Ex Parte Soo et al

Patent Trial and Appeal BoardNov 27, 2012

11483951 (P.T.A.B. Nov. 27, 2012)

UNITED STATES PATENT AND TRADEMARKOFFICE 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. 11/483,951 07/07/2006 Jyr Hong Soo 010190/DSM/BCVD/JPFEIFER 8675 44257 7590 11/28/2012 PATTERSON & SHERIDAN, LLP - - APPM/TX 3040 POST OAK BOULEVARD, SUITE 1500 HOUSTON, TX 77056 EXAMINER HORNING, JOEL G ART UNIT PAPER NUMBER 1712 MAIL DATE DELIVERY MODE 11/28/2012 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 JYR HONG SOO, MATTHEW SPULLER, MICHAEL S. COX, MARTIN JAY SEAMONS, AMIR AL-BAYATI, BOK HOEN KIM, and HICHEM M’SAAD ____________ Appeal 2011-011972 Application 11/483,951 Technology Center 1700 ____________ Before RICHARD E. SCHAFER, RICHARD TORCZON, and CHRISTOPHER L. CRUMBLEY, Administrative Patent Judges. CRUMBLEY, Administrative Patent Judge. DECISION ON APPEAL This is an appeal under 35 U.S.C. § 134 from the Examiner’s final rejection of Claims 4 and 5 of the above-referenced application. We have jurisdiction under 35 U.S.C. § 6(b). We AFFIRM. Appeal 2011-011972 Application 11/483,951 2 STATEMENT OF THE CASE The appealed claims are directed to a method for plasma processing. Claim 4, set forth below, is representative of the subject matter on appeal: 4. A method for plasma processing, comprising: providing a substrate in a plasma processing chamber; flowing a gas mixture into the chamber; applying an RF power to an electrode to form a plasma in the chamber; collecting the value of the DC bias of the electrode during RF ramp up, wherein the value is collected at intervals from 0.1 ms to 500 ms; and adjusting an application parameter of the RF power applied to the electrode in response to the collected value of the DC bias, wherein adjusting the application parameter further comprises: adjusting an RF power ramp-up rate. Appellants have argued the patentability of Claims 4 and 5 together, therefore Claim 5 stands or falls together with Claim 4. 37 C.F.R. § 41.37(c)(1)(vii). The Examiner relies upon the following evidence of unpatentability: Aoi JP 2001032078 Feb. 6, 2001 Reitman US 6,420,194 Jul. 16, 2002 Tabery US 6,605,514 Aug. 12, 2003 Águas “Plasma diagnostics of a PECVD system using different R.F. electrode configurations,” Vacuum, vol. 56, p. 31-37 (2000). Appeal 2011-011972 Application 11/483,951 3 Nguyen “High-density plasma chemical vapor deposition of silicon- based dielectric films for integrated circuits,” IBM J. of Res. and Dev., vol. 43, no. 1/2, p. 109-125 (Jan-Mar 1999). The Rejected Claims Claims 4 and 5 stand rejected under 35 U.S.C. § 103(a) as obvious over Tabery in view of Aoi, in view of Águas, in view of Nguyen, in view of Reitman. The Issue Presented The issue before us on appeal is whether the prior art in combination teaches or suggests all elements of the claimed invention, specifically whether the prior art teaches or suggests a method comprising “adjusting an RF power ramp-up rate.” ANALYSIS Plasma processes are a known method for deposition or etching of material layers in the manufacture of integrated circuits. Spec. ¶ 0002. These processes involve the use of a gas-filled chamber containing an integrated circuit substrate, across which an electric field gradient is applied. Aoi ¶ 0014. The electric field generates a plasma within the chamber, however it is known that this discharge may result in damage to the substrate. Spec. ¶ 0003. Appellants attempt to address this known problem by, in the words of Claim 4, “adjusting an RF power ramp-up rate.” Appeal 2011-011972 Application 11/483,951 4 The Examiner rejected Appellants’ claims, finding that the prior art teaches or suggests each limitation of the claims. Appellants dispute only one of these findings: that the prior art, and specifically Nguyen, teaches “adjusting an RF power ramp-up rate.” App. Br. 9-10.1 According to Appellants, “Nguyen never establishes a [sic] RF power ramping rate as a parameter, much less