Ex Parte Fujiwara et al

Patent Trial and Appeal Board

Mar 2, 2017

13604452 (P.T.A.B. Mar. 2, 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.
13/604,452 09/05/2012 Kazuyuki FUJIWARA 005700-ME0005 1277
78198 7590 03/06/2017
StiiHehaker & Rraokett PP EXAMINER
8255 Greensboro Drive GONDARENKO, NATALIA A
Suite 300
Tysons, VA 22102 ART UNIT PAPER NUMBER
2891
NOTIFICATION DATE DELIVERY MODE
03/06/2017 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
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PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
BEFORE
THE PATENT TRIAL AND APPEAL BOARD
Ex parte KAZUYUKI FUJIWARA,1
Kazunori Inoue, and Takahito Yamabe
Appeal 2015-006681
Application 13/604,452
Technology Center 2800
Before MARK NAGUMO, GEORGE C. BEST, and JULIA HEANEY,
Administrative Patent Judges.
NAGUMO, Administrative Patent Judge.
DECISION ON APPEAL
Kazuyuki Fujiwara, Kazunori Inoue, and Takahito Yamabe
(“Fujiwara”) timely appeal under 35 U.S.C. § 134(a) from the Final
Rejection2 of all pending claims 5—8. We have jurisdiction. 35 U.S.C. § 6.
We reverse for the reasons well-stated by Fujiwara.
1 The real party in interest is identified as Mitsubishi Electric Corporation.
(Appeal Brief, filed 16 February 2015 (“Br.”), 2.)
2 Office action mailed 11 September 2014 (“Final Rejection”; cited as
“FR”).
Appeal 2015-006681
Application 13/604,452
OPINION
A. Introduction3
The subject matter on appeal relates to wiring films used as an
electrode of a thin-film transistor, for example, on an array substrate of a
liquid crystal display apparatus. (Spec. 1,11. 5—8.) The ’452 Specification
teaches that general prior art wet etching techniques for aluminum (Al) films
result in substantially vertical sidewalls of the Al wiring film. The vertical
side walls cause the insulating film formed on the Al wiring film, in the
words of the Specification, “to have a poor step coverage characteristic, and,
as a result, cause [] a reduction of a breakdown voltage of the insulating film,
broken wiring of the wiring film of an upper layer, or the like, which
eventually causes a drop in the yield of the product.” {Id. at 2,11. 8—11.)
Prior art tapered profile wiring films are said to require careful control of the
constantly-changing etchant composition. {Id. at 11. 12—15.) Fujiwara seeks
patent protection for an aluminum wiring film that can be applied to an
active matrix substrate of a display apparatus with good contact and that can
be covered better with insulating layers to increase the breakdown voltage.4
The composition and purpose of the various layers of the wiring films
can be understood best by considering the method of making the wiring film.
The improved tapered wiring films are obtained by providing a first
3 Application 13/604,452, Wiring film and active matrix substrate using the
same, and method for manufacturing wiring film, filed 5 September 2012,
claiming the benefit of an application filed in Japan on 6 September 2011.
We refer to the “’452 Specification,” which we cite as “Spec.”
4 USPTO records indicate that claims to the process of making the wiring
films are the subject of co-pending division 14/340,284.
2
Appeal 2015-006681
Application 13/604,452
layer 201a5 of aluminum doped with 0.5 to 10 mol% of a group 10 metal
(i.e., Ni, Pd, or Pt), a second layer 201b doped with 10-40 mol% nitrogen,
and a third layer 201c that can be identical to the first layer. (Id. at 16,
11. 20-25; Fig. 13, not reproduced here.) The same target can be sputtered to
form all three layers, with nitrogen gas mixed with the Ar gas for reactive
sputtering of the second layer. (Id. at 17,1. 23, to 18,1. 3.) The group 10
metals are said to increase the etching rate of the aluminum with respect to
organic alkaline developing solutions such as tetramethylammonium
hydroxide (“TMAH”) by a factor of at least five. (Id. at 10,11. 1 4.) The
presence of nitrogen in the second layer is said to decrease the etching rate
relative the etching rate of the first and third layers, preferably by a factor of
at least five. (Id. at 18,11. 13—16.)
Tapered wiring films are prepared by provide a photoresist mask 102
on top of the three-layered film, and etching the film with TMAH, as shown
in Fig. 14, below.
(Fig. 14 shows photoresist 102 on tri-layered TMAH-etched film 201}
5 Throughout this Opinion, for clarity, labels to elements are presented in
bold font, regardless of their presentation in the original document.
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Appeal 2015-006681
Application 13/604,452
Nitrogen-doped A1 layer 201b resists etching, so Ni-doped layer 201c is
etched laterally underneath photoresist 102, resulting in notches 103.
{Id. at 19,11. 5—11.) Next, the entire assembly is subjected to wet etching
with a PAN series etchant (phosphoric acid, acetic acid, and nitric acid
series), which etches all the metal layers, resulting in an inclined sidewall of
the A1 wiring film, as illustrated in Fig. 15, below.
(Fig. 15 shows mask 102 on top of PAN-etched tapered wiring film 201}
Photoresist 102 is then removed, leaving a tapered wiring film as shown in
Fig. 12, below.
(Fig. 12 shows three-layered tapered wiring film 201 on substrate 100}
Claim 5 is representative and reads:
A wiring film comprising:
a first layer made of a first A1 alloy containing at least one
element of Ni, Pd, and Pt;
a second layer laid on said first layer and made of a
second Al alloy containing nitrogen; and
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Application 13/604,452
a third layer laid on said second layer and made of a third
A1 alloy containing at least one element of Ni, Pd, and Pt,
wherein the wiring film has a tapered shape in cross section
with a width smaller in an upper portion thereof than
a width in a bottom portion thereof.
(Claims App., Br. 7; some indentation, paragraphing, and emphasis added.)
