Ex Parte Weidman et al

Board of Patent Appeals and Interferences

Jan 25, 2012

11385038 (B.P.A.I. Jan. 25, 2012)

UNITED STATES PATENT AND TRADEMARKOFFICE
UNITED STATES DEPARTMENT OF COMMERCE
United States Patent and Trademark Office
Address: COMMISSIONER FOR PATENTS
P.O. Box 1450
Alexandria, Virginia 22313-1450
www.uspto.gov
APPLICATION NO. FILING DATE FIRST NAMED INVENTOR ATTORNEY DOCKET NO. CONFIRMATION NO.
11/385,038 03/20/2006 Timothy W. Weidman APPM/009920US02/PPC/ELESS 8743
44257 7590 01/25/2012
PATTERSON & SHERIDAN, LLP - - APPM/TX
3040 POST OAK BOULEVARD, SUITE 1500
HOUSTON, TX 77056
EXAMINER
BAREFORD, KATHERINE A
ART UNIT PAPER NUMBER
1715
MAIL DATE DELIVERY MODE
01/25/2012 PAPER
Please find below and/or attached an Office communication concerning this application or proceeding.
The time period for reply, if any, is set in the attached communication.
PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
____________________

BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
____________________

Ex parte TIMOTHY W. WEIDMAN,
ARULKUMAR SHANMUGASUNDRAM, KAPILA WIJEKOON,
SCHUBERT S. CHU, FREDERICK C. WU, and KAVITA SHAH
____________________

Appeal 2011-000217
Application 11/385,038
Technology Center 1700
____________________

Before FRED E. McKELVEY, PETER F. KRATZ, and
RAE LYNN P. GUEST, Administrative Patent Judges.

GUEST, Administrative Patent Judge.

DECISION ON APPEAL
I. STATEMENT OF CASE
Appellants appeal under 35 U.S.C. § 134 from the Examiner’s
decision to reject claims 1-38. We have jurisdiction under 35 U.S.C. § 6(b).
We AFFIRM.
Appellants’ invention relates to a method of depositing a copper-
containing material within a feature, such as a via, aperture, trench, or
contact, of a semiconductor device using a seed layer prior to electroless
plating (Spec. ¶¶ [0002]-[0004] and [0022]). Appellants identify in the
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Background section of the Specification that the use of a seed layer was
known in the art (a) as a surface capable of electron transfer for nucleation
of the copper material during electroless deposition and (b) as an adhesion
layer to the underlying barrier layer or contact surface (Spec. ¶¶ [0006] and
[0007]). Thus, Appellants’ invention includes a method for depositing a
seed layer, particularly a ruthenium seed layer, and an electroless copper
plating solution to achieve improved adhesion and improved copper plating
properties (Spec. ¶¶ [0008] and [0022]). Claims 1, 6, 9, and 15 are
illustrative:
1. A method for forming a conductive material within
a feature on a substrate, comprising:
forming a ruthenium seed layer selectively onto a contact
surface within a feature on a substrate during a vapor deposition
process, wherein sidewalls of the feature remain substantially
free of the ruthenium seed layer during the vapor deposition
process; and
depositing a copper-containing layer on the ruthenium
seed layer while filling the feature during an electroless
deposition process.
6. The method of claim 2, wherein the electroless
deposition process includes exposing the substrate to an
electroless solution comprising a copper source and at least one
additive selected from the group consisting of an accelerator, a
suppressor, a leveler, and combinations thereof.
9. The method of claim 6, wherein a surface of the
copper-containing layer adjoins the sidewall of the feature at an
angle of less than 90° from the sidewall.
15. The method of claim 14, wherein the leveler is
1-(2-hydroxyethyl)-2- imidazolidinethione.
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The Examiner relies upon the following evidence:
First Named Inventor Document No. Issue or Pub. Date
Bickford
Zhao
Hong
Gabe
Hongo
Tsao
US 5,318,803
US 5,674,787
US 6,008,117
US 6,773,573 B2
US 7,033,463 B1
US 7,208,404 B2
Jun. 7, 1994
Oct. 7, 1997
Dec. 28, 1999
Aug. 10, 2004
Apr. 25, 2006
Apr. 24, 2007
Soininen US 2002/0004293 A1 Jan. 10, 2002
The Examiner maintains, and Appellants seek review of, the
following rejections:
1. The rejection of claims 1-5, 16-18, 29, and 30 under 35 U.S.C.
§ 103(a) as unpatentable over Hong in view of Zhao, Bickford, and
Soininen;
2. The rejection of claims 6-8, 19-21, 31, and 37 under 35 U.S.C.
§ 103(a) as unpatentable over all of the above cited references and
further in view of Hongo;
3. The rejection of claims 9-14, 22-27, and 32-36 under 35 U.S.C.
§ 103(a) as unpatentable over all of the above cited references and
further in view of Tsao;
4. The rejection of claim 38 under 35 U.S.C. § 103(a) as unpatentable
over the references applied to claim 6 and further in view of Gabe;
and
5. The rejection of claims 15 and 28 under 35 U.S.C. § 103(a) as
unpatentable over all of the above cited references and further in view
of Gabe.
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With respect to each of the rejections, Appellants address all the
separately rejected claims as a group.1 Therefore, we decide this Appeal on
the basis of claims 1, 6, 9, 15, and 38 for the respective rejections.
II. DISCUSSION
We adopt the Examiner’s findings in the Answer as our own and add
any additional findings of fact appearing below for emphasis.
A. ISSUE ON APPEAL
With respect to claim 1, the Examiner acknowledges that the
electroless copper plating process taught by Hong does not include a
ruthenium seed layer as claimed (Ans. 5). Accordingly, the Examiner
concludes that it would have been obvious for one of ordinary skill in the art
to have modified Hong to include a copper seed layer as taught by Zhao
because Zhao teaches catalyzing a bottom of a feature “for optimum
electroless plating” (Ans. 7). Similarly, the Examiner concludes that one of
ordinary skill in the art would have substituted the copper seed layer in the
combined method of Hong and Zhao with a ruthenium seed layer because
Bickford teaches that ruthenium and copper are both well-known and
suitable seed layers for catalyzing a surface for copper electroless plating
(Ans. 6-7). Finally, the Examiner concludes that one of ordinary skill in the
art would have applied the ruthenium seed layer using a process in which a
ruthenium oxide layer is applied by vapor deposition using ruthenium

