Appeal No. 96-1848
Application 08/161,604
three layers extend around the tungsten plug since the plug
is defined through all three layers. Haskell does not meet
this limitation because the silicon nitride layer 28b
corresponding to the "sealing layer" is removed during
manufacture. The deficiency of Haskell is not cured by
Deleonibus. We give no weight to the process-type
limitation "etched" because it has not been argued or shown
that this limitation produces a different final structure.
For these reasons, we conclude that the examiner has failed
to establish a prima facie case of obviousness with respect
to claim 26. The deficiency of Haskell and Deleonibus with
respect to claim 26 is not cured by Shirai, as applied in
the rejection of dependent claim 29. The rejection of
claims 26-30 is reversed.
Claims 29 and 33: Haskell, Deleonibus, and Shirai
The rejection of claim 29 has been reversed.
Haskell discloses a silicon nitride layer of about 800
Angstroms ± 5% (col. 5, lines 10-13), but indicates that
"[t]he minimum and maximum thickness depend on the etch
uniformity of the process and apparatus" (col. 5,
lines 15-17). The examiner applies Shirai, which teaches
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