an important one.” Id. at 10. In response, the Examiner notes that Nguyen teaches that the RF power should be gradually ramped-up during processing in order to minimize the RF power surge which can damage the substrate. Ans. 5-6 (citing Nguyen 112, col. 2). The Examiner thus concludes that Nguyen specifically teaches that how quickly the RF power is increased has an effect on damage to the substrate wafer. Id. at 7. Appellants attempt to distinguish Nguyen on the basis that the paragraph cited by the Examiner is “the only instance where ramping is discussed, and does not recite language such as ‘how quickly’ or ‘how gradually’ as suggested by the Examiner.” Reply Br. 2. Appellants therefore argue that “the rate at which the RF bias is ramped is never changed during processing” in Nguyen. Id. At the outset, we note that Appellants incorrectly assert that the paragraph cited by the Examiner is “the only instance where ramping is 1 We refer to the Appeal Brief filed January 28, 2011 (“App. Br.”), the Examiner’s Answer mailed April 11, 2011 (“Ans.”), and Appellants’ Reply Brief filed June 1, 2011 (“Reply Br.”). Appeal 2011-011972 Application 11/483,951 5 discussed.” Nguyen contains at least two other mentions of ramping the RF power applied in the chamber. See, e.g., Nguyen 120 col. 2, 121 col. 1. Furthermore, at least one of these mentions notes that the rate of ramping may be initially slowed to prevent damage to the substrate, contradicting Appellants’ statement that the “rate at which the RF bias is ramped is never changed during processing.” Id. at 120 col. 2 (“it is also possible to ramp up the rf biasing slowly for the first 5-10 seconds of the deposition process to … avoid the GC corner erosion”). Based on the portion of Nguyen cited by the Examiner and these additional teachings, we find that Nguyen discloses that a gradual ramping of RF power during the deposition process is advantageous. Furthermore, the reference teaches that the rate of ramping may be adjusted during the process, for example during the first 5-10 seconds of the process, to further avoid damage to the substrate. Changing the rate of RF ramping during processing is taught by Nguyen. Even assuming arguendo that Nguyen does not expressly teach adjusting the RF ramping rate during processing, our ultimate conclusion would not change. The person of ordinary skill in the art seeking to minimize power surges by implementing Nguyen’s RF ramping would adjust the ramping rate during processing to determine what “gradual” rate is optimal. See KSR Int’l Co. v. Teleflex Inc., 550 U.S. 398, 421 (2007) (“A person of ordinary skill is also a person of ordinary creativity, not an automaton.”). The reference therefore suggests to a person of ordinary skill Appeal 2011-011972 Application 11/483,951 6 in the art to adjust the RF ramping rate during processing to reduce substrate damage. Appellants’ remaining argument, that other portions of Nguyen discuss process parameters which do not include power ramping rate, does not alter our conclusion. App. Br. 10. The portions cited by Appellants, which discuss parameters such as RF power, gas-flow ratios, and substrate temperature, do not expressly exclude other parameters discussed elsewhere in the reference. Furthermore, as the Examiner correctly notes, the parameters Appellants cite are parameters considered important to the properties of the deposited material, not the minimization of damage to the substrate. Ans. 8. Minimization of substrate damage is discussed in other portions of Nguyen, where gradual power ramping is disclosed to be a parameter. CONCLUSION For the foregoing reasons, we find that the prior art teaches or suggests the sole limitation at issue on appeal, “adjusting an RF power ramp- up rate.” We therefore affirm the rejection of Claims 4 and 5 as obvious under 35 U.S.C. § 103(a). 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 Appeal 2011-011972 Application 11/483,951 7 sld