Ex parte Madan

Board of Patent Appeals and Interferences

Sep 18, 1998

08188630 (B.P.A.I. Sep. 18, 1998)

Application for patent filed January 27, 1994,1
entitled "Stacked DRAM Structure," which is a continuation of
Application 07/919,345, filed July 23, 1992, now abandoned.
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THIS OPINION WAS NOT WRITTEN FOR PUBLICATION
The opinion in support of the decision being entered
today (1) was not written for publication in a law
journal and (2) is not binding precedent of the Board.
_______________
Paper No. 19
UNITED STATES PATENT AND TRADEMARK OFFICE

BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES

Ex parte SUDHIR K. MADAN

Appeal No. 96-1449
Application 08/188,6301

ON BRIEF

Before THOMAS, BARRETT, and LEE, Administrative Patent
Judges.
BARRETT, Administrative Patent Judge.
DECISION ON APPEAL
Appeal No. 96-1449
Application 08/188,630
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This is a decision on appeal under 35 U.S.C. § 134 from
the final rejection of claims 9-28, all of the claims
pending in the application.
We reverse.
BACKGROUND
The disclosed invention is directed to a stacked
capacitor structure for semiconductor memory devices.
Storage electrodes of prior art stacked capacitors are
limited in distance from neighboring circuit elements and
from each other by the minimum lithographic feature size F,
as shown in figure 4. Appellant forms a conformal conductor
layer over the storage electrode to a thickness T enlarging
the dimensions of the storage electrode by 2T, which reduces
the distance between neighboring circuit elements, as shown
in figure 5.
Claim 9 is reproduced below.
9. A microelectronic device, said microelectronic
device comprising:
a) a substrate including a conductive region;
b) an insulating layer overlying said substrate
having a storage node contact window overlying a
selected area of said conductive region;
c) a storage electrode comprising a stem-shaped
Appeal No. 96-1449
Application 08/188,630
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section and a crown-shaped section, said stem-shaped
section lying within said storage node contact window
and in electrical communication with said conductive
region of said substrate and extending above said
insulating layer, said crown-shaped section
electrically connected to and overlying said stem-
shaped section;
d) a storage electrode enlarging layer conformably
covering and in electrical communication with selected
portions of said crown-shaped section of said storage
electrode and that portion of said stem-shaped section
of said storage electrode that extends above said
insulating layer, and overlying the portion of said
insulating layer that lies beneath said crown-shaped
section of said storage electrode;
e) a dielectric layer conformably covering said
storage electrode and said storage electrode enlarging
layer; and
f) a conductive layer covering said dielectric
layer and forming a plate electrode capacitively-
coupled to said storage electrode and said storage
electrode enlarging layer.
The examination team (hereinafter, the "examiner")
relies on the following prior art references:
Bae et al. (Bae) 5,095,346 March 10,
1992
Reinberg et al. (Reinberg) 5,142,438 August 25,
1992
(filed November 15,
1991)
Ogawa et al. (Ogawa) 5,164,337 November 17,
1992
(filed October 31,
1990)
Hamamoto et al. (Hamamoto) 5,235,199 August 10,
Appeal No. 96-1449
Application 08/188,630
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1993
(filed February 7,
1992)
Claims 9-13 stand rejected under 35 U.S.C. § 103 as
being unpatentable over Ogawa or Bae in view of Reinberg.
With regard to the "storage electrode enlarging layer," the
examiner states (Office Action entered July 12, 1994, Paper
No. 10, page 3, referred to in the Final Rejection, Paper
No. 13; Examiner's Answer, page 4):
It does not matter how the enlarging layer is
made, the final product is still the same. The storage
electrode and the enlarging layer are made of the same
material, therefore an arbitrary border can be drawn
around the outer periphery of the storage electrode and
labeled an enlarging layer.
The examiner further finds that Ogawa and Bae do not teach a
dielectric layer of tantalum pentoxide as recited in
claim 12 and concludes that providing a layer of tantalum
pentoxide would have been obvious over Reinberg (Paper
No. 10, page 4; Examiner's Answer, page 4).
Claims 14-28 stand rejected under 35 U.S.C. § 103 as
being unpatentable over Ogawa or Bae in view of Reinberg,
further in view of Hamamoto. The examiner finds that "Ogawa
et al. or Bae et al. do not include at least two capacitors
Appeal No. 96-1449
Application 08/188,630
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which can be considered [an] array" (Paper No. 10, page 4;
Examiner's Answer, page 5). The examiner concludes that it
would have been obvious to arrange two capacitors having the
structures of Ogawa or Bae in an array in view of the two
capacitors taught by Hamamoto (Paper No. 10, page 4;
Examiner's Answer, page 5).
We refer to the Examiner's Answer (Paper No. 16) (pages
