Appeal No. 2003-0242 Page 7
Application No. 09/484,604
On page 9 of the answer, the examiner asserts that Sandhu teaches a means of
measuring the surface friction "equivalent" to that of Birang, thus implying that it would
have been obvious at the time the invention was made to a person of ordinary skill in
the art to have substituted Sandhu's means of measuring the surface friction for
Birang's means of measuring the surface friction. We do not agree that Sandhu
teaches a means of measuring the surface friction "equivalent" to that of Birang. In that
regard, Sandhu teaches a means of measuring the surface friction which relies on a
change in the coefficient of friction between the wafer 10, polishing slurry 18, and
polishing platen 16 to change the load or amperage draw of the drive motors 26, 28.
Specifically, as the oxide coating of a wafer 10, as shown in Figure 1 of Sandhu, is
removed to the plane of the tops of the IC devices the coefficient of friction will change
and that change is detected by a different amperage draw of the current meters 22, 24.
Since no such "equivalent" change occurs in the conditioning process of Birang (i.e.,
neither the conditioning head 12 nor the polishing pad 14 undergoes an abrupt change
in the coefficient of friction as when the oxide coating of a wafer 10 is removed to the
plane of the tops of IC devices as in Sandhu), there is no suggestion, incentive or
motivation in the applied prior art to combine the teachings thereof to arrive at the
claimed invention. The mere fact that the prior art could be modified in the manner
suggested by the examiner does not make such a modification obvious unless the prior
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