 134(a) from the Examiner's
decision to finally reject claims 1-30, which constitute all the claims
pending in this application. We have jurisdiction under 35 U.S.C. § 6(b).
We REVERSE.
1 In explaining our Decision, we refer to the Specification filed February 4,
2014 ("Spec."); Final Office Action dated November 10, 2016 ("Final
Act."); Advisory Action dated January 3, 2017 ("Adv. Act."); Appeal Brief
filed April 18, 2017 ("Appeal Br."); Examiner's Answer dated August 11,
2017 ("Ans."); and Reply Brief filed October 2, 2017 ("Reply Br.").
2 Appellant is Applicant Infineon Technologies AG (Bib Data Sheet 1 ),
which is also identified as the real party in interest (Appeal Br. 3).
Appeal2018-000058
Application 14/171,839
The Claimed Invention
Appellant's disclosure relates to a wafer based BEOL (back end of
line) process for chip embedding. Spec. ,r 1. The Specification describes a
semiconductor device, including a semiconductor body with a drift region
and a gate electrode arranged adjacent to the drift region; a contact structure
provided over the drift region of the semiconductor body and having a first
metal layer, an adhesion layer over the first metal layer and a second metal
layer over the adhesion layer; and a method for manufacturing the
semiconductor device. Id. ,r,r 6, 85; see also Abstract.
Claim 1 is illustrative of the claimed subject matter on appeal and is
reproduced below from the Claims Appendix to the Appeal Brief:
1. A semiconductor device, comprising:
a semiconductor body having a front side and a
back side opposite to the front side, the semiconductor
body comprising a semiconductor layer, a drift region
and a gate electrode arranged adjacent to the drift region,
wherein the drift region and the gate electrode are
incorporated within the semiconductor layer; and
a contact structure provided over the
semiconductor body at a position located over the drift
region of the semiconductor body and having a first
metal layer, an adhesion layer over the first metal layer
and a second metal layer over the adhesion layer,
wherein the contact structure electrically and
mechanically contacts the drift region at the front side of
the semiconductor body, and wherein the first metal layer
does not extend over the gate electrode; and
a back side metal layer disposed on the back side
of the semiconductor body, wherein the back side metal
layer electrically contacts the drift region at the back side
of the semiconductor body.
Appeal Br. 22 (Claims App.).
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Appeal2018-000058
Application 14/171,839
The References
The Examiner relies on the following prior art references as evidence
in rejecting the claims on appeal:
Wieczorek et al.,
("Wieczorek")
Chang et al.,
("Chang")
Wu
Hayashi
Hsieh
US 2002/0056879 Al May 16, 2002
US 2007 /0075360 Al Apr. 5, 2007
US 2007 /0075362 Al Apr. 5, 2007
US 2008/0073706 Al Mar. 27, 2008
US 2009/0315106 Al Dec. 24, 2009
The Rejections
On appeal, the Examiner maintains (Ans. 1-2) the following
rejections:
1. Claims 1-8, 13, 14--18, and 26-30 rejected under
35 U.S.C. § 103 as being unpatentable over Wu in view of Hsieh
("Rejection 1 "). Final Act. 3.
2. Claims 9 and 19 rejected under 35 U.S.C. § 103 as being
unpatentable over Wu and Hsieh as applied to claims 1 and 14, respectively
above, and further in view of Hayashi ("Rejection 2"). Final Act. 11.
3. Claims 10-12 and 20-23 rejected under 35 U.S.C. § 103 as
being unpatentable over Wu and Hsieh as applied to claims 1 and 14,
respectively above, and further in view of Wieczorek ("Rejection 3"). Final
Act. 12.
4. Claims 24 and 25 rejected under 35 U.S.C. § 103 as being
unpatentable over Wu in view of Chang and Hsieh ("Rejection 4"). Final
Act. 15.
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Appeal2018-000058
Application 14/171,839
Re;ection 1
OPINION
Having considered the respective positions advanced by the Examiner
and Appellant in light of this appeal record, we reverse the Examiner's
Rejection 1 for principally the same reasons provided by Appellant at pages
14--18 of the Appeal Brief and pages 3-8 of the Reply Brief. We add the
following.
The Examiner determines that the combination of Wu and Hsieh
suggests a semiconductor device satisfying all of the limitations of claim 1
and thus, concludes that the combination would have rendered the claim
obvious. Final Act. 3-5 (citing Wu, Figs. 3A-3G, ,r,r 21, 25-27; Hsieh, Fig.
3, ,r,r 14, 35, and 44).
The Examiner concludes that
it would have been obvious to one having ordinary skill
in the art at the time the invention was made to use the
back side metal layer disposed on the back side of the
semiconductor body, wherein the back side metal layer
electrically contacts the drift region at the back side of
the semiconductor body of Hsieh with the structure of
Wu to provide lower resistance drain ohmic contacts.
Id. at 4--5 (citing Hsieh ,r 25). The Examiner finds and acknowledges that,
from a structural standpoint, the proposed combination of Wu and Hsieh
would result in "the modification of the contact structure of Wu to include
the source contact plugs of Hsieh." Ans. 3.
