Ex Parte Dysard et al

Board of Patent Appeals and Interferences

Jan 30, 2012

11448205 (B.P.A.I. Jan. 30, 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.
11/448,205 06/07/2006 Jeffrey Dysard 100343 3592
29050 7590 01/30/2012
STEVEN WESEMAN
ASSOCIATE GENERAL COUNSEL, I.P.
CABOT MICROELECTRONICS CORPORATION
870 NORTH COMMONS DRIVE
AURORA, IL 60504
EXAMINER
DAHIMENE, MAHMOUD
ART UNIT PAPER NUMBER
1713
MAIL DATE DELIVERY MODE
01/30/2012 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 JEFFREY DYSARD, SRIRAM ANJUR,
TIMOTHY JOHNS and ZHAN CHEN
____________

Appeal 2010-008167
Application 11/448,205
Technology Center 1700
____________

Before CHUNG K. PAK, JEFFREY T. SMITH and
KAREN M. HASTINGS, Administrative Patent Judges.

SMITH, Administrative Patent Judge.

DECISION ON APPEAL

Appeal 2010-008167
Application 11/448,205

2
STATEMENT OF THE CASE
This is an appeal under 35 U.S.C. § 134 from a final rejection of
claims 7 through 25. We have jurisdiction under 35 U.S.C. § 6.
Appellants’ invention relates to a chemical mechanical polishing
(CMP) method. App. Br. 2. Claims 7 and 14 are illustrative:
7. A chemical-mechanical polishing (CMP) method for
polishing a silicon nitride-containing substrate, the method
comprising the steps of:
(a) contacting a surface of a silicon nitride-containing
substrate with a polishing pad and an aqueous CMP
composition, the CMP composition comprising about 0.01 to
about 15 percent by weight of colloidal silica, about 10 to about
100,000 ppm of at least one acidic component having a pKa in
the range of about 1 to about 4.5, and an aqueous carrier
therefor, wherein the polishing composition has a pH in the
range of about 0.5 pH units less than the pKa of the at least one
acidic component to about 1.5 pH units greater than the pKa;
and
(b) causing relative motion between the polishing pad
and the substrate while maintaining a portion of the CMP
composition in contact with the surface between the pad and the
substrate for a time period sufficient to abrade silicon nitride
from the surface.
14. A chemical-mechanical polishing (CMP) method for
selectively removing silicon nitride in the presence of silicon
oxide in a substrate, the method comprising the steps of:
(a) abrading a surface of a substrate comprising silicon
nitride and silicon oxide with a polishing composition including
about 0.01 to about 15 percent by weight of colloidal silica,
about 10 to about 100,000 ppm of at least one acidic component
having a pKa in the range of about 1 to about 4.5, and an
aqueous carrier therefor, wherein the polishing composition has
Appeal 2010-008167
Application 11/448,205

3
a pH in the range of about 0.5 pH units less than the pKa of the
at least one acidic component to about 1.5 pH units greater than
the pKa.
The Examiner relied on the following references in rejecting the
appealed subject matter:
Kurata 609 US 2005/0181609 A1 August 18, 2005
Kurata 7711 WO 2006/035771 A1 April 6, 2006

Appellants request review (App. Br. 3) of the following rejections
from the Examiner’s final office action:
Claims 7-13 stand rejected under 35 U.S.C. § 103(a) as being
unpatentable over Kurata 609.
Claims 14-25 stand rejected under 35 U.S.C. § 103(a) as being
unpatentable over Kurata 771.

OPINION
Rejection of Claims 7-13 Under 35 U.S.C. § 103(a)
The dispositive issue on appeal is: Did the Examiner err in
determining that Kurata 609 describes or suggests a chemical-mechanical
polishing (CMP) method using a polishing composition having a pH in the
range of about 0.5 pH units less than the pKa of the at least one acidic

1 We rely on U.S. Published Application 2007/0218811 A1, published
September 20, 2007, as the translation for the Kurata 771 reference in our
discussion of the rejection. U.S. Published Application 2007/0218811 A1
was made of record by the Examiner on December 12, 2008. Since
Appellants and the Examiner refer to the Kurata 771 reference throughout
the Briefs and Answer, we will cite to the primary reference as Kurata 771 to
avoid confusion. However, cited passages will refer to the U.S. Published
Application 2007/0218811 A1.
Appeal 2010-008167
Application 11/448,205

