Appeal No. 2005-2351
Application No. 09/904,112
a second tantalum oxide film by a CVD method; and (d) performing
a second heat treatment on the second tantalum oxide film (col.
5, ll. 31-38). These heat treatments are carried out at a high
temperature in an oxidation atmosphere (col. 5, ll. 58-59). The
lower electrode 54 may be made from a ruthenium film (col. 18,
ll. 22-24). This ruthenium film is oxidized during the heat
treatment of the tantalum oxide insulating film to form ruthenium
oxide (col. 20, l. 66-col. 21, l. 2). Therefore, contrary to
appellants’ arguments, there is no need for “choosing” ruthenium
as the electrode material since the use of a ruthenium film as
the lower electrode 54 is clearly described by Kunitomo.
Furthermore, as conceded by appellants (Brief, page 7; Answer,
page 9), if ruthenium is used as the lower electrode, the lower
electrode will be oxidized during the heat treatment of the
tantalum oxide insulating film. We note that Kunitomo only
teaches restricting further oxidation during crystallization of
the tantalum oxide films when ruthenium oxide is formed as the
lower electrode 54 since these lower electrodes have already been
oxidized (col. 21, ll. 23-30).
As correctly argued by appellants (Brief, page 7; Reply
Brief, page 2), Kunitomo does not explicitly describe that the
oxidation of the lower electrode and first layer of high
6
Page: Previous 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Next
Last modified: November 3, 2007