Appeal No. 1998-2422
Application 08/488,380
Appellant argues that the suitability of Keogh for
alignment of PCB layers does not make that system suitable for
lithography tool alignment in semiconductor manufacture
because the alignment tolerances required for semiconductor
manufacture are at least two orders of magnitude smaller than
for multi-layer PCB fabrication (Br4).
The Examiner does not respond to this argument.
Nevertheless, we are not persuaded by the argument because
Appellant provides no reason why one of ordinary skill in the
art would not have considered it obvious to scale the coils in
Keogh down to the appropriate size for positioning of a
lithography tool. Since there is no difference between the
coils and detection system of Keogh and the claimed invention
other than the size needed for the appropriate positioning
accuracy, we do not see how the teachings of Keogh can be
considered inappropriate for a lithographic positioning tool.
Appellant argues that because small coils are required
for semiconductor manufacture, the lithographic tool must be
in intimate contact with the wafer and the coils on the wafer,
and that conventional prior art lithographic tools require
high vacuum pressure to achieve intimate contact which does
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