Ex Parte Tejnil

Patent Trial and Appeal Board

Jun 20, 2013

11889574 (P.T.A.B. Jun. 20, 2013)

UNITED STATES PATENT AND TRADEMARK OFFICE
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BEFORE THE PATENT TRIAL AND APPEAL BOARD
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Ex parte EDITA TEJNIL
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Appeal 2011-004790
Application 11/889,574
Technology Center 2600
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Before JOHN A. JEFFERY, JAMES B. ARPIN, and
TRENTON A. WARD, Administrative Patent Judges.

WARD, Administrative Patent Judge.

DECISION ON APPEAL
Appellant appeals under 35 U.S.C. § 134(a) from the final rejection of
claims 1-18. We have jurisdiction under 35 U.S.C. § 6(b), and we heard the
appeal on June 11, 2013.
We affirm-in-part.
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STATEMENT OF THE CASE
The Rejection on Appeal
Claims 1-18 stand rejected under 35 U.S.C. § 103(a) as unpatentable
over Fan (US 2007/0140552 A1; published June 21, 2007) and Ye (US
7,488,933 B2; issued Feb. 10, 2009).1

The Invention
The claimed invention is directed to a method for determining an
optimal set of calibration test patterns to be utilized to calibrate a model of
simulating the imaging performance of an optical imaging system. See
Claim 1. The claimed invention involves generating a cross-correlation
transform function that defines the optical imaging system and then selecting
test structures that contribute to all of the terms in the cross-correlation
transform function. Spec. ¶ [010]. Claim 1 is illustrative and is reproduced
below, with certain limitations emphasized:
1. A computer-implemented method of selecting an
optimum set of calibration test patterns to be utilized to
calibrate a model for simulating the imaging performance of an
optical imaging system; said method comprising the steps of:
defining a model equation representing the imaging
performance of said optical imaging system;
transforming said model equation into a plurality of
discrete functions;
identifying a respective calibration pattern for each of
said plurality of discrete functions, each calibration pattern
corresponding to one of said plurality of discrete functions

1 Throughout this opinion, we refer to (1) the Appeal Brief (App. Br.) filed
July 15, 2010, (2) the Examiner’s Answer (Ans.) mailed October 18, 2010,
and (3) the Reply Brief (Reply Br.) filed December 20, 2010.
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being operative for manipulating said one of said plurality of
discrete functions during a calibration process; and
storing said calibration test patterns identified as
corresponding to said plurality of discrete functions, said
calibration test patterns being utilized to calibrate said model
for simulating the imaging performance of an optical imaging
system,
wherein one or more of the above steps are implemented
by the computer.

DISCUSSION
A. Obviousness Rejection of Claims 1-12, 14, 16, and 18 over Fan and Ye

