Ex Parte Fabry et al

Patent Trial and Appeal Board

Apr 18, 2013

12281550 (P.T.A.B. Apr. 18, 2013)

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.
12/281,550 09/03/2008 Laszlo Fabry WAS0968PUSA 3214
22045 7590 04/19/2013
BROOKS KUSHMAN P.C.
1000 TOWN CENTER
TWENTY-SECOND FLOOR
SOUTHFIELD, MI 48075
EXAMINER
NGUYEN, NGOC YEN M
ART UNIT PAPER NUMBER
1734
MAIL DATE DELIVERY MODE
04/19/2013 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 PATENT TRIAL AND APPEAL BOARD
____________

Ex parte LASZLO FABRY,
UWE PAETZOLD, and MICHAEL STEPP
____________

Appeal 2012-000787
Application 12/281,550
Technology Center 1700
____________

Before BRADLEY R. GARRIS, JEFFREY T. SMITH, and
GEORGE C. BEST, Administrative Patent Judges.

BEST, Administrative Patent Judge.

DECISION ON APPEAL

Appeal 2012-000787
Application 12/281,550
2
On October 8, 2010, the Examiner finally rejected claims 10-17 and
19-25 of Application 12/281,550 under 35 U.S.C. § 103(a) as obvious and
claims 10-17 and 19-20 under 35 U.S.C. § 112, ¶ 2 as indefinite. Appellants1
seek reversal of these rejections pursuant to 35 U.S.C. § 134(a). We have
jurisdiction under 35 U.S.C. § 6(b).
For the reasons set forth below, we REVERSE.
BACKGROUND
The ’550 application describes a process for producing trichlorosilane,
SiHCl3. In the process, a fluidized bed of metallurgical grade silicon
particles reacts with gaseous hydrogen chloride at a temperature between
290°C and 400°C. The resulting equilibrium reaction produces a mixture of
compounds, including chlorosilanes (i.e., SiH(4-n)Cln, n= 0-4),
chlorodisilanes (i.e., Si2H(6-m)Clm, m=0-6), disiloxanes (i.e., HpCl(6-p)Si2O,
p=0-6), and higher siloxanes. Spec. 1-2. The product mixture is condensed
and then fractionated according to boiling point. Id. at 4-6. Compounds with
boiling points higher than that of SiCl4 are collected in a fraction that can be
called “high boilers.” Id.
The production of polycrystalline silicon from trichlorosilane
produces an exhaust gas stream that contains a similar mixture of
compounds, including a high boiler fraction. Id. at 5.
The ’550 application describes the mixing of at least a portion of the
high boilers produced by either of these processes with hydrogen chloride
and the reintroduction of that mixture into a reactor being used to produce
trichlorosilane. Id. at 4-8.

1 Wacker Chemie AG is identified as the real party in interest (App. Br. 1).
Appeal 2012-000787
Application 12/281,550
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Claim 19 is the only independent claim in the ’550 application and is
reproduced below:
19. An integrated plant process for the production of
trichlorosilane, comprising the following steps:
A) feeding hydrogen chloride to a fluidized bed reactor (1)
charged with metallurgical grade silicon and reacting the
hydrogen chloride with the metallurgical grade silicon in the
fluidized bed reactor (1) at a temperature of 290°C to 400°C to
form a gaseous chlorosilane product stream containing
trichlorosilane;
B) introducing a high boiler fraction containing high boilers,
derived from
a) the chlorosilane product stream of a plant process for
production of trichlorosilane,
b) the offgas of polycrystalline silicon production, or
c) high boilers from both a) and b),
into a saturator together with at least a portion of the hydrogen
chloride fed to the fluidized bed reactor (1) in step A) to form a
high boiler- and hydrogen chloride-containing mixture, and
C) feeding the high boiler- and hydrogen chloride-
containing mixture from the saturator in step B) to the fluidized
bed reactor (1) and recovering a chlorosilane product stream
with a greater amount of trichlorosilane than is recovered in the
absence of feeding high boilers to the fluidized bed reactor (1),
wherein when the high boiler- and hydrogen chloride-
containing mixture contains high boilers from a gaseous
chlorosilane product stream from a fluidized bed reactor for
preparing trichlorosilane, the gaseous chlorosilane product
stream is filtered to remove silicon dust such that the high
boiler- and hydrogen chloride-containing mixture is free of
silicon dust, and
Appeal 2012-000787
Application 12/281,550
4
wherein the high boilers have a boiling point at standard
pressure greater than the boiling point of silicon tetrachloride,
and are composed of silicon, chlorine and optionally hydrogen,
oxygen, and carbon.
(App. Br. Claims App’x 2 (some paragraphing and indentation added)).
REJECTIONS
In the October 8, 2010 Final Rejection (“FR”),
1. The Examiner finally rejected claims 10-17 and 19-20 under 35
U.S.C. § 112, ¶ 2 as indefinite. FR 2.
2. The Examiner finally rejected claim 17 under 35 U.S.C. § 112, ¶ 2
as indefinite. FR 3.
3. The Examiner finally rejected claims 10-17 and 19-25 under 35
U.S.C. § 103(a) as obvious over the combination of Streckel,2
Kendig,3 Kroupa,4 and, optionally, Steever5. FR 3.
DISCUSSION
Rejection 1. The Examiner rejected the ’550 application’s claims as
indefinite, contending that it is unclear whether the “gaseous chlorosilane
product stream from a fluidized bed reactor for preparing trichlorosilane”
included in the wherein clause is the same as “the chlorosilane product

