Appeal No. 2006-0291
Application No. 09/820,692
pages 4 and 6. We determine that the use of a MERIE plasma reactor is not an
essential component of the Liu process. We also determine that Schmitt is directed to
etching various materials. Finally, we determine that the examiner is not proposing that
the quartz gas distribution plate of Liu be replaced by the showerhead electrode of the
reactor of Schmitt (Answer, pages 4 and 6). Our reasoning follows. Liu
discloses that prior etching processes have been developed on the IPS Etch Reactor,
which is a high density plasma reactor (col. 3, ll. 50-57). Liu teaches that a desire exists
for performing oxide etching in more conventional capacitively coupled plasma etch
reactors producing a lower plasma density, of which the MERIE reactor is an example
(col. 3, l. 62-col. 4, l. 7; col. 6, ll. 9-17). It is well settled that a reference is not limited to
its examples. See In re Widmer, 353 F.2d 752, 757, 147 USPQ 518, 523 (CCPA 1965).
Accordingly, we determine that Liu is not limited to a MERIE reactor, nor is this reactor
an “essential” part of the Liu invention. As correctly found by the examiner, Schmitt is
directed to the use of a dual frequency capacitively coupled plasma reactor useful for
etching “various materials” (Answer, page 6, citing Schmitt, col. 1, ll. 1-40). From these
findings, we determine that it would have been obvious to one of ordinary skill in this art
at the time of appellants’ invention to use well known capacitively coupled etch plasma
reactors, such as the dual frequency capacitively coupled plasma reactor of Schmitt, to
form the plasma in the process of Liu. This conclusion is further supported since Liu
exemplifies a processing region 72 with “a showerhead having a large number of
distributed apertures 76 so as to inject a more uniform flow of processing gas into the
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