Joerg Zimmermann

Patent Trials and Appeals Board

Aug 12, 2019

14510725 - (D) (P.T.A.B. Aug. 12, 2019)

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.
14/510,725 10/09/2014 Joerg Zimmermann 21070-0089001 /
P131672US
5549
26161 7590 08/12/2019
FISH & RICHARDSON P.C. (BO)
P.O. BOX 1022
MINNEAPOLIS, MN 55440-1022
EXAMINER
RIDDLE, CHRISTINA A
ART UNIT PAPER NUMBER
2882
NOTIFICATION DATE DELIVERY MODE
08/12/2019 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
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PTOL-90A (Rev. 04/07)

UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE PATENT TRIAL AND APPEAL BOARD
____________

Ex parte JOERG ZIMMERMANN
____________

Appeal 2018-008673
Application 14/510,725
Technology Center 2800
____________

Before ROMULO H. DELMENDO, KAREN M. HASTINGS, and
MONTÉ T. SQUIRE, Administrative Patent Judges.

DELMENDO, Administrative Patent Judge.

DECISION ON APPEAL
The Applicant1 (“Appellant”) appeals under 35 U.S.C. § 134(a) from
the Primary Examiner’s final decision to reject claims 12–14 and 17–36.2
We have jurisdiction under 35 U.S.C. § 6(b).
We affirm.

1 The Applicant is “Carl Zeiss SMT GmbH” (Application Data Sheet filed
October 9, 2014, 4), which is also identified as the real party in interest
(Appeal Brief filed April 4, 2018 (“Appeal Br.”), 1).
2 Appeal Br. 5–11; Reply Brief filed September 6, 2018 (“Reply Br.”), 1–5;
Final Office Action entered December 29, 2017 (“Final Act.”), 3–25;
Examiner’s Answer entered July 10, 2018 (“Ans.”), 2–28.
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I. BACKGROUND
The subject matter on appeal relates to an illumination optical unit for
EUV3 projection lithography (Specification filed October 16, 2014
(“Spec.”), 1, ll. 13–15). Figure 1 (annotated), which is illustrative of the
claimed subject matter, is reproduced from the Drawings filed October 9,
2014, as follows:

Figure 1 above, which the Appellant refers to as “exemplary” (Appeal Br.
2), depicts a projection apparatus 1 for microlithography used in producing a
micro- or nano-structured electronic semiconductor component (i.e., a wafer
22), wherein the apparatus 1 includes, inter alia, a light source 2 that emits

