Appeal No. 2002-1757
Application No. 09/994,894
an oxidizing agent having a [sic, an] oxidation potential
greater than Ce4+; and
at least one nitrate salt.
The references relied upon by the examiner as evidence of
obviousness are:
Farkas et al. (Farkas) 5,773,364 Jun. 30, 1998
(filed Oct. 21, 1996)
Kaufman et al. (Kaufman) 5,783,489 Jul. 21, 1998
(filed Sep. 24, 1996)
All of the appealed claims are rejected under 35 U.S.C.
§ 103(a) as being unpatentable over Kaufman and Farkas. In the
paragraph bridging the third and fourth pages of the answer, the
examiner’s position is expressed as follows:
Kaufman teaches a CMP slurry whose abrasive
includes zirconia, silica, ceria, alumina and mixture
thereof. The metal oxide abrasive is formed into a
colloidal dispersion. [T]he colloidal cerium would
naturally includes of [sic] dissolved Ce3+ (as also
described in page 9, line 18 of specification). His
slurry also includes ammonium persulfate of 4 w% in
examples 1-3, which would be an oxidizing agent having
an oxidation potential greater than Ce4+ (col. 3, line
20; col. 5, line[s] 55-68; claim 7). Unlike claimed
invention, Kaufman doesn’t describe the slurry having
0.05-10wt% of soluble cerium. Farkas describes a
slurry composition having one or more oxidizing/etching
species such as ammonium nitrate, ammonium cerium
nitrate, and ammonium cerium sulfate. The ammonium
cerium sulfate and ammonium cerium nitrate (nitrate
salt) would produce soluble cerium including Ce3+, Ce4+
(col. 3, line[s] 19-25; col. 4, line 3). It would have
been obvious at the time of the invention for one skill
in the art to modify Kaufman’s slurry in light of
Farkas because Farkas teaches that one or more
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