1 Appellants point to some of the additional features recited in claims 16 and
29, and the claims depending therefrom together with a conclusory statement
that the applied prior art does not teach these features (App. Br. 14 and 16-
20; Reply Br. 11, 12, 14-16, and 20). As correctly indicated by the
Examiner, however, this summary presentation by Appellants is tantamount
to merely setting forth what a particular claim recites and does not amount to
a separate substantive argument for each of these claims (see, e.g. Ans. 21).
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tetroxide as a source and then reduced with a reductant comprising hydrogen
to provide a ruthenium metal layer, as taught by Soininen to provide a
desirable catalyzing surface (Ans. 6-7).
With respect to claim 6, the Examiner concludes that it would have
been obvious to one of ordinary skill in the art to add, for example, the
leveler taught by Hongo to the copper electroless plating baths taught by
Zhao, Hong, and/or Bickford for its known function as a leveler (see Ans. 8-
9; see Hongo, col. 7, ll. 5-40).
With respect to claim 9, the Examiner concludes that it would have
been obvious to one of ordinary skill in the art for the copper electroless
plating to result in an angled surface with respect to the sidewall of the
feature either as the result of the plating process following the uneven
contour of the base or as a result of “dishing” that would occur during
further processing, both of which are well-known phenomena described by
Tsao (Ans. 10; see Tsao, col. 6, ll. 10-45 and Figures 4 and 5).
With respect to claim 15, the Examiner concludes that it would have
been obvious to one of ordinary skill in the art to substitute the particular
leveler taught by Gabe as the leveler described by Hongo and Tsao in the
electroless plating solutions described by Hong, Zhao and/or Bickford
because Gabe describes that such levelers produce similar results (Ans. 13,
see Gabe, col. 9, ll. 24-30).
Appellants’ arguments are substantially directed to rebutting the
Examiner’s rationales for concluding obviousness based on additional
teachings of the prior art references (see generally App. Br.).
Accordingly, the issue on appeal arising from the contentions of
Appellants and the Examiner is: does the evidence support the Appellants’
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view that the Examiner’s rationale is not sufficient when considering the
teachings of the prior art references as a whole? We answer this question in
the negative.
A. CLAIM 1
Appellants question whether the skilled artisan would have applied a
seed layer and selective electroless deposition of copper as taught by Zhao in
the process taught by Hong when no such seed layer or selective deposition
is required for successful electroless plating in Hong (App. Br. 10).
The Examiner has provided a sufficient rationale for such an addition
to the process of Hong, supported by the teachings of Zhao, that activation
of a surface (a seed layer) provides for the autocatalytic reaction for the
electroless plating of copper (Ans. 14). We find the Examiner’s position
reasonable and well supported by the teachings of Zhao. Moreover,
Appellants admit in the Specification that seed layers for electroless plating
contact surfaces were well known in the art (Spec. ¶¶ [0006] and [0007]).
Appellants cannot defeat an obviousness rejection with an argument directed
to a claim feature which is acknowledged to be well known in the prior art.
See Constant v. Advanced Micro-Devices, Inc., 848 F.2d 1560, 1570 (Fed.
Cir. 1988) (“A statement . . . that something is in the prior art is binding on
an applicant and patentee for determinations of anticipation and
obviousness.”); In re Nomiya, 509 F.2d 566, 571 n.5 (CCPA 1975) (“[A]
statement by an applicant, whether in the application or in other papers
submitted during prosecution, that certain matter is ‘prior art’ to him, is an
admission that that matter is prior art for all purposes.”).
Likewise, the Examiner has provided sufficient rationale, supported
by the teachings of Zhao (Zhao, col. 5, l. 50 to col. 6, l. 2), as to why the
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skilled artisan would choose to selectively deposit copper, specifically to
