Ex parte Miyamoto

Board of Patent Appeals and Interferences

Apr 9, 2001

08606975 (B.P.A.I. Apr. 9, 2001)

1
The opinion in support of the decision being entered today was not written for
publication and is not binding precedent of the Board.
Paper No. 28
UNITED STATES PATENT AND TRADEMARK OFFICE
_____________
BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
_____________
Ex parte TAKAAKI MIYAMOTO
_____________
Appeal No. 1998-2916
Application No. 08/606,975
______________
ON BRIEF
_______________
Before FLEMING, RUGGIERO and GROSS, Administrative Patent
Judges
RUGGIERO, Administrative Patent Judge.
DECISION ON APPEAL
This is a decision on the appeal from the final rejection
of claims 1-6 and 8-16, which are the only claims remaining in
the application. Claim 7 has been canceled.
The disclosed invention relates to a method of providing
a conductive metal layer in a contact hole in an insulating
layer on a semiconductor substrate. The contact hole is
Appeal No. 1998-2916
Application No. 08/606,975
2
filled with an
electrically conductive material after an adhesion layer, and
a
barrier layer in contact with the adhesion layer, are formed
in
the contact hole. The adhesion layer is formed by reducing,
with H , a gas of a halogenated product of a group IVB2
element, at a flow ratio of 0.4 or greater of group IVB
element to H , in an ECR plasma CVD process. Appellant2
asserts at page 4 of the specification that the selection of a
flow ratio of 0.4 or greater of group IVB element to H in the2
formation of the adhesion layer reduces grain growth of the
group IVB metal, thereby improving the eventual performance of
the conductive material.
Representative claim 1 is reproduced as follows:
1. A method of producing a semiconductor device
having a contact hole in a layer on a substrate of
the device, comprising the steps of:
forming an insulating layer on a semiconductor
substrate;
forming a contact hole in the insulating layer
to expose a selected portion of the semiconductor
Appeal No. 1998-2916
Application No. 08/606,975
3
substrate, the contact hole being defined by walls
of the insulating layer;
forming an adhesion layer of a metal element
selected from the group consisting of Ti, Zr, and Hf
in the contact hole to be in contact with the
exposed substrate, the adhesion layer being formed
by reducing, with H , a gas of a halogenated product2
of the metal element in an ECR plasma CVD process,
the gas of a halogenated product of the metal
element and H being used at a (gas of said2
halogenated product)/H flow ratio equal to or2
greater than 0.4;
forming a barrier layer in contact with the
adhesion layer, said adhesion layer and barrier
layer being formed in successive steps in a chamber;
and
filling the contact hole with an electrically
conductive material.
The Examiner relies on the following prior art:
Shankar et al. (Shankar) 4,782,380
Nov. 01, 1988
Yokoyama et al. (Yokoyama) 4,897,709 Jan. 30,
1990
Dixit et al. (Dixit) 4,960,732 Oct. 02,
1990
Sandhu et al. (Sandhu) 5,173,327 Dec. 22,
1992
Akahori et al. (Akahori ‘404) 5,296,404 Mar.
22, 1994
Akahori (Akahori ‘066) 5,508,066 Apr. 16,
1996
(filed Sep. 14,
1994)
M. A. Nicolet (Nicolet) “Diffusion Barriers in Thin Films,”
Appeal No. 1998-2916
Application No. 08/606,975
The Appeal Brief was filed June 4, 1997. In response to the1
Examiner’s Answer dated September 16, 1997, a Reply Brief was filed November
17, 1997 which was acknowledged and entered by the Examiner without further
comment as indicated in the communication dated January 28, 1998.
4
Thin Solid Films, vol. 52, pgs. 415-443 (1978).
Claims 1-6 and 8-16 stand finally rejected under 35
U.S.C.
§ 103(a). As evidence of obviousness, the Examiner offers
Akahori ‘066, Sandhu, Yokoyama, Akahori ‘404, and Nicolet with
respect to claims 1-4, 6, 8-13, and 16, and adds Shankar and
Dixit to the basic combination with respect to claims 5, 14,
and 15. Claims 1-6 also stand finally rejected under the
second paragraph of 35 U.S.C. § 112 as being indefinite for
failure to particularly point out and distinctly claim the
invention.
Rather than reiterate the arguments of Appellant and the
Examiner, reference is made to the Briefs and Answer for the1
Appeal No. 1998-2916
Application No. 08/606,975
5
respective details.
OPINION
We have carefully considered the subject matter on
appeal, the rejections advanced by the Examiner, the arguments
in support of the rejections and the evidence of obviousness
relied upon by the Examiner as support for the prior art
rejection. We have, likewise, reviewed and taken into
consideration, in reaching our decision, Appellant’s arguments
set forth in the Briefs
along with the Examiner’s rationale in support of the
rejections and arguments in rebuttal set forth in the
Examiner’s Answer.
