Daniel Kandel et al.

Patent Trials and Appeals Board

Dec 2, 2021

2020004257 (P.T.A.B. Dec. 2, 2021)

UNITED STATES PATENT AND TRADEMARK OFFICE
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.
13/508,495 05/07/2012 Daniel Kandel KLA P3665US 9169
78238 7590 12/02/2021
Suiter Swantz/KLA Joint Customer Number
Suiter Swantz pc llo
14301 FNB Parkway
Suite 220
Omaha, NE 68154-5299
EXAMINER
ALKAFAWI, EMAN A
ART UNIT PAPER NUMBER
2865
NOTIFICATION DATE DELIVERY MODE
12/02/2021 ELECTRONIC
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.
Notice of the Office communication was sent electronically on above-indicated "Notification Date" to the
following e-mail address(es):
eofficeaction@appcoll.com
file@suiter.com
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PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
_________

BEFORE THE PATENT TRIAL AND APPEAL BOARD
__________

Ex parte DANIEL KANDEL,
GUY COHEN, DANA KLEIN, VLADIMIR LEVINSKI,
NOAM SAPIENS, ALEX SHULMAN, VLADIMIR KAMENETSKY,
ERAN AMIT, and IRINA VAKSHTEIN
__________

Appeal 2020-004257
Application 13/508,495
Technology Center 2800
___________

Before ADRIENE LEPIANE HANLON, BEVERLY A. FRANKLIN, and
GEORGE C. BEST, Administrative Patent Judges.

HANLON, Administrative Patent Judge.

DECISION ON APPEAL

A. STATEMENT OF THE CASE
The Appellant1 filed an appeal under 35 U.S.C. § 134(a) from an Examiner’s
decision finally rejecting claims 1–10, 21–26, and 36–41. Claims 11–20 and 27–
35 are also pending but have been withdrawn from consideration. We have
jurisdiction under 35 U.S.C. § 6(b).

1 “Appellant” refers to “applicant” as defined in 37 C.F.R. § 1.42. The Appellant
identifies the real party in interest as KLA-Tencor Corporation. Appeal Brief
dated January 9, 2020 (“Appeal Br.”), at 5.
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We REVERSE.
Representative claim 10 is reproduced below from the Claims Appendix to
the Appeal Brief. The limitations at issue are italicized.
10. A computer-implemented method for determining a quality
metric suitable for improving process control in a semiconductor
wafer fabrication process comprising:
acquiring a metrology measurement signal from a metrology
target of a wafer;
determining a plurality of overlay estimates for the metrology
target by applying a plurality of overlay algorithms to the acquired
metrology measurement signal from the metrology target, wherein a
first overlay estimate is determined for the metrology target with a
first overlay algorithm of the plurality of overlay algorithms and an
additional overlay estimate is determined for the metrology target
with an additional overlay algorithm of the plurality of overlay
algorithms, wherein the first overlay algorithm is different from the
additional overlay algorithm;
generating a statistical overlay estimate distribution based on
the plurality of overlay estimates; and
generating a quality metric for the metrology target based on a
span of the generated statistical overlay estimate distribution, wherein
the quality metric is indicative of variation of the overlay estimates as
a function of the plurality of overlay algorithms applied to the
metrology measurement signal acquired from the metrology target,
the quality metric configured to be non-zero for an asymmetric
overlay measurement signal acquired from the metrology target and is
proportional to an asymmetry-induced overlay inaccuracy in the
metrology measurement signal acquired from the metrology target.
Appeal Br. 60.
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The Examiner maintains the following grounds of rejection on appeal:
(1) claims 1–5, 7–10, 21–26, and 36–41 under 35 U.S.C. § 102(b) as
anticipated by Mieher 630;2 and
(2) claim 6 under 35 U.S.C. § 103(a) as unpatentable over Mieher 630 in
view of Mieher 744.3
B. DISCUSSION
At the outset, the Appellant argues that the Examiner fails to provide a
reasonable interpretation of claim 10. Appeal Br. 27. Claim 10 recites a method
comprising, inter alia, the following steps:
acquiring a metrology measurement signal from a metrology
target of a wafer;
determining a plurality of overlay estimates for the metrology
target by applying a plurality of overlay algorithms to the acquired
metrology measurement signal from the metrology target, wherein a
first overlay estimate is determined for the metrology target with a
first overlay algorithm of the plurality of overlay algorithms and an
additional overlay estimate is determined for the metrology target
with an additional overlay algorithm of the plurality of overlay
algorithms, wherein the first overlay algorithm is different from the
additional overlay algorithm . . . .
Appeal Br. 60 (emphasis added).
According to the Appellant, claim 10 “provides for ‘determining a plurality
of overlay estimates for the metrology target by applying a plurality of overlay
algorithms to the [single] acquired metrology measurement signal from the
metrology target.’”4 Appeal Br. 28. The Appellant argues that “[t]his limitation is