The Examiner maintains the following ground of rejection:6,7’6 7 8
Claims 5—8 stand rejected under 35 U.S.C. § 103(a) in view of the
combined teachings of Hino9 and Gotoh.10
B. Discussion
Findings of fact throughout this Opinion are supported by a
preponderance of the evidence of record.
Briefly, the Examiner finds that Hino teaches a three-layer film with
aluminum or aluminum alloy layers X', Y, and X, and that, in view of the
teachings of Gotoh, it would have been obvious to provide layer Y as a layer
of aluminum containing nitrogen.
Fujiwara urges the Examiner erred harmfully in combining the
teachings of Hino and Gotoh because Hino ([0124]) teaches that layer Y
must have a resistivity lower than the resistivity of layer X, whereas Gotoh
6 Examiner’s Answer mailed 7 May 2015 (“Ans.”).
7 Because this application was filed before the 16 March 2013 effective date
of the America Invents Act, we refer to the pre-AIA version of the statute.
8 The Examiner has withdrawn a rejection under 35 U.S.C. § 112(1) for lack
of adequate written description. (Ans. 2.)
9 Aya Hino et al., Display Device, U.S. Patent Application Publication
2010/0163877 A1 (2010).
10 Hiroshi Gotoh et al., Display Device, U.S. Patent 7,262,085 B2 (2007).
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Appeal 2015-006681
Application 13/604,452
(col. 7,11. 2-4) teaches that an aluminum alloy that contains nitrogen has
increased resistance, as recognized by the Examiner, who cites Gotoh Fig. 4
and column 7, lines 7—15. (Br., para, bridging 4—5.) Moreover, Fujiwara
urges, Gotoh (para, bridging columns 9—10), teaches that the nitrogen-
containing aluminum layers are used to form outermost surface layers in the
final product that resist corrosion during the photolithographic process.
(Br. 5, last full para.) Thus, in Fujiwara’s view, Gotoh would not have
taught or suggested introducing nitrogen into any non-surface aluminum
alloy layer. (Id. at para, bridging 5—6.)
The Examiner responds that Gotoh supports adding nitrogen to a pure-
aluminum layer to avoid forming a passive aluminum oxide on the surface
and “to provide easy and precise patterning [of] an aluminum alloy film.”
(Ans., sentence bridging 4—5.) The Examiner reasons that it would have
been obvious to maintain the relative resistivities of the layer by adjusting
the nickel-content of layers X' and X, to accommodate the resistivity
changes induced by the incorporation of nitrogen into layer Y. (Ans. 5,
11. 14—20.) In this regard, the Examiner also finds that Hino teaches
(Hino [0041]) that first layer X contains at least one element to suppress
corrosion of the aluminum alloy during processing. (Ans. 8,11. 3—5.)
The Examiner finds that Gotoh teaches against using pure aluminum in the
wiring film. Accordingly, in the Examiner’s words, it would have been
obvious to provide nitrogen to the second layer,
so that a direct contact between a pixel electrode and a third
layer (X, an upper Al-Ni alloy layer of the drain electrode) is
provided without etching the third layer (the upper layer of
the aluminum wiring film) and an aluminum wiring film has
chemical resistance against alkaline developers and stripping
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Application 13/604,452
solutions and an improved corrosion resistance (Gotoh,
Col. 4, lines 28-33; Col. 6, lines 30-34.)
(Ans. 6,11. 8-12.)
Review of the teachings of Hino and Gotoh supports Fujiwara’s
characterizations of those teachings.
The difficulty with the Examiner’s reasoning, as Fujiwara points out
(Reply11), is that Gotoh does not suggest adding nitrogen to any intermediate
layer of aluminum, but only to surface layers. Hino’s repeated disclosures
that second layer Y has a resistivity lower than the resistivity of first layer X
(e.g., Hino [0028], [0029], [0030], [0040]), and the further emphasis that this
feature is an “essential requisite condition[] of the present invention”
{id. at [0124]), require an explanation of why there would have been a
reason to incorporate some amount of nitrogen into the second layer of Hino
in a way that satisfies the relative resistivity requirement.
To show that the artisan would have had a reason to adapt Gotoh’s
teachings to incorporate nitrogen into an intermediate aluminum alloy layer
described by Hino, it might be shown, for example, that an amount of
nitrogen that would serve some useful purpose according to Gotoh would
have been expected to satisfy the “essential requisite condition” of relative
resistivities required by Hino. But, the Examiner has not directed our
attention to any credible evidence that an amount of nitrogen useful for some
purpose disclosed by Gotoh would have been expected to satisfy the
essential requisite relative resistivity conditions of Hino. Nor has the
11 Reply Brief filed 7 July 2015 (“Reply”).
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Application 13/604,452
Examiner shown that such an amount of nitrogen would have been
recognized as relevant for a purpose desirable in Hino’s wiring films.
The mere possibility that modifications might be made that might
satisfy essential conditions is not sufficient to establish a prima facie case of
obviousness. Thus, the mere possibility that other metals might raise the
resistivity of layers X and X' enough that a nitrogen-containing alloy Y
would have a lower resistivity does not suffice to establish prima facie
obviousness. The Examiner’s overall approach is not mistaken, in that
seeming “teachings away” in the prior art may be overcome by showing that
the artisan would have recognized other reasons taught by the prior art that
would have compelled modifications that lead to embodiments within the
scope of a claimed invention. But, as Fujiwara has demonstrated on the
merits, such a case has not been made on the present record.
C. Order
It is ORDERED that the rejection of claims 5—8 is reversed.
REVERSED
8