Joerg ZimmermannDownload PDFPatent Trials and Appeals BoardAug 12, 201914510725 - (D) (P.T.A.B. Aug. 12, 2019) Copy Citation 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 following e-mail address(es): PATDOCTC@fr.com 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. Appeal 2018-008673 Application 14/510,725 2 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). Appeal 2018-008673 Application 14/510,725 3 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. Appeal 2018-008673 Application 14/510,725 4 § 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. Appeal 2018-008673 Application 14/510,725 5 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 Appeal 2018-008673 Application 14/510,725 6 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). Appeal 2018-008673 Application 14/510,725 7 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 Appeal 2018-008673 Application 14/510,725 8 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.”). Appeal 2018-008673 Application 14/510,725 9 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 Copy with citationCopy as parenthetical citation