Appeal No. 1998-0129 Page 23
Application No. 08/438,062
(page 2) that
As indicated in Figure 1, it appears, however,
that barium strontium titanate . . . could
overcome many of these problems and easily satisfy
the requirements for the next generation of ULSI
DRAM’S. Rather high dielectric constant values have
been reported . . . and several companies have already
begun evaluation of various thin-film deposition
techniques for prototype production.
and that (page 7)
We have shown that very good . . . barium strontium
titanate films can be deposited via LSCVD. We have
now achieved sufficient success with this method of
deposition for complex films on four inch
wafers to
warrant construction of a new LSCVD machine for six
inch wafers.
From these teachings we find that McMillan has recognized the
problem of significant roll-off of dielectric constant at high
frequencies when using well-known high dielectric material
such as PZT. In addition, McMillan’s solution was to replace
PZT with BST to overcome many of the problems associated with
PZT. Moreover, McMillan teaches (Figure 5) that in typical
processing parameters for BST, the films were annealed at
temperatures greater than 550EC.
Appellants note (reply brief, page 6) that the examiner
(answer, page 10) has relied upon Koyama for a teaching of
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