Appeal No. 2005-0585
Application No. 09/821,478
Ma’s teachings to suggest divergent subject matter. Answer,
page 10.
The examiner states that Horak deals with the same problems
as Tao and Ma: etching nested and isolated lines on
semiconductor devices (col. 2, lines 51-65). The examiner
states that Horak teaches the basic phenomenon of etching bias
in Tao’s plasma etching (col. 1, lines 34-54) as well as Ma’s
RIE-etching (col. 1, lines 55-col.2, line 20). The examiner
states that Horak uses Ma’s O-RIE etching to trim the etch masks
prior to etching the underlying polysilicon layer (col. 3, lines
11-15). The examiner states that the space charge effect is
mitigated by adjusting the “etching” and “sputtering” species in
the gases (col. 3, lines 20-27). The examiner states that this
is the same technique used in the instant invention. The
examiner notes further that Horak teaches the equivalence of
metal conductor etching and polysilicon etching to control gate
CD using O-RIE (col. 8, lines 44-50). Answer, pages 10-11.
The examiner also states that appellant argues (instant
brief: p.8) that Ma teaches “avoiding microloading” (col. 3,
lines 10-28), while Horak teaches “compensating for subsequent
normal etching process to prevent a nested/isolated offset-
effect” (col. 6, lines 49-col. 7, line 2), and thus, the two
references are incompatible. The examiner disagrees for the
following reasons.
The examiner states that Ma solves the problem of
nested/isolated offset in etching a conductor layer using a
photoresist mask. The examiner states that Ma does so by
adjusting the RF power and frequency such that the sputtering
phenomenon and etching phenomenon are balanced (“space charge
effect”). This leads to little or no re-deposition of the
photoresist (“profile microloading”) during the conductor etch.
10
Page: Previous 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Next
Last modified: November 3, 2007