Ex Parte Zojaji et al

Board of Patent Appeals and Interferences

Jun 29, 2011

11242613 (B.P.A.I. Jun. 29, 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.
11/242,613 10/03/2005 Ali Zojaji 009793 USA P 01 /FEP/EPI 5499
44257 7590 06/29/2011
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
06/29/2011 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 ALI ZOJAJI and ARKADII V. SAMOILOV
____________

Appeal 2010-004987
Application 11/242,613
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 2010-004987
Application 11/242,613

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STATEMENT OF THE CASE
This is an appeal under 35 U.S.C. § 134 from a final rejection of
claims 1 through 8, 10, 11, 14 through 16, 18, 21 through 23, 25 through 27,
29, 31, 32, 34, and 35. We have jurisdiction under 35 U.S.C. § 6.
Appellants’ invention is directed “to methods of etching and
depositing silicon-containing materials while forming electronic devices.”
Spec. 2. Claim 1 is illustrative of the subject matter on appeal and is
reproduced below:
1. A method for forming a silicon-containing material on
a substrate surface, comprising:
positioning a substrate comprising a silicon material
containing a contaminant within a process chamber;
exposing the substrate to an etching gas comprising
chlorine gas and a silicon source at a temperature of less than
about 800°C during an etching process to remove the
contaminant;
exposing the substrate to a deposition gas during a
deposition process; and
exposing the process chamber to a chamber clean gas
comprising the chlorine gas and the silicon source during a
chamber clean process.

Appeal 2010-004987
Application 11/242,613

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The Examiner relied on the following references1 in rejecting
the appealed subject matter:
Nagashima et al. US 5,129,958 July 14, 1992
Zhao et al. US 5,983,906 November 16, 1999
U’Ren US 6,580,104 B1 June 17, 2003

Appellants, App. Br. 10, request review of the following rejection
from the Examiner’s final office action:
1. Claims 1-8, 10, 11, 14-16, 18, 21-23, 25-27, 29, 31, 32, 34, and 35 are
rejected under 35 U.S.C. § 103(a) as being unpatentable over U’Ren and
further in view of Zhao and Nagashima.

OPINION

The dispositive issue for the rejection under 35 U.S.C. § 103(a) is:
Did the Examiner err in determining that the combination of U’Ren, Zhao
and Nagashima would have led one skilled in the art to a process combining
the chlorine gas of Zhao and the silicon source of Nagashima to clean the
deposition chamber of U’Ren so as to arrive at the subject matter of
independent claims 1, 15, 27, and 31? 2
After thorough review of the respective positions provided by
Appellants and the Examiner, we answer this question in the affirmative and
REVERSE.
The Examiner found that U’Ren teaches a method of treating a silicon
substrate “comprising: positioning a substrate having silicon material and
contaminant within a process chamber; cleaning the substrate to remove the

1 The Examiner refers to Birrittella et al. (US 4,663,831) “to show prior art.”
Ans. 5. We will not address this reference, as the Examiner does not rely on
it in the rejection.
2 We will limit our discussion to independent claim 1 as representative.
Appeal 2010-004987
Application 11/242,613

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contaminant by using a gas source including hydrogen chloride and a silicon
source of dichlorosilane at a T [Temperature] of 650 degrees Celsius; [and]
epitaxially depositing a layer on the substrate.” Ans. 3. The Examiner also
found that U’Ren “doesn’t describe a step of cleaning the chamber with
chlorine and silicon source gases.” Id. The Examiner relies on Zhao to
teach the use of chlorine and argon to clean a chamber. Id. The Examiner
additionally relies on Nagashima to teach the use of a silicon source (silane)
to clean a chamber. Id. The Examiner concludes that “[c]leaning the
chamber with such gas combination of chlorine and silicon source with no
change in their perspective [respective] functions would produce predictable
results and obvious to one skilled in the art at the time of the invention was
made.” Id. In response to Appellants’ arguments, the Examiner asserts that
“[s]ince chlorine and silicon-containing gases have been known for cleaning
the deposition chamber as shown [by the Zhao and Nagashima references]
above and used together to clean the contamination on the substrate as
taught by U’ren (this would also clean any contamination on the chamber
walls).” Ans. 5. The Examiner concludes that “one skilled in the art would
have combined known elements in the prior art with no changes in their
respective functions” (id. at 5-6) and that the combination “would have
yielded predictable results” (id. at 6).
Appellants argue that “the Examiner has not provided the required
evidence for why the skilled artesian would be motivated to combine the
chlorine of Zhao with the silane of Nagashima into a single process gas.”
App. Br. 12. Appellants further argue that (1) “Nagashima teaches using a
reducing gas step after fluorine plasma to reduce the fluorine residue”
Appeal 2010-004987
Application 11/242,613

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(Reply Br. 2) and (2) “Zhao uses chlorine in conjunction with a plasma to
etch material deposits” (id. at 2-3).
During examination, the Examiner bears the initial burden of
establishing a prima facie case of obviousness. In re Oetiker, 977 F.2d
1443, 1445 (Fed. Cir. 1992). The Examiner’s mere conclusory statements
are not sufficient to support the prima facie case of obviousness.
“[R]ejections on obviousness grounds cannot be sustained by mere
conclusory statements; instead, there must be some articulated reasoning
with some rational underpinning to support the legal conclusion of
obviousness.” KSR Int’l Co. v. Teleflex, Inc., 550 U.S. 398, 418 (2007)
(quoting In re Kahn, 441 F.3d 977, 988 (Fed. Cir. 2006)).
We agree with Appellants that the Examiner has not adequately
explained why a person of ordinary skill in the art would have combined
U’Ren, Zhao and Nagashima to arrive at a method including a chamber
cleaning step using the silicon source (silane) in a mixture with chlorine as
described by the subject matter of independent claim 1.
U’Ren is directed to a method “to clean and remove contaminants
from silicon surfaces prior to epitaxial deposition of silicon-germanium.”
U’Ren, col. 3, ll. 59-61. We note that Zhao’s chamber cleaning steps are
associated with the deposition of titanium on semiconductor substrates.
Zhao, Abstract; col. 5, ll. 12-16. We also note that Nagashima’s chamber
cleaning steps are for the removal of “fluorine residues, remaining therein
from a plasma fluorine cleaning step” (emphasis added). Nagashima, col. 1,
ll. 57-62. Thus, the semiconductor processes of Zhao and Nagashima are
distinct from the semiconductor process of U’Ren in that the contaminants
addressed by Zhao and Nagashima are not present in U’Ren.
Appeal 2010-004987
Application 11/242,613

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The Examiner has not adequately explained why a person of ordinary
skill in the art would have modified the process of U’Ren to incorporate a
cleaning step from the combined teachings of Zhao and Nagashima, both of
which are directed to dissimilar semiconductor processes, to arrive to a
method including a chamber cleaning step using a gaseous mixture
comprising a silicon source (silane) and chlorine as described by the subject
matter of independent claim 1. The Examiner has not adequately explained
how the cleaning steps of Zhao (chlorine gas) and Nagashima (silane) would
have been adaptable for the semiconductor process of U’Ren.
Accordingly, we reverse the Examiner’s rejection.
ORDER
The rejection of claims 1-8, 10, 11, 14-16, 18, 21-23, 25-27, 29, 31,
32, 34, and 35 under 35 U.S.C. § 103(a) as being unpatentable over U’Ren,
Zhao and Nagashima is reversed.

REVERSED

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