Ex Parte Kameda et alDownload PDFPatent Trial and Appeal BoardJun 15, 201712379471 (P.T.A.B. Jun. 15, 2017) 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. 12/379,471 02/23/2009 Kenji Kameda 139679.01 6816 759025944 OLIFF PLC P.O. BOX 320850 ALEXANDRIA, VA 22320-4850 06/19/2017 EXAMINER MARKOFF, ALEXANDER ART UNIT PAPER NUMBER 1711 NOTIFICATION DATE DELIVERY MODE 06/19/2017 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): OfficeAction25944@oliff.com j armstrong @ oliff.com PTOL-90A (Rev. 04/07) UNITED STATES PATENT AND TRADEMARK OFFICE BEFORE THE PATENT TRIAL AND APPEAL BOARD Ex parte KENJI KAMEDA,1 Jie Wang, and Yuji Urano Appeal 2016-0006082 Application 12/379,471 Technology Center 1700 Before MARKNAGUMO, KAREN M. HASTINGS, and JENNIFER R. GUPTA, Administrative Patent Judges. NAGUMO, Administrative Patent Judge. DECISION ON APPEAL Kenji Kameda, Jie Wang, and Yuji Urano (“Hitachi”) timely appeal under 35 U.S.C. § 134(a) from the Final Rejection3 of all pending claims 1- 5, 7-9 and 11-21. We have jurisdiction. 35 U.S.C. § 6. We reverse. 1 The real party in interest is identified as Hitachi Kokusai Electric Inc. (“Hitachi”). (Appeal Brief, filed 12 February 2015 (“Br.”), 1.) 2 Heard 13 June 2017. The Official Transcript, which was not available when this Opinion was entered, will be made of record. 3 Office Action mailed 13 August 2014 (“Final Rejection”; cited as “FR”), as modified by the Advisory Action entered 22 October 2014, entering an amendment cancelling claim 22. Appeal 2016-000608 Application 12/379,471 OPINION A. Introduction4 The subject matter on appeal relates to a method of manufacturing semiconductor devices (independent claim 1) in which a silicon nitride (Si3N4, hereinafter, “SiN”) film built up on the interior surfaces of the processing chamber and on internal members, such as a boat holding multiple substrates, is removed efficiently. The ’471 Specification explains that SiN, deposited by chemical vapor deposition methods on substrate wafers, also builds up on the interior surfaces of the processing chamber and on the exposed internal members. At some thickness, the film begins to peel off, leading to particles in the processing chamber. (Spec. 1 [0002].) The inventors found that particles are produced profusely under standard processing conditions at film thicknesses of about 2 pm, corresponding to about 12 runs of SiN film formation. {Id. at 38-39 [0101], discussing Fig. 8.) Thus, frequent cleaning or removal of the SiN film is necessary. The Specification teaches that prior art methods of removing the SiN film involve the use of hydrogen fluoride (HF) gas. {Id. at 2 [0003].) Although HF removes the SiN film, it tends to corrode exposed metal surfaces in the processing chamber and to erode quartz members such as the “boats” that hold the wafer substrates being processed in the chamber. {Id. at [0004].) Moreover, immediately after cleaning with HF, decreased 4 Application 12/379,471, Method for manufacturing semiconductor device and substrate processing apparatus, filed 23 February 2009 as a division of 12/292,995, filed 2 December 2008, now abandoned, claiming the benefit of three applications filed in Japan on 5 Dec 2007, 27 Feb 2008, and on 8 Oct 2008. We refer to the “’471 Specification,” cited as “Spec.” 2 Appeal 2016-000608 Application 12/379,471 film formation rates are often observed. (Id.) (In the words of the Specification, “[t]he decreased film formation rates is presumed to be caused by an increased effective surface area of the surfaces of quartz members (the reaction tube 103[5] and the boat 102). . . due to cracks on the surfaces of the quartz members because of cumulative film formations.” (Id. at 9 [0018].)) Hitachi seeks patent protection for methods and apparatuses that avoid these problems, i.e., that suppress the corrosion of the metal and the degradation of the quartz, and yet can be conducted with minimal down time and interruption of the wafer-processing. These goals are said to be obtained by unloading the processed substrates from the processing chamber, returning the boat to the chamber (still at the processing temperature), and then force-cooling the chamber rapidly enough to generate cracks in the SiN film. The SiN film is then removed by introducing fluorine gas, without any hydrogen-containing gas (especially HF), to the processing chamber at a first temperature. Then, at a second temperature between 450°C and 500°C, the surface of the quartz member is smoothened by supplying fluorine gas, again without any hydrogen-containing gas, to the inside of the processing chamber. This “smoothening” is said to remove adhered materials such as minute quartz powders generated due to quartz cracks, as well as removing the quartz cracks themselves. (Id. at 23 [0054].) Again, the disclosed process is said to suppress corrosion of the exposed metal and breakage of the quartz members. Moreover, the forced cooling can be conducted rapidly, so the down time due to cleaning is 5 Throughout this Opinion, for clarity, labels to elements are presented in bold font, regardless of their presentation in the original document. 