Ex Parte RAMAVAJJALA et al

Patent Trials and Appeals BoardApr 11, 2019

13440412 - (D) (P.T.A.B. Apr. 11, 2019)

UNITED STA TES p A TENT AND TRADEMARK OFFICE APPLICATION NO. FILING DATE FIRST NAMED INVENTOR 13/440,412 04/05/2012 MADHU SUDAN RAMAV AJJALA 23494 7590 04/15/2019 TEXAS INSTRUMENTS IN CORPORA TED PO BOX 655474, MIS 3999 DALLAS, TX 75265 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 ATTORNEY DOCKET NO. CONFIRMATION NO. TI-70771 9961 EXAMINER CRANDALL, JOEL DILLON ART UNIT PAPER NUMBER 3723 NOTIFICATION DATE DELIVERY MODE 04/15/2019 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): uspto@ti.com PTOL-90A (Rev. 04/07) UNITED STATES PATENT AND TRADEMARK OFFICE BEFORE THE PATENT TRIAL AND APPEAL BOARD Ex parte MADHU SUDAN RAMA V AJJALA, PRAKASH LAKSHMIKANTHAN, and PATRICK DAVID NOLL Appeal2018-006232 Application 13/440,412 1 Technology Center 3700 Before STEP AN ST AI CO VICI, MICHAEL L. HOELTER, and MICHELLE R. OSINSKI, Administrative Patent Judges. ST AI CO VICI, Administrative Patent Judge. DECISION ON APPEAL STATEMENT OF THE CASE- Madhu Sudan Ramavajjala et al. ("Appellants") appeal under 35 U.S.C. Â§ 134(a) from the Examiner's decision in the Final Office Action (dated July 28, 2017, hereinafter "Final Act.") rejecting claims 1, 3, and 8-10. 2 We have jurisdiction over this appeal under 35 U.S.C. Â§ 6(b ). 1 Texas Instruments Incorporated is identified as the real party in interest in Appellants' Appeal Brief (filed Dec. 4, 2017, hereinafter "Appeal Br."). Appeal Br. 2. 2 Claims 2, 4--7, and 11-22 are canceled. Appeal Br. 8-9 (Claims App.). Appeal2018-006232 Application 13/440,412 We REVERSE. SUMMARY OF DECISION INVENTION Appellants' invention is directed to a chemical-mechanical planarization method that employs a model for manufacturing an integrated circuit. Spec. para. 5. Claim 1, the sole independent claim, is representative of the claimed invention and reads as follows: 1. A method for fabricating an integrated circuit, comprising: providing a partitioned chemical-mechanical planarization (CMP) model having: (i) device specific model parameters including: a pre-CMP thickness of a film covering an in-process device, a post-CMP target thickness for said film covering said in-process device, and a device group property of said in-process device including a metal pattern density, and (ii) a common model parameter including a polish rate from an unpatterned pilot wafer; determining a polish time by applying said partitioned CMP model to a patterned product wafer, the applying including: deriving a coefficient based on the metal pattern density; and multiplying the coefficient with a difference between the pre-CMP thickness and the post-CMP thickness; and performing a CMP process on a patterned product wafer using a slurry and a CMP recipe based on said polish time. 2 Appeal2018-006232 Application 13/440,412 REJECTION The Examiner rejects claims 1, 3, and 8-10 under 35 U.S.C. Â§ I03(a) as being unpatentable over Patel et al. (US 6,623,333 Bl, iss. Sept. 23, 2003, hereinafter "Patel") and Chen (US 5,643,050, iss. July 1, 1997). ANALYSIS Independent claim 1 recites, inter alia, "a device group property of said in- process device including a metal pattern density." Appeal Br. 8 (Claims App.). The Examiner finds that "Patel fails to explicitly disclose the 'metal pattern density.'" Final Act. 3. The Examiner turns to Chen to disclose that the term "'pattern' refers to 'conductor interconnection wiring patter[n]s'." Id. (citing Chen, col. 4, 11. 31-33). Thus, according to the Examiner, "the 'pattern size and film density' variations accounted for in the equation of Patel refer to the metal film density." Id. ( citing Patel, col. 2, 11. 57---60). The Examiner explains that because "'pattern' refers to a metal pattern ... [it] also [refers] to metal pattern sizes." Id. (citing Chen, col. 2, 11. 3-6, col. 4, 11. 31-33; Patel, col. 2, 11. 57-60). Appellants argue that The term "pattern size" plainly means the size of a pattern, which does not necessarily describe or otherwise depend on the density of the pattern. Likewise, the term "film density" as expressed in Patel means the density of the dielectric film, which may or may not have anything to do with metal pattern or metal density. Appeal Br. 5. Thus, according to Appellants, "there is simply no proof that the 'metal patterns' in Chen ha[ve] sufficient nexus with the dielectric 'film density' or the 'pattern size' of Patel to conjure up the 'metal pattern density' that is missing from both of these references." Id. at 6. 3 Appeal2018-006232 Application 13/440,412 In response, the Examiner takes the position that "[ w ]hen Patel refers to 'film density,' one [of ordinary skill in the art] would consider that Patel is referring to the density of the entire film." Examiner's Answer (dated Apr. 5, 2018, hereinafter "Ans.") 7. The Examiner further asserts that although Patel does not refer to the metallic pattern of a semiconductor wafer when referring to "pattern size," Chen discloses that a skilled artisan "would interpret 'pattern size' to correspond to the size of the interconnection wiring patterns ... , or in other words, the metallic pattern size." Id. ( citing Chen, col. 4, 11. 