2 U.S. Patent No. 6,541,650 B2, issued April 1, 2003.
3 U.S. Patent Application Publication No. 2002/0187096 A1, published Dec.
12, 2002.
4 M.G. Kroupa, High Boiling Residue Recovery Process for the Synthesis of
Trichlorosilane, in SILICON FOR THE CHEMICAL INDUSTRY VI (H.A. Øye et
al., eds.), 201-07 (2002).
5 U.S. Patent No. 3,863,577, issued Feb. 4, 1975.
Appeal 2012-000787
Application 12/281,550
5
stream of a plant process for production of trichlorosilane” specified in step
B) of claim 19 (Ans. 5). Appellants deny that the claim is unclear (App. Br.
6-7; Reply Br. 1 (“Appellants have read and reread this claim and find it to
be perfectly understandable, clear, and particular, when viewed by one
skilled in the art.”)).
We agree with Appellants. The claim language is sufficiently clear to
meet the requirements of § 112, ¶ 2. Step B) states that one of the possible
sources of the high boiler fraction can be any process used to produce
trichlorosilane. The wherein clause merely specifies that, if that process uses
a fluidized bed reactor, the gaseous chlorosilane stream must be filtered to
remove silicon dust.
Rejection 2. The Examiner appears to have withdrawn this rejection.
On January 10, 2011, Appellants filed an Amendment After Final which
appears to have addressed this rejection. Neither the January 21, 2011
Advisory Action nor the Examiner’s Answer mentions the rejection. We
therefore treat it as having been withdrawn.
Rejection 3. The Examiner rejected the ’550 application’s claims as
obvious over the combination of Streckel, Kendig, Kroupa, and, optionally,
Steever (Ans. 5-10). Appellants contend that this rejection is flawed for the
following reasons: (1) Steever is not available for use in an obviousness
rejection because it is not analogous art (App. Br. 12-14), and (2) the
combination of Streckel, Kendig, and Kroupa does not suggest recycling at
least a portion of the high boiler stream into a fluidized bed reactor for
making trichlorosilane (Id. at 8-12). For the reasons set forth below, we find
these arguments persuasive and, therefore, reverse the Examiner’s rejection.
First, we address the availability of Steever as a reference for use in
this obviousness rejection.
Appeal 2012-000787
Application 12/281,550
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References within the statutory terms of 35 U.S.C. § 102
qualify as prior art for an obviousness determination only when
analogous to the claimed invention. Two separate tests define
the scope of analogous prior art: (1) whether the art is from the
same field of endeavor, regardless of the problem addressed
and, (2) if the reference is not within the field of the inventor’s
endeavor, whether the reference still is reasonably pertinent to
the particular problem with which the inventor is involved.
In re Bigio, 381 F.3d 1320, 1325 (Fed. Cir. 2004).
Appellants argue “[t]he field of endeavor of Appellants is the
production of TCS in a fluidized reactor, the fluidized bed of which is
composed of silicon, a reactant in the process. The field of endeavor of
Steever is the incineration of municipal waste such as garbage and sewage
sludge.” (App. Br. 13). Appellants further argue “the problem solved by
Steever is preventing after-burning in a municipal incinerator while
maintaining complete combustion of the municipal waste.” (Id.).
The Examiner has not adequately refuted Appellants’ arguments by
explaining why Steever qualifies as analogous art to the claimed subject
matter. In fact, the Examiner does not offer any substantive response to
Appellants’ arguments and appears to concede that Steever is not analogous
to the claimed subject matter. (Ans. 17 (“Appellants argue that Steever is a
non-analogous reference. Granted that it is true, Steever is only optionally
applied . . . .”)).
Because the Examiner has not met the burden of establishing that
Steever is analogous art, Steever is unavailable for use in a § 103 rejection of
the ’550 application’s claims. Second, Appellants contend that “[n]one of the
prior art, alone or in combination discloses, teaches, or suggests recycle of a
high boiler stream to a [trichlorosilane] fluidized bed reactor” (App. Br. 8).
Appeal 2012-000787
Application 12/281,550
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After a review of Streckel, Kendig, and Kroupa, we conclude that
Appellants are correct for the following reasons.
The Examiner relies upon Streckel as the primary reference in this
obviousness rejection (Ans. 5-6). Streckel describes the production of
chlorosilanes from silicon metal dust, disilanes, and/or organosilanes whose
radicals are selected from hydrogen, chlorine, and organic radicals (Id.).
Streckel describes the reaction of these starting materials with hydrogen and
chlorine gases in a single process step that occurs in two stages. First, the
mixture of reactants is introduced into a combustion tube, where the
hydrogen and chlorine react to form hydrogen chloride. Streckel col. 2,
ll. 34-50. This reaction is highly exothermic and heats the reactant stream to
temperatures in excess of 400°C. Id. at col. 2, ll. 51-61. At those
temperatures, the hydrogen chloride reacts with the silicon source(s) to
produce chlorosilanes, including trichlorosilane.
The Examiner admits that Streckel does not describe or suggest that
the reactants are introduced into a fluidized bed reactor (Ans. 6). To cure this
deficiency, the Examiner argues that Streckel discloses that the silicon dust
used as a silicon source has a particle size of less than 100 μm, and
preferably less than 50 μm (Ans. 12 (citing Streckel col. 3, ll. 62-64)). The
Examiner asserts that particles of this size can be used in a fluidized bed
(Ans. 12-13 (citing Pflugler6 claim 1 as evidence)). In the alternative,7 the

