Appeal No. 1998-0242
Application No. 08/295,593
made of a material selected from the group consisting
of Al O , MgO, ZrO , SiC and Si N , and being capable of2 3 2 3 4
withstanding hot-pressing at a temperature of at least
1100ºC;
whereby said barrier sleeve substantially prevents
a reducing gas from penetrating to the powdered metal
oxide target starting material, said barrier sleeve
being substantially unreactive with the powdered target
starting material during hot pressing, and said
powdered target starting material being volatile and
thermally unstable during hot pressing.
The examiner relies upon the following references as
evidence of obviousness:
Brierley 2,886,849 May 19, 1959
Weigert1 DE 41 24 471 C1 Jun. 24, 1991
Appellants’ claimed invention is directed to an apparatus
and process for making metal oxide sputtering targets. The
apparatus comprises a graphite die assembly and a barrier sleeve
which lines the graphite die assembly die cavity. The barrier
sleeve is made of a material selected from a Markush group that
includes Al O . According to appellants, “[t]he purpose of the2 3
barrier sleeve is to substantially prevent a reducing gas from
penetrating to the powdered metal oxide starting material” (page
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