Ex Parte Ohtani et al

Board of Patent Appeals and Interferences

Nov 2, 2006

09197767 (B.P.A.I. Nov. 2, 2006)

The opinion in support of the decision being entered today was not written
for publication in a law journal and is not binding precedent of the Board.

UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
____________

Ex parte HISASHI OHTANI, MISAKO NAKAZAWA, and SATOSHI MURAKAMI
____________

Appeal No. 2006-1372
Application No. 09/197,767
Technology Center 2800
____________

HEARD: October 18, 2006
____________

Before JERRY SMITH, GROSS, and LEVY, Administrative Patent Judges.
GROSS, Administrative Patent Judge.

DECISION ON APPEAL
This is a decision on appeal from the examiner's final rejection of claims 1
through 5, 16, 22 through 27, 40, and 46 through 74, which are all of the claims pending
in this application.
Appellants’ invention relates to a semiconductor device having transistor, an
interlayer insulating film, and a reflective pixel electrode over the insulating film. An
embedded conductive layer fills a contact hole in the interlayer insulating layer to
connect the pixel electrode with the transistor, and the surface of the embedded
conductive layer is flush with the interlayer insulating layer. Claim 1 is illustrative of the
claimed invention, and it reads as follows:

Appeal Number: 2006-1372
Application Number: 09/197,767

1. A semiconductor device comprising:

at least one transistor;

at least one interlayer insulating film formed over said transistor, said interlayer
insulating film having at least one contact hole;

an embedded conductive layer provided to fill said contact hole wherein a top
surface of said embedded conductive layer is flush with a top surface of said interlayer
insulating film; and

a reflective pixel electrode having a flat upper surface thereon, formed on said
interlayer insulating film wherein said reflective pixel electrode is electrically connected
to said transistor through said embedded conductive layer,

wherein the embedded conductive layer comprises a conductive material
dispersed in a medium, the conductive material being selected from the group consisting
of carbon, zinc oxide, aluminum, and nickel.

The prior art references of record relied upon by the examiner in rejecting the
appealed claims are:
Liu 5,536,950 Jul. 16, 1996
Miyawaki 5,644,370 Jul. 01, 1997
Fukunaga 5,706,064 Jan. 06, 1998
Yamazaki 5,990,542 Nov. 23, 1999 (Dec. 16, 1996)
Sato 6,081,305 Jun. 27, 2000 (May 21, 1996)
Okita 6,097,453 Aug. 01, 2000 (Jun. 02, 1997)
Izumi 6,400,428 Jun. 04, 2002 (Mar. 20, 1996)

Claims 1, 5, 16, 22 through 27, 40, 46, 47, 51, 55, 59, 63, 67, 68, 71, and 72 stand
rejected under 35 U.S.C. § 103 as being unpatentable over Liu in view of Fukunaga and
Izumi.
Claims 2, 22 through 27, 40, 48, 52, 56, 60, and 64 stand rejected under 35 U.S.C.
§ 103 as being unpatentable over Liu in view of Yamazaki, Fukunaga, and Izumi.
Claims 3, 22 through 27, 40, 49, 53, 57, 61, 65, 69, 70, 73, and 74 stand rejected
under 35 U.S.C. § 103 as being unpatentable over Sato in view of Okita, Fukunaga, and
Miyawaki.
Claims 4 and 50 stand rejected under 35 U.S.C. § 103 as being unpatentable over
Sato in view of Okita, Miyawaki, and Yamazaki.
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Appeal Number: 2006-1372
Application Number: 09/197,767

Claims 54, 58, 62, and 66 stand rejected under 35 U.S.C. § 103 as being
unpatentable over Sato in view of Okita, Miyawaki, Yamazaki, and Fukunaga
Claims 1, 2, 5, 22 through 27, 40, 47, 48, 51, 52, 55, 56, 59, 60, 63, 64, 67, 68, 71,
and 72 stand rejected under 35 U.S.C. § 103 as being unpatentable over Fukunaga in
view of Liu, and Izumi.
Reference is made to the Examiner's Answer (mailed June 16, 2005) for the
examiner's complete reasoning in support of the rejections, and to appellants’ Brief (filed
March 17, 2005) and Reply Brief (filed August 18, 2005) for appellants’ arguments
thereagainst.