avoid the subsequent mechanical polishing (CMP) away of the extra copper
that extends above the feature, as taught by Hong (Ans. 14). Appellants’ do
not convincingly rebut this finding or reasoning by the Examiner.
Appellants further question whether a skilled artisan would have used
a ruthenium seed layer in the process of Hong as modified by Zhao because
Zhao teaches disadvantages to copper electroless plating when using
palladium as a seed layer, specifically an increase in resistance and a
decrease in stability of the copper deposit (App. Br. 12). Appellants further
explain that ruthenium and palladium are both platinum group metals
“which have many similar physical properties, chemical properties, and
usually occur together in the same mineral deposits . . . while the physical
and chemical properties of copper distinguishes those of palladium or
ruthenium” (Reply Br. 6).
We agree with the Examiner that Bickford provides sufficient
evidence that ruthenium was known as an alternative to copper as a seed
layer for copper electroless deposition, and that, accordingly, one of ordinary
skill in the art would have expected success in using ruthenium as a seed
layer for the electroless deposition of copper in the processes taught by
Hong and Zhao (see e.g. Bickford, col. 4, ll. 35-37). Appellants present no
convincing evidence that the chemical and physical properties of palladium
or ruthenium are sufficiently similar that one of ordinary skill in the art
would have been persuaded against using ruthenium over the teaching in
Bickford that ruthenium was a known seed layer, by the reference to
palladium in Zhao. Appellants’ attorney arguments do not take the place of
evidence in the record. In re Pearson, 494 F.2d 1399, 1405 (CCPA 1974).
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Further, we agree with the Examiner that the disadvantages taught by
Zhao do not rebut the teachings of Bickford, that palladium, ruthenium and
copper all effectively function as seed layers for electroless plating of
copper, but rather would have merely suggested reasons why palladium may
not be as preferred as copper. In re Gurley, 27 F.3d 551, 552-3 (Fed. Cir.
1994) (“A known or obvious composition does not become patentable
simply because it has been described as somewhat inferior to some other
product for the same use. . . . [I]n general, a reference will teach away if it
suggests that the line of development flowing from the reference’s
disclosure is unlikely to be productive of the result sought by the
applicant.”).
Appellants also question the addition of the teaching of Soininen
because Soininen does not teach the same copper electroless plating process
disclosed in the teachings of Hong, Zhao, and Bickford, and, in fact, teaches
that among alternative for depositing copper, a seed layer is “only needed for
the electroplating process” (App. Br. 11) (citing Soininen, ¶ [0036]). We
disagree that the skilled artisan would be persuaded against using the
ruthenium deposition process taught by Soininen in the process of Hong as
modified by the teachings of Zhao and Bickford. As discussed above,
Appellants cannot dispute that it was known in the art to use a seed layer for
electroless deposition, and the Examiner has provided sufficient evidence
that a ruthenium seed layer would also be obvious for electroless deposition.
Likewise, as pointed out by the Examiner, one of ordinary skill in the art
would recognize that the benefits of depositing a ruthenium seed layer by the
process of Soininen would have been advantageous, despite the process used
for depositing the subsequent copper layer (Ans. 16 and 20; see Soininen, ¶¶
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[0047] and [0048] (describing that the ALD deposition method for
depositing ruthenium provides good adhesion, structural integrity, reduced
pinhole formation, and excellent step coverage on features such as vias,
trenches, etc.)). “[I]f a technique has been used to improve one device, and
a person of ordinary skill in the art would recognize that it would improve
similar devices in the same way, using the technique is obvious unless its
actual application is beyond his or her skill.” KSR Int'l Co. v. Teleflex Inc.,
550 U.S. 398, 417 (2007).
