Appeal 2007-4189
Application 10/164,986
202 USPQ 171, 174 (CCPA 1979). In the present case, the claimed
invention and the invention of the AAPA are directed to semiconductor etch
chamber equipment that employs shadow masks. Flach and Clark are
directed to the construction industry. Thus, Flach and Clark are not in the
same field of endeavor as the claimed invention and the AAPA.
Thus, we must now determine whether Flach and Clark are reasonably
pertinent to the particular problem to be solved. The issue turns on whether
Flach and Clark describe materials that would be suitable for use in
semiconductor etch chamber equipment.
The Specification describes the semiconductor fabrication equipment
that utilizes a shadow ring as follows:
In an etch chamber equipped with a plasma generating
device and an E-chuck, a shadow ring may be utilized as a seal
around the peripheral edge of the wafer. The shadow ring, also
known as a focus ring, is utilized for achieving a more uniform
plasma distribution over the entire surface of the wafer and for
restricting the distribution of the plasma cloud to only the wafer
surface area. The uniform distribution function may be further
enhanced by a RF bias voltage applied on the wafer during a
plasma etching process. Another function served by the
shadow ring is sealing at the wafer level the upper compartment
of the etch chamber which contains the plasma from the lower
compartment of the etch chamber which contains various
mechanical components for controlling the E-chuck. This is
important since it prevents the plasma from attacking the
hardware components contained in the lower compartment of
the etch chamber. In order to survive high temperature and
hostile environments, a shadow ring is frequently constructed of
a ceramic material such as quartz.
(Specification 3-4).
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