Ex Parte LI

Board of Patent Appeals and Interferences

Jul 20, 2009

11388085 (B.P.A.I. Jul. 20, 2009)

UNITED STATES PATENT AND TRADEMARK OFFICE
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BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
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Ex parte SHOUTIAN LI
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Appeal 2009-001767
Application 11/388,085
Technology Center 1700
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Decided:1 July 20, 2009
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Before ALLEN R. MACDONALD, Vice Chief Administrative Patent Judge,
and CATHERINE Q. TIMM and BEVERLY A. FRANKLIN,
Administrative Patent Judges.

TIMM, Administrative Patent Judge.

DECISION ON APPEAL

I. STATEMENT OF THE CASE

1 The two-month time period for filing an appeal or commencing a civil
action, as recited in 37 C.F.R. § 1.304, begins to run from the Decided Date
shown on this page of the decision. The time period does not run from the
Mail Date (paper delivery) or Notification Date (electronic delivery).

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Application 11/388,805

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Appellant appeals under 35 U.S.C. § 134(a) from the Examiner’s
decision rejecting claims 1-13. We have jurisdiction under 35 U.S.C. § 6(b).
We AFFIRM.
The invention relates to a polishing composition. Claim 1 is
illustrative:
1. A chemical-mechanical polishing system for polishing a substrate
comprising:

(a) a polishing component selected from the group consisting of a
polishing pad, an abrasive, and a combination thereof,

(b) a liquid carrier,

(c) an oxidizing agent that oxidizes at least part of a substrate,
wherein the oxidizing agent is present in an amount of about 0.5 wt.% or
less based on the weight of the liquid carrier and any components dissolved
or suspended therein, and

(d) a halogen anion selected from the group consisting of chloride,
bromide, and a combination thereof, wherein the liquid carrier with any
components dissolved or suspended therein has a pH of about 3 of less.

The Examiner maintains, and Appellant appeals, the following
rejections:
A. The rejection of claims 1-7 and 9-13 under 35 U.S.C. § 103(a) as
unpatentable over Kurata (US 2006/0037251 A1, pub. Feb. 23, 2006) in
view of Thomas (US 2005/0104048 A1, pub. May 19, 2005); and
B. The rejection of claim 8 under 35 U.S.C. § 103(a) as unpatentable
over Kurata and Thomas and further in view of Oshima (US 7,014,534 B2,
issued Mar. 21, 2006).
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With regard to the rejection of claims 1-7 and 9-13, Appellant argues
no claim apart from the others. Therefore, in accordance with 37 C.F.R.
§ 41.37(c)(1)(vii), we select a single claim as representative to decide the
issues on appeal. We select claim 1.
II. DISPOSITIVE ISSUE
The Examiner finds that Kurata describes a polishing medium, which
resembles the claimed “polishing system” in that it includes an abrasive, a
liquid carrier (water), an oxidizing agent in concentrations overlapping the
claimed concentration, and a pH of 3 or less (Ans. 3). The Examiner
acknowledges that Kurata does not teach introducing a halogen anion into
the polishing medium as required by claim 1 (Ans. 3). The Examiner,
however, finds that Thomas describes a polishing medium including
chloride or bromide halogen anionic components added to reduce the noise
level in the polishing zone (Ans. 3). The Examiner concludes that it would
have been obvious to one of ordinary skill in the art to modify Kurata’s
polishing medium with the halogen anions of Thomas for the noise reducing
benefit expressed in Thomas (Ans. 3).
Appellant contends that the teachings of Kurata and Thomas are such
that one of ordinary skill in the art would not have combined the two
disclosures (Br. 6), and that even if one of ordinary skill in the art were to
combine the teachings, the result would not necessarily meet the
requirements of the claims (Br. 7).
The issue is: Has Appellant established that the Examiner reversibly
erred in finding that Thomas provides a suggestion to include chloride
and/or bromide halogen anions in the polishing medium of Kurata to obtain
a polishing medium having the composition of claim 1?
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III. FINDINGS OF FACT
The following enumerated Findings of Fact (FF) are particularly
relevant in resolving the issue on appeal:
1. Both Kurata and Thomas are directed to formulating polishing
compositions for chemical-mechanical polishing (CMP) of
semiconductor wafers. The composition is specifically formulated
for forming wirings (copper interconnects) within the dielectric
layer of the semiconductor device after the deposition of a barrier
layer and metal wiring layer. (Kurata ¶¶ [0002], [0011], [0014], and
[0031-33]; Thomas ¶¶ [0001-02] and [0028].)
2. Figures 1(f) to 1(h) of Kurata illustrate the polishing process.
Figures 1(f) to 1(h) are reproduced below:

Fig. 1 shows the steps of polishing (Kurata, ¶ [0030]).
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3. As taught in both Kurata and Thomas polishing occurs in two-steps.
The first polishing step removes excess wiring metal, e.g., copper,
(layer 15 shown in Fig. 1(f). The second step removes the
underlying barrier layer, e.g., a tantalum-based layer, (Kurata’s
depicted layer 14). After the second step, the desired conductor
material remains within the trenches of the silicon dioxide layer
(Kurata’s layer 11). (Kurata, ¶ [0011], Thomas, ¶ [0003].)
4. Conventionally, polishing media used in CMP was comprised of an
oxidizing agent and abrasive grains, to which a metal-oxide-
dissolving agent and a protective-film-forming agent were
optionally added (Kurata, ¶ [0006]).
5. The polishing media of Kurata and Thomas are similar to the
conventionally known media and to each other in components
(compare Kurata, ¶¶ [0034], [0039], [0041-44] with Thomas, ¶¶
[0015], [0019-23], and [0025]).
6. The two polishing media of Kurata have a pH less than 3 and low
oxidizing-agent concentration, i.e., 0.01 to 3 % by weight
7. Kurata explains that, “[w]here its pH is less than 3, the etching rate
of the copper or copper alloy comes [sic, becomes] higher, but,
because of the sufficiently low concentration of the oxidizing agent,
can be controlled by the protective-film-forming agent [such as
BTA].” (Kurata, ¶¶ [0039], [0046].)
8. Thomas focuses on the problem of high friction in the polishing
zone. This friction can cause vibrations resulting in a loud stick-slip
event that continues throughout the first step polish cycle and has
undesirable effects (Thomas, ¶ [0004]).
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9. Thomas solves the friction problem by adding salts, or mixtures
thereof, to effectively reduce noise levels from vibration during first
step of polishing. (Thomas, ¶ [0009]).
10. Thomas suggests using salts including chloride and bromide anions
(Thomas, ¶ [0011]).
11. Thomas adds the anionic component to a polishing medium
containing 1-15 wt.% oxidizer, a level of oxidizer higher than that
of Kurata and higher than the claimed level (Thomas, ¶ [0019]).
12. Thomas discloses adding an inhibitor such as BTA “to control
copper interconnect removal rate.” According to Thomas, adjusting
the concentration of the inhibitor “adjusts the interconnect metal
removal rate.” (Thomas, ¶ [0020].)
13. Thomas further discloses that benzotriazole (BTA) decreases copper
polishing rate, but in excessive amounts, BTA increases vibration
noise (Thomas, ¶ [0005]).
IV. PRINCIPLES OF LAW
An improvement in the art is obvious if "it is likely the product not of
innovation but of ordinary skill and common sense." KSR Int’l v. Teleflex
Inc., 550 U.S. 398, 421 (2007). One of the ways in which a claim’s subject
matter can be proved obvious is by establishing that there existed at the time
of invention a known problem for which there was an obvious solution
encompassed by the claims. KSR at 419-420.
V. ANALYSIS
We agree with the Examiner that Appellant's arguments are not
persuasive because, as the Examiner points out, Thomas provides an express
disclosure that adding halogen anions, such as chloride and bromide anions,
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to a CMP polishing medium will effectively reduce the noise level in the
polishing zone (Ans. 5; FF 8-10). This express disclosure provides a
sufficient reason to add the halogen anions of Thomas into the first polishing
medium of Kurata. “As long as some motivation or suggestion to combine
the references is provided by the prior art taken as a whole, the law does not
require that the references be combined for the reasons contemplated by the
inventor.” In re Beattie, 974 F.2d 1309, 1312 (Fed. Cir. 1992).
We are cognizant of the fact that Thomas discloses adding the noise
reducing halogen anions to a polishing medium of higher oxidizer
concentration than contained in the Kurata composition (FF 11). However,
Kurata describes a polishing media having oxidizing agent in low
concentrations, such as 0.5 wt.%, containing similar components to the
polishing medium of Thomas, and which is for the same use, i.e., for
polishing interconnect metal such as copper and barrier metal such as
tantalum (FF 1-6). Given the similarities in composition and intended use,
we cannot agree with Appellant that “[t]here is no indication that high noise
levels accompany the use of the polishing medium disclosed in the Kurata
‘251 application.” (Br. 7.) In fact, it is reasonable to conclude that the noise
level problem would be present when polishing with Kurata’s polishing
medium, and it is further reasonable to conclude that one of ordinary skill in
the art would look to the teachings of Thomas to solve the noise problem.
The evidence provided by the Examiner supports the Examiner’s finding of
a reason to combine.
We also cannot agree with Appellant that Kurata’s and Thomas’
teachings of using BTA are incompatible such that one of ordinary skill in
the art would not have added the halogen anion of Thomas in the polishing
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composition of Kurata. Both Kurata and Thomas teach that BTA can be
added to control the etching rate of copper (FF 7 and 12). BTA, in fact, was
known to decrease copper etching rate (FF 13). The references provide
evidence showing that adjusting BTA levels to control copper etching rate
was within the level of ordinary skill in the art. The combined teachings of
Kurata and Thomas provide guidance for adding BTA in amounts effective
to adjust copper etching rate to desired rates.
In fact, the teachings regarding BTA further support the Examiner’s
conclusion of obviousness. Thomas further teaches that it was known in the
art that BTA in excessive amounts increases vibration noise (FF 13). The
fact that Kurata teaches adding BTA provides further evidence that vibration
noise would occur during polishing using the polishing medium of Kurata.
Kurata provides a reason for using low concentrations of oxidizing
agent and Thomas provides a reason for using halogen anions in a polishing
medium. Given the guidance provided in the references, we determine that
the weight of the evidence supports the Examiner’s conclusion of
obviousness.
Appellant has therefore not established that the Examiner reversibly
erred in finding that Thomas provides a suggestion to include chloride
and/or bromide halogen anions in the polishing medium of Kurata to obtain
a polishing medium having the composition of claim 1.
Turning to the rejection of claim 8, Appellant relies upon the
arguments made against the above discussed primary rejection, and further
contends that the additional reference cited by the Examiner, Oshima, fails
to remedy the deficiencies of the primary rejection. For the reasons
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discussed above, Appellant has not established that the Examiner reversibly
erred.
VI. CONCLUSION
Appellant has limited the scope of the arguments to the above issues
and does not further contest the Examiner’s rejection of the claims.
Therefore, we sustain the rejections of the Examiner.
VII. DECISION
The decision of the Examiner is affirmed.
VIII. 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)(1)(v).
AFFIRMED

cam

STEVEN WESEMAN
ASSOCIATE GENERAL COUNSEL, I.P.
CABOT MICROELECTRONICS CORP.
870 NORTH COMMONS DRIVE
AURORA IL 60504