referred to as "EA__") for a further statement of the
examiner's position and to the Appeal Brief (Paper No. 15)
(pages referred to as "Br__") for the appellant's position.
OPINION
The examiner errs by failing to give patentable weight
to the claimed storage electrode "enlarging layer." The
claims recite an "enlarging layer conformably covering and
in electrical communication with" selected portions of the
storage electrode (claims 1 and 21) or first and second
storage electrodes (claim 14). It is clear that the
"enlarging layer" is separate structure in addition to the
storage electrode. Neither Ogawa nor Bae has a distinct and
separate "enlarging layer" on the storage electrode. Ogawa
discloses a storage electrode 11 covered with a dielectric
Appeal No. 96-1449
Application 08/188,630
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film 12 and a cell plate 13 (figure 1H). Bae discloses a
stacked capacitor which comprises a hollow storage electrode
22 of polysilicon layers 19, 21, and 23 (figure 3) around an
oxide core 20 (figure 4F), the storage electrode being
covered with a dielectric film 24 and then with a plate
electrode layer 25 (figure 3). Bae discloses that several
capacitors can be manufactured at the same time (col. 4,
lines 23-35).
Although no case law support has been cited for the
examiner's position, we interpret the statement that "[i]t
does not matter how the enlarging layer is made, the final
product is still the same" (Paper No. 10, page 3; EA4) to be
product-by-process-type reasoning. The patentability of
product-by-process claims is discussed in In re Thorpe,
777 F.2d 695, 697, 227 USPQ 964, 966 (Fed. Cir. 1985):
[E]ven though product-by-process claims are limited by
and defined by the process, determination of
patentability is based on the product itself.
[Citations omitted.]
The patentability of a product does not depend on
its method of production. If the product in a
product-by-process claim is the same as or obvious from
a product of the prior art, the claim is unpatentable
even though the product was made by a different
process. [Citations omitted.]
Appeal No. 96-1449
Application 08/188,630
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The rejection states that because the final product is a
conductive storage electrode, it does not make a difference
whether or not the storage electrode was covered with an
"enlarging layer." We disagree with the examiner's
reasoning.
We agree with appellant's rebuttal to the examiner's
rejection (Br4):
This argument ignores the fact that the enlarging layer
will be detectable as a separate and distinct layer
from the storage electrode. The layers may or may not
be formed of the same material. Even if they are of
the same material, their interface can be found by
crystallography or other means.
A storage electrode having an "enlarging layer" is not the
same physical product as a storage electrode without an
enlarging layer. The examiner's statement that "[t]he
storage and the enlarging layer are made of the same
material" (Paper No. 10, page 3; EA4), is not accurate. The
claims do not require the materials to be the same and
appellant has pointed out that even if they were, the
structure of the enlarging layer would be distinguishable
from the structure of the storage electrode. The fact that
two structures, a storage electrode covered by an enlarging
layer and a storage electrode of the same overall size but
Appeal No. 96-1449
Application 08/188,630
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without an enlarging layer, may be electrically identical
does not mean they are physically and mechanically identical
in structure. Therefore, we conclude that the examiner has
failed to establish a prima facie case of obviousness. The
rejection of claims 9-28 is reversed.
The examiner states (EA6): "The examiner has cited the
reference Reinberg et al. that teaches the feature of an
added conformal layer and discussed reasons why it would be
[sic, have been] obvious to use one in Ogawa et al. or Bae
et al." We find Reinberg applied in the examiner's actions
to teach only using tantalum pentoxide as a replacement for
ONO dielectric layers (EA4, two places), not for teaching a
storage electrode enlarging layer. Reinberg has a tantalum
oxide dielectric layer 33 covered by a thin barrier layer 41
of a material such as silicon nitride to prevent undesirable
interaction between layer 33 and the polysilicon cell plate
layer (col. 4, line 57 to col. 5, line 1), but does not
disclose an enlarging layer on the storage electrode.
CONCLUSION
The rejection of claims 9-28 is reversed.
REVERSED
Appeal No. 96-1449
Application 08/188,630
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JAMES D. THOMAS )
Administrative Patent Judge )
)
)
)
) BOARD OF
PATENT
LEE E. BARRETT ) APPEALS
Administrative Patent Judge ) AND
) INTERFERENCES
)
)
)
JAMESON LEE )
Administrative Patent Judge )
Appeal No. 96-1449
Application 08/188,630
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Brian C. McCormack
TEXAS INSTRUMENTS INCORPORATED
Patent Activity, M/S 219
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