Ex Parte Mieczkowski et al

Patent Trial and Appeal Board

Mar 30, 2017

13431583 (P.T.A.B. Mar. 30, 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.
13/431,583 03/27/2012 Van Mieczkowski 5308-1476 2574
65106 7590
MYERS BIGEL, P.A.
P.O. BOX 37428
RALEIGH, NC 27627
EXAMINER
BRADFORD, PETER
ART UNIT PAPER NUMBER
2897
NOTIFICATION DATE DELIVERY MODE
04/03/2017 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):
u spto @ my ersbigel. com
PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
BEFORE THE PATENT TRIAL AND APPEAL BOARD
Ex parte VAN MIECZKOWSKI, HELMUT HAGLEITNER,
and WILLIAM T. PULZ
Appeal 2016-002163
Application 13/431,58s1
Technology Center 2800
Before ROMULO H. DELMENDO, DONNA M. PRAISS, and
MONTE T. SQUIRE, Administrative Patent Judges.
PRAISS, Administrative Patent Judge.
DECISION ON APPEAL2
1 Appellants identify the real party in interest as Cree Inc. App. Br. 1.
2 In this decision we make reference to the Specification filed Mar. 27, 2012
(“Spec.”), the Final Office Action mailed Sept. 30, 2014 (“Final Act.”), the
Appeal Brief filed May 22, 2015 (“App. Br.”), the Examiner’s Answer
mailed Oct. 16, 2015 (“Ans.”), and the Reply Brief filed Dec. 11, 2015
(“Reply Br.”).
Appeal 2016-002163
Application 13/431,583
STATEMENT OF THE CASE
Appellants appeal under 35 U.S.C. § 134(a) from the Examiner’s final
rejection of claims 1—14 and 16—19. We have jurisdiction under
35 U.S.C. § 6(b).
The Invention
Appellants claim a semiconductor device comprising a wide bandgap
semiconductor material comprising a via and a via plug. Claim 1 is
illustrative (key limitation in dispute italicized):
1. A semiconductor device comprising:
a wide bandgap semiconductor material comprising a first
metallization structure on a first surface and at least one via
extending from a second surface of the semiconductor material
that is opposite the first surface to the first metallization
structure; and
a via plug provided within the at least one via, wherein the
via plug is configured to prevent metal migration during
operation of the semiconductor device.
App. Br. 11 (Claims Appx.).
The References
Takenouchi et al., (“Takenouchi”) US 5,744,758
Asai et al., (“Asai”)
Hougham et al., (“Hougham”)
Yang et al., (“Yang”)
Ring et al., (“Ring”)
Volant et al., (“Volant”)
Lin et al., (“Lin”)
Tsui et al., (“Tsui”)
US 2008/0277148 Al
US 2009/0032962 Al
US 2009/0057907 Al
US 2009/0104738 Al
US 2011/0095435 Al
US 2011/0169139 Al
US 2011/0304026 Al
Apr. 28, 1998
Nov. 13, 2008
Feb. 5, 2009
Mar. 5, 2009
Apr. 23, 2009
Apr. 28, 2011
July 14, 2011
Dec. 15,2011
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Appeal 2016-002163
Application 13/431,583
The Rejections
The Examiner maintains, and Appellants appeal, the rejections under
35 U.S.C. § 103(a) as follows: (1) claims 1, 4, 5, 13, 14, 16, and 18 over Lin
in view of Ring, (2) claims 2—12 and 19 over Lin, Ring, Tsui, Yang,
Hougham, Volant, and Takenuchi, (3) claims 14 and 16 over Lin, Ring, and
Tsui, and (4) claim 17 over Lin, Ring, Tsui, and Yang. Ans. 2; App. Br. 5—
9; Linal Act. 3—8.
OPINION
We reverse. We need to address only independent claim 1, which is
the sole independent claim, because each of the rejections is based on the
same combination of Lin and Ring.
The Examiner finds that Lin discloses all of the limitations of claim 1
except for the substrate being a wide bandgap semiconductor. Ans. 3^4.
The Examiner also finds that “Lin discloses a method for forming a
packaged substrate with a via that is applicable to many different kinds of
devices, including many wide bandgap devices.” Pinal Act. 4 (citing “the
monolithic microwave integrated circuits of Ring which are formed of
silicon carbide substrates.”). The Examiner concludes that “[i]t would have
been obvious to use the method of Lin to make a SiC device in order to
produce a chip with a reliable via that will not delaminate.” Ans. 4 (citing
Lint 18).
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Application 13/431,583
In the Appeal Brief, Appellants contend that the Examiner’s rejection
is flawed because “there is no motivation to combine Lin and Ring.” App.
Br. 5. Specifically, Appellants contend that “Ring addresses problems
associated with etching SiC” and that “etching SiC is generally anisotropic”
while “[ejtching in silicon is generally isotropic.” Id. at 5—6. According to
Appellants, Ring discloses that “multiple etch steps are performed to account
for the different features” and “substituting the method of Lin, which only
pertains to etching silicon . . . would render Ring unsatisfactory for its
intended purpose.” Id. at 6 (citing Ring 140). Regarding forming a via
structure in the via hole as disclosed in Lin and applying the method to the
the disclosure of Ring, Appellants argue that because Lin’s trench formation
is relied upon in the rejection, the methodology applied in Lin would render
Ring unsatisfactory for its intended purpose. Id. at 7—8. Appellants also
argue that because the methods used in silicon as disclosed in Lin will not
work in Ring, the Examiner’s reason for combining Ring with Lin is flawed
and the combination is improper. Id. at 8.
The Examiner responds that “appellant has presented its own
combination of the references and argues against that.” Ans. 2. The
Examiner restates the rejection as follows:
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Application 13/431,583
The only difference between Lin and the claimed invention is
that Lin does not disclose a wide bandgap semiconductor
material in which the via is formed. Ring was cited for a device
