Appeal 2007-1394
Application 10/301,464
Appellants’ invention is directed to a chemical mechanical polishing
(CMP) polisher wafer pedestal (chuck) comprising a plate and a non-
adhesive edge contact ring connected to the plate. According to Appellants,
reducing the contact between a wafer pedestal and the active dies of a wafer
to be held thereon can be accomplished via the disposition of an edge
contact ring on a top plate shaped surface of the pedestal (Specification 1-4).
A prior art film that allegedly covered a larger portion of the top plate
surface of a pedestal is acknowledged to be known in the art (Specification
1-3, Figs. 1-2). However, Appellants’ invention is said to reduce
contamination of the wafer surface with potentially contaminating film
materials; that is, particles shed by such a film material (Specification 3-4).
The provision of an edge contact ring with a specified maximum width is
disclosed as one embodiment or part of an embodiment of reduced contact
pedestal covering(s) that provide wafer support without the edge ring
contacting the active die of the wafer (Specification 5, Figs. 5 and 6). The
edge ring can be made from the same material as the prior art plate film
covering (id.). Claims 5 and 15 are illustrative and reproduced below:
5. A wafer pedestal of a CMP polisher comprising:
a plate having ports for providing deionized water and a vacuum, said
plate located in said CMP polisher;
a non-adhesive edge-contact ring connected to said plate, said non-
adhesive edge-contact ring also coupled to a face down wafer substantially
in areas of said wafer not containing full active die.
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