Ex Parte Sandhu

Board of Patent Appeals and Interferences

Jan 21, 2004

09496081 (B.P.A.I. Jan. 21, 2004)

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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and is not binding precedent of the Board.
Paper No. 18
UNITED STATES PATENT AND TRADEMARK OFFICE

BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES

Ex parte GURTEJ S. SANDHU

Appeal No. 2004-0016
Application No. 09/496,081

ON BRIEF

Before KIMLIN, WARREN and OWENS, Administrative Patent Judges.
KIMLIN, Administrative Patent Judge.
DECISION ON APPEAL
This is an appeal from the final rejection of claims 32,
36-39 and 43-45. The examiner has withdrawn the rejection of
claim 35 on appeal and objected to the claim as being dependent
upon a rejected base claim (see page 2 of Answer, last
paragraph). Claim 32 is illustrative:
32. A capacitor in a semiconductor device, said capacitor
comprising:
Appeal No. 2004-0016
Application No. 09/496,081
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a bottom capacitor plate consisting essentially of amorphous
TiN;
a layer of dielectric material overlying said bottom
capacitor plate; and
a top capacitor plate over lying [sic, overlying] said layer
of dielectric material
The examiner relies upon the following references as
evidence of obviousness:
Gonzalez et al. (Gonzalez) 5,168,073 Dec. 01, 1992
Sandhu et al. (Sandhu) 5,335,138 Aug. 02, 1994
Lee et al. (Lee) 2,245,762 Jan. 01, 1992
(United Kingdom Patent Application)
Appellant's claimed invention is directed to a capacitor in
a semiconductor device wherein the capacitor comprises, inter
alia, a bottom capacitor plate consisting essentially of
amorphous TiN. According to appellant, "[t]he capacitor will
function as a storage capacitor for a semiconductor device and
particularly for a dynamic random access memory device" (page 2
of principal brief, paragraph five).
Appealed claims 32, 36, 39 and 43 stand rejected under
35 U.S.C. § 103 as being unpatentable over Gonzales in view of
Lee. Claims 37, 38, 44 and 45 stand rejected under 35 U.S.C.
§ 103 as being unpatentable over Gonzales in view of Lee and
Sandhu.
Appeal No. 2004-0016
Application No. 09/496,081
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We have carefully reviewed the respective positions advanced
by appellant and the examiner. In so doing, we find ourselves in
agreement with appellant that the examiner has failed to
establish a prima facie case of obviousness for the claimed
subject matter. Accordingly, we will not sustain the examiner's
rejections.
The examiner appreciates that "Gonzáles fails to teach a
bottom capacitor plate consisting essentially of amorphous TiN"
(page 4 of Answer, last paragraph). Instead, Gonzales discloses
a bottom capacitor plate comprising TiN and tungsten. However,
citing Lee's disclosure of a semiconductor device having an
amorphous TiN layer in a contact hole structure, the examiner
concludes that:
[I]t would have been an obvious modification to someone
with ordinary skill in the art, at the time of the
invention, to modify the structure as taught by
Gonzáles to include a bottom capacitor plate consisting
essentially of amorphous TiN, as suggested by Lee, in
order to improve the characteristics of the diffusion
barrier at a contact hole portion and prevent the
occurrence of defects such as cracks, as disclosed on
page 5, lines 22-31.
(Page 4 of Answer, last paragraph). We understand the examiner's
position that it would have been obvious to replace the bottom
capacitor plate of Gonzales, comprising TiN and tungsten, with a
bottom capacitor plate consisting essentially of only TiN.
Appeal No. 2004-0016
Application No. 09/496,081
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The rejection cannot stand because the examiner has failed
to establish that one of ordinary skill in the art would have
found it obvious to form a bottom capacitor plate with
essentially only TiN. Gonzales, like Lee, discloses that TiN is
a diffusion barrier between the N+ junction and the tungsten, but
Gonzales provides no teaching that the TiN layer, alone, can
function as a bottom capacitor plate without the tungsten. Lee,
likewise, is deficient in providing such a teaching since, as
acknowledged by the examiner, Lee is not directed to a capacitor
but only, at best, "a generic contact structure which can be
provided on different types of semiconductor devices" (page 7 of
Answer, paragraph one). Hence, without the teaching that a layer
consisting essentially of TiN can function as a bottom capacitor
plate, the examiner's rejection lacks the requisite factual
support. In re Warner, 379 F.2d 1011, 1017, 154 USPQ 173, 177-78
(CCPA 1967).
Sandhu, cited by the examiner for disclosing a capacitor
including a high dielectric constant material and particular
capacitor structures, does not alleviate the deficiency of the
combined teachings of Gonzales and Lee discussed above.
Appeal No. 2004-0016
Application No. 09/496,081
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In conclusion, based on the foregoing, the examiner's
decision rejecting the appealed claims is reversed.
REVERSED
EDWARD C. KIMLIN )
Administrative Patent Judge )
)
)
)
)
CHARLES F. WARREN ) BOARD OF PATENT
Administrative Patent Judge ) APPEALS AND
) INTERFERENCES
)
)
)
TERRY J. OWENS )
Administrative Patent Judge )
ECK:clm
Appeal No. 2004-0016
Application No. 09/496,081
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David J. Paul, Patent Agent
Micron Semiconductor Inc.
2805 East Columbia Road
Boise, ID 83706