Ex Parte Dantz et al

Board of Patent Appeals and Interferences

Jun 26, 2012

12039351 (B.P.A.I. Jun. 26, 2012)

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.
12/039,351 02/28/2008 Dirk Dantz WSAG 0133 PUS1 7325
22045 7590 06/26/2012
BROOKS KUSHMAN P.C.
1000 TOWN CENTER
TWENTY-SECOND FLOOR
SOUTHFIELD, MI 48075
EXAMINER
SONG, MATTHEW J
ART UNIT PAPER NUMBER
1714
MAIL DATE DELIVERY MODE
06/26/2012 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 DIRK DANTZ, WILFRIED VON AMMON, DIRK
ZEMKE, and FRANZ SEGIETH
____________________

Appeal 2011-001779
Application 12/039,351
Technology Center 1700
____________________

Before CHUNG K. PAK, CATHERINE Q. TIMM, and
JEFFREY T. SMITH, Administrative Patent Judges.

TIMM, Administrative Patent Judge.

DECISION ON APPEAL
Appellants appeal under 35 U.S.C. § 134 from the Examiner’s
decision to reject claim 4 under 35 U.S.C. § 103(a) as obvious over
Aydelott1 in view of Applicants’ Admitted Prior Art (Admission)2, Ehlert3,
and Chiou4. We have jurisdiction under 35 U.S.C. § 6(b).

1Aydelott et al., US 6,106,611, patented Aug. 22, 2000.
2 Spec. § 2 at pages 2-3.
Appeal 2011-001779
Application 12/039,351

2
We AFFIRM for the reasons articulated by the Examiner in the
Answer. We add the following primarily for emphasis.
Claim 4, the only claim pending in the Application, reads as follows:
4. A process for producing a silicon single crystal a [sic]
<113> orientation, comprising
pulling a first silicon single crystal having a <100>
orientation in a furnace with a first pulling rate which does not
cause dislocations in the first silicon single crystal, wherein the
first silicon single crystal is pulled according to the Czochralski
method and comprises an ingot and two first conical end pieces,
one of said conical end pieces having a first length and
being connected to a first dash seed; and
pulling a second silicon single crystal having a <113>
orientation in said furnace with a second pulling rate which is at
most 90% of the first pulling rate, wherein the second silicon
single crystal is pulled according to the Czochralski method and
comprises a second ingot and two second conical end pieces,
one of said second conical end pieces having a second length
and being connected to a second dash seed having a length of at
most 70 mm and a diameter of at most 5 mm at its narrowest
point, and the second length being at least 30 mm longer than
the first length.
(Claims App. at Br. 10.)
The claim requires pulling two silicon crystals according to the
Czochralski method. In the Czochalski method, a single crystal is formed by
pulling a seed crystal from a silicon melt in several phases (Spec. 1-2;
Aydelott, col. 1, ll. 17-60; Ehlert, col. 1, ll. 21-43; Chiou, col. 1, ll. 38). In
the first phase, the seed is pulled upward at a relatively quick rate to form a

3 Ehlert et al., US 6,267,815 B1, patented Jul. 31, 2001.
4 Chiou et al., US 5,487,355, patented Jan. 30, 1996.
Appeal 2011-001779
Application 12/039,351

