Ex Parte Min et al

Board of Patent Appeals and Interferences

Jun 15, 2010

10882745 (B.P.A.I. Jun. 15, 2010)

UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
____________

Ex parte YONGKI MIN and CENGIZ A. PALANDUZ
____________

Appeal 2010-000687
Application 10/882,745
Technology Center 1700
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Decided: June 15, 2010
____________

Before EDWARD C. KIMLIN, BRADLEY R. GARRIS, and
CATHERINE Q. TIMM, Administrative Patent Judges.

KIMLIN, Administrative Patent Judge.

DECISION ON APPEAL

This is an appeal from the final rejection of claims 1-5, 8-11, 17, and
18. Claims 1 and 8 are illustrative:
1. A method comprising:

forming a capacitor structure comprising a first electrode
material, and a thin film of ceramic material having a high
dielectric constant and a thickness less than one micron on the
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Application 10/882,745

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first electrode material, and a second electrode material on the
ceramic material;

determining an equilibrium conductivity of the thin film of
ceramic material as a function of thermodynamic state
parameters;

determining a limiting value of a reducing atmosphere of the
first electrode material or the second electrode material; and

after forming the capacitor structure, sintering the thin film of
ceramic material at an oxygen partial pressure in a range
selected where, based on the equilibrium conductivity and the
limiting value of a reducing atmosphere, a point defect state of
the thin film of ceramic material defines the thin film of
ceramic material as insulating without oxidation of the
electrode material.
8. A method comprising:
depositing a thin film of ceramic material having a high
dielectric constant on a first electrically conductive foil;
depositing a second electrically conductive foil on the thin film
of ceramic material;
determining an equilibrium conductivity of the thin film of
ceramic material as a function of thermodynamic state
parameters;
determining a limiting value of a reducing atmosphere of the
electrode material; and
based on the equilibrium conductivity and the limiting value of
a reducing atmosphere, sintering the thin film of ceramic
material in a reducing atmosphere at an oxygen partial
pressure that minimizes the mobility of point defects in the thin
film of ceramic material to transition to a level corresponding to
a greater conductivity of the thin film of ceramic material.
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The Examiner relies upon the following references as evidence of
obviousness:

Yadav 5,952,040 Sep. 14, 1999
Borland 2005/011857 A1 Jan. 20, 2005

Christian Ohly et al., “High Temperature Conductivity Behavior of Doped
SrTiO3 Thin Films,” Integrated Ferroelectrics, 2001, Vol. 33 pp. 363-372.

Appellants’ claimed invention is directed to a method comprising
depositing a thin film of ceramic material on a first electrode material and
depositing a second electrode material on the ceramic material. The ceramic
material is sintered at an oxygen partial pressure based on the equilibrium
conductivity and the limiting value of a reducing atmosphere of the first
electrode material or the second electrode material.
Appealed claims 1-5, 8-11, 17 and 18 stand rejected under 35 U.S.C.
§ 103(a) as being unpatentable over Borland in view of Ohly and Yadav.
Appellants do not present separate arguments for the dependent
claims on appeal. Accordingly, the dependent claims stand or fall together
with the independent claims on which they depend.
We have thoroughly reviewed each of Appellants’ arguments for
patentability. However, we are in complete agreement with the Examiner
that the claimed subject matter would have been obvious to one of ordinary
skill in the art within the meaning of § 103 in view of the applied prior art.
Accordingly, we will sustain the Examiner’s rejection for essentially those
reasons expressed in the Answer.
Appellants do not dispute the Examiner’s factual determination that
Borland, like Appellants, discloses a method of making a thin film capacitor
comprising the steps of forming a thin film ceramic material having a high
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dialectic constant on a first electrode material and forming a second
electrode material on the ceramic material, as well as sintering or annealing
the ceramic material. As appreciated by the Examiner, Borland does not
expressly teach determining an equilibrium conductivity of the ceramic
material as a function of thermodynamic state parameters, such as
temperature and oxygen partial pressure, and determining a limiting value of
a reducing atmosphere of the electrode material.
However, as set forth by the Examiner, Ohly teaches that the
conductivity behavior of thin ceramic films of the perovskite type differ
substantially from the conductivity behavior of bulk ceramics with respect to
temperature and oxygen partial pressure. Accordingly, based on the Ohly
disclosure, we agree with the Examiner that “[d]eterming the equilibrium
conductivity of the thin film of the ceramic as a function of thermodynamic
state parameters (temperature, oxygen partial pressure and ceramic
composition) would have been obvious to one of ordinary skill in the art”
(Ans. 5, second para.). Appellants have not refuted the Examiner’s
reasoning that one of ordinary skill in the art would have appreciated that the
defect chemistry behavior of Borland’s thin ceramic film is different from
that of a bulk material and, therefore, “would have known to choose the
oxygen partial pressure for annealing the thin film ceramic based on the
conductivity behavior of a thin film of the ceramic with respect to oxygen
partial pressure and temperature” (id.).
Also, since it was known in the art that it is desirable to avoid
oxidizing the electrode material during the sintering step, we agree with the
Examiner that “[b]y using phase stability diagrams of copper at a particular
annealing temperature to determine maximum oxygen partial pressure at
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which annealing can take [place] while avoiding oxidation of copper”, the
claimed “step of determining the limiting value of reducing atmosphere of
the electrode material is obviously performed” (Ans. 6, first full para.).
Appellants have apprised us of no error in the Examiner’s rationale that
“[u]sing the combination of the conductivity behavior of thin film ceramic
material with phase stability diagrams for copper would have been obvious
to one of ordinary skill in the art to determine oxygen partial pressure
required so as to not reduce the dielectric while also avoiding oxidation of
the copper foil” (id.).
Appellants submit that, as discussed in their application, “there is a
range (a sweet spot) of processing conditions of temperature and pressure for
sintering a high-k ceramic material without oxidizing a metal and without
creating a leaky ceramic material” (Prin. Br. 9, first full para.). However,
since the Examiner has established that the thermodynamic state parameters
of the sintering step are result effective variables with respect to the
conductivity of the thin ceramic material and the oxidation state of the
electrode material, we concur with the Examiner that it would have been a
matter of obviousness for one of ordinary skill in the art to resort to routine
experimentation to determine the so-called “sweet spot” of processing
parameters. Appellants have presented no convincing rationale for why it
would have been nonobvious for one of ordinary skill in the art to determine
both the equilibrium conductivity of the thin ceramic film and the limiting
value of a reducing atmosphere of the electrode material for establishing the
optimum sintering conditions. In re Boesch, 617 F.2d 272, 276(CCPA
1980).
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Application 10/882,745

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Appellants have not contested the Examiner’s legal conclusion that,
based on the collective teachings of Borland, Ohly and Yadav, it would have
been obvious for one of ordinary skill in the art to sinter the ceramic material
either before or after depositing the second electrode material.
As a final point, we note that Appellants base no argument upon
objective evidence of nonobviousness, such as unexpected results.
In conclusion, based on the foregoing and the reasons well stated by
the Examiner, the Examiner’s decision rejecting the appealed claims is
affirmed.
No time period for taking any subsequent action in connection with
this appeal may be extended under 37 C.F.R. § 1.136(a)(1)(v).

AFFIRMED

kmm

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