3 Appeal 2016-000608 Application 12/379,471 diminished, and the decreased film formation is also suppressed on the subsequent SiN film formation runs, also leading to more efficient operations. {Id. at 5 [0009].) Claim 1 is representative and reads: A method for manufacturing a semiconductor device comprising: loading a substrate into a processing chamber in which a quartz member and a metal member are contained; performing a processing of forming a silicon nitride film on the substrate by supplying a processing gas into the processing chamber heated to a processing temperature by a heater provided outside of the processing chamber; unloading the processed substrate out of the processing chamber; after the forming of the silicon nitride film, [1] purging an inside of the processing chamber with a gas while applying a thermal impact to the silicon nitride film deposited on a surface of the quartz member in the processing chamber by decreasing a temperature in the processing chamber to a temperature lower than the processing temperature, so as to forcibly generate a crack in the silicon nitride film, in a state where the substrate is not present in the processing chamber, [3] wherein the decreasing of the temperature in the processing chamber to the temperature lower than the processing temperature is performed by a forced-cooling mechanism outside of the processing chamber, the forced-cooling mechanism being oriented to cover the processing chamber and the heater by means of a heat insulation cover; 4 Appeal 2016-000608 Application 12/379,471 at a time point when a thickness of the silicon nitride film accumulated on the surface of the quartz member in the processing chamber reaches a predetermined thickness before the silicon nitride film starts peeling off or dropping, [2] removing the silicon nitride film deposited on the surface of the quartz member in the processing chamber by thermo-chemical reaction, by supplying a fluorine gas solely or a fluorine gas diluted by an inert gas solely without supplying a hydrogen- containing gas to the inside of the processing chamber heated to a first temperature, in the state where the substrate is not present in the processing chamber; and after the removing of the silicon nitride film, [2'] smoothening the surface of the quartz member by etching the surface of the quartz member by supplying the fluorine gas solely or the fluorine gas diluted by the inert gas solely without supplying the hydrogen-containing gas to the inside of the processing chamber heated to a second temperature, by the heater, in the state where the substrate is not present in the processing chamber, [4] wherein the second temperature is set to not less than 450°C and not more than 500°C, and wherein corrosion of the metal member and breakage of the quartz member are suppressed. (Claims App., Br. Al-2; some indentation, paragraphing, emphasis, and bracketed labels6 to argued features added.) Claim 2 depends from claim 1 and requires that a cooling medium flow outside of the processing chamber in the purging step [1]. 6 We generally follow the labels used by Hitachi in the Brief. (Br. 10.) 5 Appeal 2016-000608 Application 12/379,471 Independent claims 7 and 8 cover a corresponding apparatus, and remaining independent claim 19 covers a method of operating the apparatus. The Examiner maintains the following grounds of rejection7’8’9: A. Claims 1-5, 7-9 and 11-21 stand rejected under 35 U.S.C. § 103(a) in view of the combined teachings of Hasebe10 and Okada.* 11 Al. Claims 1-5, 7-9 and 11-21 stand rejected under 35 U.S.C. § 103(a) in view of the combined teachings of Hasebe, Nodera,12 and Okada. 7 Examiner’s Answer mailed 13 August 2015 (“Ans.”). 8 Because this application was filed before the 16 March 2013 effective date of the America Invents Act, we refer to the pre-AIA version of the statute. 9 The amendment under 37 C.F.R. § 1.116 filed 14 October 2014, cancelling claim 22, was entered (Advisory Action 22 October 2014), removing all rejections of claim 22. 10 Kazuhide Hasebe and Mitsuhiro Okada, Film forming method, film forming system and recording medium, U.S. Patent Application Publication 2006/0141782 Al (2006), now U.S. Patent No. 7,416,978 (26 August 2008). 11 Mitsuhiro Okada et al., Film formation apparatus and method of using the same, U.S. Patent Application Publication 2006/0068598 Al (2006), now U.S. Patent No. 7,470,637 (30 December 2008). 12 Nobutake Nodera et al., Film formation apparatus and method for using same, U.S. Patent Application Publication 2009/0117743 Al (2009), based on an application filed 7 October 2008; now U.S. Patent No. 8,080,477 (20 December 2011). 