Ex Parte Chandrachood et al

Board of Patent Appeals and Interferences

May 30, 2012

11044358 (B.P.A.I. May. 30, 2012)

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.
11/044,358 01/27/2005 Madhavi Chandrachood 9836
USA/MASK/MASK-ETCH/A
9746
44182 7590 05/30/2012
PATTERSON & SHERIDAN, LLP Appm/NJ
APPLIED MATERIALS INC
3040 Post Oak Boulevard
SUITE 1500
Houston, TX 77056-6582
EXAMINER
RAYMOND, BRITTANY L
ART UNIT PAPER NUMBER
1722
MAIL DATE DELIVERY MODE
05/30/2012 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 MADHAVI CHANDRACHOOD, AJAY KUMAR, and
WAI-FAN YAU
____________

Appeal 2011-004527
Application 11/044,358
Technology Center 1700
____________

Before BRADLEY R. GARRIS, MARK NAGUMO, and
KAREN M. HASTINGS, Administrative Patent Judges.

GARRIS, Administrative Patent Judge.

DECISION ON APPEAL

Appellants appeal under 35 U.S.C. § 134 from the Examiner's
rejection of claim 16 under 35 U.S.C. § 103(a) as unpatentable over Tanaka
(US 2002/0177050 A1, pub. Nov. 28, 2002) in view of Meyer (US
4,504,574, issued Mar. 12, 1985). We have jurisdiction under 35 U.S.C. § 6.
We REVERSE.

Appeal 2011-004527
Application 11/044,358

2
Appellants claim a method of forming a photomask comprising
providing a film stack having a patterned first photoresist layer and
"depositing a conformal polymer layer on the patterned first resist layer"
(claim 16).
Further details regarding this method are set forth in claim 16 which
reads as follows:
16. A method of forming a photomask, comprising:

providing a film stack in a processing chamber, the film stack having
an optically transparent silicon based material having a molybdenum layer
disposed thereon, a patterned light-shielding layer disposed on the
molybdenum layer and a composite mask having at least a patterned first
photoresist layer, wherein the patterned light shielding layer comprises a
plurality of structures between a plurality of first openings in the light
shielding layer exposing the molybdenum layer;

plasma etching the molybdenum layer to form a molybdenum layer
opening exposing the optically transparent silicon based material using the
composite mask, wherein the plasma etching the molybdenum layer further
comprises depositing a conformal polymer layer on the patterned first resist
layer prior to forming the patterned light shielding layer;

depositing a second photoresist layer on the light-shielding layer;

patterning the second photoresist layer on a [sic] the light-shielding
layer, wherein the second photoresist layer fills the molybdenum layer
opening after patterning and wherein the second photoresist layer defines a
plurality of second openings at a center portion of each of the plurality of
structures; and

plasma etching the light-shielding layer using the second photoresist
layer as an etch mask to form the plurality of second openings exposing the
molybdenum layer.

Appeal 2011-004527
Application 11/044,358

3
The Examiner concedes that Tanaka fails to disclose depositing a
polymer layer on a first resist layer as required by claim 16 (Ans. 4). The
Examiner finds that "Meyer discloses a process for making a resist mask
resistant to plasma etching comprising . . . exposing the photoresist to a
carbon monoxide plasma to form a treatment on the surface of the
photoresist" (id. at para. bridging 4-5).
The Examiner concludes that it would have been obvious "to have
deposited a polymer layer on the photoresist prior to etching, as suggested
by Meyer, in the process of Tanaka because Meyer teaches that this prevents
the resist from being damaged during the etching procedure and thus
prevents the lower layers from having an altered pattern" (id. at 5).
Regarding this obviousness conclusion, it is the Examiner's position that the
carbon monoxide plasma treatment of Meyer "results in a conformal
polymer layer on the photoresist patterns" and that "reacting a plasma with a
photoresist layer to form a conformal polymer layer would be equivalent to
depositing a polymer layer on photoresist patterns" (id. at para. bridging 7-
8).
We find persuasive merit in Appellants' argument that Meyer contains
no teaching or suggestion that the carbon monoxide plasma treatment results
in the polymer layer deposition step required by claim 16 (see, e.g., App. Br.
12 and Reply Br. 2-3). In this regard, we emphasize that the Examiner has
provided this record with no factual evidence or technical reasoning in
support of the position that Meyer's treatment results in the claimed polymer
layer.

Appeal 2011-004527
Application 11/044,358

4
The decision of the Examiner is reversed.
REVERSED

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