KLA-Tencor Corporation

Patent Trials and Appeals BoardMay 13, 2021

2020002511 (P.T.A.B. May. 13, 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. 14/851,887 09/11/2015 Guoheng Zhao KLAP193US;P4105US1 8173 112811 7590 05/13/2021 KLA-Tencor Corporation and Simpson & Simpson PLLC 5555 Main Street Williamsville, NY 14221 EXAMINER FAYE, MAMADOU ART UNIT PAPER NUMBER 2884 NOTIFICATION DATE DELIVERY MODE 05/13/2021 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): patentEFS@idealawyers.com PTOL-90A (Rev. 04/07) UNITED STATES PATENT AND TRADEMARK OFFICE ____________ BEFORE THE PATENT TRIAL AND APPEAL BOARD ____________ Ex parte GUOHENG ZHAO and DAVID W. SHORTT ____________ Appeal 2020-002511 Application 14/851,887 Technology Center 2800 ____________ Before JEFFREY T. SMITH, MICHAEL P. COLAIANNI, and MERRELL C. CASHION, JR., Administrative Patent Judges. CASHION, Administrative Patent Judge. DECISION ON APPEAL STATEMENT OF THE CASE Pursuant to 35 U.S.C. § 134(a), Appellant1 appeals from the Examiner’s decision finally rejecting claims 1–15. We have jurisdiction under 35 U.S.C. § 6(b). We REVERSE and enter a NEW GROUND OF REJECTION pursuant to 37 C.F.R. § 41.50(b). 1 We use the word “Appellant” to refer to “applicant” as defined in 37 C.F.R. § 1.42. Appellant identifies the real party in interest as KLA- Tencor Corporation. Appeal Br. 2. Appeal 2020-002511 Application 14/851,887 2 The invention generally relates to systems and methods for detecting defects on a semiconductor wafer surface using a laser beam to generate an enhanced electric field and excite particle surface defects for detection. Spec. ¶¶ 3–5. Claim 1 illustrates the invention and is reproduced below from the Claims Appendix of the Appeal Brief: 1. A system for inspecting a surface of a wafer comprising: a source generating an optical beam at a deep ultraviolet wavelength; a solid immersion lens comprising a front surface adjacent the surface of the wafer, the solid immersion lens receiving the optical beam at a single angle greater than the critical angle with respect to a normal of the surface of the wafer, positioned such that the air gap between the lens and the wafer surface is less than the wavelength, an evanescent wave generated between the front surface and the surface of the wafer induces an enhanced electric field being generated at the wafer surface, at least one particle on the wafer receiving the enhanced electric field generating a scattered light at an angle less than the critical angle with respect to the normal of the surface of the wafer; a detector receiving the scattered light and generating a corresponding electrical signal; and a processor receiving and analyzing the electrical signal. Independent claim 9 is directed to a method for inspecting a surface of a wafer essentially using the apparatus of claim 1 above. Appellant requests review of the following rejections from the Examiner’s Final Office Action dated January 10, 2019: Appeal 2020-002511 Application 14/851,887 3 I. Claims 1–4, 9, and 10 rejected under pre-AIA 35 U.S.C. § 103(a) as unpatentable over Leenders (US 2011/0273687 A1, published Nov. 10, 2011) and Zhan (US 6,934,024 B2, issued Aug. 23, 2005); II. Claims 5 and 6 rejected under pre-AIA 35 U.S.C. § 103(a) as unpatentable over Leenders, Zhan, and Cozier (US 6,441,359 B1, published Aug. 27, 2002); III. Claim 7 is rejected under pre-AIA 35 U.S.C. § 103(a) as unpatentable over Leenders, Zhan, and Mimouni (US 2009/0205090 A1, published Aug. 13, 2009); IV. Claims 8 and 13 rejected under pre-AIA 35 U.S.C. § 103(a) as unpatentable over Leenders, Zhan, and further in view of Milster (US 2010/0053599 A1, issued Mar. 4, 2010) and Schultz (US 6,180,415 B1, published Jan. 30, 2001); V. Claim 11 rejected under pre-AIA 35 U.S.C. § 103(a) as unpatentable over Leenders, Zhan, and Vladimirsky (US 2014/0264054 A1, published Sept. 18, 2014); VI. Claim 12 rejected under pre-AIA 35 U.S.C. § 103(a) as unpatentable over Leenders, Zhan, and Kawaki (US 2008/0239292 A1, published Oct. 2, 2008); VII. Claim 14 rejected under pre-AIA 35 U.S.C. § 103(a) as unpatentable over Leenders, Zhan, and Eda (US 2006/0228095 A1, published Oct. 12, 2006); and VIII. Claim 15 rejected under pre-AIA 35 U.S.C. § 103(a) as unpatentable over Leenders, Zhan, and further in view of Shibata (US 2012/0019816 A1, published Jan. 26, 2012) and Eda. OPINION After review of the respective positions the Appellant provides in the Appeal and Reply Briefs and the Examiner provides in the Final Office Appeal 2020-002511 Application 14/851,887 4 Action and the Answer, we reverse the Examiner’s prior art rejections of claims 1–15 for the reasons the Appellant presents.2 We first note that independent claim 1 is a “system” claim. In order to be patentable the subject matter of a claim must fit into one and only one of the statutory claims of invention enunciated in 35 U.S.C. § 101, i.e., a process, machine, manufacture, or composition of matter. Claims cannot be directed to combinations of those classes of invention. See IPXL Holdings, L.L.C. v. Amazon.com, Inc., 430 F.3d 1377, 1384 (Fed. Cir. 2005) (claims to a combination