Appellant indicates (Brief, page 6) that claims 1-6 stand
or fall together as a group while claims 8-15 stand or fall
together as a separate group. Consistent with this
indication, separate arguments for patentability have been
provided only for the limitations recited in independent
claims 1 and 8, which we will
select as the representative claims for each group. We will
consider the claims separately only to the extent that
Appeal No. 1998-2916
Application No. 08/606,975
From the record in this case, it is apparent that Appellant 2
inadvertently omitted dependent claim 16 from its proper grouping with its
base claim 1.
6
separate arguments are of record in this appeal. Note In re2
King, 801 F.2d 1324, 1325, 231 USPQ 136, 137 (Fed. Cir. 1986);
In re Sernaker, 702 F.2d 989, 991, 217 USPQ 1, 3 (Fed. Cir.
1983).
It is our view, after consideration of the record before
us, that claims 1-6 particularly point out the invention in a
manner which complies with 35 U.S.C. § 112, second paragraph.
It is further our view that the evidence relied upon and the
level of skill in the particular art would have suggested to
one of ordinary skill in the art the obviousness of the
invention as set forth in claims 1-6 and 16. We reach the
opposite conclusion with respect to claims 8-15. Accordingly,
we affirm-in-part.
With respect to the Examiner’s 35 U.S.C. § 112, second
paragraph, rejection of appealed claims 1-6, we note that a
claim must set out and circumscribe a particular area with a
reasonable degree of precision and particularity when read in
light of the disclosure as it would be by the artisan. In re
Appeal No. 1998-2916
Application No. 08/606,975
7
Moore, 439 F.2d
1232, 1235, 169 USPQ 236, 238 (CCPA 1971). Acceptability of
the
claim language depends on whether one of ordinary skill in the
art would understand what is claimed in light of the
specification. Seattle Box Co. v. Industrial Crating &
Packing, Inc., 731 F.2d 818, 826, 221 USPQ 568, 574 (Fed. Cir.
1984).
After reviewing the arguments of record, we are in
agreement with Appellant (Brief, page 7) that no ambiguity or
lack of clarity exists in the claim language. While the
Examiner has objected to the language “equal to or greater
than 0.4" in independent claims 1 and 5, no legal authority
has been cited by the Examiner for the asserted principle that
a recitation of an upper limit is required to establish the
metes and bounds of the claims. While an open-ended
recitation of a range of values is undisputedly broader that a
bounded range recitation, it is well settled that the breadth
of a claim is not to be equated with indefiniteness. In re
Miller, 441 F.2d 689, 692, 169 USPQ 597, 600 (CCPA 1971).
Appeal No. 1998-2916
Application No. 08/606,975
The Examiner, through apparent inadvertence, failed to include claim3
16, which by dependence includes the language of claim 1 found objectionable
by the Examiner, in this rejection.
8
It is our view that the skilled artisan, having
consideredthe specification in its entirety, would have no
difficulty
ascertaining the scope of the invention recited in claims 1-6.
Therefore, the rejection of claims 1-6 under the second
paragraph of 35 U.S.C. § 112 is not sustained.3
Turning to a consideration of the Examiner’s 35 U.S.C.
§ 103(a) rejection of the appealed claims, we note that, as a
general proposition in an appeal involving a rejection under
35 U.S.C. § 103, an Examiner is under a burden to make out a
prima facie case of obviousness. If that burden is met, the
burden of going forward then shifts to Appellant to overcome
the prima facie case with argument and/or evidence.
Obviousness is then determined on the basis of the evidence as
a whole and the relative persuasiveness of the arguments. See
In re Oetiker, 977 F.2d 1443, 1445, 24 USPQ2d 1443, 1444 (Fed.
Cir. 1992); In re Hedges, 783 F.2d 1038, 1039, 228 USPQ 685,
Appeal No. 1998-2916
Application No. 08/606,975
9
686 (Fed. Cir. 1986); In re Piasecki, 745 F.2d 1468, 1472, 223
USPQ 785, 788 (Fed. Cir. 1984); and In re Rinehart, 531 F.2d
1048, 1052, 189 USPQ 143, 147 (CCPA 1976).
With respect to the obviousness rejection of
representative independent claim 1, after reviewing the
Examiner’s analysis
(Answer, pages 4-7), it is our view that such analysis
carefully points out the teachings of the applied prior art
references, reasonably indicates the perceived differences
between this prior art and the claimed invention, and provides
reasons as to how and
why the prior art teachings would have been modified and/or
combined to arrive at the claimed invention. In our opinion,
the Examiner's analysis is sufficiently reasonable that we
find that the Examiner has at least satisfied the burden of
presenting a prima facie case of obviousness. The burden is,
therefore, upon Appellant to come forward with evidence or
arguments which persuasively rebut the Examiner’s prima facie
case of obviousness. Only those arguments actually made by
Appeal No. 1998-2916
Application No. 08/606,975
10
Appellant have been considered in this decision. Arguments
which Appellant could have made but chose not to make in the
Briefs have not been considered [see 37 CFR § 1.192(a)].
