Ex Parte Davis et al

Board of Patent Appeals and Interferences

Mar 27, 2012

10674568 (B.P.A.I. Mar. 27, 2012)

UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
____________

Ex parte FENTON MATTHEW DAVIS and
JOHN M. YAMARTINO
____________

Appeal 2009-014637
Application 10/674,568
Technology Center 1700
____________

Before PETER F. KRATZ, KAREN M. HASTINGS, and
MICHAEL P. COLAIANNI, Administrative Patent Judges.

KRATZ, Administrative Patent Judge.

DECISION ON APPEAL
This is a decision on an appeal under 35 U.S.C. § 134 from the
Examiner’s final rejection of claims 1, 3, 4, 6-13, 15-18, 20, 21, 23-30, 32,
33, and 50-59. We have jurisdiction pursuant to 35 U.S.C. § 6.

Appeal 2009-014637
Application 10/674,568

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Appellants’ claimed invention is directed to a method for monitoring
an etch process, such as a mask trimming process. Claim 1 is illustrative
and is reproduced below:
1. A method for monitoring an etch process, comprising:

(a) performing pre-etch critical dimension (CD) measurements of a
substrate to generate pre-etch measurement information;

(b) applying an outlier filter to remove outliers in the pre-etch
measurement information;

(c) analyzing the pre-etch measurement information to determine
that a patterning is of a sufficient quality to allow for etching of the
substrate and to determine process parameters to an etch process;

(d) providing the substrate along with the pre-etch measurement
information to an etch reactor;

(e) etching the substrate in the etch reactor to form structures in the
substrate using the etch process, wherein the pre-etch measurement
information in combination with etch process monitoring are used to
in-situ monitor an etch process endpoint, wherein the etch process
monitoring comprises:

directing radiation onto the substrate, wherein an intensity of the
radiation is modulated at a frequency of about 10 Hz; and

collecting a portion of the radiation reflected from the substrate to
determine critical dimension of the structures formed in the substrate;
and

(f) terminating the etch process based on the etch process
monitoring having identified that the etch process has reached the etch
process endpoint.
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Application 10/674,568

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The Examiner relies on the following prior art references as evidence
in rejecting the appealed claims:
Toprac 6,379,980 B1 Apr. 30, 2002
Payne 5,329,381 Jul. 12, 1994
Tanaka 6,616,759 B2 Sep. 9, 2003
Knoot 6,130,415 Oct. 10, 2000
Yonezawa 2003/0222231 A1 Dec. 4, 2003
Shoham 2004/0028267 A1 Feb. 12, 2004
Egermeier 2002/0006677 A1 Jan. 17, 2002
Wilby 2003/0141572 A1 Jul. 31, 2003
Klippert II 6,136,712 Oct. 24, 2000
Morioka 2004/0060659 A1 Apr. 1, 2004
Petrucci WO 01/24254 A1 Apr. 5, 2001
Grimbergen 6,390,019 B1 May 21, 2002
Yu 6,368,982 B1 Apr. 9, 2002
Grimbergen 6,406,924 B1 Jun. 18, 2002
Cha 6,319,767 B1 Nov. 20, 2001

The Examiner maintains the following grounds of rejection:
I. Claims 1, 3, 4, 6, 7, 17, 18, 20, 23, and 24 stand rejected under 35
U.S.C. §103(a) as being unpatentable over Toprac (U.S. Patent No.
6,379,980) in view of Payne (U.S. Patent No. 5,329,381) or Tanaka (U.S.
Patent No. 6,616,759), Knoot (U.S. Patent No. 6,130,415) and further in
view of Yonezawa (U.S. Publ. No. 2003/0222231) or Shoham (U.S. Publ.
No. 2004/0028267) or Egermeier (U.S. Publ. No. 2002/0006677) as
evidenced by Wilby (U.S. Publ. No. 2003/0141572).
II. Claims 1, 3, 4, 6- 9, 11-13, 15, 17, 18, 20, 23-26, 28-30 and 32 stand
rejected under 35 U.S.C. §103 as being unpatentable over Klippert II (U.S.
Patent No. 6,136,712) in view of Payne or Tanaka, Knoot and further in
view of Yonezawa or Shoham or Egermeier.
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Application 10/674,568