with a similar via through a wide bandgap semiconductor. The
advantage of using the via plug 124 as taught by Lin (to prevent
delamination) is general, and can be straightforwardly applied to
prevent delamination in wide bandgap devices such as that of
Ring. Thus Ring was cited only for the proposition that vias are
formed in wide bandgap devices, and can benefit from the
method of forming a buffer plug in a via hole disclosed by Lin.
Id. at 3. Regarding Appellants’ argument that the method of forming a via
from Lin cannot be applied to form a via in Ring, the Examiner says that “is
difficult to evaluate .. . because Lin does not disclose any specific method of
forming the via hole.” Id. at 4. After addressing etching and drilling
disclosures in the cited references, the Examiner states that Appellants’
argument is “inapplicable to the rejections” because “[t]he examiner does
not propose etching the via hole of Ring using the etching process of Lin.”
Id. at 6. The Examiner also responds that Appellants “never explained why
the method of forming the via structure in the hole, the inventive portion of
Lin, cannot be separated from the etching process used to form the via.” Id.
at 8.
In the Reply Brief, Appellants argue that one of ordinary skill in the
art would not have incorporated only the buffer plug of Lin into the via of
Ring because Lin uses the buffer plug to address a specific situation. Reply
Br. 2—3. According to Appellants, “Lin teaches that by forming a soft buffer
plug 124 in the via 114 between the conductive trace layer 120 and the
protective layer 126, such delamination may be avoided because the soft
buffer plug 124 is only partially cured and hence will exhibit poor adhesion
to an adjacent material layer.” Id. at 3. Appellants further argue that there is
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Application 13/431,583
no reason a skilled artisan would have been motivated to use the plug of Lin
in the device of Ring because Ring “does not use any protection layer” and
therefore Ring also “does not disclose a protection layer that is formed of a
material that tends to shrink under certain conditions.” Id. at 4.
Appellants also assert that Ring discloses a via in its semiconductor
device that is “completely filled with a conductive contact plug 40/41.” Id.
at 3 (citing Figs. 10 and 11, items 40, 41; bolding and underlining omitted).
Thus, “the only material deposited in the via of Ring is conductive contact
metal 40/41.” Id., (bolding omitted). According to Appellants, including
the buffer plug of Lin in the device of Ring would be counterproductive as it
would reduce the amount of metal in the via [of Ring] and hence increase
the resistance of the contact.” Id. at 4—5. Finally, Appellants argue that
claim 1 requires that via plug be “configured to prevent metal migration
during operation of the semiconductor device” and that the Specification
describes a cured high temperature polymer may be used to prevent such
metal migration. Id. at 5 (citing Spec. 1 33). Appellants contend there is
“no indication in Lin that... a partially cured buffer plug will prevent metal
migration.” Id.
We agree with Appellants that the stated reasons for combining Lin
and Ring do not have a rational underpinning to support the Examiner’s
combination. Obviousness of a claim cannot be proved “merely by
demonstrating that each of its elements was, independently, known in the
prior art.” KSRInt’l Co. v. Teleflex, Inc., 550 U.S. 398, 418 (2007).
“[T]here must be some articulated reasoning with some rational
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Application 13/431,583
underpinning to support the legal conclusion of obviousness.” Id. (quoting
In re Kahn, 441 F.3d 977, 988 (Fed. Cir. 2006)).
The Examiner’s finding that one of ordinary skill in the art would
have modified Lin’s semiconductor device comprising a via plug with a
wide bandgap semiconductor material as disclosed by Ring “to prevent
delamination in wide bandgap devices” is not reasonable because we are
directed to no evidence on this record that Ring’s wide bandgap device
requires that a conductive trace layer be prevented from delaminating as
does Lin’s device, which has a protection layer causing a pull up force that
Lin’s plug offsets. Ans. 2—3 (citing Lin 118); Reply Br. 4. Nor are we
directed to any evidence of “other advantages of the structure disclosed by
Lin” (Final Act. 4) or that the advantage of using the via plug taught by Lin
“can be straightforwardly applied to prevent delamination in wide bandgap
devices” (Ans. 3). Based on the record before us, the preponderance of the
evidence does not support the combination of Lin’s device, comprising a via
plug, with the wide bandgap semiconductor material of Ring for the purpose
of preventing delamination with the via plug.
We therefore reverse the rejection of claim 1 over the combination of
Lin and Ring for the reasons stated above and in the Reply Brief. Reply Br.
2—5. Because claim 1 is the only independent claim and the deficiencies of
the combination of Lin and Ring apply equally to the rejections of dependent
claims 2—14 and 16—19, we reverse the rejection of claims 2—14 and 16—19
for the same reason. Accordingly, we reverse the rejections of claims 1—14
and 16-19 under 35 U.S.C. § 103(a).
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Application 13/431,583
DECISION/ORDER
The rejections under 35 U.S.C. § 103(a) of claims 1—14 and 16—19 are
reversed.
It is ordered that the Examiner’s decision is reversed.
REVERSED
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