Tokyo Electron Limited

Patent Trials and Appeals Board

Oct 16, 2020

2019005920 (P.T.A.B. Oct. 16, 2020)

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.
15/152,950 05/12/2016 Lior Huli TTCA 540US2 2586
37694 7590 10/16/2020
WOOD, HERRON & EVANS, LLP (TOKYO ELECTRON)
2700 CAREW TOWER
441 VINE STREET
CINCINNATI, OH 45202
EXAMINER
DUDA, KATHLEEN
ART UNIT PAPER NUMBER
1737
NOTIFICATION DATE DELIVERY MODE
10/16/2020 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):
abilton@whe-law.com
usptodock@whe-law.com
PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
BEFORE THE PATENT TRIAL AND APPEAL BOARD

Ex parte LIOR HULI and NIHAR MOHANTY1

Appeal 2019-005920
Application 15/152,950
Technology Center 1700
Before ERIC B. GRIMES, LINDA M. GAUDETTE and LILAN REN,
Administrative Patent Judges.
GRIMES, Administrative Patent Judge.

DECISION ON APPEAL

This is an appeal under 35 U.S.C. § 134(a) involving claims to a
method of patterning substrates, which have been rejected for obviousness
and obviousness-type double patenting. We have jurisdiction under
35 U.S.C. § 6(b).
We REVERSE.

1 Appellant identifies the real party in interest as Tokyo Electron Limited.
Appeal Br. 3. We use the word “Appellant” to refer to “applicant” as defined
in 37 C.F.R. § 1.42.
Appeal 2019-005920
Application 15/152,950

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STATEMENT OF THE CASE
In material processing methodologies, pattern etching
comprises the application of a layer of radiation-sensitive
material, such as photo-resist, to an upper surface of a substrate,
the formation of a pattern in the layer of radiation-sensitive
material using photo-lithography, and the transfer of the pattern
formed in the layer of radiation-sensitive material to an
underlying thin film on the substrate using an etching process.
Spec. ¶ 2.2 “Extreme ultra violet (EUV) lithography shows promising results
for feature sizes below 40 nm.” Id. ¶ 3.
The Specification discloses a patterning method in which “[t]he
lithography process 402 is deliberately set to an underdose level by using
less energy from the EUV source than the target energy to fabricate the
target CD [critical dimension].” Id. ¶ 41. “[T]he lesser energy used in the
lithography step increases the substrate throughput.” Id.
As a result of using less energy, “the CD 404 of the structures 406 are
set to be wider than the target CD.” Id. In a subsequent “shrink process 410,
the structures 426 are shrunk more than the target CD.” Id. Finally, in a
“growth process 430, the structures 446 are grown to the target CD size 444
by adding material 460.” Id. The Specification also describes a similar
process in which the critical dimension (CD) is that of the contact hole
between structures, rather than that of the structures themselves. See id. ¶ 42.
The Specification states that “exposure is performed at a reduced
EUV dose to achieve adequate throughput and this invention reduces the

2 Specification filed May 12, 2016, as amended March 30, 2018.
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Application 15/152,950

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EUV energy in order to get around the RLS[3] tradeoff . . . by corrective
steps, such as CD shrink and CD growth.” Id. ¶ 60.
Claims 1–20 are on appeal. Claims 1 and 14 are the only independent
claims and are reproduced below (with emphasis added to disputed
limitations):
1. A method for patterning substrates in a patterning system
having a throughput in substrates per hour, the method comprising for
each of the substrates:
forming a layer of radiation-sensitive material on the
substrate;
preparing a pattern in the layer of radiation-sensitive
material using an extreme ultra violet (EUV) lithographic process, the
pattern being characterized by material structures having a critical
dimension (CD) and a roughness;
following the preparing the pattern, performing a shrink
process to remove material from the material structures to reduce the
CD to a reduced CD; and
following the performing the shrink process, performing a
growth process to add material to the material structures to grow the
reduced CD to a target CD;
wherein the method for each of the substrates has a
patterning time that enables the patterning system to operate with a
throughput of 50 substrates per hour or more while controlling the line
width roughness (LWR) and line edge roughness (LER) of each of the
substrates.