OPINION
We have carefully considered the claims, the applied prior art references, and the
respective positions articulated by appellants and the examiner. As a consequence of our
review, we will reverse the obviousness rejections of claims 1 through 5, 16, 22 through
27, 40, and 46 through 74.
The examiner begins (Answer, pages 3 and 9) by rejecting claims 1, 5, 16, 22
through 27, 40, 46, 47, 51, 55, 59, 63, 67, 68, 71, and 72 over Liu in view of Fukunaga
and Izumi. The examiner asserts (Answer, pages 4 and 10) that although Liu’s device
has a transparent pixel electrode, it would have been obvious “to form Liu’s pixel
electrode either as a transparent electrically conductive film or as a reflective electrical
conductive film, depending upon the desired display device type for the liquid crystal
display device, as taught by Izumi.”
As pointed out by appellants (Brief, page 9), Liu’s objective is to create a better
transmissive display. In particular, Liu discloses (column 1, lines 32-39) that present
high resolution active matrix liquid crystal displays (AMLCDs) result in low aperture
ratios, which requires a brighter backlight, which consumes extra power. Liu teaches
(column 2, lines 36-38) that “a need exists for AMLCD pixel and transistor design that
provide . . . [a] high pixel aperture ratio.” Liu further discloses (column 6, lines 27-29)
that the high aperture ratio achieved by his design “allows use of a lower power backlight
and improves the display brightness and efficiency.” To make Liu’s pixel electrode
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Appeal Number: 2006-1372
Application Number: 09/197,767

reflective would defeat the purpose of Liu’s device. The Federal Circuit has held that "a
proposed modification [is] inappropriate for an obviousness inquiry when the
modification render[s] the prior art reference inoperable for its intended purpose. In re
Gordon, 733 F.2d 900, 902, 221 USPQ 1125, 1127 (Fed. Cir. 1984)." In re Fritch, 972
F.2d 1260, 1265-1266 n.12, 23 USPQ2d 1780, 1783 n.12 (Fed. Cir. 1992). Therefore, we
cannot accept the examiner's proposed modification of Liu. Consequently, we cannot
sustain the obviousness rejection of claims 1, 5, 16, 22 through 27, 40, 46, 47, 51, 55, 59,
63, 67, 68, 71, and 72 over Liu in view of Fukunaga and Izumi.
The examiner (Answer, page 5) rejects claims 2, 22 through 27, 40, 48, 52, 56,
60, and 64 over Liu in view of Yamazaki, Fukunaga, and Izumi. Again the examiner
proposes changing Liu’s transparent pixel electrode to a reflective pixel electrode. As
explained supra, such a modification would render Liu inoperable for its intended
purpose. Accordingly, we cannot sustain the obviousness rejection of claims 2, 22
through 27, 40, 48, 52, 56, 60, and 64 over Liu in view of Yamazaki, Fukunaga, and
Izumi.
Next the examiner (Answer, page 6) rejects claims 3, 22 through 27, 40, 49, 53,
57, 61, 65, 69, 70, 73, and 74 over Sato in view of Okita, Fukunaga, and Miyawaki. The
examiner rejects (Answer, page 8) claims 4 and 50 over Sato in view of Okita, Miyawaki,
and Yamazaki, and (Answer, page 9) claims 54, 58, 62, and 66 over Sato in view of
Okita, Miyawaki, Yamazaki, and Fukunaga. The examiner (Answer, page 7) recognizes
that Sato and Okita fail to teach the claimed materials for filling Sato’s contact hole 171
through insulating layer 170. The examiner, therefore, turns to Fukunaga asserting
(Answer, page 7) that Fukunaga discloses an embedded conductive layer of indium tin
oxide or organic conductive layer of carbon or polymer to “provide a color liquid crystal
display devices [sic] having high speed response, low power consumption, and low
prices, as taught by Fukunaga et al (column 3, lines 30-34).”
Appellants argue (Brief, page 13) that Sato fails to teach or suggest that the
embedded conductive layer and the reflective pixel electrode are formed as distinct
features, as recited in the claims. Instead, according to appellants, Sato discloses that the
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Appeal Number: 2006-1372
Application Number: 09/197,767