3 “EUV” appears to be an acronym for “extreme ultraviolet” (see, e.g., Ruoff
et al. (“Ruoff”), WO 2011/157643 A1, published December 22, 2011, 3, ll.
11–15).
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EUV (Spec. 11, 18–12, l. 17). A “pupil generating device” and
“illumination pupil,” which are recited in claim 1, are not specifically
labeled or identified in Figure 1 above. According to the Appellant,
however, the “pupil generating device . . . includes a field facet 71 of field
facet mirror 6” (Appeal Br. 3). In addition, the Specification states that
“Figure 7 [not reproduced] schematically illustrates the illumination of the
central object field point OF on the reticle 17 in the object field 18 via an
illumination pupil 31 of the illumination optical unit 23” (Spec. 17, ll. 10–
12).
Representative claim 12 is reproduced from the Claims Appendix to
the Appeal Brief, as follows:
12. An optical unit configured to obliquely illuminate an
illumination field, the optical unit comprising:
a pupil generating device configured so that, during
operation of the optical unit, an illumination pupil brings about a
dependency of an imaging telecentricity on a structure variable
of an object in the illumination field so that a dependency of the
imaging telecentricity on the structure variable of the object is at
least partly compensated due to an interaction of the oblique
illumination with structures of the object,
wherein the optical unit is an EUV projection lithography
illumination optical unit.
(Appeal Br. 13 (emphasis added)).
II. REJECTIONS ON APPEAL
On appeal, the Examiner maintains several rejections, as follows:
A. Claims 32 and 36 under 35 U.S.C. § 112, ¶ 4, as failing to further
limit the subject matter of the claims (i.e., claims 17 and 28,
respectively) upon which they depend;
B. Claims 12–14, 17–19, 21, 22, 24, 34, and 35 under 35 U.S.C.
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§ 103(a) as unpatentable over Ruoff in view of Endres et al.4
(“Endres”);
C. Claims 20, 23, and 25–31 under 35 U.S.C. § 103(a) as
unpatentable over Ruoff, Endres, and Lowisch et al.5
(“Lowisch”);
D. Claim 32 under 35 U.S.C. § 103(a) as unpatentable over Ruoff,
Endres, and Gortych et al.6 (“Gortych”);
E. Claim 33 under 35 U.S.C. § 103(a) as unpatentable over Ruoff,
Endres, and Mulder et al.7 (“Mulder”); and
F. Claim 36 under 35 U.S.C. § 103(a) as unpatentable over Ruoff,
Endres, Lowisch, and Gortych.
(Ans. 2–29; Final Act. 3–25).
III. DISCUSSION
Rejection A. The Examiner’s rejection is based on the position that
the limitation “the illumination pupil is mirror symmetric with respect to at
least one coordinate selected from the group consisting of the first main
coordinate of the object field and the second main coordinate of the object
field” in claims 32 and 36 (Appeal Br. 17–18 (emphases added)) is
inconsistent with the requirement in claims 17 and 28, respectively, which
recite that “the illumination pupil is non-mirror symmetric with respect to at
least one coordinate selected from the group consisting of the first main

4 US 2009/0251677 A1, published October 8, 2009.
5 US 2004/0137677 A1, published July 15, 2004.
6 US 5,680,588, issued October 21, 1997.
7 US 2008/0239268 A1, published October 2, 2008.
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coordinate of the object field and the second main coordinate of the object
field” (id. at 13–14, 16) (Ans. 2–3).
We agree with the Appellant that this rejection is not well-founded.
As the Appellant points out (Appeal Br. 6), base claim 17, for example,
reads on embodiments in which the illumination pupil is non-mirror
symmetric with respect to the first main coordinate of the object field but not
necessarily to the second main coordinate of the object field; and claim 32,
which depends from claim 17, reads on embodiments in which the
illumination pupil is mirror symmetric with respect to the second main
coordinate of the object field but not the first main coordinate of the object
field. Hence, we discern no inconsistency between claim 17 and claim 32.
The same or analogous reasoning also applies to claims 28 and 36.
Therefore, we cannot sustain Rejection A.
Rejections B–F. The Appellant provides the same arguments against
Rejections B through F, focusing only on claim 12 (Appeal Br. 7–11).
Consistent with the manner in which the Appellant argues against the
rejections, we limit our discussion to claim 12, which we designate as
representative pursuant to 37 C.F.R. § 41.37(c)(1)(iv). All other claims
subject to Rejections B through F stand or fall with claim 12.
The Examiner finds that Ruoff describes an optical unit (i.e., an EUV
projection illumination optical unit) comprising “an illumination pupil [that]
brings about a dependency of an imaging telecentricity on a structure
variable of an object in the illumination field due to an interaction of the
oblique illumination with the structures of the object” (Final Act. 4; see also
Ans. 3–4). The Examiner acknowledges that “Ruoff does not appear to
explicitly describe a pupil generating device configured so that a
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dependency of the imaging telecentricity on the structure variable of the
object is at least partly compensated” (Final Act. 5; Ans. 4). The Examiner
finds, however, that Endres discloses the missing limitations by teaching
correction diaphragms 17, 26, and 40 to correct the telecentricity for the
illuminated object field points (Final Act. 5; Ans. 4). Based on these
findings, the Examiner concludes that a person having ordinary skill in the
art would have been prompted to combine Ruoff and Endres in the manner
claimed by the Inventor (Final Act. 5; Ans. 4–5).
The Appellant contends that “it would not have been obvious to a
person of ordinary skill in the art to modify Ruoff based on Endres in the
manner indicated by the Examiner” because Endres discloses a different
source of telecentricity error than those disclosed and solved in Ruoff
(Appeal Br. 8). Specifically, the Appellant argues that “Endres’[s]
discussion of telecentricity does not relate to a dependency of the
telecentricity on the objects but instead relates to a dependency of the
telecentricity on the position of the object field” (id. (citing Endres Figs. 14
and 15)). The Appellant argues that “[i]n addition, Ruoff uses a multi-layer
reflectivity coating on his mask and mentions several times that the
reflectivity is as high as possible” (id.). According to the Appellant, “[e]ven
if a person of ordinary skill in the art would have somehow considered
Endres, that person would have rejected Endres’[s] approach for
manipulating telecentricity because Endres teaches to stop away certain parts
of the pupil illumination leading to unavoidable light losses” (id.).
The Appellant’s arguments fail to identify reversible error in the
Examiner’s rejection. In re Jung, 637 F.3d 1356, 1365 (Fed. Cir. 2011).
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Ruoff teaches that “imaging errors . . . are produced owing to the
shadowing or the rigorous effects of the mask structure and which become
perceptible in particular in the form of a telecentricity error” (Ruoff 6, ll. 25–
28; see also id. at 25, ll. 1–4; Figs. 3a–3c). According to Ruoff, a multi-
layer coating having a reflectivity that varies over the incidence angle range
of the radiation, which strikes the mask, results in a variation of apodization
in the objective pupil, which also results in a telecentricity error during
imaging (id. at 6, l. 25–7, l. 2).
Endres’s Figure 1 (annotated), which is similar to the Inventor’s
Figure 1, is reproduced as follows:

Endres’s Figure 1 above shows a projection exposure apparatus 1 including,
inter alia, a radiation source that emits EUV, wherein a structure on a reticle
arranged in an object field (not shown) is exposed and imaged onto a light-
sensitive region of a wafer arranged in a region of the image field in the
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image plane 7 (Endres, ¶¶ 74–76). According to Endres, a correction
diaphragm (e.g., diaphragm 17) may be included to improve illumination
parameters including telecentricity, i.e., “better controllable illumination
parameters of telecentricity and ellipticity by comparison with the prior art”
(id. ¶¶ 4–6, 18, and 24).
Although the Appellant is correct that Endres discloses a relationship
between telecentricity and field position (id., Figs. 14 and 15), Endres does
not place any limitations as to the structure being imaged and teaches that
the disclosed “advantages can be achieved using an illumination optical unit
in combination with a known projection optical unit” (id. ¶ 20). Under these
circumstances, we discern no reversible error in the Examiner’s position
(Ans. 27–28) that when Endres’s correction diaphragm is implemented into
a known projection optical unit, such as that shown in Ruoff, the function
recited in claim 12 (“a dependency of the imaging telecentricity on the
structure variable of the object is at least partly compensated due to an
interaction of the oblique illumination with structures of the object”) would
necessarily follow from the combination of the prior art references. The
Appellant offers no objective evidence to the contrary. In re Wiseman, 596
F.2d 1019, 1023 (CCPA 1979) (rejecting the appellants’ argument that “a
structure suggested by the prior art, and, hence, potentially in the possession
of the public, is patentable to them because it also possesses an [i]nherent
but hitherto unknown, function which they claim to have discovered”); Ex
parte Obiaya, 227 USPQ 58, 60 (BPAI 1985) (“The fact that appellant has
recognized another advantage which would flow naturally from following
the suggestion of the prior art cannot be the basis for patentability when the
differences would otherwise be obvious.”).
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For these reasons, and those provided by the Examiner, we sustain
Rejections B through F.
IV. SUMMARY
Rejection A is not sustained. Rejections B through F are sustained.
Therefore, the Examiner’s final decision to reject claims 12–14 and 17–36 is
affirmed.
No time period for taking any subsequent action in connection with
this appeal may be extended under 37 C.F.R. § 1.136(a).

AFFIRMED