The Examiner finds that Fan discloses all elements of the claimed
invention, except Fan does not disclose a set of optimal calibration
level patches including calibration test patterns. Ans. 5. The Examiner cites
Ye, in combination with Fan, as teaching or suggesting a set of optimal
calibration test patterns to be utilized to calibrate a model. Ans. 5-6.
Appellant argues that the Examiner fails to properly establish a prima facie
case of obviousness and that the claims have been rejected based on an
incorrect claim interpretation. App. Br. 7-11. We address Appellant’s
arguments seriatim.
First, Appellant argues that the present invention is directed to the
selection of optimal calibration test patterns to calibrate a simulation model
of “a lithographic imaging tool that is used to fabricate an integrated circuit.”
App. Br. 7 (emphasis omitted). Furthermore, Appellant argues that Fan is
not directed to a lithographic imaging tool, but rather describes calibrating
an image producing system. Id. Although Appellant argues that its
independent claims are directed to a “lithographic imaging tool,” Appellant
fails to identify to any limitations in the independent claims that narrow the
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scope to such a “lithographic imaging tool.” Instead, as noted by the
Examiner, independent claims 1, 5, and 9 are more broadly directed to an
“optical imaging system.” Ans. 4. We are not persuaded that the Examiner
erred in applying the “image producing system” disclosed in Fan against the
“optical imaging system” recited in the independent claims.
Second, Appellant argues that although Fan and the present invention
use similar, known mathematical techniques, “the context of the
mathematical technique in the present invention is entirely different from
that of Fan.” App. Br. 8 (emphasis omitted). Specifically, Appellant argues
that Fan does not teach or suggest how each of the calibration test patterns is
operatively related to a corresponding one of the plurality of discrete
functions, as required by independent claims 1, 5, and 9. Before analyzing
the sufficiency of the cited teachings in Fan, we note that Appellant’s claims
1, 5, and 9 do not require implementing a specific mathematical technique,
but rather recite only that each calibration pattern be “identified for” and be
“operative for manipulating” one of the discrete functions.
The Examiner maps the “identifying a respective calibration pattern”
step of independent claims 1, 5, and 9 to Fan’s teaching of a method of
selecting an optimal set of calibration patches. Ans. 4 (citing Fan ¶ [0008]).
Fan teaches a method for selecting an optimal set of calibration patches for
an image producing system and Fan discloses that:
This method of selecting an optimal set of S number of
calibration patches includes acquiring a set of K number of
basis eigen vectors and model parameters which represent the
image producing system having G number of colors and
computing the optimal set of S number of colors selected from
the set of G number of colors.
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Fan ¶ [0008]. Thus, the Examiner finds that Fan teaches selecting
calibration patches for multiple basis eigen vectors. Ans. 4. In Appellant’s
opening Brief, Appellant states that “in Fan, the numbers K and S seem to be
independent of each other, and there is no teaching or suggestion of any
correspondence between the number K and S.” App. Br. 9 (emphasis
added). Appellant later contradicts this statement in its Reply Brief by
stating that “Fan merely teaches finding an optimal number S of patches for
a given set of G colors and an initial set of eigen vectors, and during
calibration the S patches are used to adjust the weights of the K eigen
vectors.” Reply Br. 4 (emphasis added). Appellant, therefore, concedes to
the Examiner’s findings that Fan teaches a correspondence between the S
patches and the K eigen vectors, namely that Fan teaches using the S number
of calibration patches to adjust the weights of the K number of basis eigen
vectors. See Ans. 4 (citing Fan ¶¶ [0008, 20]). Thus, we are not persuaded
by Appellant’s argument that Fan does not teach or suggest that each of the
calibration test patterns is related operatively to a corresponding one of the
plurality of discrete functions.
Third, Appellant argues that the Examiner’s claim interpretation in the
Advisory Action is unreasonable and that independent claims 1, 5, and 9
require a “one-to-one correspondence between the discrete functions and the
calibration patterns.” App. Br. 10. The Examiner states in the Advisory
Action that “the limitation ‘each discrete function has one-to-one
correspondence with a calibration pattern’ is not claimed.” Advisory
Action (mailed Apr. 1, 2010) at 2. To the extent that Appellant argues that
the independent claims require that each calibration pattern corresponds to
one and only one discrete function, we agree with the Examiner’s statement
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in the Advisory Action. See App. Br. 10. We determine that the claim
language “identifying a respective calibration pattern for each of said
plurality of discrete functions, each calibration pattern corresponding to one
of said plurality of discrete functions being operative for manipulating said
one of said plurality of discrete functions during a calibration process”
(claim 1) requires that at least one calibration pattern be “identified for” and
“be operative for manipulating” at least one discrete function. This claim
language, however, does not prohibit one calibration pattern from
manipulating more than one discrete function. In other words, while the
independent claims require at least a one-to-one relationship between a
calibration pattern and a discrete function, the claims do not prohibit a one-
to-many relationship between a calibration pattern and many discrete
functions.
Because Fan discloses that the S patches are used to adjust the weights
of the K eigen vectors (see Fan ¶¶ [0008, 20]; see also Reply Br. 4), we are
not persuaded by Appellant’s arguments that Fan does not teach or suggest
how each of the calibration test patterns is related operatively to a
corresponding one of the plurality of discrete functions. Accordingly, we
are not persuaded by Appellant’s arguments regarding the cited prior art.
Therefore, we sustain the Examiner’s rejection of independent claims 1, 5,
and 9, and dependent claims 2-4, 6-8, 10-12, 14, 16, and 18 not separately
argued.

B. Obviousness Rejection of Claims 13, 15, and 17 over Fan and Ye

Appellant separately argues that the rejection of dependent claims 13,
15, and 17 is improper. App. Br. 12-13. Specifically, Appellant argues that
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the following limitations from dependent claims 13, 15, and 17 are not
taught or suggested by Ye:
obtaining a mask layout comprising a plurality of
patterns;
calculating overlap integrals of the mask layout with each
of the plurality of discrete functions;
identifying regions in the mask layout with the highest
overlap integral values; and
using patterns in the mask layout from the identified
regions with the highest overlap integral values as the selected
calibration test pattern.
App. Br. 12-13. The Examiner relies upon Ye as teaching or suggesting
these claimed limitations. Ans. 11-12 (citing Ye, col. 9, ll. 13-15; col. 9, l.
30 – col. 10, l. 29). While the cited portions of Ye teach creating masks for
a circuit design and selecting a plurality of circuit patterns from actual
circuit designs as calibration patterns, we are persuaded by Appellant’s
argument that Ye fails to teach, at least, “using patterns in the mask layout
from the identified regions with the highest overlap integral values as the
selected calibration test pattern,” as required by claims 13, 15, and 17.
Based on the record before us, we conclude that the Examiner erred in the
obviousness rejection of dependent claims 13, 15, and 17. Accordingly, we
do not sustain the rejection of dependent claims 13, 15, and 17.

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ORDER
The Examiner’s decision rejecting claims 1-12, 14, 16, and 18 is
affirmed.
The Examiner’s decision rejecting claims 13, 15, and 17 is reversed.
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)(iv). See 37
C.F.R. § 41.50(f).

AFFIRMED-IN-PART

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