6 U.S. Patent Application Publication No. 2005/026803 A1, published Oct.
13, 2005.
7 The Examiner’s Answer presents a third argument, which is based on
Steever (Ans. 10). Because we have determined that the Examiner has not
established that Steever qualifies as prior art that may be used in an
obviousness rejection of the ’550 application’s claims, we do not address the
merits of the Examiner’s arguments based upon Steever.
Appeal 2012-000787
Application 12/281,550
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Examiner turns to Kroupa for its statement that a fluidized bed reactor is
commonly used to produce chlorosilanes from hydrogen chloride and silicon
(Id. at 10, 12 (citing Kroupa 202)).
We do not find the Examiner’s arguments persuasive. First, in the
absence of Kroupa, the mere fact that Streckel describes small silicon
particles as a possible silicon source in its process does not, in and of itself,
amount to a description or a suggestion that those particles either comprise
or are introduced into a fluidized bed. Second, the Examiner’s finding that
Kroupa’s description of a typical trichlorosilane production process
remedies this deficiency (Ans. 10) is incorrect. The cited portion of Kroupa
describes the first step in the production of trichlorosilane as the reaction of
hydrogen chloride with silicon in a fluidized bed reactor. That portion of
Kroupa, however, describes the isolation of the high boiling fraction of the
product mixture for disposal as incinerable waste. Kroupa 202. Neither the
cited portion nor any other part of Kroupa suggests reintroducing the high
boilers to a fluidized bed reactor for further production of trichlorosilane.8
The Examiner’s rejection, therefore, is based upon an erroneous
determination that the combination of Streckel and Kroupa describes or
suggests the recycling of the high boiler fraction of the product gases into a
fluidized bed reactor for use in further production of trichlorosilane. We
cannot sustain this rejection.

8 We further note that Kendig neither describes nor suggests the use of a
fluidized bed reactor.
Appeal 2012-000787
Application 12/281,550
9
CONCLUSION
For the reasons set forth above, we cannot sustain any of the
Examiner’s rejections of the ’550 application’s claims on the bases set forth
by the Examiner. Thus, we reverse the rejections of claims 10-17 and 19-25.

REVERSED

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