14. A method for patterning a substrate, comprising:
forming a layer of radiation-sensitive material on a
substrate;

3 “It is known in the art that there is a tradeoff relationship between
Resolution, LWR [line width roughness], and Sensitivity, often called the
LRS [sic] tradeoff triangle.” Spec. ¶ 3.
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preparing a contact hole (C/H) pattern in the layer of
radiation-sensitive material using a lithographic process, the pattern
being characterized by a critical dimension (CD) and a contact edge
roughness (CER);
following the preparing the C/H pattern, performing an
exposure process to a lower energy than the target energy, the
exposure process forming a smaller C/H CD than the expected C/H
CD,
performing a CD growth process to remove material
adjacent to the C/H pattern to create a C/H CD larger than the
expected C/H CD; and
performing a CD shrink back process to add material
adjacent to the C/H pattern to reduce the C/H CD to a target CD.

The claims stand rejected as follows:
Claims 1–20 under 35 U.S.C. § 103 as obvious based on Hetzer,4
either Bae5 or Amblard,6 and Eisenmann7 (Ans. 3) and
Claims 1, 7–10, and 14–16 for obviousness-type double patenting
based on claims 1–3 of U.S. Patent 9,086,631 (Ans. 6).
OPINION
Obviousness
All of the claims stand rejected as obvious based on Hetzer, Bae or
Amblard, and Eisenmann. Bae and Amblard, however, are only cited with
regard to a “process of using a coating in the shrink process” (Ans. 4), as
recited in dependent claim 2.

4 Huli et al., WO 2014/035871 A1; pub. March 6, 2014. The Examiner and
Appellant refer to this reference as “Hetzer,” so we do as well.
5 Bae et al., US 2011/0117490 A1; pub. May 19, 2011.
6 Amblard, US 6,764,946 B1; iss. July 20, 2004.
7 Eisenmann et al., US 2008/0295061 A1; pub. Nov. 27, 2008.
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With respect to the independent claims, the Examiner finds that
“Hetzer teaches a method of patterning an EUV resist” that includes forming
a layer of radiation-sensitive material and forming a pattern. Id. at 3. “The
pattern is taught to have critical dimensions and roughness.” Id.
The Examiner also finds that “the pattern 122 is slimmed to reduce
critical dimension. . . . The process can include vapor smoothing.” Id. at 3–4.
“Paragraph 0042 teaches that after the smoothing process the roughness is
reduced about 33%.” Id. at 4. The Examiner thus finds that “Hetzer . . .
teaches using a shrink process and a growth process to reduce pattern line
roughness.” Id. at 5.
Appellant notes that claim 1 requires “performing a growth process to
add material to the material structures to grow the reduced CD to a target
CD,” and claim 14 likewise requires “performing a CD shrink back process
to add material adjacent to the C/H pattern to reduce the C/H CD to a target
CD.” Appeal Br. 5. Appellant argues that “both claims 1 and 14 recite a
method of first removing material to affect the CD (increase or decrease)
and thereafter adding material to oppositely affect the CD (decrease or
increase).” Id.
Appellant argues that “reducing surface roughness according to
Hetzer does not include adding material to the structure.” Id. at 6. Appellant
states that, “[a]ccording to Hetzer, ‘the vapor-phase environment 430 reacts
with the exposed portions of the layer of radiation-sensitive material 420 to
cause “melting” or reflowing of the radiation-sensitive material.’” Id.
Appellant argues that “[t]he smoothing process as described does not
expressly include material addition.” Id.
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That is, “[c]laims 1 and 14 require that material be added to the
structures. One skilled in the art would understand that the plain meaning of
adding material to a structure involves new material that was not previously
present on the structure. That interpretation is consistent with Appellant’s
specification.” Id. at 9. Appellant argues that “Hetzer is simply relocating
existing material on the structure and does not meet the plain meaning of ‘to
add material to the material structures’ or ‘to add material adjacent to the
C/H pattern.’” Id.
The Examiner responds that “[t]he smoothing process of Hetzer
teaches that the material is moved from one location to another which would
be adding material to the desired area.” Ans. 6.
We conclude that the rejection is based on an unreasonably broad
interpretation of the claim limitations requiring a step “to add material.”
“[D]uring examination proceedings, claims are given their broadest
reasonable interpretation consistent with the specification.” In re Hyatt, 211
F.3d 1367, 1372 (Fed. Cir. 2000).
Claim 1 recites “performing a growth process to add material to the
material structures” (emphasis added). Claim 14 similarly recites
“performing a CD shrink back process to add material adjacent to the C/H
pattern” (emphasis added). The definition of “add” is “to join or unite so as
to bring about an increase or improvement.”8 Thus, the plain meaning of
“adding” material requires an increase in the material compared to what was
previously present.