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III. Claims 1, 3, 4, 6-9, 11-13, 15, 17, 18, 20, 23-26, 28-30 and 32 stand
rejected under 35 U.S.C. §103 as being unpatentable over Morioka (U.S.
Patent Publication No. 2004/0060659) in view of Payne or Tanaka, Knoot,
and further in view of Yonezawa or Shoham or Egermeier.
IV. Claims 1, 3, 4, 6-9, 11-13, 15, 17, 18, 20, 23-26, 28-30 and 32 stand
rejected under 35 U.S.C. §103 as being unpatentable over Petrucci (WO
01/24254) in view of Payne or Tanaka, Knoot, and further in view of
Yonezawa or Shoham or Egermeier.
V. Claims 1, 3, 4, 6-9, 11-13, 15, 17, 18, 20, 23-26, 28-30 and 32 stand
rejected under 35 U.S.C. §103 as being unpatentable over Grimbergen ‘019
(U.S. Patent No. 6,390,019) in view of Payne or Tanaka, Knoot, and further
in view of Yonezawa or Shoham or Egermeier.
VI. Claims 10, 20 and 27 stand rejected under 35 U.S.C. §103 as being
unpatentable over Toprac in view of Payne or Tanaka, Knoot, and
Yonezawa or Shoham or Egermeier as applied to claims 1, 3, 4, 6, 7, 17, 18,
20, 23, and 24, and further in view of Yu (U.S. Patent No. 6,368,982).
VII. Claims 10, 20 and 27 stand rejected under 35 U.S.C. §103 as being
unpatentable over Morioka in view of Payne or Tanaka, Knoot, and further
in view of Yonezawa or Shoham or Egermeier as applied to claims 1, 3, 4, 6,
7, 17, 18, 20 and 23- 24, and further in view of Yu.
VIII. Claims 16 and 33 stand rejected under 35 U.S.C. §103 as being
unpatentable over Grimbergen’019 in view of Payne or Tanaka, Knoot, and
Yonezawa or Shoham or Egermeier as applied to claims 1, 3,4, 6-9, 11-13,
15, 17-20, 23-26, 28-30 and 32, and further in view of Grimbergen '924
(U.S. Patent No. 6,406,924).
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Application 10/674,568

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IX. Claim 21 stands rejected under 35 U.S.C. §103 as being unpatentable
over Toprac in view of Payne or Tanaka, Knoot, and Yonezawa or Shoham
or Egermeier as applied to claims 1, 3, 4, 6, 7, 17, 18, 20, 23, and 24 and
further in view of Cha (U.S. Patent No. 6,319,767).
X. Claims 50-59 stand rejected under 35 U.S.C. §103 as being
unpatentable over Grimbergen ‘019 in view of Payne or Tanaka, Knoot, and
Yonezawa or Shoham or Egermeier and further in view of Cha and Yu.
XI. Claims 50-59 stand rejected under 35 U.S.C. §103 as being
unpatentable over Toprac or Klippert II or Petrucci or Morioka in view of
Payne or Tanaka, Knoot, and Yonezawa or Shoham or Egermeier and
further in view of Cha and Yu.
We reverse the stated rejections. Our reasoning follows.
Regarding Rejection I, the Examiner acknowledges that Toprac does
not disclose several features required by all of the rejected claims, including:
(1) the application of a filter for removing outliers in pre-etch measurement
information (step b of independent claims 1 and 18), and (2) modulating, at a
frequency of about 10 Hz, an intensity of radiation directed onto a substrate
(step e of independent claims 1 and 18) (Ans. 5). In an attempt to bridge at
least a portion of the acknowledged gap between Applicants’ claimed
invention and the teachings of Toprac, the Examiner additionally relies on
Payne or Tanaka for allegedly suggesting the use of an outlier filter in
Toprac’s monitoring method and further relies on Knoot for allegedly
teaching/suggesting the claimed modulation of radiation intensity directed at
a substrate (Ans. 5 and 6).1

