Ex Parte Liu et al

Board of Patent Appeals and Interferences

Jan 26, 2009

10238767 (B.P.A.I. Jan. 26, 2009)

UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
____________

Ex parte WUPING LIU, BEICHAO ZHANG,
and LIANG CHOO HSIA
____________

Appeal 2008-3271
Application 10/238,767
Technology Center 1700
____________

Decided: January 26, 2009
____________

Before EDWARD C. KIMLIN, LINDA M. GAUDETTE, and
MICHAEL P. COLAIANNI, Administrative Patent Judges.

GAUDETTE, Administrative Patent Judge.

DECISION ON APPEAL
This is an appeal from the final rejection of claims 1-5, 7-14, 16, 17,
33-36, 38-44, 46-48, and 51-56, the only claims pending in the Application.
We have jurisdiction under 35 U.S.C. § 6(b).
We AFFIRM.
Claim 1 is illustrative of the invention and is reproduced below:
1. A method of creating copper interconnects, using damascene
processing, comprising:

Appeal 2008-3271
Application 10/238,767

providing a semiconductor substrate, said substrate having
been provided with points of electrical contact, at least one
first copper interconnect having been created in a layer of
dielectric overlying said substrate, said at least one first
copper interconnect being aligned with and overlying at least
one of said points of electrical contact, the surface of said at
least one first copper interconnect being lower than the surface
of said layer of dielectric by a recess height, causing first
copper plug recesses having a recess cross-section;

creating a layer of barrier material over said first copper
interconnect having a height about equal to said recess height
and having a cross section about equal to said recess cross-
section, said creating a layer of barrier material over said
first copper interconnect comprising:

(i) depositing a layer of barrier material over said layer
of dielectric, thereby filling said first copper plug recesses
with barrier material; and

(ii) patterning said layer of barrier material, removing
said barrier material from said layer of dielectric, leaving
said barrier material inside said first copper plug recesses;
and

creating at least one second copper interconnect aligned
with and overlying said at least one first copper interconnect.

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The Examiner relies on the following prior art references to show
unpatentability:
Havemann 6,130,156 Oct. 10, 2000
Gupta US 6,274,499 Aug. 14, 2001
Yeh US 2002/0098673 Jul. 25, 2002

Appellants request review of the following grounds of rejection:
1. claims 1-3, 7-12, 16, 17, 33, 34, 38-42, 46-48, and 51-56 under 35
U.S.C. § 103(a) as unpatentable over Yeh in view of Gupta; and
2. claims 4, 5, 13, 14, 35, 36, 43, and 44 under 35 U.S.C. § 103(a) as
unpatentable over Yeh in view of Gupta as applied to claims 3, 12, 34, and
42, and further in view of Havemann.
ISSUE
The issue presented for our review with respect to each ground of
rejection is: have Appellants identified reversible error in the Examiner’s
determination that the combined teachings of the references disclose the
invention as claimed?
We answer this question in the negative as to each ground of rejection
for the reasons well stated in the Answer (see Ans. 7-10).
FINDINGS OF FACT (“FF”)
1. The Examiner finds that Yeh discloses the invention as claimed in
independent claims 1, 10, 33, and 41, with the exception of disclosing
a first copper interconnect having a surface “lower than the surface of
[said] layer of dielectric by a [recess height]” and “creating a [layer
of] barrier material over [said] first copper interconnects.” (Ans. 4.)
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2. Appellants do not dispute the Examiner’s findings with respect to the
teachings of Yeh. (App. Br. 15 (last para.)-17; see also, App. Br. 23
(first full para.).)
3. The Examiner finds that Gupta discloses a method of preventing
copper contamination of an intermetal dielectric layer during etching.
(Ans. 4.) The Examiner notes that in Gupta’s method, a barrier cap is
formed over a copper layer which is below the surface of the dielectric
layer by a measurable amount. (Ans. 4.)
4. Appellants do not dispute the Examiner’s findings with respect to the
teachings of Gupta. (App. Br. 18-21; see also, App. Br. 23 (first full
para.).)
5. The Examiner contends that:
[i]t would have been obvious to one of ordinary skill in
the art at the time the invention was made to modify the
invention of Yeh to have the first copper interconnect
below the surface of the dielectric layer by a measurable
amount and then capped with a barrier material because
of the desire to prevent copper contamination of the
intermetal dielectric layer during etching.