of statutory claims of invention are not permitted and are indefinite). We interpret the system claim as directed to an apparatus, i.e., a structure which can be termed a machine or manufacture under 35 U.S.C. § 101. Claim 1 recites a surface inspection device comprising a solid immersion lens (SIL) to direct an optical beam at a particular angle to detect surface defects on a wafer substrate. The Examiner finds Leenders teaches a device comprising a SIL that receives an optical beam to be directed to a substrate. Final Act. 3. The Examiner finds that Leenders’s SIL does not receive the optical beam to generate an evanescent wave as claimed. Id. at 4. The Examiner turns to Zhan as teaching that it is known to direct an optical beam to a SIL as claimed for the benefit of determining the characteristics of the substrate. Id. The Examiner determines that it would have been obvious to a person skilled in the art to modify Leenders’s device by directing the optical beam 2 We limit our discussion to independent claims 1 and 9, from which all other claims depend from. Appeal 2020-002511 Application 14/851,887 5 passing through the SIL, as Zhan teaches, to arrive at the claimed invention. Appellant argues Leenders is directed to a lithographic apparatus comprising a cleaning device, a particle detector, and a patterning device to generate a circuit pattern on an individual layer of an IC, where the patterning device comprises the SIL. Appeal Br. 7–8. Appellant contends that “Leenders specifically describes the use of a separate radiation source 41 disposed frontward of the SIL 51 [in the particle detector 40], that outputs a beam 42, which beam 42 is not described as a DUV beam and which beam 42 is not passed through a SIL.” Id. at 8 (emphasis omitted). Appellant also argues that Zhan uses the SIL and an optical beam to determine the surface properties of a substrate. Id. at 9. Thus, Appellant argues that, absent impermissible hindsight, there is no reason to modify Leenders’s patterning device comprising a SIL in view of Zhan’s teachings to make it an inspection device because Leenders teaches a separate inspection device. Id. at 9–10. Appellant’s arguments identify reversible error in the Examiner’s determination of obviousness. The Examiner bears the initial burden of presenting a prima facie case of obviousness. In re Oetiker, 977 F.2d 1443, 1445 (Fed. Cir. 1992). “[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 legal conclusion of obviousness.” In re Kahn, 441 F.3d 977, 988 (Fed. Cir. 2006), quoted with approval in KSR Int’l Co. v. Teleflex Inc., 550 U.S. 398, 418 (2007). As Appellant argues, the Examiner has not provided an adequate technical explanation with the requisite rational underpinning of why or how Appeal 2020-002511 Application 14/851,887 6 one skilled in the art, absent impermissible hindsight, would have modified Leenders’s patterning device in view of Zhan’s teachings to arrive at the claimed invention. In addition, the Examiner does not provide an adequate explanation of why such a combination would be suitable for Leenders’s purpose of generating a circuit pattern on an individual layer of an IC. That is because, even if one skilled in the art would have combined the teachings of the cited art, it would appear that the resulting overall apparatus would have two inspection devices and no patterning device. The rejection of method claim 9 also falls for the reasons we give above and because the Examiner is modifying Leenders’s method of generating a circuit pattern on an individual layer of an IC to become a method of surface inspection, per Zhan’s teachings, without explaining how the modified method would be suitable for Leenders’s purpose. Accordingly, we REVERSE the Examiner’s prior art rejections of claims 1–15 under 35 U.S.C. § 103(a) for the reasons the Appellant presents and we give above. New Ground of Rejection Pursuant to our authority under 37 C.F.R. § 41.50(b), we reject claims 1 and 9 under 35 U.S.C. § 103(a) as unpatentable over Zhan (US 6,934,024 B2, published Aug. 23, 2005) in view of Shibata (US 2012/0019816 A1, published Jan. 26, 2012). With respect to independent claim 1, Zhan discloses an ellipsometric apparatus for analyzing various properties of a surface of a wafer, including morphology, surface roughness, and others. Zhan col. 1, ll. 16–27; col. 6, ll. 24–32. Given that Zhan detects surface roughness as a property to be Appeal 2020-002511 Application 14/851,887 7 analyzed, one skilled in the art would have reasonably inferred from this disclosure that Zhan’s device is capable of detecting defects on the surface of a wafer. See In re Fritch, 972 F.2d 1260, 1264–65 (Fed. Cir. 1992) (holding that a reference stands for all of the specific teachings thereof as well as the inferences one of ordinary skill in the art would have reasonably been expected to draw therefrom). Like Appellant’s system, Zhan’s system comprises a light source (40), a solid immersion lens (SIL) 50, 51, a detector (analyzer) 46, and processor 34. Zhan Figures 2, 4, col. 6, ll. 40–60; col. 7, ll. 6–29. Zhan further discloses passing an optical beam from the