Appeal No. 2005-0123
Application No. 10/114,759
specifically for depositing aluminum by traditional PVD
processes, not for electroplating copper.
We note that Xu does disclose (column 27, lines 55-59) that
copper may be substituted for the aluminum, and that the copper
is "subject to the same limitations as Al contacts and
interconnects, and thus can enjoy similar benefits of the
invention." Further, claim 59 of Xu suggests forming three
sublayers of a refractory metal (tantalum), a refractory metal
nitride (tantalum nitride), and a third sublayer with a pure
metal (tantalum) at the top surface prior to depositing copper.
However, claim 59 also indicates that the copper is formed by
sputtering. Therefore, Xu's teachings appear to be limited to
using a pure metal sublayer under the metal interconnect only
when the metal interconnect is sputter deposited.
Simpson suggests (column 4, lines 6-12) that a conductive
seed layer is necessary under electroplated copper. However, as
Simpson indicates that the seed layer may be titanium, tantalum,
titanium nitride, or tantalum nitride, Simpson fails to provide
adequate motivation for forming a pure metal sublayer under the
copper if the copper is electroplated rather than sputter
deposited. Therefore, we cannot sustain the obviousness
rejection of claims 1 through 10 as presented by the examiner.
6
Page: Previous 1 2 3 4 5 6 7 8 9 10 11 12 Next
Last modified: November 3, 2007