(Ans. 4-5.)
6. Appellants argue that even if properly combined, Yeh and Gupta fail
to disclose all of the claim limitations. (App. Br. 23.) More
specifically, Appellants argue that: (1) “the cap layer that is provided
by the claimed invention comprises a layer of barrier material, which
is an electrical conductor, while the cap layer of the Gupta et al.
invention comprises a dielectric” (App Br. 21), and (2) unlike Gupta,
the method of the invention does not require additional steps of
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etching the cap layer prior to forming additional interconnects over
the copper interconnects. (App. Br. 22.)
7. Independent claims 1, 10, 33, and 41 do not specify the material from
which the barrier layer is formed or include any other language which
indicates that the barrier material is limited to an electrical conductor.
(See Ans. 8.)
8. Appellants have not identified any language in the Specification
which limits the claimed barrier material to an electrical conductor.
(See Spec. 11-12 (discussing materials for the barrier layer).)
9. Independent claims 1, 10, 33, and 41 use the term “comprising” to
introduce the recited method steps. (See Ans. 8.)
10. The Examiner finds that Yeh in view of Gupta discloses the invention
as claimed in dependent claims 4, 5, 13, 14, 35, 36, 43, and 44, with
the exception of “the use of argon sputtering to remove the barrier
layer” (Ans. 6).
11. The Examiner finds that “Havemann discloses that in forming metal
interconnects, that [sic] must be a good cleanup at the bottom of the
via by sputter etching using argon to remove residue that might have
accumulated during the etching of the dielectric (col. 4, 1. 61-65).”
(Ans. 6-7.)
12. Appellants do not dispute the Examiner’s findings with respect to the
teachings of Havemann. (App. Br. 27, 30.)
13. The Examiner contends that:
[i]t would have been obvious to one of ordinary skill in
the art at the time the invention was made to modify the
invention of Yeh in view of Gupta to follow the etch
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removal of the barrier layer at the bottom of the via with
an argon sputter etch because of the desire to remove any
remaining residue remaining from the barrier layer
removal etch.

(Ans. 7.)
14. The Examiner maintains that one of ordinary skill in the art would
have understood that Havemann’s “argon sputter etch would be
performed until there is no remaining residue. Thus, the argon sputter
etch conditions are result effective.” (Ans. 7.)
15. Appellants have not presented any arguments or evidence to refute the
Examiner’s findings with respect to the aforementioned level of
understanding of the ordinary artisan (FF 14). (See App. Br. 26-30.)

PRINCIPLES OF LAW
Appellants have the burden on appeal to the Board to demonstrate
error in the Examiner's position. See In re Kahn, 441 F.3d 977, 985-86 (Fed.
Cir. 2006) (“On appeal to the Board, an applicant can overcome a rejection
[under § 103] by showing insufficient evidence of prima facie obviousness
or by rebutting the prima facie case with evidence of secondary indicia of
nonobviousness.”) (quoting In re Rouffet, 149 F.3d 1350, 1355 (Fed. Cir.
1998)). Therefore, we look to Appellants' Brief to show error in the
proffered prima facie case. See 37 C.F.R. § 41.37(c)(1)(vii).
In making a patentability determination, analysis must begin with the
question, "what is the invention claimed?" since "[c]laim interpretation, . . .
will normally control the remainder of the decisional process." Panduit
Corp. v. Dennison Mfg. Co., 810 F.2d 1561, 1567-68 (Fed. Cir. 1987); see
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also, In re Self, 671 F.2d 1344, 1348 (CCPA 1982) (“Many of appellant's
arguments fail from the outset because, … they are not based on limitations
appearing in the claims.”).
During examination, claims terms must be given their broadest
reasonable construction consistent with the specification. In re Icon Health
and Fitness, Inc., 496 F.3d 1374, 1379 (Fed. Cir. 2007). “‘[C]omprising’ is
a term of art used in claim language which means that the named elements
are essential, but other elements may be added and still form a construct
within the scope of the claim.” In re Crish, 393 F.3d 1253, 1257 (Fed. Cir.
2004) (quoting Genentech, Inc. v. Chiron Corp., 112 F.3d 495, 501 (Fed.
Cir. 1997)).
The test for obviousness is what the collective teachings of the prior
art would have suggested to one of ordinary skill in the art. In re Young, 927
F.2d 588, 591 (Fed. Cir. 1991). As explained by the Supreme Court, “[i]f a
person of ordinary skill can implement a predictable variation, § 103 likely
bars its patentability. For the same reason, if 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., 127 S. Ct. 1727, 1740 (2007).

ANALYSIS
Appellants argue that several inventive features are not disclosed or
suggested (FF 6) by the Examiner’s proposed combination of references.
However, Appellants have not identified error in the Examiner’s
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determination that the claims, as drafted, do not recite these argued features.
(See FF 7-9.) Appellants have not presented persuasive arguments or
evidence (FF 2, 4, 12, 15) to refute the Examiner’s findings with respect to
the teachings of the individual references (FF 1, 3, 11, 14). Nor have
Appellants pointed to any error in the Examiner’s proposed motivation (FF
5, 13) for combining the references. Accordingly, we find that a
preponderance of the evidence favors the Examiner’s conclusion of
obviousness with respect to each ground of rejection.
CONCLUSION
Appellants have not identified reversible error in the Examiner’s
obviousness rejections. The decision of the Examiner rejecting claims 1-5,
7-14, 16, 17, 33-36, 38-44, 46-48, and 51-56 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)(iv).

AFFIRMED

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