In response, Appellant asserts that the Examiner has
failed to establish a prima facie case of obviousness since
the proposed combination of references “does not teach or
suggest the claimed invention including the recited flow ratio
to produce the
adhesion layer as claimed.” (Brief, page 9). Initially,
Appellant contends that Sandhu, relied on by the Examiner to
teach the claimed ratio of 0.4 or greater of a halogenated gas
product (e.g. TiCl ) to H , is of little value to the skilled4 2
artisan since there is no recognition of the problem of grain
growth of Ti in a contact hole addressed by Appellant.
After reviewing the prior art references in light of
Appellant’s argument, we are in general agreement with the
Examiner’s position as stated in the Answer. Contrary to
Appellant’s contention, we find clear suggestion in the cited
references for the Examiner’s combination. It is clear from
the disclosure of Akahori ‘066 (e.g. column 5, lines 1-3) that
Appeal No. 1998-2916
Application No. 08/606,975
11
full step coverage of the plasma deposited material in a
contact hole is contemplated. We are convinced that the
skilled artisan, seeking guidance as to the proper halogenated
gas to H flow ratio to achieve maximum coverage would be led2
to the teachings of Sandhu which suggests the proper flow
ratio range of 0.1 to 0.5 of metal source gas to reactive gas
(e.g. TiCl to H ) to achieve the desired full coverage result. 4 2
It is not necessary
that the references be combined for the same reasons as
Appellant. The fact that Appellant has recognized another
advantage which would flow naturally from the suggestions of
the prior art, i.e. prevention of contact hole grain growth of
Ti, cannot be the basis for patentability when the differences
would otherwise be obvious. Ex parte Obiaya, 227 USPQ 58, 60
(Bd. Pat. App. & Inter. 1985).
Appellant further contends that none of the prior art,
particularly Sandhu, teaches or suggests the particular
claimed halogenated product to H flow ratio of 0.4 or2
greater. We do not find such argument to be persuasive. It
Appeal No. 1998-2916
Application No. 08/606,975
12
is apparent to us that Sandhu’s disclosed flow ratio range of
0.1 to 0.5 overlaps the claimed flow ratio range of “equal to
or greater than 0.4.” Further, in factual situations where
claimed ranges overlap or lie inside ranges disclosed by the
prior art, a prima facie case of obviousness has been held to
exist. In re Wertheim, 541 F.2d 257, 267, 191 USPQ 90, 100
(CCPA 1976); In re Geisler, 116 F.3d 1465, 1469-71, 43 USPQ2d
1362, 1365-66 (Fed. Cir. 1997).
This prima facie case serves to shift the burden to
Appellant to come forward with evidence which establishes the
criticality of the claimed range, generally by a showing that
the claimed range achieves unexpected results relative to the
prior art range, or that the prior art, in any material way,
teaches away from the claimed range. In re Malagari, 499 F.2d
1297, 1301, 182 USPQ 549, 553 (CCPA 1974); In re Woodruff, 919
F.2d 1575, 1577, 16 USPQ2d 1934, 1936 (Fed. Cir. 1990); Ex
parte Lee, 31 USPQ2d 1105, 1107 (Bd. Of Pat. App. & Inter.
1993).
In attempting to address this burden, Appellant refers
Appeal No. 1998-2916
Application No. 08/606,975
13
to the description in the specification which includes
comparative examples at pages 7-10 which indicate the complete
conformal nature of a Ti layer with the inner surface of a
contact hole at a plasma deposition flow rate of TiCl to H at4 2
a ratio of 0.8. In contrast, at a TiCl to H flow rate ratio4 2
of 0.2, a granular non-conformal Ti layer resulted. We do not
find such evidence to be persuasive. We note initially that
the burden is on Appellant to show that any difference in test
results are in fact unexpected and significant. Ex parte
Gelles, 22 USPQ2d 1318,
1319 (Bd. Pat. App. & Inter. 1992). Further, the evidence
presented must be commensurate in scope with the claims which
the
evidence is offered to support. Where the claimed limitations
in
question involve a prescribed range of values, it is important
to consider whether the showing of alleged unexpected results
occurs over the entire claimed range. In re Clement, 622 F.2d
1029, 1036, 206 USPQ 289, 296 (CCPA 1980). Our review of the
comparative example evidence presented in Appellant’s
specification indicates a particular lack of a showing down to
Appeal No. 1998-2916
Application No. 08/606,975
14
the 0.4 lower limit TiCl to H flow rate as claimed.4 2
We further disagree with Appellant’s contention that
Sandhu’s disclosure of flow rate values lower than the claimed
0.4 value amount to a teaching away from the claimed
invention. Each reference must be read, not in isolation, but
for what it fairly teaches in combination with the prior art
as a whole. It is improper to downgrade a reference on the
basis that it teaches away, unless it teaches away in the
context of the combination of references. In re Keller, 642
F. 2d 413, 425, 208 USPQ 871, 881 (CCPA 1981); In re Merck &
Co., Inc., 800 F. 2d 1091, 1096, 231
USPQ 375, 380 (Fed. Cir. 1986). In our view, Sandhu’s
teaching of a flow rate ratio 0.4 or greater as presently
claimed is not devalued because of the suggested flow rate
ratios below the claimed lower 0.4 limit.
