Ex Parte Samoilov

Board of Patent Appeals and Interferences

Sep 27, 2011

11752477 (B.P.A.I. Sep. 27, 2011)

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.
11/752,477 05/23/2007 ARKADII V. SAMOILOV APPM/009793.C1/FEP/EPI/AG 3826
44257 7590 09/27/2011
PATTERSON & SHERIDAN, LLP - - APPM/TX
3040 POST OAK BOULEVARD, SUITE 1500
HOUSTON, TX 77056
EXAMINER
DEO, DUY VU NGUYEN
ART UNIT PAPER NUMBER
1713
MAIL DATE DELIVERY MODE
09/27/2011 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 ARKADII V. SAMOILOV
____________

Appeal 2010-005698
Application 11/752,477
Technology Center 1700
____________

Before CATHERINE Q. TIMM, JEFFREY T. SMITH, and
LINDA M. GAUDETTE, Administrative Patent Judges.

SMITH, Administrative Patent Judge.

DECISION ON APPEAL

Appeal 2010-005698
Application 11/752,477

2
STATEMENT OF THE CASE
This is an appeal under 35 U.S.C. § 134 from the final rejection of
claims 1, 3-12 and 27.1 We have jurisdiction under 35 U.S.C. § 6.
Appellant’s claimed invention relates to a method for etching a silicon
material comprising exposing the silicon-containing material to an etching
gas comprising chlorine gas (Cl2) and a silicon source gas to remove the
contaminant. Claim 1 is illustrative:

1. A method for etching a silicon material on a substrate
surface, comprising:

positioning a substrate comprising a silicon-containing
material within a process chamber, wherein a contaminant is
disposed on the silicon-containing material;

heating the substrate to a temperature of less than 800ºC;
and

exposing the silicon-containing material to an etching gas
comprising chlorine gas (Cl2) and a silicon source gas to
remove the contaminant and a predetermined thickness of the
silicon-containing material during an etching process.

Appellant requests review of the following rejection (App. Br. 8) from
the Examiner’s final office action:
1. Claims 1, 3-12 and 27 stand rejected under 35 U.S.C. § 103(a) as
unpatentable over U’Ren, US 6,580,104 B1 (issued June 17, 2003) and
Butterbaugh, US 5,716,495 (issued Feb. 10, 1998).2

1 According to the Examiner, claims 13, 15-19, 21-26, and 28 have been
canceled. (Ans. 3).
Appeal 2010-005698
Application 11/752,477

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OPINION3
The dispositive issue for the rejections is: Did the Examiner err in
determining that U’Ren describes a method for etching a silicon material
comprising exposing the silicon-containing material to an etching gas
comprising chlorine gas (Cl2) and a silicon source gas to remove the
contaminant and a predetermined thickness of the silicon-containing
material during an etching process as required by the subject matter of
independent claim 1?
We answer this question in the negative and AFFIRM.
Appellant argues that U’Ren does not teach removal of a
predetermined thickness of silicon-containing material from the substrate
because the process of U’Ren includes dichlorosilane that acts as a precursor
for deposition of silicon to replace silicon which may be etched away during
the cleaning process. (App. Br. 9). Appellant further argues that the
combination of U’Ren and Butterbaugh is not proper because the references
do not teach that chlorine gas can be combined with a silicon source gas to
replenish silicon during cleaning. (Id. at 10).
The Examiner found that U’Ren discloses a method of forming a
silicon containing material on a substrate comprising cleaning the substrate
to remove the contaminant by using a gas source including hydrogen
chloride and a silicon source of dichlorosilane at 650°C. (Ans. 3). In the

2 The Examiner cited Yamada (US 6,159,862) col. 4, ll. 25-27 as evidence of
the state of the art at the time of the invention. (Final Rejection 5).
3 Appellant did not argue the dependent claims separately in the Briefs.
Accordingly, the dependent claims stand or fall together with the respective
independent claim.
Appeal 2010-005698
Application 11/752,477

4
process of U’Ren, a sufficient amount of silicon is removed in conjunction
with removal of the contaminants which are subsequently replenished due to
the presence of a dichlorosilane. Thus, the process of U’Ren includes
removal of a predetermined thickness of silicon containing material.
(U’Ren, col. 4, ll. 11-26). The Examiner acknowledges that U’Ren differs
from the claimed invention in that chlorine gas (Cl2) is not used to remove
contaminants. (Ans. 3). The Examiner found the use of Cl2 to remove
contaminants from a silicon substrate was known to persons of ordinary skill
in the art as exemplified by Butterbaugh. (Id.) The Examiner properly
concluded that it would have been obvious to a person of ordinary skill in
the art to incorporate Cl2 into the process of U’Ren to further aid in cleaning
silicon substrates.
We agree with the Examiner’s obviousness determination. It is not
argued that Cl2 was not known by persons of ordinary skill in the art to be
suitable for cleaning silicon containing substrates. (See Butterbaugh). The
fact that Cl2 was known by persons of ordinary skill in the art to be suitable
for cleaning silicon containing substrates supports an obviousness
determination because it has long been held obvious to combine two known
materials for their known function. See In re Kerkhoven, 626 F.2d 846, 850
(CCPA 1980). Appellant has not provided a technical explanation why a
person of ordinary skill in the art would have expected that chlorine gas
could not have been combined with a silicon source gas to replenish silicon
during cleaning.
We also agree with the Examiner that the claimed invention does not
exclude replenishing of the silicon material that has been removed during the
cleaning process. We note the present Specification discloses that an
Appeal 2010-005698
Application 11/752,477

5
epitaxy layer can be applied to the clean substrate in the same process
chamber as used during the removing step. (Spec. [0010]).

For the foregoing reasons and those set forth in the Answer, based on
the totality of the record, we determine that the preponderance of evidence
weighs in favor of obviousness, giving due weight to Appellant’s arguments.
Accordingly, the Examiner’s rejection is affirmed.

ORDER
The rejection of claims 1, 3-12 and 27 under 35 U.S.C. § 103(a) as
unpatentable over U’Ren and Butterbaugh is affirmed.

TIME PERIOD
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).

AFFIRMED

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