Rohm and Haas Electronic Materials CMP Holdings, Inc.

Patent Trials and Appeals Board

Dec 24, 2021

2021000041 (P.T.A.B. Dec. 24, 2021)

UNITED STATES PATENT AND TRADEMARK OFFICE
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.
16/080,441 08/28/2018 Wei-Wen Tsai 78878-US-PCT 1059
61611 7590 12/24/2021
ROHM AND HAAS ELECTRONIC MATERIALS
CMP HOLDINGS, INC.
c/o DUPONT SPECIALTY PRODUCTS USA, LLC
P. O. Box 2915
Wilmington, DE 19805
EXAMINER
PHAM, THOMAS T
ART UNIT PAPER NUMBER
1713
NOTIFICATION DATE DELIVERY MODE
12/24/2021 ELECTRONIC
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.
Notice of the Office communication was sent electronically on above-indicated "Notification Date" to the
following e-mail address(es):
PTO-Legal.PRC@dupont.com
PTOL-90A (Rev. 04/07)

UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE PATENT TRIAL AND APPEAL BOARD
____________

Ex parte WEI-WEN TSAI, LIN-CHEN HO, CHEN-PING LEE,
and JIUN-FANG WANG
____________

Appeal 2021-000041
Application 16/080,441
Technology Center 1700
____________

Before DONNA M. PRAISS, JEFFREY R. SNAY, and
DEBRA L. DENNETT, Administrative Patent Judges.

SNAY, Administrative Patent Judge.

DECISION ON APPEAL

STATEMENT OF THE CASE
Pursuant to 35 U.S.C. § 134(a), Appellant1 appeals from the
Examiner’s decision to reject claims 1–10. We have jurisdiction under
35 U.S.C. § 6(b).
We REVERSE.

1 “Appellant” refers to “applicant” as defined in 37 C.F.R. § 1.42. Appellant
identifies DuPont de Nemours, Inc. as the real party in interest. Appeal Br.
2.
Appeal 2021-000041
Application 16/080,441

2
CLAIMED SUBJECT MATTER
The invention relates to chemical mechanical polishing. Spec. ¶ 1.
Claim 1 is the sole independent claim and reads as follows:
1. A method of polishing a substrate, comprising:
providing the substrate, wherein the substrate comprises
tungsten (W) and titanium (Ti);
providing a chemical mechanical polishing composition,
consisting of, as initial components:
water;
an oxidizing agent;
a chitosan;
a colloidal silica abrasive having a permanent positive
surface charge;
a dicarboxylic acid, wherein the dicarboxylic acid is
selected from the group consisting of propanedioic acid and 2-
hydroxypropanedioic acid;
a source of iron (III) ions; and,
optionally, a pH adjusting agent;
providing a chemical mechanical polishing pad, having a
polishing surface;
creating dynamic contact at an interface between the
chemical mechanical polishing pad and the substrate; and
dispensing the chemical mechanical polishing
composition onto the polishing surface of the chemical
mechanical polishing pad at or near the interface between the
chemical mechanical polishing pad and the substrate;
wherein at least some of the tungsten (W) and at least
some of the titanium (Ti) are polished away from the substrate;
and wherein the chemical mechanical polishing composition
provided has a removal rate selectivity between the tungsten
(W) and the titanium (Ti) of 2 ≥ 100.
Appeal Br. 7 (Claims Appendix).