1 The Examiner relies on several other additional references for allegedly
suggesting at least one other feature common to all of the rejected claims
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The Examiner maintains that: (1) “it would have been obvious for one
of ordinary skill in the art at the time of the invention to have used outlier
filter to remove noise in order to improve the accuracy of pre-etch
measurement” (Ans. 5); and (2) based on Knoot’s disclosed 10 Hz
modulation frequency (col. 7, ll. 43-47) that is used “while measuring
optical pyrometer signals indicating temperature”, the modulation of
Toprac’s “measurement signal by 10 Hz would have been obvious to one of
ordinary skill in the art at the time of the invention” (Ans. 5).
However, the Examiner’s obviousness position lacks an adequate
foundation in both evidentiary support and persuasive reasoning to establish
that the asserted modifications of Toprac’s method of monitoring the
performance of a removal tool would have been obvious to one of ordinary
skill in the art to effect in a manner that would have been in keeping with
Toprac’s desired method and that would have resulted in a process
corresponding to Appellants’ claimed process. In this regard, Toprac’s pre-
etch measurement is directed to measuring the thickness of a process layer
formed on a wafer, which process layer covered wafer is then subjected to a
monitored process layer removal operation using a tool, such as an etch
removal tool (col. 2, ll. 32-38 and 44-50; col. 3, ll. 32-52, and col. 4, ll. Ll.
54-62; see, e.g., Fig 3, items 300, 310, and 320).
The Examiner does not articulate how the thickness measurement of
Toprac corresponds to the claimed critical dimension (CD) measurements.2

(Ans. 6). The Examiner does not rely on these additional references for
suggesting the differences identified above.
2 According to paragraph 4 of the subject Specification, “smallest widths for
elements of an etch mask, such as lines, columns, openings, spaces between
lines, and the like” are “critical dimensions.” Also, 20-200 nm submicron
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However, assuming the pre-etch thickness measurement of Toprac does so
correspond, the argued application of an outlier filter to remove outliers
from the pre-etch information (process layer thickness measurement
information) of Toprac is lacking in evidentiary support and an adequate
explanation from the Examiner, as urged by Appellants (App. Br. 11-13;
Reply Br. 2-5). In this regard, the teachings of Payne concerns a nonlinear
noise cleaning outlier filter that pertains to the removal of noise from a data
base obtained from a scanned image, such as a scanned photograph, as part
of Payne’s disparate process that includes logarithmic correction of the
image data before or after the outlier filter cleaning, as part of an engraving
method (Payne, abstract, col. 7, l. 15- col. 8, l. 32). The Examiner has not
explained how the disparate teachings of Payne in combination with Toprac
provides a reasonable suggestion for one of ordinary skill in the art to apply
an outlier filter, as employed by Payne, to the pre-etch process layer
thickness measurement information of Toprac.
Nor has the Examiner reasonably articulated how Tanaka taken with
Toprac would have suggested the proposed application of an outlier filter to
the pre-etch process layer thickness measurement information of Toprac.
We note that the portion of Tanaka relied upon by the Examiner (Tanaka,
col. 5, ll. 15-16) is in the middle of a discussion provided by Tanaka with
respect to the use of robust regression to remove abnormal (outlier) data
points from data used for prediction in developing an accurate model
predictive equation for particular process results during a semiconductor

dimensions in ultra large scale integrated circuits are critical dimensions. In
contrast, thickness measurements are described as additional measurements
that are to be determined.
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Application 10/674,568

