Ex Parte Givens

Board of Patent Appeals and Interferences

Jan 26, 2005

08801812 (B.P.A.I. Jan. 26, 2005)

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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and is not binding precedent of the Board.
UNITED STATES PATENT AND TRADEMARK OFFICE

BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES

Ex parte JOHN H. GIVENS

Appeal No. 2005-0479
Application No. 08/801,812

ON BRIEF

Before KIMLIN, OWENS and WALTZ, Administrative Patent Judges.
KIMLIN, Administrative Patent Judge.
DECISION ON APPEAL
This is an appeal from the final rejection of claims 1-28
and 36-63. Claims 1 and 46 are illustrative:
1. A method for manufacturing an interconnect structure
comprising:
forming a recess within a dielectric material situated on a
semiconductor lower substrate, said recess extending below a top
surface of said dielectric material;
forming a diffusion barrier layer on the recess within the
dielectric material;
forming a seed layer on the diffusion barrier layer, the
diffusion barrier layer being composed of a material having a
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Application No. 08/801,812
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melting point greater than or equal to that of a material from
which the seed layer is composed;
forming an electrically conductive layer on the seed layer
including the portion of the seed layer within said recess, the
material from which the diffusion barrier layer is composed
having a melting point greater than that of a material from which
the electrically conductive layer is composed, the material from
which the seed layer is composed having a melting point greater
than or equal to that of the material from which the electrically
conductive layer is composed;
forming an energy absorbing layer on said electrically
conductive layer, said energy absorbing layer having a greater
thermal absorption capacity than that of said electrically
conductive layer;
applying, omnidirectionally, energy to said energy absorbing
layer to cause said electrically conductive layer to flow within
said recess; and
removing portions of the energy absorbing layer and the
electrically conductive layer that are situated above the top
surface of the dielectric material.
46. A method for manufacturing an interconnect structure, the
method comprising:
forming a dielectric material over a semiconductor substrate
and having a top surface;
forming a recess within the dielectric material extending
from the top surface of the dielectric material to the
semiconductor substrate;
filling the recess with an electrically conductive material,
wherein filling the recess with the electrically conductive
material further comprises:
forming a diffusion barrier layer in contact with the
semiconductor substrate and the dielectric material;
forming a seed layer upon the diffusion barrier layer
and composed of a material having a melting point less than
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that of the material from which the diffusion barrier layer
is composed and being selected from a group consisting of
ceramics, metallics, and intermetallics;
forming a conductor layer upon the seed layer including
the portion of the seed layer within said recess; and
forming an energy absorbing layer on the conductor
layer that is composed of a material having both a higher
thermal insulation capacity and electric insulation capacity
than that of the material from which the conductor layer is
composed;
wherein the recess includes:
a first portion having an uniform width and extending within
the dielectric material to the top surface of the dielectric
material;
a second portion having a height and a uniform width that is
less than the width of the first portion and that is not greater
than 25% of the height, the second portion extending from the
semiconductor substrate to terminate at the first portion; and
wherein the filling the recess is performed by causing the
electrically conductive material to flow within the recess by
applying omnidirectional heating.
The examiner relies upon the following references as
evidence of obviousness:
Xu et al. (Xu '461) 5,847,461 Dec. 8, 1998
Yim 5,869,395 Feb. 9, 1999
Xu et al. (Xu '721) 6,217,721 B1 Apr. 17, 2001
Appellant's claimed invention is directed to a method for
making an interconnect structure which entails forming diffusion
barrier, seed and electrically conductive layers within a recess
in a dielectric material situated on a substrate. The
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electrically conductive layer is formed on the seed layer and has
an energy absorbing layer formed thereon which causes the
conductive layer to flow within the recess when energy is applied
to the energy absorbing layer.
The appealed claims stand rejected under 35 U.S.C. § 103 as
follows:
(a) claims 1, 3-5, 7-11 and 36-45 over Xu '461 in view of
Xu '721;
(b) claims 2, 6 and 12-15 over Xu '461 in view of Xu '721