6 Appeal 2016-000608 Application 12/379,471 B. Discussion The Board’s findings of fact throughout this Opinion are supported by a preponderance of the evidence of record. Hitachi’s arguments for patentability focus on limitations recited in claim 1, to which we direct our attention primarily. Briefly, the Examiner finds that Hasebe describes a processing apparatus and method that carries out the claimed process but for the SiN removal [2] and smoothening [2'] steps. (FR 3—4.) The Examiner finds that Okada describes such steps in a similar process, and concludes that it would have been obvious to modify the process described by Hasebe by adding the cleaning and planarizing steps taught by Okada. {Id. at 4-5.) The Examiner also finds thatNodera discloses similar deposition and cleaning steps, and concludes that the claimed process would have been obvious in view of the combined teachings of all three references. {Id. at 8-10.) Initially, we reject Hitachi’s arguments (Br. 11-13; Reply131 ^4) that the Examiner erred in finding motivation to combine the cleaning and planarizing teachings of Okada with the SiN cracking and purging step taught by Hasebe. Hasebe is concerned with improving a prior art process by providing more “recipes” for purging. Hitachi does not direct our attention to any credible evidence that Hasebe teaches that steps to remove SiN films and steps to planarize the substrates should not be conducted. Hitachi argues further that Hasebe does not teach the forced cooling required by feature [3] of claim 1 because “Hasebe’s portion 52, alleged to be the 13 Reply Brief filed 13 October 2015 (“Reply”). 7 Appeal 2016-000608 Application 12/379,471 cooling mechanism, is disclosed as a heating furnace provided with heater 51.” (Br. 16, 4th para.; Reply 6, 1st full para.) This argument gives insufficient weight to the Examiner’s finding that “[t]he cooling mechanism comprises cover (52) and cooler g[as] means (58, 56, 54, 55, and 57). All of these parts are located outside of the chamber (2).” (FR 12, last sentence; see also Ans. 21, last para., through 22.) Hitachi also argues that “the cooling mechanism is recited to cover both the processing chamber and the heater.” (Br. 16, last para.) Claim 1, however, recited that this occurs “by means of a heat insulation cover.” Although the nature of the wall of furnace 52, indicated by slanted lines in Hasebe Figure 1, does not appear to be specified, we do not find credible an argument that it is not—or that it would not have been obvious—to provide that wall as an insulating wall for thermal efficiency and safety. (Cf. FR 12; Ans. 21-22.) However, as Hitachi urges (Br. 14-15; Reply 4-6), the critical flaw in the Examiner’s findings is that Okada does not teach or suggest planarizing gases that do not contain hydrogen fluoride. On the contrary, Okada teaches that, “[a]s shown in FIG. 5D, where the planarizing gas did not contain hydrogen fluoride, quartz cracks were essentially not removed. Accordingly, it has been confirmed that the planarizing gas needs to contain hydrogen fluoride.” (Okada 6 [0092]; italics added.) The Examiner offers several responses, the first three of which (that the claims do not exclude the planarizing steps as disclosed by Okada; that claim 1 does not require that the removing and smoothening steps be conducted at different temperatures; and that Hasebe cures any deficiencies of Okada regarding the proper temperature of reaction with fluorine (Ans. 19-20)) are not persuasive because they do not address the limitation 8 Appeal 2016-000608 Application 12/379,471 that the step of planarization is required to be conducted without supplying a hydrogen-containing gas to the inside of the chamber. The Examiner’s final argument, that the claims do not require removing of cracks, but only an unspecified amount of smoothing {id. at 20), is not well-taken in view of Okada’s teaching that “it has been confirmed that the planarizing gas needs to contain hydrogen fluoride.” (Okada 6 [0092].) Disclosures are presumed to be directed to persons having ordinary skill in the art. The Examiner has not directed our attention to any credible evidence that such persons would have understood the term “smoothening,” as used by Hitachi, or the term “planarizing,” as used by Okada, to have such broad meanings that they would include only minute removal of cracks. A rejection for obviousness fails if any limitation is not accounted for properly. Both of the Examiner’s obviousness rejections rely on erroneous findings regarding Okada discussed above. Accordingly, we reverse both obviousness rejections. C. Order It is ORDERED that the rejections of claims 1-5, 7-9 and 11-21 are reversed. REVERSED 9 Copy with citationCopy as parenthetical citation