2 US 2008/0094630 A1, to Mieher et al., published April 24, 2008 (“Mieher 630”).
3 US 2009/0284744 A1, to Mieher et al., published November 19, 2009 (“Mieher
744”).
4 The Appellant discloses that “[a]n overlay measurement generally specifies how
accurately a first patterned layer aligns with respect to a second patterned layer
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NOT directed toward using a different algorithm on each individual target such
that each target ‘has its own measurement/algorithm’ as asserted by the Examiner.”
Appeal Br. 32 (emphasis added).
The Appellant’s interpretation of claim 10 is supported by the claim
language. Claim 10 recites the step of “acquiring a metrology measurement signal
from a metrology target.” Appeal Br. 60 (emphasis added). According to claim
10, a plurality of overlay estimates are subsequently determined for that metrology
target “by applying a plurality of overlay algorithms” to the metrology
measurement signal acquired during the previous step.5 Appeal Br. 60 (emphasis
added).

disposed above or below it or how accurately a first pattern aligns with respect to a
second pattern disposed on the same layer.” Spec. ¶ 4. Similarly, Mieher 630
discloses that the relative position of structures within a sample may be called
“overlay.” Mieher 630, at ¶ 4. The Appellant discloses that an “[o]verlay error is
the misalignment between any of the patterns used at different stages of
semiconductor integrated circuit manufacturing.” Spec. ¶ 4.
5 Independent claim 36 recites a system comprising, inter alia,
a metrology system configured to acquire a a [sic] metrology signal
from a metrology target of a wafer [and]
a computing system including one or more processors configured to
execute program instructions stored in memory, the program
instructions configured to cause the one or more processors to:
determine a plurality of overlay estimates for the metrology
target by applying a plurality of overlay algorithms to the acquired
metrology measurement signal from the metrology target . . . .
Appeal Br. 71 (emphasis added). Similar to claim 10, we interpret the system
recited in claim 36 as being configured to determine a plurality of overlay
estimates for the single metrology target “by applying a plurality of overlay
algorithms” to the single metrology measurement signal acquired from the
metrology target.
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Similarly, claims 1 and 21 recite, inter alia, the steps of “acquiring a
plurality of overlay metrology measurement signals from a plurality of metrology
targets” and “determining a plurality of overlay estimates for each of the plurality
of overlay metrology measurement signals by applying a plurality of overlay
algorithms to each overlay metrology measurement signal.” Appeal Br. 55, 65
(emphasis added). We interpret claims 1 and 21 as reciting that a plurality of
overlay estimates are determined for each overlay metrology measurement signal
by applying a plurality of overlay algorithms to a single overlay metrology
measurement signal. See Appeal Br. 32 (contending that the claims on appeal
provide for various steps that may be performed for each “metrology measurement
signal”).
Turning to the anticipation rejection on appeal, the Examiner directs our
attention to paragraph 57 of Mieher 630, which discloses that an estimate of an
overlay error E present between structures can be calculated “using a linear
approximation [i.e., an algorithm] based on the difference spectra properties P1
and P2.” See, e.g., Final Act. 10.6 Mieher 630 discloses that P1 and P2 are
obtained in the following manner. “Initially, an incident radiation beam is directed
towards each of the four targets A, B, C, and D to measure four spectra SA, SB, SC,
and SD from the four targets.”7 Mieher 630, at ¶ 53 (emphasis added). Thus, the
spectra SA, SB, SC, and SD acquired from targets A, B, C, and D, respectively, each
correspond to the claimed metrology measurement signal. See Mieher 630, at ¶ 54
(spectra SA, SB, SC, and SD “could include any type of spectroscopic ellipsometry