32-33). Thus, the Examiner determines that because Patel "specifically uses density as the measurement for size of the film in its entirety ... , it's safe to say that Patel would use 'density' to measure the size of just the metal pattern as well." Id. (citing Patel, col. 5, 11. 36-38). It is undisputed that Patel discloses "pattern size" and "film density." See Patel, col. 5, 1. 37. Nonetheless, the dispute between Appellants and the Examiner is whether Patel's disclosure of "pattern size" constitutes the claimed "metal pattern density." For the following reasons we do not agree with the Examiner's position. It is well settled that "[p]rior art references may be 'indicative of what all those skilled in the art generally believe a certain term means ... [and] can often help to demonstrate how a disputed term is used by those skilled in the art."' In re Cortright, 165 F.3d 1353, 1358 (Fed. Cir. 1999) (internal citation omitted). In this case, we appreciate that Chen discloses "a layer of planarized insulation above [a] metal pattern" and "insulating layers ... over ... conductor interconnection wiring patterns." See Chen, col. 2, 11. 5-6, col. 4, 11. 30-33 ( emphasis added). Hence, we agree with the Examiner that a person of ordinary skill in the art of 4 Appeal2018-006232 Application 13/440,412 semiconductor manufacturing, in light of Chen's disclosure, would understand that the term "pattern," as used in Patel, refers to the "pattern" of a metal layer. Ans. 7. Such an interpretation is consistent with Patel's disclosure of a method for polishing "pre-metal, inter-metal dielectric, and other types of films on semiconductor wafers." Patel, col. 2, 11. 59---61. Patel's pre-metal ("PMD") or inter-metal ("IMD") films refer to insulating dielectric films that overlie a silicon layer or a metal layer, respectively. 3 Hence, both Patel and Chen distinguish between an insulating dielectric layer/film and a "metal pattern" layer with "interconnect[ed] wiring patterns." Accordingly, we do not agree with the Examiner's finding that Patel's pre-metal or inter-metal dielectric films also include metallic conductors, and, thus, we do not agree that "[ w ]hen Patel refers to 'film density,' ... Patel is referring to the density of the entire film." Ans. 7 (emphasis added). Rather, we find that when referring to "film density," Patel is referring to the density of the pre-metal or inter-metal dielectric films that overlie a silicon layer or a metal layer, respectively. 4 Accordingly, as Patel, in light of Chen, distinguishes between an insulating "dielectric film" and a "metal pattern" layer with "interconnect[ ed] wiring patterns," we do not agree with the Examiner that "Patel would use 'density' to measure the size of ... the metal pattern as well." Ans. 7 ( citing Patel, col. 5, 11. 36-38, Chen, col. 4, 11. 32-33). Such a position requires speculation on the 3 See, e.g., Lee (US 2005/0255681 Al, pub. Nov. 17, 2005, para. 6) ("The PMD layer is an insulating layer that is provided for separation between a polysilicon gate and an overlying metal layer.") and Lou (US 6,358,845 Bl, iss. Mar. 19, 2002, col. 1, 11. 12-14) ("Inter-metal dielectrics are insulative materials that are used for insulating metal interconnect layers."). 4 Although Patel refers to "other types of films," the Examiner has not made any findings with respect to such "other types of films," and, thus, to determine that such films include metallic conductors would require speculation. 5 Appeal2018-006232 Application 13/440,412 Examiner's part, which cannot form the basis for concluding obviousness. Appellants are correct that "the term 'pattern size' plainly means the size of a pattern," which is not the same as "the density of a pattern" because "size" and "density" are "different and independent measurements." Reply Br. 2-3. 5 In conclusion, for the foregoing reasons, the Examiner has not established by a preponderance of the evidence that Patel's disclosure of "pattern size" constitutes the claimed "metal pattern density," as called for by independent claim 1. Therefore, the Examiner's legal conclusion of obviousness is not supported by sufficient factual evidence, and thus, cannot stand. See In re Warner, 379 F.2d 1011, 1017 (CCP A 1967) (holding that "[ t ]he legal conclusion of obviousness must be supported by facts. Where the legal conclusion is not supported by facts it cannot stand.") (footnote omitted). Accordingly, for the foregoing reasons, we do not sustain the rejection under 35 U.S.C. Â§ 103(a) of claims 1, 3, and 8-10 as unpatentable over Patel and Chen. SUMMARY The Examiner's decision to reject claims 1, 3, and 8-10 under 35 U.S.C. Â§ 103(a) as unpatentable over Patel and Chen is reversed. REVERSED 5 An ordinary and customary meaning of the terms "size" and "density" is "the spatial dimensions, proportions, magnitude, or bulk of anything" and "mass per unit volume," which measures "compactness," respectively See size and density definitions, Dictionary.Com, https://www.dictionary.com/browse/size; https://www.dictionary.com/browse/density (last visited Apr. 2, 2019). 6