Appeal No. 2005-1108
Application No. 10/442,900
Zhang’s teachings, a result which clearly would be untenable.4
Decreasing the thickness of the plate/blank ostensibly would
weaken same and surely reduce its useful life due to wear. As
pointed out by the appellants, Zhang evidences no appreciation of
the problem solved by the claimed provision of an insert having a
thickness at least about 20 microns greater than the thickness of
the plate, namely: to inhibit removal of contaminating material
from the plate and any resulting contamination of the wafer.
Indeed, Zhang’s allowance that the inserts need not be replaced
until they are slightly thinner than the plate would exacerbate
this problem even while solving the particular wafer quality
problem addressed by the reference. Given the totality of these
circumstances, it is apparent that the only suggestion for
modifying Zhang’s wafer carrier such that the thickness of the
insert is at least about 20 microns greater than the thickness of
the plate as recited in independent claims 1 and 20 stems from
hindsight knowledge impermissibly gleaned from the appellants’
disclosure.
4 Zhang explains with respect to a prior art ring R (see
Figure 7), which corresponds to the inserts 39, that the ring
must be “slightly thinner than the wafer, so that the pads of the
polishing machine will contact substantially the entirety of both
sides of the wafer” (column 1, lines 22 through 24).
6
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