8 https://www.merriam-webster.com/dictionary/add?src=search-dict-box,
last accessed October 7, 2020.
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The Specification’s description of the inventive processes is consistent
with this definition of “add.” See, e.g., ¶ 41 (“In the shrink process 410, the
structures 426 are shrunk more than the target CD and results in a smaller
line 424 than the target CD and bigger space 428. . . . In the growth process
430, the structures 446 are grown to the target CD size 444 by adding
material to the lines 464.”); see also Fig. 4.
We therefore conclude that the claim language reciting “to add
material” requires a “growth process” (claim 1) or “shrink back process”
(claim 14) that results in the presence of more material after the process than
was present before that process.
Hetzer describes a smoothing process in which “the layer of radiation-
sensitive material 420 is exposed to a vapor-phase environment 430.” Hetzer
¶ 39.
The vapor-phase environment 430 reacts with the exposed
portions of the layer of radiation-sensitive material 420 to cause
“melting” or reflowing of the radiation-sensitive material within
the chemically treated surface layer 435 to form a reflowed
layer 440 and, thus, smooth the exposed surface of the layer of
radiation-sensitive material 420.
Id. ¶ 40. “Thereafter, . . . the pattern 422 is subjected to a drying process to
remove any residue from the exposure to the vapor-phase environment 430.”
Id. ¶ 41.
Thus, in Hetzer’s process, the surface of the radiation-sensitive
material is melted to allow the material to form a reflowed layer and thereby
smooth the surface. However, that melting and reflowing simply
redistributes the material that is already present; Hetzer does not describe
adding material to what was present before the smoothing process. Hetzer
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therefore does not describe a smoothing process “to add material” as
required by claims 1 and 14.
The Examiner cites Eisenmann only with respect to claim 14. The
Examiner finds that “Eisenmann teaches an underexposure to produce the
desired pattern.” Ans. 5. However, the Examiner has not pointed to any
disclosure in Eisenmann that makes up for the deficiency in Hetzer
discussed above.
We therefore reverse the rejection of claims 1–20 as obvious based on
Hetzer, Bae or Amblard, and Eisenmann.
Obviousness-type double patenting
Claims 1, 7–10, and 14–16 stand rejected for obviousness-type double
patenting based on claims 1–3 of U.S. Patent 9,086,631. The Examiner
states:
Although the claims at issue are not identical, they are not
patentably distinct from each other because the patent teaches a
process which uses a slimming step and smoothing step. The
slimming step is equivalent to the shrink step in the current
application and the smoothing step is equivalent to the growth
step in the current application.
Ans. 6.
The smoothing process described in the ’631 patent, however, is
identical to the one described by Hetzer. See ’631 patent 6:18–58. Like
Hetzer, the ’631 patent describes smoothing by “‘melting’ or reflowing of
the radiation-sensitive material.” Id. at 6:44–45. We therefore reverse the
obviousness-type double patenting rejection for the reasons discussed above.
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Application 15/152,950

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DECISION SUMMARY
In summary:
Claims
Rejected
35 U.S.C. § Reference(s)/Basis Affirmed Reversed
1–20 103 Hetzer, Bae/Amblard,
Eisenmann
1–20
1, 7–10,
14–16
Nonstatutory Double
Patenting
1, 7–10,
14–16
Overall
Outcome
1–20

REVERSED