As to Appellant’s argument (Brief, page 13) that the
Examiner has failed to consider evidence of non-obviousness in
the specification, we agree with the Examiner that, contrary
to Appellant’s assertion, this evidence has in fact been
Appeal No. 1998-2916
Application No. 08/606,975
15
considered. This consideration is not made in a vacuum
however but, rather, evaluated along with evidence of
obviousness present in the record. In our opinion, the
evidence relied upon by Appellant
when weighed against the substantial evidence of obviousness
is not sufficient to overcome the Examiner’s prima facie case
and, accordingly, the Examiner’s 35 U.S.C. § 103(a) rejection
of representative claim 1, and claims 2-6 and 16 which fall
with claim 1, is sustained.
We next consider the Examiner’s obviousness rejection of
representative independent claim 8 and note that, while we
found Appellant’s arguments to be unpersuasive with respect to
representative claim 1 discussed supra, we reach the opposite
conclusion with respect to claim 8. Instead of a recited flow
rate ratio of “equal to or greater than 0.4" as in claim 1, a
value within the flow rate range taught in the prior art,
claim 8
recites a flow rate ratio of “approximately 0.8", a value
Appeal No. 1998-2916
Application No. 08/606,975
The Examiner did not question the definiteness of the language4
“approximately 0.8" and no rejection based on the second paragraph of 35
U.S.C. § 112 is before us. In applying prior art to claim 8, the Examiner
interpreted “approximately 0.8" as reciting a value higher than 0.5, the
highest flow rate ratio suggested by the prior art, an interpretation which we
do not find to be unreasonable.
16
outside of any of the ranges of the prior art. Despite a4
lack of any explicit teaching of the claimed flow rate ratio
in the prior art, the Examiner nevertheless suggests (Answer,
pages 6 and 12) the obviousness to the skilled artisan of
arriving at the claimed
flow rate ratio value through routine optimization. Our
review of the record in this application, however, reveals a
total lack of support for the Examiner’s position. We are not
inclined to dispense with proof by evidence when the
proposition at issue is not supported by a teaching in a prior
art reference, common knowledge or capable of unquestionable
demonstration. Our reviewing court requires this evidence in
order to establish a
prima facie case. In re Knapp-Monarch Co., 296 F.2d 230, 232,
132 USPQ 6, 8 (CCPA 1961); In re Cofer, 354 F.2d 664, 668, 148
USPQ 268, 271-72 (CCPA 1966).
Appeal No. 1998-2916
Application No. 08/606,975
17
For the above reason, since all of the limitations of
representative independent claim 8 are not taught or suggested
by the prior art, the Examiner has not established a prima
facie case of obviousness. Accordingly, the Examiner’s
35 U.S.C. § 103 rejection of independent claim 8, as well as
claims 9-15 dependent thereon, is not sustained.
In summary, we have not sustained the Examiner’s
35 U.S.C. § 112, second paragraph, rejection of claims 1-6.
With respect to the Examiner’s 35 U.S.C. § 103 rejection of
the appealed claims, we have sustained the rejection of claims
1-6 and 16, but
have not sustained the rejection of claims 8-15. Therefore,
the Examiner’s decision rejecting claims 1-6 and 8-16 is
affirmed-in-part.
No time period for taking any subsequent action in
connection with this appeal may be extended under 37 CFR
§ 1.136(a).
AFFIRMED-IN-PART
Appeal No. 1998-2916
Application No. 08/606,975
18
MICHAEL R. FLEMING )
Administrative Patent Judge )
)
)
) BOARD OF PATENT
JOSEPH F. RUGGIERO ) APPEALS AND
Administrative Patent Judge ) INTERFERENCES
)
)
)
ANITA PELLMAN GROSS )
Administrative Patent Judge )
jfr/vsh
Appeal No. 1998-2916
Application No. 08/606,975
19
RONALD P. KANANEN, ESQ.
RADER, FISHMAN & GRAUER, P.L.L.C.
1233 20TH STREET, NW
SUITE 501
WASHINGTON, DC 20036