4
component to about 1.5 pH units greater than the pKa as required by the
subject matter of independent claim 7? 2
We answer this question in the negative and, therefore, we AFFIRM.
We affirm for the reasons presented by the Examiner and add the following.
The Examiner found that Kurata 609 discloses a chemical mechanical
polishing (CMP) method similar to Appellants’ claimed CMP method. The
Examiner recognized that Kurata 609 did not expressly disclose the
polishing composition as having a pH in the range of about 0.5 pH units less
than the pKa of the at least one acidic component to about 1.5 pH units
greater than the pKa, as required by the subject matter of independent claim
7. Ans. 3-4. However, the Examiner found that Kurata 609 discloses a pKa
range of less than 3.7 and a pH range from 2-5 that overlaps the claim’s pKa
and pH ranges. Id. at 4. The Examiner concluded that Appellants’ claimed
pKa and pH ranges would have been obvious to one of ordinary skill in the
art in view of Kurata 609’s disclosure. Id.
Appellants argued that Kurata 609 fails to teach a pH range for the
polishing composition dependent on the pKa of the acidic component and
that Kurata 609 does not provide the guidance to one skilled in the art to
arrive to the pKa and pH values as set forth by the claimed dependency of
pH and pKa. App. Br. 6.
We are unpersuaded by Appellants’ line of argument and agree with
the Examiner’s reasoning that it would have been obvious to one skilled in
the art to arrive to a CMP method employing a polishing composition having
pKa and pH within the ranges required by the subject matter of independent

2 Appellants did not argue dependent claims 8-13 separately in the principal
Brief. Accordingly, the dependent claims stand or fall together with
independent claim 7 and we will limit our discussion to independent claim 7.
Appeal 2010-008167
Application 11/448,205

5
claim 7 based on the disclosure of Kurata 609. A prima facie case of
obviousness typically exists when the ranges of a claimed composition
overlap the ranges disclosed in the prior art. See e.g., In re Geisler, 116 F.3d
1465, 1469 (Fed. Cir. 1997); In re Woodruff, 919 F.2d 1575, 1578 (Fed. Cir.
1990); In re Malagari, 499 F.2d 1297, 1303 (CCPA 1974). Such is the case
here. Appellants have not disputed that Kurata 609’s pKa and pH ranges
overlap the claimed pKa and pH ranges. On the contrary, Appellants
acknowledge that the claimed pKa and pH may overlap for some of the acid
compounds listed by Kurata 609. App. Br. 6.
Appellants argued that Table 2 in the Specification allegedly shows
unexpected results from the pKa and pH dependency. The burden of
showing unexpected results rests on the person who asserts them by
establishing that the difference between the claimed invention and the
closest prior art was an unexpected difference. See In re Klosak, 455 F.2d
1077, 1080 (CCPA 1972). The unexpected results must be established by
factual evidence, and attorney statements are insufficient to establish
unexpected results. See In re Geisler, 116 F.3d at 1470-71. Appellants have
not explained why these results are unexpected. Moreover, the Specification
does not describe why the improvement shown in Table 2 is considered
unexpected.
Appellants additionally argued that Kurata 609 does not teach or
suggest polishing or abrading silicon nitride as required by independent
claim 7. App. Br. 4. Appellants further argued that the Examiner’s assertion
that Kurata 609 describes the silicon nitride exposed after the barrier layer is
removed must be polished is unsupported by evidence. Id.at 5.
Appeal 2010-008167
Application 11/448,205

6
We agree with the Examiner’s reasoning that Kurata 609 discloses
polishing of a silicon nitride substrate. Ans. 8, Kurata 609 para. [0111]. We
are unpersuaded by Appellants’ argument that a person skilled in the art
would not recognize the description of over-polishing to clearly suggest that
silicon nitride is polished or abraded by the disclosed compositions. Reply
Br. 5. Appellants have not pointed to any section of Kurata 609 or provided
any other evidence to support this statement.
We find no error in the Examiner’s conclusion that Kurata 609’s
disclosure above provides the skilled artisan with the motivation to provide a
CMP method of polishing a silicon nitride substrate using a polishing
composition having a pH in the range of about 0.5 pH units less than the
pKa of the at least one acidic component to about 1.5 pH units greater than
the pKa as required by the subject matter of independent claim 7.
For the foregoing reasons and those presented by the Examiner, we
affirm the rejection of claims 7-13 under 35 U.S.C. § 103(a) as being
unpatentable over Kurata 609.