electrode itself fills the contact hole, and none of the additional references remedies this
shortcoming of Sato. We agree with appellants.
Sato discloses (column 14, lines 5-23) that third metal layer 180 is formed on
third insulating layer 170 and penetrates the insulating layer to contact the surface of the
second metal layer below the insulating layer. Sato further states (column 13, lines 40-
43) that third metal layer180 is “formed through insulating layer.” The pixel electrode
181 is formed by patterning metal layer 180. Thus, Sato discloses forming as a single
element the reflective pixel electrode and the conductive material which penetrates the
insulating layer to connect the pixel electrode to the drain electrode. Nothing in Sato
suggests forming the two portions separately and of different materials. Further, Okita
discloses (column 7, lines 59-61) that metal electrode 108 is connected through hole 507
to transparent pixel electrode 508. Figure 6 of Okita shows no separation between pixel
electrode 508 and the material in contact hole 507, and we find no disclosure in Okita
that would suggest having the two elements separate. Thus, Okita does not remedy the
deficiency of Sato.
Fukunaga discloses (column 40, line 65-column 41, line 20) that by using the
functional layer as a flattening layer, high speed and response and high yield can be
obtained. Further, the high degree of smoothness allows for a high aperture ratio, which
lowers power consumption. Last, the use of the functional layer for the color filter
reduces the number of manufacturing steps and the amount of material, which increases
yield. In other words, it is not the material of the embedded conductive layer that yields
high speed response, low power consumption, and low prices, as asserted by the
examiner, but, rather, it is the color functional layer. Thus, Fukunaga fails to cure the
deficiency of Sato.
Miyawaki discloses (column 7, line 67-column 8, line 11) that when an indium tin
oxide pixel electrode is formed over an insulating layer, the indium tin oxide may not
reach the transistor drain through the insulating layer resulting in a poor connection
between the pixel electrode and the drain. Miyawaki teaches using a metal such as
tungsten or aluminum, which will reach the drain through the insulating layer, thereby
increasing the reliability of the liquid crystal display. Thus, Miyawaki suggests using
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Appeal Number: 2006-1372
Application Number: 09/197,767

different materials for the pixel electrode and the interconnect when the pixel electrode is
made of indium tin oxide, but we would have to resort to speculation to find that different
materials should be used when the pixel electrode is made of metal. In other words,
Miyawaki also fails to remedy the shortcomings of Sato, and we cannot sustain the
rejection of claims 3, 22 through 27, 40, 49, 53, 57, 61, 65, 69, 70, 73, and 74 over Sato
in view of Okita, Fukunaga, and Miyawaki.
The examiner rejects claims 4 and 50 over Sato in view of Okita, Miyawaki, and
Yamazaki and claims 54, 58, 62, and 66 over Sato in view of Okita, Miyawaki,
Yamazaki, and Fukunaga. Each of independent claims 4 and 50 includes the same
limitations found lacking from the combination of Sato, Okita, Fukunaga, and Miyawaki.
Yamazaki discloses (column 6, lines 7-9) that a contact hole is created in an insulating
layer and then indium tin oxide is sputtered and patterned to fill the hole and form the
pixel electrode. Thus, Yamazaki fails to suggest the use of separate materials for the
pixel electrode and for filling the contact hole. Accordingly, Yamazaki does not remedy
the deficiency of the above combination, and we cannot sustain the rejection of claims 4
and 50 over Sato in view of Okita, Miyawaki, and Yamazaki nor of claims 54, 58, 62,
and 66 over Sato in view of Okita, Miyawaki, Yamazaki, and Fukunaga.
The examiner lastly rejects claims 1, 2, 5, 22 through 27, 40, 47, 48, 51, 52, 55,
56, 59, 60, 63, 64, 67, 68, 71, and 72 over Fukunaga in view of Liu, and Izumi. The
examiner (Answer, page 3) relies on insulating layer 413/414 of Fukunaga for the
insulating layer that is to be formed over the first conductive layer in each of the
independent claims. Insulating layer 413/414 is used as a color filter by Fukunaga. If
one were to make the second conductive layer (or pixel electrode) reflective, as suggested
by the examiner (Answer, page 12) to make the device reflective, the color filter layer
would no longer be functional, as light would be reflected before reaching the color filter
layer. As this modification would render the prior art reference inoperable for its
intended purpose, we cannot accept the examiner's proposed modification of Fukunaga.
See Id. Therefore, we will not sustain the rejection of claims 1, 2, 5, 22 through 27, 40,
47, 48, 51, 52, 55, 56, 59, 60, 63, 64, 67, 68, 71, and 72 over Fukunaga in view of Liu,
and Izumi.
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Appeal Number: 2006-1372
Application Number: 09/197,767

CONCLUSION
The decision of the examiner rejecting claims 1 through 5, 16, 22 through 27, 40,
and 46 through 74 under 35 U.S.C. § 103 is reversed.
REVERSED

JERRY SMITH )
Administrative Patent Judge )
)
)
)
) BOARD OF PATENT
ANITA PELLMAN GROSS ) APPEALS
Administrative Patent Judge ) AND
) INTERFERENCES
)
)
)
STUART S. LEVY )
Administrative Patent Judge )
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Appeal Number: 2006-1372
Application Number: 09/197,767

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