Ex parte Summerfelt

Board of Patent Appeals and Interferences

Jul 29, 1998

08252727 (B.P.A.I. Jul. 29, 1998)

Application for patent filed June 2, 1994.1
1
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not binding precedent of the Board.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. 13
UNITED STATES PATENT AND TRADEMARK OFFICE
__________
BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
__________
Ex parte SCOTT R. SUMMERFELT
__________
Appeal No. 96-0859
Application No. 08/252,7271
__________
ON BRIEF
__________
Before KRASS, JERRY SMITH and BARRETT, Administrative Patent
Judges.
KRASS, Administrative Patent Judge.
DECISION ON APPEAL
This is a decision on appeal from the final rejection of
claims 1 through 14, all of the claims pending in the
application.
Appeal No. 96-0859
Application No. 08/252,727
2
The invention pertains to integrated circuits and, more
particularly, to structures within integrated circuits, such
as capacitors, which employ sacrificial oxygen sources in
order to prevent reduction of oxygen containing materials.
Maintaining a high dielectric constant is essential in order
to build smaller capacitors while maintaining the same
capacitance. Many high dielectric constant materials depend
for their electrical properties on their oxygen content. Yet,
the many fabrication steps in the manufacture of DRAMs and
other structures generally reduce high dielectric constant
materials which contain oxygen resulting in a degradation or
nullification of their advantageous electrical properties.
Accordingly, the instant invention is said to provide for the
prevention of reduction of oxygen containing dielectric
materials during VLSI processing through the use of
sacrificial oxygen sources provided near the oxygen containing
material and subject to certain requirements, disclosed at
page 4 of the specification.
Representative independent claim 1 is reproduced as
follows:
Appeal No. 96-0859
Application No. 08/252,727
3
1. A structure in an integrated circuit, said structure
comprising
a substrate;
a lower electrode comprised of electrically conductive
oxygen source material on said substrate;
a layer of oxygen-containing dielectic material on said
lower electrode; and
an upper electrode in contact with said layer.
The examiner relies on the following references:
Rodriguez et al. (Rodriguez) 3,274,468 Sep.
20, 1966
Short 3,798,516 Mar. 19,
1974
Claims 1 through 14 stand rejected under 35 U.S.C. 103 as
unpatentable over Rodriguez and Short.
Reference is made to the briefs and answer for the
respective positions of appellant and the examiner.
OPINION
We reverse.
At the outset, we note, in passing, that while we
generally agree with appellant’s position, we find
Appeal No. 96-0859
Application No. 08/252,727
4
unpersuasive appellant’s argument [principal brief - page 9]
that both Rodriguez and Short are directed to monolithic
capacitors while the instant invention is directed to
integrated circuits. Column 1, lines 10-15, of Rodriguez,
indicating a desire for miniaturization of components within
printed circuits, would clearly have led the skilled artisan
to apply the Rodriguez teachings to integrated circuits.
The examiner’s rationale for the stated rejection is, in
toto:
Rodriguez teaches a typical capacitor structure
having a pair of electrodes of a material “that will
not melt or oxidize” such as platinum or palladium
surrounding an oxygen containing dielectric such as
barium strontium titanate (see columns 2-3).
Although Rodriguez teaches a material “that will not
melt or oxidize”, it is well-known to those of
ordinary skill in the art that platinum or palladium
do in fact oxidize externally. Short is cited as
showing titanates are commonly supplied with oxygen
additives. Rodriguez being cited in Short, the
references are considered an analogous combination
[answer - page 3].
Thus, the examiner employs Rodriguez for a teaching of
the use of materials which will not oxidize when the point of
the instant invention, as claimed, is to use materials which
will oxidize so as to prevent reduction, i.e. loss of oxygen,
of the dielectric which is composed of materials which do
Appeal No. 96-0859
Application No. 08/252,727
5
oxidize. The examiner then appears to employ Short to explain
that despite Rodriguez’ teaching, platinum and palladium do
oxidize. We find nothing in Short which contradicts anything
taught by Rodriguez. However, notwithstanding whether Short
and Rodriguez are in conflict, the examiner has clearly failed
to set forth a prima facie case of obviousness in that the
examiner has failed to address key claim limitations.
Each of the independent claims calls for, in one form or
another, an “oxygen source material.” This term is
specifically defined at the top of page 11 of the
specification as “a material with oxygen partial pressure
P (O ) which is greater than the partial pressure at which theR 2
oxygen-containing dielectric is reduced, referred to herein as
the critical partial pressure P (O ).” Claim 14 specificallyC 2
recites functional language attached to the recitation of the
oxygen source material such that “partial pressure of oxygen
at all points in said dielectric is sufficiently high to
prevent reduction of said dielectric.” Yet, the examiner
never appears to come to grips with this language. The
examiner has pointed to nothing in the applied references
which provide for the claimed “oxygen source material.”
Appeal No. 96-0859
Application No. 08/252,727
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At the bottom of page 4 of the answer, in discussing
instant claim 14, the examiner appears to indicate that the
oxide dielectrics of the prior art are being equated to the
claimed “oxygen source material.” However, merely because
oxide compounds have oxygen as a component thereof, this does
not make such compounds “oxygen source material,” as claimed
and as specifically defined in the specification. Moreover,
with regard to claim 14, even if the applied references showed
an “oxygen source material, as defined in the instant
specification,” used as the dielectric, which it does not,
claim 14 requires the “oxygen source material” to be “disposed
nearby” the capacitor and not to be part of the dielectric
since the dielectric is recited separately.
Accordingly, since the examiner failed to present a prima
facie case of obviousness, taking all claim limitations into
account, we will not sustain the examiner’s rejection of
claims 1 through 14 under 35 U.S.C. 103.
The examiner’s decision is reversed.
REVERSED
Appeal No. 96-0859
Application No. 08/252,727
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ERROL A. KRASS )
Administrative Patent Judge)
)
)
)
JERRY SMITH ) BOARD OF PATENT
Administrative Patent Judge) APPEALS AND
) INTERFERENCES
)
)
LEE E. BARRETT )
Administrative Patent Judge)
Appeal No. 96-0859
Application No. 08/252,727
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Chris D. Plyant
Texas Instruments Inc.
P.O. Box 655474, M/S 219
Dallas, TX 75265