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processing operation (Tanaka, col. 2, ll. 32-63, col. 3, l. 31- col. 4, l. 28, col.
5, ll. 5-56; Figs 1A, 1B, 5A- 7). The Examiner’s conclusive obviousness
assertion concerning improving the accuracy of pre-etch measurement by
removing noise does not explain why one of ordinary skill in the art would
have been led by the combined teachings of Toprac and Tanaka or Payne to
apply an outlier filter, as employed by Payne or in light of the robust
regression method of Tanaka to the pre-etch process layer thickness
measurement information of Toprac (Ans. 5).
Concerning step e of independent claim 1 and step e of independent
claim 18, the Examiner has not reasonably articulated why one of ordinary
skill in the art would have been led to direct radiation onto the substrate of
Toprac such that “an intensity of the radiation is modulated at a frequency of
about 10Hz” as part of a critical dimension determination of structures
formed in the substrate of Toprac as required by rejected claim 1and the
rejected claims that depend thereon or as part of a mask trimming etch
process as required by rejected claim 18 and the rejected claims that depend
thereon based on the Examiner’s reliance on Knoot’s disclosed 10 Hz AC
frequency associated with a pyrometer (Ans. 5; Knoot, col. 7, ll. 43-47).
The Examiner does not persuasively explain why one of ordinary skill
in the art would have considered Knoot’s AC signal frequency that is used in
association with Knoot’s temperature measurement system as a suggestion
for a particular frequency modulation of a radiation intensity to be associated
with radiation to be directed at Toprac’s substrate. See In re Kahn, 441
F.3d 977, 988 (Fed. Cir. 2006) ("[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
Appeal 2009-014637
Application 10/674,568

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legal conclusion of obviousness"), cited with approval in KSR Int'l. Co. v.
Teleflex Inc., 550 U.S. 398, 417-18 (2007).
As argued by Appellants, the Examiner’s rejection lacks a persuasive
evidentiary basis (App. Br. 13; Reply Br. 4). In this regard, it is well settled
that rejections based on § 103(a) must rest on a factual basis with these facts
being interpreted without hindsight reconstruction of the invention from the
prior art. See In re Warner, 379 F.2d 1011, 1017 (CCPA 1967).
We reach the same result for substantially similar reasons with respect
to Rejections II –XI (Examiner’s Rejections labeled 3-12). In this regard,
we note the Examiner acknowledges that Klippert II, Morioka, Petrucci, and
Grimbergen (Rejections II –V, respectively) “do not disclose outlier filtering
during pre-etch measurement and intensity of radiation monitoring [sic.;
modulation] during etch process” ( Ans. 10) and the Examiner asserts that
the teachings of the same secondary references “are applied to compliment”
the teachings of the several other primary reference’s teachings “in a way, as
above, to get to the claimed invention” (Ans. 8-10).
Rejections VI –IX are directed to dependent claims. The additional
references applied therein are utilized by the Examiner to allegedly suggest
limitations added by certain dependent claims subject to these rejections, not
for ameliorating any deficiency in the base rejections (Ans. 10-14).
Rejections X and XI involve claims 50-59 and these obviousness
rejections, between them, involve the same combinations of a primary
reference and Payne or Tanaka, and Knoot, along with certain other common
references associated with the other rejections (Ans. 14-17). Claim 50, the
sole independent claim among claims 50-59, is directed to a mask trimming
process that includes an outlier filter application step and a radiation
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Application 10/674,568

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intensity modulation step corresponding to steps b and e of claims 1 and 18,
discussed above. For reasons substantially the same as discussed above, the
Examiner’s proposed combination of the applied primary references together
with Payne or Tanaka, and Knoot falls short in suggesting the process of
claim 50.
It follows that all of these rejections fail for substantially the same
reasons. In this regard, it is well settled that "the examiner bears the initial
burden, on review of the prior art or on any other ground, of presenting a
prima facie case of unpatentability." In re Oetiker, 977 F.2d 1443, 1445
(Fed. Cir. 1992).

ORDER
The Examiner’s decision to reject the appealed claims is reversed.

REVERSED

tc

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APPLICATION NO. FILING DATE FIRST NAMED INVENTOR ATTORNEY DOCKET NO. CONFIRMATION NO.
10/674,568 09/29/2003 Matthew Fenton Davis 6716/ETCH/SILICON 3852
44257 7590 03/27/2012
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03/27/2012 PAPER
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