Appeal No. 1999-2347
Application 08/892,560
Although not expressly (or, at least, not clearly) stated in the
rejection, it is apparently the Examiner's position is that with
these three material layers, the negative limitation of "without
forming non-conductive back-sputtered compounds on sidewalls of
said via" would be inherently met because no back-sputtering is
mentioned. Appellants' position is that none of the references
suggest overcoming the problem of metal sputtering during oxide
via etching and, so, do not suggest the negative limitation of
"without forming non-conductive back-sputtered compounds on
sidewalls of said via" even if combined as suggested by the
Examiner.
The basic flaw in Appellants' arguments is the failure to
recognize that Erie expressly discloses that the barrier layer 18
(etch stop layer) must be kept thin to allow it to be removed
rapidly before the aluminum metallization interconnect is etched
to avoid sputtering of aluminum oxide (col. 2, line 65 to col. 3,
line 8). Thus, Erie specifically discusses etching to avoid the
problem of sputtering of the metal layer.
Appellants argue (Br13-14) that the Ti xOy dielectric barrier
in Erie is used to "permit rapid removal ... in this region
without substantial effect on an underlying dielectric layer"
(col. 2, lines 62-64) and "[t]hus, Erie et al. does not recognize
the problem of metal sputtering during oxide via etching" (Br14).
However, Appellants refer to the paragraph in Erie before the
- 18 -
Page: Previous 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Next
Last modified: November 3, 2007