Appeal 2010-008167
Application 11/448,205

7
Rejection of Claims 14-25 Under 35 U.S.C. § 103(a) 3
The dispositive issue on appeal is: Did the Examiner err in
determining that Kurata 711 describes or suggests a chemical mechanical
polishing (CMP) method for selectively removing silicon nitride in the
presence of silicon dioxide in a substrate with a polishing composition
having colloidal silica as required by the subject matter of independent claim
14?
We answer this question in the negative and, therefore, we AFFIRM.
We again affirm for the reasons presented by the Examiner and add the
following.
The Examiner found that Kurata 771 discloses a chemical mechanical
polishing (CMP) method similar to Appellants’ claimed CMP method
except that Kurata 711 does not expressly disclose the polishing composition
as having colloidal silica as a component of the polishing composition. Ans.
6. The Examiner found that Kurata 711 discloses the use of colloidal silica
in polishing compositions to polish substrates containing silicon dioxide and
silicon nitride that results in a different rate of removal of the specified layer.
Id.; Kurata 711 para. [0004]. The Examiner found that Kurata 711 utilizes

3 The dispositive issue for independent claim 20 is substantially the same as
the dispositive issue for independent claim 14 since they are both directed to
selective removal of silicon nitride versus another component in a substrate
(either silicon dioxide (claim 14) or polysilicon (claim 20)) with a polishing
composition comprising colloidal silica. We note that Appellants’
arguments do not separately address the subject matter of independent claim
20. App. Br. 7. We will focus our discussion on independent claim 14 with
the understanding that the discussion applies equally to independent claim
20. We also note that Appellants did not argue dependent claims 15-19 and
21-25 separately in the principal Brief. Accordingly, the dependent claims
stand or fall together with their respective independent claims.
Appeal 2010-008167
Application 11/448,205

8
cerium oxide particles instead of colloidal silica for better polishing
selectivity of silicon oxide over silicon nitride. Ans. 6. The Examiner
concluded that it would have been obvious to one skilled in the art in
appropriate situations to use colloidal silica instead of cerium oxide particles
in a polishing composition such as when the desired selectivity for polishing
silicon oxide versus silicon nitride is reversed. Id. at 6-7.
Appellants argued that Kurata 711 fails to teach a method of
selectively removing silicon nitride in the presence of silicon oxide in a
substrate using colloidal silica with the claimed acidic component at the
claimed pH levels. App. Br. 7. Appellants also argued that the Examiner’s
reliance on the background section of Kurata 711’s disclosure to show that
colloidal silica-based compositions are used to polish substrates containing
silicon dioxide and silicon nitride does not teach preferentially polishing
silicon nitride over silicon dioxide as claimed. Id.
We are unpersuaded by Appellants’ arguments and agree with the
Examiner’s reasoning that it would have been obvious to one skilled in the
art to arrive to a CMP method for selectively removing silicon nitride in the
presence of silicon dioxide in a substrate with a polishing composition
having colloidal silica as required by the subject matter of independent claim
14 based on the disclosure of Kurata 711. Ans. 6-7.
We agree with the Examiner that Kurata 711 discloses it was known
that both cerium oxide and colloidal silica were suitable for polishing silicon
dioxide and silicon nitride on a substrate. Id. at 6-7, 8. We also agree with
the Examiner that Kurata 711 provides the basic suggestion that the
selectivity of the nitride polishing will increase by changing the abrasive
particles to colloidal silica. Id. at 9. While Appellants rely on Table 6 in the
Appeal 2010-008167
Application 11/448,205

9
Specification to support an allegation of preferential polishing of silicon
nitride over silicon dioxide (App. Br. 7), independent claim 14, as correctly
noted by the Examiner, does not require a specific selectivity. Ans. 8. Thus,
we find no error in the Examiner’s conclusion that it would have been
obvious to one skilled in the art to use colloidal silica instead of cerium
oxide particles in a polishing composition when the desired selectivity for
polishing silicon oxide versus silicon nitride is reversed in view of Kurata
711’s disclosure. Id. at 6-7.
For the foregoing reasons and those presented by the Examiner, we
affirm the rejection of claims 14-25 under 35 U.S.C. § 103(a) as being
unpatentable over Kurata 711.

ORDER
The rejection of claims 7-13 under 35 U.S.C. § 103(a) as being
unpatentable over Kurata 609 is affirmed.
The rejection of claims 14-25 under 35 U.S.C. § 103(a) as being
unpatentable over Kurata 711 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)(v).

AFFIRMED

bar