Appeal No. 2005-1108
Application No. 10/442,900
inserts 39 mounted in the openings for holding respective wafers
W. The inserts act as buffers between the wafers and the blank
to protect the edges of the wafers from damage. Under repeated
processing operations, the plastic inserts, which are softer than
the metal blank, will gradually wear away until they reach a
minimum thickness at which the quality of the processed wafers
will suffer. To combat this problem, Zhang provides for the
inserts to be removably mounted in the blank to allow them to be
replaced when necessary. Zhang teaches that the preferred
thickness of a new insert is about 1 to 2 microns thinner than
the “target” or end thickness of a polished wafer (see column 4,
lines 35 through 37), that the preferred thickness of the blank
is about 10 microns less than the thickness of a new insert (see
column 4, lines 44 and 45), and that the inserts should be
replaced after they are worn to a minimum thickness of about 10-
15 microns less than the “target” thickness of the wafer (see
column 5, lines 23 through 26).
As framed and argued by the appellants, the dispositive
issue in the appeal is whether Zhang would have rendered obvious
a wafer carrier responding to the limitation in independent claim
1, and the corresponding limitation in independent claim 20,
requiring the thickness of the insert to be at least about 20
4
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