light source through the SIL at an angle greater than the critical angle to generate an evanescent wave between the wafer and the SIL. Zhan col. 9, ll. 3–37. In view of the substantial similarity between Zhan’s device and the claimed inspection system and their operation, one skilled in the art would have reasonably inferred that Zhan’s evanescent wave would also generate an enhanced electric field that would generate scattered light upon detection of a defect. As Appellant notes (Appeal Br. 9), Zhan does not teach the light source being in the deep ultraviolet (DUV) wavelength range. However, Zhan discloses the light source for illumination and detection can be of any suitable wavelength and that the light source can be laser beams. Zhan col. 17, ll. 1–11 and ll. 30–40. Shibata discloses an inspection apparatus for detection of semiconductor wafer defects. Shibata Abstr., ¶¶ 4, 8, 14, 26. Shibata also discloses that it is known to use a DUV light source at a predetermined angle to efficiently detect scattered light from target defects. Id. ¶ 26. Therefore, given that Zhan discloses using a light source for illumination and detection Appeal 2020-002511 Application 14/851,887 8 of any suitable wavelength, it would have been obvious to one of ordinary skill in the art to substitute Zhan’s light source with Shibata’s DUV light source because Shibata teaches DUV light as useful to inspect the surface of semiconductor wafers in an efficient way. Moreover, Appellant has not argued criticality or unexpected results stemming from the use of the DUV wavelength range in conjunction with the inspection system. Independent claim 9 recites the use of passing a deep ultraviolet (DUV) optical beam through a lens to generate an evanescent wave and inducing an enhanced electrical field from the optical beam and thereby generating scattered light and detecting and processing the scattered light. Zhan teaches a method of illuminating a wafer using a light source to detect surface roughness and morphology of a surface with the claimed elements except for the use of DUV light. Zhan Figures 2, 4, col. 6, ll. 40– 60; col. 7, ll. 6–29. As we note above, Shibata teaches the use of DUV light for efficient detection of scattered light from target defects. Shibata ¶¶ 4, 14, 26. Therefore, for the reasons we give above, we determine it would have been obvious to one of ordinary skill in the art to modify the method of Zhan by substituting Zhan’s light source with Shibata’s DUV light source to provide an efficient way of inspecting the wafer surface. Our new ground of rejection focuses only on independent claims 1 and 9, and we leave it to the Examiner the evaluation of the patentability of dependent claims 2–8 and 10–15 over the combined teachings of Zhan and Shibata. Appeal 2020-002511 Application 14/851,887 9 DECISION SUMMARY In summary: Claims Rejected 35 U.S.C. § Reference(s)/Basis Affirmed Reversed New Ground 1–4, 9, 10 103(a) Leenders, Zhan 1–4, 9, 10 5, 6 103(a) Leenders, Zhan, Cozier 5, 6 7 103(a) Leenders, Zhan, Mimouni 7 8, 13 103(a) Leenders, Zhan, Milster, Schultz 8, 13 11 103(a) Leenders, Zhan, Vladimirsky 11 12 103(a) Leenders, Zhan, Kawaki 12 14 103(a) Leenders, Zhan, Eda 14 15 103(a) Leenders, Zhan, Shibata, Eda 15 1, 9 103(a) Zhan, Shibata 1, 9 Overall Outcome 1–15 1, 9 TIME PERIOD FOR RESPONSE This decision contains a new ground of rejection pursuant to 37 C.F.R. § 41.50(b). Section 41.50(b) provides that “[a] new ground of rejection pursuant to this paragraph shall not be considered final for judicial review.” Section 41.50(b) also provides: When the Board enters such a non-final decision, the appellant, within two months from the date of the decision, must exercise one of the following two options with respect to the new ground Appeal 2020-002511 Application 14/851,887 10 of rejection to avoid termination of the appeal as to the rejected claims: (1) Reopen prosecution. Submit an appropriate amendment of the claims so rejected or new Evidence relating to the claims so rejected, or both, and have the matter reconsidered by the examiner, in which event the prosecution will be remanded to the examiner. The new ground of rejection is binding upon the examiner unless an amendment or new Evidence not previously of Record is made which, in the opinion of the examiner, overcomes the new ground of rejection designated in the decision. Should the examiner reject the claims, appellant may again appeal to the Board pursuant to this subpart. (2) Request rehearing. Request that the proceeding be reheard under § 41.52 by the Board upon the same Record. The request for rehearing must address any new ground of rejection and state with particularity the points believed to have been misapprehended or overlooked in entering the new ground of rejection and also state all other grounds upon which rehearing is sought. Further guidance on responding to a new ground of rejection can be found in the Manual of Patent Examining Procedure § 1214.01. No time period for taking any subsequent action in connection with this appeal may be extended under 37 C.F.R. § 1.136(a)(1)(iv). REVERSED; 37 C.F.R. § 41.50(b)