Appeal No. 2001-2544
Application No. 08/995,108
The Rejection of Claims 8-17 Under 35 U.S.C. § 103(a)
The examiner has found that Gelatos teaches a method of
producing a barrier layer for the subsequent overlay of a
conductive layer which includes the deposition (via sputtering)
of a first layer of TiNx followed by a second layer of Ti, both
layers being 100-300 Å. A copper conductive layer is deposited
while keeping the temperature at 190°C. (Examiner’s Answer, page
3, lines 4-17).
The examiner further has found that Gelatos suggests the use
of Ta for the nitride, and that Landers teaches the use of a
Ta/TaN or Ti/TiN as barrier layers. The examiner thus concludes
that it would have been obvious to employ Ta and its
corresponding nitride in the barrier layer of Gelatos as they are
equivalents. (Examiner’s Answer, page 4, lines 1-14).
Our review of Gelatos reveals that it is quite explicit in
teaching an interface layer between copper and the underlying
semiconductor substrate preferably including a titanium sputtered
onto the dielectric to a thickness of 100-300 angstroms, followed
by a titanium nitride sputtering at a thickness of 300-500
angstroms, followed by a titanium sputtering at a thickness of
about 100-300 angstroms. Copper is then deposited thereon. (See
column 3, line 39-column 4, line 38). The copper is preferably
deposited using a cold wall deposition system maintained at a
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