Appellant argues that the Examiner's rejection should be reversed
because "one skilled in the art would not have a reason or have been
motivated to combine the teachings of Wu and Hsieh as proposed." Appeal
Br. 15; see also Reply Br. 3-8. In particular, Appellant contends that it
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Appeal2018-000058
Application 14/171,839
would not make sense to introduce the contact plug 222 of Hsieh into the
device of Figure 3G of Wu because the structure of Wu's device is
specifically designed for planar contacts and not for contact plugs. Id. at 16-
17 ( citing Wu, Fig. 3G; Hsieh, Fig. 3). Appellant argues that, in effect, the
Examiner's proposed combination would result in Wu's device, which is
based and designed around planar contacts exposed at the surface of the
semiconductor body, being modified and replaced to include the trench
contact plugs of Hsieh. Reply Br. 3.
Appellant maintains that
it would be illogical to replace Wu's planar structures
(e.g., elements 210/211), which are located above the
semiconductor body (201 ), with contact plugs from
Hsieh positioned above said semiconductor body for the
reason that Hsieh specifically discloses replacing planar
structures with contact plugs that extend into and within a
semiconductor body.
Id. at 7 (formatting omitted).
The weight of the evidence supports Appellant's argument. We agree
that the Examiner has not established by a preponderance of the evidence
that one of ordinary skill in the art would have combined the teachings of
Wu and Hsieh to arrive at the claimed invention for the reasons proposed by
the Examiner. In re Oetiker, 977 F.2d 1443, 1445 (Fed. Cir. 1992) (holding
that the examiner bears the initial burden of establishing a prima facie case
of obviousness).
As Appellant correctly points out (Appeal Br. 16; Reply. Br. 3), Wu's
device is specifically designed for planar contacts (210/211) located above
the semiconductor body 201, and not for contact plugs. Wu, Fig. 3G, ,r 27
( disclosing that the "source metal layer 211 is formed over a formed
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Appeal2018-000058
Application 14/171,839
structure surface"). As shown in Figure 3G of Wu, the p-base diffusion ring
204b and the heavily-doped n+ source diffusion ring 205b are both designed
to extend to and be exposed at the surface of the semiconductor body 201.
Id. ,I 28.
In contrast, as shown in Figure 3 of Hsieh, Hsieh's device requires
contact plugs 222 that extend down into the semiconductor layer to reach
and contact then+ region 212 and p region 204. Hsieh ,r 35 ("Trench
contacts are penetrating through source region 212 and into the body region
204 with an area of P+ doped area 240 at the bottom of each trench to reduce
the resistance between trench contact metal plug 222 and body region in the
trench MOSFET device portion."). As further contrast to Wu's device with
planar contacts, Hsieh explicitly discloses at paragraph 12 that in its
invention "the planar contact for both the MOSFET devices and Schottky
barrier rectifier devices are replaced by the trench Schottky structure."
The Examiner does not identify evidence or provide reasoning
sufficient to support a finding that one of ordinary skill would have had
reason to modify Wu's device to replace planar contacts exposed at the
surface of the semiconductor body with trench contact plugs that extend
down into the semiconductor body, as would be required to arrive at the
claimed invention. See KSR Int'! Co. v. Teleflex Inc., 550 U.S. 398,418
(2007) (requiring "reasoning with some rational underpinning to support the
legal conclusion of obviousness") ( quoting In re Kahn, 441 F .3d at 988). In
particular, at pages 3-5 of the Answer, the Examiner does not persuasively
respond to Appellant's principal argument that one of ordinary skill would
have had no reason to modify Wu's device in the manner claimed. For
example, the Examiner does not direct us to any teaching or suggestion in
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Application 14/171,839
the prior art regarding the technical feasibility of substituting planar contacts
with trench contact plugs; or why one of ordinary skill in the art would have
had a reasonable expectation of success in modifying Wu's device in such a
manner.
The Examiner's assertions that "[A]ppellant's approach to forming the
claimed contact structure is commonly known" (Ans. 4) and that Wu's
device and the prior art "produce the same result, a common source
electrode" (id. at 5) are not persuasive because they are conclusory and,
without more, insufficient to sustain the Examiner's rejection. In re Kahn,
441 F.3d 977,988 (Fed. Cir. 2006) (holding that rejections "cannot be
sustained by mere conclusory statements").
We, therefore, cannot sustain the Examiner's rejection.
Accordingly, we reverse the Examiner's rejection of claims 1-8, 13,
14--18, and 26-30 under 35 U.S.C. § 103 as obvious over the combination of
Wu and Hsieh.
Reiections 2. 3. and 4
The foregoing deficiencies in the Examiner's analysis and conclusion
regarding Rejection 1 and flawed reasoning for combining Wu and Hsieh are
not remedied by the Examiner's findings regarding the additional references
or combination of references cited in support of the second, third, and fourth
grounds of rejection (Rejections 2, 3, and 4 stated above).
Accordingly, for principally the same reasons discussed above in
reversing the Examiner's Rejection 1, we also reverse the Examiner's
Rejections 2, 3, and 4.
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Appeal2018-000058
Application 14/171,839
DECISION
The Examiner's rejections of claims 1-30 are reversed.
It is ordered that the Examiner's decision is reversed.
REVERSED
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