Appeal 2007-2285
Application 10/871,151
Section 103 in view of the applied prior art. Since the difference between the
claims presently on appeal and those before the Board in the prior appeal
does not affect the reasoning set forth in the prior Board decision, we will
sustain the Examiner's rejection.
We appreciate that Fillipiak does not expressly teach the presence of a
layer of tantalum nitride between the tantalum and copper layers, but we
remain of the opinion that "Xu evidences the obviousness of employing a
tantalum nitride layer between the tantalum and copper layers of Fillipiak for
the purpose of providing the benefits taught by Xu, e.g., resistance to
electrode migration" (sentence bridging pages 8-9 of prior decision). Also,
as explained by the Examiner, "it would have been obvious to modify the
interconnect structure of Fillipiak by forming a TaN layer between the
tantalum layer 106 and the copper base layer 108, because as taught by Xu,
such TaN would provide highly [sic, high] conductivity, and highly smooth
surface (col. 28, ll. 6-11)"(Answer 4, first para., last sentence).
We find no merit in Appellants' argument that Xu actually states that
TiN provides good conductivity and a highly smooth surface, and that "the
qualities of 'good conductivity' and a 'smooth surface' are properties of TiN,
not TaN" (Principal Br. 12, first para.). According to Appellants, the cited
art does "not suggest that it is desirable to a TaN layer for the purpose of
providing a smooth surface and high conductivity" (id.)[sic]. We fully
concur with the Examiner that one of ordinary skill in the art would have
reasonably expected that the advantages specifically associated with TiN
would have transferred to the compound that Xu teaches is a viable
substitute when copper is used as the interconnect metal, namely, TaN (see
3
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