and Yim;
(c) claims 16-28 and 57-63 over Xu '461 in view of Xu '721
and Yim; and
(d) claims 46-56 over Xu '461 in view of Xu '721 and Yim.
Appellant submits at page 4 of the Brief that the following
groups of claims stand or fall together: (I) claims 1-15 and
36-45; (II) claims 16-28 and 57-63; and (III) claims 46-56.
However, since appellant has presented substantive arguments only
for the subject matter defined by claims 1 and 46, we will limit
our consideration to the examiner's rejections of claims 1 and
46.
We have thoroughly reviewed each of appellant's arguments
for patentability. However, we are in complete agreement with
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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 rejections for the reasons set forth in
the Answer, which we incorporate herein, and we add the following
primarily for emphasis.
Appellant does not dispute the examiner's factual
determination that Xu '461 discloses many of the claimed steps
for making an interconnect structure with the exception of
heating the diffusion barrier layer in an environment
substantially containing nitrogen gas and forming a seed layer on
the diffusion barrier layer. Also, appellant does not contest
the examiner's legal conclusion that, based on Xu '721, it would
have been obvious for one of ordinary skill in the art to heat
the diffusion barrier layer in a nitrogen environment. Indeed,
independent claims 1 and 46, with which all the appealed claims
stand or fall, fail to recite the step of heating in an
environment containing nitrogen gas.
The principal argument advanced by appellant is that Xu '461
provides a "teaching away" from utilizing the seed layer
presently claimed and disclosed by Xu '721. In support of this
argument appellant cites Xu '461 at column 1, line 56 through
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column 2, line 27. However, we do not subscribe to appellant's
position that the reference disclosure is tantamount to a
teaching away from using seed layers, in general, in methods of
forming interconnect structures of the type disclosed by Xu '461.
Rather, we find that the cited portion of Xu '461 is particularly
specific to seed layers of tungsten which sometimes result in the
formation of undesirable crystallographic forms of aluminum. Xu
'461 provides no teaching away of using the presently claimed
seed layer of titanium nitride, which is also the seed layer used
by Xu '721. Furthermore, as for the use of the seed layer
resulting in more complexity, cost and less reliability in the
process, this would seem to apply to appellant's process as well.
Appellant has submitted no argument, let alone evidence, that the
process of the instant invention is not more complex and costly
than processes that eschew seed layers. It is well settled that
it is a matter of obviousness for one of ordinary skill in the
art to eliminate or include a feature of the prior art, along
with its attendant advantages and disadvantages. As explained by
the examiner, the prior art establishes that it was known in the
art to employ seed layers in methods for forming interconnect
structures of the type claimed.
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Concerning the particular size and profile of the recess
recited in claim 46 on appeal, we fully concur with the examiner
that it is a matter of prima facie obviousness for one of
ordinary skill in the art to resort to routine experimentation to
determine the optimum dimensions of a structure. Appellant
points to no disclosure of criticality for the profile of the
claimed recess in the present specification. Moreover, Yim
discloses a recess profile that generally corresponds to the
profile of the claimed recess in the sense that it has a second
portion that is less in width than the first portion.
As a final point, we note that appellant bases no argument
upon objective evidence of nonobviousness, such as unexpected
results, which would serve to rebut the inference of obviousness
established by the examiner.
In conclusion, based on the foregoing and the reasons well-
stated by the examiner, the examiner's decision rejecting the
appealed claims is affirmed.
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No time period for taking any subsequent action in
connection with this appeal may be extended under 37 CFR
§ 1.136(a)(1)(iv) (effective Sep. 13, 2004; 69 Fed. Reg. 49960
(Aug. 12, 2004); 1286 Off. Gaz. Pat. Office 21 (Sep. 7, 2004)).
AFFIRMED
EDWARD C. KIMLIN )
Administrative Patent Judge )
)
)
)
)
TERRY J. OWENS ) BOARD OF PATENT
Administrative Patent Judge ) APPEALS AND
) INTERFERENCES
)
)
)
THOMAS A. WALTZ )
Administrative Patent Judge )
ECK:clm
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Application No. 08/801,812
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Gregory M. Taylor
Workman, Nydegger & Seeley
1000 Eagle Gate Tower
60 East South Temple
Salt Lake City, UT 84111