Appeal No. 95-3455
Application 07/945,902
dichlorosilane instead of silane for reducing tungsten
hexafluoride. Koyama et al. also recognize improvement in the
life of the tunnel oxide by using dichlorosilane, an
improvement attributed to lower fluorine concentration.
From all of the above-noted, art recognized advantages,
there would have been ample motivation to have used
dichlorosilane in place of silane for reducing tungsten
hexafluoride to prepare a tungsten silicide layer in a
floating gate electrode. We realize that not every reference
on which we have relied uses dichlorosilane for the same
purpose that appellants use dichlorosilane. Nonetheless, each
reference relied on does teach that dichlorosilane reduces
tungsten hexafluoride to tungsten silicide. It is by now
well-settled that all that is required to establish a prima
facie case of obviousness is some motivation in the prior art
to do what
appellants have done, coupled with a reasonable expectation of
success.
We are satisfied that the skilled chemical engineer,
versed in the art of semiconductor manufacture, would have
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