USOO7780793B2 (12) United States Patent (10) Patent No.: US 7,780,793 B2 Yang et al. (45) Date of Patent: Aug. 24, 2010 (54) PASSIVATION LAYER FORMATION BY (56) References Cited PLASMA CLEAN PROCESS TO REDUCE U.S. PATENT DOCUMENTS NATIVE OXDE GROWTH 4,209,357 A 6, 1980 Gorin et al. (75) Inventors: Haichun Yang, Santa Clara, CA (US); (Continued) Xinliang Lu, Fremont, CA (US); Chien-Teh Kao, Sunnyvale, CA (US); FOREIGN PATENT DOCUMENTS Mei Chang, Saratoga, CA (US) CN 13755.75 10, 2002 (73) Assignee: Applied Materials, Inc., Santa Clara, (Continued) CA (US) OTHER PUBLICATIONS PCT International Search Report and Written Opinion dated Jun. 23. (*) Notice: Subject to any disclaimer, the term of this 2009 for International Application No. PCT/US2008/087436. patent is extended or adjusted under 35 (Continued) U.S.C. 154(b) by 140 days. Primary Examiner Michael Kornakov (21) Appl. No.: 11/962,791 Assistant Examiner—Ryan Coleman (74) Attorney, Agent, or Firm Patterson & Sheridan, LLP (22) Filed: Dec. 21, 2007 (57) ABSTRACT (65) Prior Publication Data Embodiments described herein provide methods for remov US 2008/O160210 A1 Jul. 3, 2008 ing native oxide Surfaces on Substrates while simultaneously passivating the underlying Substrate Surface. In one embodi Related U.S. Application Data ment, a method is provided which includes positioning a Substrate containing an oxide layer within a processing cham (60) Continuation-in-part of applic at1On No. 11 /622.437, ber, adjusting a first temperature of the substrate to about 80° filed on Jan. 11, 2007, which is a continuation-in-part C. or less, generating a cleaning plasma from a gas mixture of application No. 1 1/137,609, filed on May 24, 2005, within the processing chamber, Such that the gas mixture now Pat. No. 7,396,480, which is a division of appli- contains ammonia and nitrogen trifluoride having an NH/ cation No. 117063,645, filed on Feb. 22, 2005. NF molar ratio of about 10 or greater, and condensing the (60) Provisional application No. 60/547,839, filed on Feb. cleaning plasma onto the substrate. A thin film, containing ammonium hexafluorosilicate, is formed in part, from the 26, 2004. native oxide during a plasma clean process. The method further includes heating the Substrate to a second temperature (51) Int. Cl. of about 100° C. or greater within the processing chamber BOSB 6/00 (2006.01) while removing the thin film from the substrate and forming (52) U.S. Cl. ............................. 134/1.2: 134/19; 134/31 a passivation Surface thereon. (58) Field of Classification Search ....................... 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