Appeal No. 2003-1556
Application 09/288,932
structure as claimed, however, includes a removable spacer layer
which is “adapted to be completely removed when isotropically
etched.” Hence, the ability of the removable spacer layer to be
completely removed when isotropically etched is a capability
requirement of part of the claimed semiconductor structure.
The examiner considers Kobayashi’s second insulator
layer (26) to correspond to the appellant’s removable spacer
layer (answer, pages 3-4). The examiner argues that one of
ordinary skill in the art would have been led to replace
Kobayashi’s second insulator layer with Cathey’s removable spacer
layer (21) (col. 4, line 63 - col. 5, line 2; col. 5, lines 9-13)
so that the layer could be removed without significantly etching
the first insulator layer (24) and enlarging the size of a buried
contact opening between adjacent word lines (answer, page 4).
Kobayashi, however, does not indicate that any of the first
insulator layer is removed when the desired portion of the second
insulator layer is etched away. In fact, Kobayashi shows that
after the second insulator layer has been etched, the first
insulator layer remains almost completely covered by the second
insulator layer (figure 2D). Moreover, Kobayashi leaves a
portion of the second insulator layer in place to surround or
confine the contact hole (col. 4, lines 5-14; figure 2G). For
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