6 Final Office Action dated December 26, 2018.
7 Mieher 630 discloses that targets A, B, C, and D are designed to have offsets Xa,
Xb, Xc, and Xd, respectively, between first and second structure portions. Mieher
630, at ¶ 10.
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or reflectometry signals”). Mieher 630 discloses that spectrum SB (from target B)
is subtracted from spectrum SA (from target A) and spectrum SD (from target D) is
subtracted from spectrum SC (from target C) to form two difference spectra D1 and
D2. Mieher 630, at ¶ 55. Next, a difference spectrum property P1 is said to be
obtained from the difference spectra D1, and a difference spectrum property P2 is
said to be obtained from the difference spectrum D2. Mieher 630, at ¶ 55. Mieher
630 discloses:
The difference spectra properties P1 and P2 are generally obtained
from any suitable characteristic of the obtained difference spectra D1
and D2. The difference spectra properties P1 and P2 may also each
simply be a point on the each difference spectra D1 or D2 at a
particular wavelength. By way of other examples, difference spectra
properties P1 and P2 may be the result of an integration of averaging
of the difference signal, equal the an average of the SE alpha signal,
equal a weighted average which accounts for instrument sensitivity,
noise or signal sensitivity to overlay.
Mieher 630, at ¶ 55.
After difference spectra properties P1 and P2 are obtained, Mieher 630
discloses that a single overlay error E may then be calculated directly from the
difference spectra properties P1 and P2. Mieher 630, at ¶ 56. Mieher 630
discloses that the overlay error E may be determined using a linear approximation
(i.e., an algorithm) based on the difference spectra properties P1 and P2, which are
acquired from four different signals (i.e., spectra SA, SB, SC, and SD) of four
different metrology targets (i.e., targets A, B, C, and D, respectively). Mieher 630,
at ¶ 56; see also Appeal Br. 42.
In contrast, claim 10 recites that a plurality of overlay estimates are
determined for a single metrology target by applying a plurality of overlay
algorithms to a single metrology measurement signal. Appeal Br. 60. In the
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anticipation rejection on appeal, the Examiner does not direct us to any disclosure
in Mieher 630 describing that a plurality of overlay algorithms are applied to a
single metrology measurement signal (e.g., spectra SA) acquired from a single
metrology target (e.g., target A) to determine a plurality of overlay estimates as
recited in claim 10. See Appeal Br. 32 (arguing that the Examiner has not cited
any portion of Mieher 630 whereby multiple overlay estimates are determined
based on multiple algorithms applied to a single metrology measurement signal of
a single metrology target). For that reason, the anticipation rejection of claims 1–
5, 7–10, 21–26, and 36–41 is not sustained.
The Examiner’s reliance on Mieher 744 in the obviousness rejection of
claim 6 does not cure the deficiency in Mieher 630 identified above. See Final
Act. 34 (relying on Mieher 744 for its teaching of transmitting a set of correctables
to one or more process tools); see also Appeal Br. 53 (arguing that Mieher 744
does not cure the deficiencies in Mieher 630). Therefore, the obviousness rejection
of claim 6 based on the combination of Mieher 630 and Mieher 744 also is not
sustained.
C. CONCLUSION
The Examiner’s decision is reversed.

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Application 13/508,495

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In summary:

Claim(s)
Rejected
35 U.S.C. § Reference(s)/Basis Affirmed Reversed
1–5, 7–10,
21–26, 36–41
102(b) Mieher 630 1–5, 7–10,
21–26, 36–41
6 103(a) Mieher 630,
Mieher 744
6
Overall
Outcome
1–10, 21–26,
36–41

REVERSED