Appeal No. 2006-0293
Application No. 10/071,809
Representative independent claim 1 is reproduced below:
1. A method comprising, etching a metal silicide layer during fabrication of an
integrated circuit in a Cl2/02 environment having an 02 concentration of greater than or
equal to 25% by volume,
wherein the Cl2/02, environment is provided at a pressure of approximately 2-40
mili-Torr, and wherein the etching is a metal silicide etch that is selective to poly-silicon
with a ratio of etch rates of at least 30.
The examiner has relied upon the following references as evidence of
obviousness:
Tsai 5,880,033 Mar. 09, 1999
Langley et al. (Langley), “One-Chamber Polycide Sandwich Etching,” Semiconductor
International, pp. 95-97, October 1989.
Appellant relies upon the following reference as evidence of non-obviousness:
Nojiri et al. (Nojiri), J. Vac. Sci. Technol., B14(3), May/June 1996, pp. 1791-1795.
Claims 1, 3-12, 14, 15, 21 and 27 stand rejected under
35 U.S.C. § 103(a) as unpatentable over Tsai (Answer, page 3). Claims 22, 23 and 25
stand rejected under 35 U.S.C. § 103(a) as unpatentable over Tsai in view of Langley
(Answer, page 4). We reverse both rejections on appeal essentially for the reasons
stated in the Brief and those reasons set forth below. Pursuant to our authority under
37 CFR § 41.50(a)(1)(2004), we also remand this application to the examiner for action
consistent with our remarks below.
OPINION
2
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