Appeal 2021-000041
Application 16/080,441

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REJECTION
Claims 1–10 stand rejected under 35 U.S.C. § 103(a) as being
unpatentable over Ohta,2 Hoshi,3 and Dockery.4
OPINION
Claim 1 recites, inter alia, providing a polishing composition
“consisting of” the components specified in the claim, including a colloidal
silica abrasive. In rejecting claim 1, the Examiner finds Ohta discloses a
polishing composition that includes a combination of colloidal silica and
fumed silica. Ans. 3. To meet the “consisting of” recitation of the claim, the
Examiner finds one of ordinary skill in the art would have had a reason to
exclude fumed silica from Ohta’s composition because “Ohta discloses that
the difference between the etch rate of the tungsten layer and the silicon
oxide layer becomes smaller as the mixing ratio of colloidal silica
abrasives/total abrasives becomes larger,” and “Ohta teaches that it is
desirable to have the same etch rate between the metal layer and the silicon
oxide layer to avoid dishing.” Id.
Appellant argues Ohta fails to provide a reason to use a polishing
composition that does not contain fumed silica. Appeal Br. 4–5.
Ohta discloses a polishing slurry adapted for chemical mechanical
polishing of metal deposited on dielectric films. Ohta 2:4–14. According to
Ohta, conventional polishing compositions containing only fumed silica as
abrasive grains results in an uneven surface, or “dishing,” due to the fumed

2 US 8,062,548 B2, issued November 22, 2011.
3 US 2011/0039475 A1, published February 17, 2011.
4 US 2017/0121560 A1, published May 4, 2017.
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Application 16/080,441

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silica’s high polishing rate for the metal film. Id. 1:32–43. To address that
problem, Ohta teaches adding colloidal silica to the fumed silica
composition at a determined mixing ratio such that the composition polishes
the metal and dielectric materials at desired relative rates. Id. 2:4–14. By
selecting the mixing ratio between fumed silica and colloidal silica, “the
selectivity ratio between the polishing rate on the metal film made of
tungsten, etc. and the polishing rate on the dielectric film (oxide film) can be
controlled, therefore allowing decreases in the dishing and erosion.” Id.
6:6–11. Ohta teaches providing the colloidal silica at concentrations ranging
from 1–99% relative to the combined amount of fumed and colloidal silica.
Id. 4:25–29. Regardless of the relative amounts, Ohta characterizes the
disclosed invention as a polishing slurry having at least two kinds of
abrasive grains, preferably colloidal and fumed silica. Id. 1:59–67.
Appellant’s argument that the Examiner has not identified a reason to
exclude fumed silica from Ohta’s compositions is persuasive. The
Examiner’s findings that Ohta teaches a desire for equal metal and dielectric
polishing rates, and that Ohta shows the difference between such rates
decreases with increasing colloidal silica, are not supported by a
preponderance of the evidence. Ohta discloses a desire to achieve a
metal/dielectric selectivity ratio that reduces dishing, not equal polishing
rates. See Ohta 5:39–47 (noting disclosed examples exhibiting polishing
selectivity ratios of 2 and 4). Even if Ohta were viewed as teaching a
desired selectivity ratio of 1, Ohta’s Figure 3 depicts equal tungsten and
dielectric polishing rates occurring at a colloidal silica mixing ratio
substantially less than 100%. See Ohta Fig. 3 (depicting tungsten and SiO2
polishing rates at different colloidal silica mixing ratios). Ohta’s
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Application 16/080,441

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characterization of films polished without fumed silica as exhibiting a large
number of flaws and defects due to scratches and adsorbed polishing
particles, id. 8:20–24, also is contrary to the Examiner’s finding that Ohta
would have provided a reason to omit fumed silica from Ohta’s polishing
composition.
In light of the foregoing, we are persuaded the Examiner has not
identified evidence to support the finding that Ohta would have provided a
reason to exclude fumed silica from the disclosed polishing composition.
The Examiner does not rely on either Hoshi or Dockery in a manner which
would cure that deficiency.
Accordingly, the Examiner’s rejection is not sustained.
CONCLUSION
The Examiner’s decision rejecting claims 1–10 is reversed.
DECISION SUMMARY
In summary:
Claim(s)
Rejected
35 U.S.C.
§
Reference(s)/Basis Affirmed Reversed
1–10 103 Ohta, Hoshi,
Dockery
1–10

REVERSED