3
long thin monocrystalline crystal neck according to Dash’s principle (id.).
Pulling to form this thin long portion prevents dislocations from propagating
to the main body of the crystal ingot (id.). Once the neck is long enough to
effectively terminate dislocations, the crystal is expanded in diameter
through the shoulder portion to the main body of the single crystal (see, e.g.,
Aydelott, col. 1, ll. 54-56).
In the process of claim 4, the first pulled crystal has a <100>
orientation and the second has a <113> orientation. As found by the
Examiner, both these crystalline forms were known in the art (Ans. 4, citing
Spec. 1-2).
Appellants’ claim 4 recites the pulling rate and length of the conical
end piece of the <113> single crystal in terms relative to the <100> single
crystal.
The Examiner finds that the prior art as a whole indicates that the
pulling rate and length parameters of the claim are result effective variables
that one of ordinary skill in the art would have optimized through routine
experimentation (Ans. 3-6). Appellants acknowledge that pulling rate can
be optimized (Br. 5). The evidence also supports the Examiner’s finding
that the length of the neck (dash seed) was also something optimized by
those of ordinary skill in the art to eliminate dislocations in the single
crystal. In fact, throughout the Czochralski process, the diameter and length
of the single crystal neck, shoulder (conical end piece), and main body are
controlled by changing the temperature of the melt and/or by changing the
rate at which the crystal is pulled (see, e.g., Ehlert, col. 1, ll. 13-19; Chiou,
col. 1, ll. 20-23; Chiou, col. 4, ll. 43-62; and Chiou, Fig. 7).
Appeal 2011-001779
Application 12/039,351

4
Appellants contend, however, that such optimization does not result in
the claimed invention. Appellants state that they “have discovered that the
process parameters for forming a single crystal having the <100> can be
used as a guide for the optimal conditions for pulling the <113>” (Br. 4).
They further state that “the process parameters from the formation of the
first silicon crystal having the <100> orientation are used to define useful
conditions for the <113> orientation” (id.).
However, there is no written descriptive support for Appellants’
characterization of the claimed process. The Specification merely conveys
that parameters such as growth rate and dash seed length have to be taken
into account in order to pull a dislocation-free <113> crystal and that these
parameters are different than the “standard process parameters,” i.e.,
different than the process parameters used to form <100> oriented single
crystals (Spec. 3). The Specification discloses comparisons of the pulling
rate and dash seed length to the parameters “customary for pulling <100>
orientation single crystals” (Spec. 3-4), but this is not the same as using the
<100> parameters of an executed process of forming a <100> orientation
crystal as a guide to define the parameters to be used to form the <113>
orientation single crystal.
Claim 4 requires the pulling of two crystals, one of <100> orientation
and one of <113> orientation, and further requires that the second pull rate
and second end length have values within particular ranges. While those
ranges for the <113> pulled crystal are defined in terms of the pull rate and
conical end length associated with the <100> crystal, the ranges are still
numerical ranges of speed and length of presumably ascertainable values.
Appeal 2011-001779
Application 12/039,351

5
There is no dispute that it was known in the art to use the Czochralski
method to form single crystals of <100> orientation (Spec. 1). Appellants’
Specification states that “[a] process for producing a <113> orientation
silicon single crystal by using the Czochralski method does not form part of
the prior art.” (Spec. 3.) However, Aydelott states that in order to obtain the
desired monocrystalline atomic structure, one merely starts with a seed
crystal of the desired structure (Aydelott, col. 1, ll. 23-27). Ehlert also
speaks in terms of starting with a seed crystal of “a given structure” (Ehlert,
col. 1, ll. 30-33). Moreover, Chiou discloses no particular limitation of the
orientation of the single crystal. The evidence as a whole supports the
Examiner’s conclusion that it would have been obvious to one of ordinary
skill in the art to select a seed of <113> orientation to pull a silicon single
crystal of <113> orientation.
Furthermore, as explained above, the Examiner has provided evidence
that the pulling rate and neck, i.e., dash seed, dimensions were routinely
optimized in order to produce dislocation-free single crystals (Ans. 4-6).
Furthermore, the prior art optimizes these parameters for the same result as
desired by Appellants, i.e., to minimize dislocations in the resulting single
crystal. It is reasonable to conclude such optimization would result in a pull
rate and dash seed length within the ranges of claim 4.
The evidence of record supports the Examiner’s determination that
Appellants’ process is merely the optimization of the Czochralski process of
<113> orientation single crystals (Ans. 7).
CONCLUSION
We sustain the Examiner’s rejection.
Appeal 2011-001779
Application 12/039,351

6
DECISION
The Examiner’s decision is affirmed.
TIME PERIOD FOR RESPONSE
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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