LIN, Chun-Li et al.Download PDFPatent Trials and Appeals BoardOct 24, 201913460868 - (D) (P.T.A.B. Oct. 24, 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. 13/460,868 05/01/2012 Chun-Li LIN 2011.1233/1085.946 5568 54657 7590 10/24/2019 DUANE MORRIS LLP (TSMC) IP DEPARTMENT 30 SOUTH 17TH STREET PHILADELPHIA, PA 19103-4196 EXAMINER CULBERT, CHRISTOPHER A ART UNIT PAPER NUMBER 2815 MAIL DATE DELIVERY MODE 10/24/2019 PAPER 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. PTOL-90A (Rev. 04/07) UNITED STATES PATENT AND TRADEMARK OFFICE ____________ BEFORE THE PATENT TRIAL AND APPEAL BOARD _______________________________________ Ex parte CHUN-LI LIN, YI-FANG LI, CHUN-SHENG WU, PO-HSIUNG LEU, and DING-I LIU __________________________________ Appeal 2019-000963 Application 13/460,868 Technology Center 2800 _ ____________________________ Before KAREN M. HASTINGS, N. WHITNEY WILSON, 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 a final rejection of claims 1–8, which constitute all the claims pending in this application. We have jurisdiction under 35 U.S.C. § 6(b). We AFFIRM. 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 Taiwan Semiconductor Manufacturing Co., Ltd. App. Br. 2. Appeal 2019-000963 Application 13/460,868 2 The invention is principally directed to “a method of manufacturing an isolation layer in semiconductor devices, and more particularly, to a method of manufacturing a void-free shallow trench isolation layer.” Spec. ¶ 1. Claim 1 is illustrative of the subject matter claimed and is reproduced below from the Claims Appendix to the Appeal Brief: 1. A method for manufacturing a shallow trench isolation film, the method comprising: forming a pad oxide film pattern and a silicon nitride film pattern on a semiconductor substrate, wherein the silicon nitride film defining an isolation region and exposing the semiconductor substrate in the isolation region; forming a trench with a predetermined depth in the semiconductor substrate by etching the exposed portion of the semiconductor substrate; forming a side wall oxide film on the inner walls of the trench; filling the trench with a first buried insulating oxide film and etching back the first buried insulating oxide film leaving only a portion of the first buried insulating oxide film in the trench with a reduced trench opening; depositing a second buried insulating oxide film over the first buried insulating oxide film in the trench covering the first buried insulating oxide film to a thickness that is enough to fill the reduced trench opening, wherein as the second buried insulating oxide film fills the reduced trench opening by growing from sidewalls toward center of the reduced trench opening, a seam is formed near the center; planarizing the second buried insulating oxide film until the surface of the silicon nitride film is exposed, whereby the first and second buried insulating oxide films form an STI oxide film structure having a top surface, whereby the seam is left near the top surface in a central region of the second buried insulating oxide film structure; Appeal 2019-000963 Application 13/460,868 3 removing the seam by removing the central region of the second buried insulating oxide film, thus forming a cap opening in the second buried insulating oxide film, wherein the cap opening comprises a trapezoidal cross-section; depositing a layer of high density oxide material on the second buried insulating oxide film and filling the cap opening, wherein the cap opening filled with the high density oxide material forming a high density cap; and removing excess high density oxide material, leaving behind the high density cap in the center of the STI oxide film. Appellant requests review of the following rejections from the Examiner’s Final Office Action: I. Claims 1, 2, 7, and 8 rejected under pre-AIA 35 U.S.C. § 103(a) as unpatentable over Applicant’s Admitted Prior Art (AAPA), as represented by Lin (US 2013/0292791 A1, published November 7, 2013 and corresponding to the instant Application) and Chen (US 2004/0142562 A1, published July 22, 2004). II. Claims 3–6 rejected under pre-AIA 35 U.S.C. § 103(a) as unpatentable over AAPA, Chen and Yang (US 7,611,963 B1, issued November 3, 2009). Appellant presents arguments only for claim 1 and relies on these arguments to address the grounds of rejection of all dependent claims. See generally Appeal Br. Accordingly, we decide the appeal as to all grounds of rejection based on the arguments presented for claim 1. OPINION After review of the respective positions Appellant provides in the Appeal and Reply Briefs and the Examiner provides in the Final Action and the Answer, we AFFIRM the Examiner’s rejections of claims 1–8 under 35 Appeal 2019-000963 Application 13/460,868 4 U.S.C. § 103(a) for essentially the reasons the Examiner presents in the Final Office Action and the Answer. We add the following for emphasis. Claim 1 The Examiner finds Applicant’s Admitted Prior Art (AAPA), as represented by Lin, discloses a known method for manufacturing a shallow trench isolation film that differs from the claimed invention in that the known method does not address the formation of a seam that can lead to an undesirable void. Final Act. 2–3; Lin Figures 1B–1G, ¶¶ 13, 18. The Examiner finds Chen teaches that seams lead to voids in the STI’s oxide layers and further teaches addressing this problem by depositing a layer of high density oxide material on the top-most buried insulating oxide layer and removing excess high density oxide material to form a high density cap in the center of the STI’s oxide film. Final Act. 3; Chen Figures 1E and 1F; ¶¶ 19, 20. The Examiner acknowledges that Chen does not disclose removing a central region of the top-most buried insulating oxide film containing the seam to form a cap opening wherein the cap opening comprises a trapezoidal cross-section. Final Act. 3. However, the Examiner finds that AAPA discloses as conventional to form layers within buried oxide layers by etching an undesirable portion of the buried oxide layer that result in trapezoidal openings