Appellants also contend that Soininen teaches depositing the
ruthenium oxide layer as an ALD process and not a chemical vapor
deposition (CVD) process (App. Br. 11). Claim 1 recites that the ruthenium
oxide be deposited by “a vapor deposition process,” and is not limited
specifically to CVD. Further, the Examiner has found that the ALD
deposition process is a type of vapor deposition (Ans. 16-17), a fact which is
not contested by Appellants. See In re Eskild, 387 F.3d 987, 988 (CCPA
1968) (accepting as fact statements made by the Examiner to which
Appellants have raised no challenge).
Appellants also contend that Soininen does not teach reducing the
ruthenium oxide layer using hydrogen, as claimed (App. Br. 12). Claim 1
recites only the deposition of a ruthenium seed layer “during a vapor
deposition process” (claim 1). It is not until claim 3 where chemical
reduction of the seed layer is recited, and it is not until claim 4 where
particular reductants are recited (claims 3 and 4). Since Appellants do not
present separate arguments with respect to claims 3 and 4, we need not
address this argument. See 37 C.F.R. § 41.37(c)(1)(vii) (“When multiple
claims subject to the same ground of rejection are argued as a group by
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appellant, the Board may select a single claim from the group of claims that
are argued together to decide the appeal with respect to the group of claims
as to the ground of rejection on the basis of the selected claim alone.”).
Nonetheless, the Examiner has interpreted the language of claim 4 reciting
“hydrogen, atomic hydrogen, [and] derivatives thereof,” as being met by the
hydrogen radicals and hydrogen-containing molecules taught by Soininen
(Ans. 18), an interpretation which is not convincingly contested by
Appellants.
B. CLAIMS 6, 9, 15, and 38
With respect to the additional teachings of Hongo, Appellants contend
that Hongo teaches away from electroless plating because it teaches that an
electroplating process is inefficient, and Appellants suggest a lack of
obviousness because Zhao and Hongo are directed towards solving different
problems, specifically copper layer initiation and plating rates, respectively
(App. Br. 15).
With respect to the additional teachings of Tsao, Appellants contend
that Tsao teaches away from a seed layer of ruthenium because it teaches
instead a seed layer of copper (App. Br. 17).
With respect to the additional teachings of Gabe, Appellants contend
that a lack of obviousness is suggested because Zhao and Gabe are directed
towards solving different problems, specifically copper layer initiation and
using a leveler in a plating bath (App. Br. 19; Reply Br. 17 and 19).
We are not persuaded that the Examiner’s conclusions of obviousness
are untenable based on Appellants’ arguments. In each case, the Examiner
has provided sound reasoning based on facts presented in the prior art for
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concluding that claims 6, 9, 15 and 38, would have been obvious to the
skilled artisan.
We find no convincing evidence that Hongo or Tsao teaches away
from any particular copper electroless plating technique either because it
argues against an alternative process (electroplating) or because it teaches
the use of an alternative seed layer. Neither argument is directed to the
electroless copper plating techniques previously described by Hong, Zhao,
and/or Bickford, to which the teachings of Hongo and Tsao are particularly
applied. Likewise, we are not persuaded against the Examiner’s conclusions
merely because the art addresses different problems from one another, where
“any need or problem known in the field of endeavor at the time of
invention and addressed by the patent can provide a reason for combining
the elements in the manner claimed.” KSR, 550 U.S. at 420 (emphasis
added). Such arguments do not specifically address the Examiner’s
positions articulated in the Answer or explain why these positions are
untenable.
III. DECISION
We affirm the Examiner’s decision.
IV. TIME PERIOD FOR RESPONSE
No time period for taking any subsequent action in connection with
this appeal may be extended under 37 C.F.R. § 1.136(a).

AFFIRMED

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