which are then filled. Final Act. 3; Lin Figure 1E, ¶¶ 18, 20. Thus, the Examiner determines that it would have been obvious to one having ordinary skill in the art to arrive at the claimed invention from the combined teachings of AAPA and Chen. Final Act. 3–4. Appellant argues that Chen does not recognize the problem of undesired seams remaining even after the second buried oxide layer is planarized and the need to remove these seams. App. Br. 6. Appellant Appeal 2019-000963 Application 13/460,868 5 contends that Chen teaches a complete solution to eliminating the void or seam formed in the trench and, thus, one skilled in the art would not have sought to modify a method that completely eliminates voids or seams in the trench after the second oxide layer was grown and planarized. Id. at 5. These arguments do not persuade us of reversible error in the Examiner’s determination of obviousness. As the Examiner notes, Chen discloses a desire for no voids or seams formed in an STI trench. Final Act. 3; Ans. 7–8; Chen ¶ 19. Further, Appellant does not dispute the Examiner’s finding that Chen teaches a solution to unwanted seams in STI that leads to voids in the oxide layers in STI. Appeal Br. 4; Final Act. 3. Thus, Appellant has not explained adequately why Chen’s disclosure is not a recognition that the presence of voids and/or seams are generally undesirable in STI trenches. With respect to Appellant’s argument that Chen does not teach elimination of voids or seams after a second oxide layer was grown and planarized (Appeal Br. 5), we agree with the Examiner that the argument does not address the rejection presented for review on appeal. As the Examiner notes, the basis of the rejection is the modification of the AAPA with the teachings of Chen. Final Act. 2–4; Ans. 5–6. As the Examiner further notes, the AAPA teaches the STI structure comprising a second buried oxide layer. Final Act. 3–4; Ans. 7–8; Lin Figure 1F. Appellant does not explain sufficiently why Chen’s teachings would not lead one skilled in the art to eliminate voids or seams when present in any oxide layer. Thus, Appellant has not explained why one skilled in the art, using no more than ordinary creativity, would not have been capable of incorporating Chen’s technique into the AAPA’s teachings. See KSR Int’l Co. v. Teleflex Inc., 550 U.S. 398, 421 (2007) (“A person of ordinary skill is also a person Appeal 2019-000963 Application 13/460,868 6 of ordinary creativity, not an automaton.”); see also In re Sovish, 769 F.2d 738, 743 (Fed. Cir. 1985) (presuming skill on the part of one of ordinary skill in the art). Appellant argues that the Examiner improperly asserted that Appellant’s disclosure on paragraph 18 (of Lin) as describing the formation of layers within buried oxide layers by etching an undesirable portion of the buried oxide layer to form openings to be filled as “popular” without providing additional support for the assertion. Appeal Br. 5. Appellant contends that the relied-upon disclosure, when read in the appropriate context, describes the problem to be solved, the formation of the undesirable seam in the second buried insulation oxide film. Id. at 5–6. Thus, Appellant asserts that this disclosure cannot provide the motivation for one of ordinary skill in the art to modify Chen’s method to arrive at the process of Claim 1. Id. at 6. Appellant’s arguments are unavailing for the following reasons. First, we agree with the Examiner that AAPA’s reference to etching an undesirable portion of a buried oxide layer as “popular” would have led one skilled in the art to understand that this is an accepted and known practice in this art. Ans. 6. Appellant’s arguments to the contrary are not supported by any objective evidence. Appellant, at most, has provided mere attorney arguments and such arguments of counsel cannot take the place of evidence. See In re De Blauwe, 736 F.2d 699, 705 (Fed. Cir. 1984); In re Payne, 606 F.2d 303, 315 (CCPA 1979). Second, the premise of this argument is that Chen is limited to a single buried oxide layer and does not contemplate eliminating voids or seams present in a second buried oxide layer. However, as previously discussed, Appeal 2019-000963 Application 13/460,868 7 the Examiner relies on AAPA for the STI structure involving more than one oxide layer. Final Act. 2–3; Ans. 6; Lin Figure 1F, ¶ 13. Thus, the argument is not persuasive of reversible error because, as the Examiner points out, Appellant does not address the rejection of claim 1 that the Examiner presents as principally based on modifying AAPA with the teachings of Chen. Ans. 5–6; Final Act. 2–4; see generally Appeal and Reply Br. With respect to the problems associated with the voids and seams, we refer to our previous discussion of Chen’s disclosure of a desire for no voids or seams formed in the STI trench. We have also considered Appellant’s arguments that Chen’s method does not etch back the first oxide layer before application of the second oxide layer. Appeal Br. 7. However, this argument also does not address the rejection of claim 1 that the Examiner presents as principally based on modifying AAPA with the teachings of Chen. Ans. 5–6; Final Act. 2–4. The Examiner relies on the AAPA for the “etch back” limitation and Appellant’s arguments does not contest this part of the rejection. Appellant has not explained adequately why one skilled in the art would not have addressed the formation of voids or seams in a second buried layer in a manner similar to how it was addressed in the first buried layer. Accordingly, we AFFIRM the Examiner’s prior art rejections of claims 1–8 under 35 U.S.C. § 103(a) for the reasons presented by the Examiner and given above Appeal 2019-000963 Application 13/460,868 8 CONCLUSION In summary: Claims Rejected 35 U.S.C. § Basis Affirmed Reversed 1, 2, 7, 8 § 103(a) Applicant’s Admitted Prior Art (Lin), Chen 1, 2, 7, 8 3–6 § 103(a) Applicant’s Admitted Prior Art (Lin), Chen, Yang 3–6 Overall Outcome 1–8 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). AFFIRMED Copy with citationCopy as parenthetical citation