Appeal 2006-2870
Application 10/401,509
appeal. In particular, the Examiner contends that, although Appellants
disclose that overlay is one lithography process parameter to be measured
and, further, that various optical techniques are known for measuring the
lithography process parameters, there is no disclosure of the detection and
analysis of diffraction efficiency to determine lateral shift between device
layers as claimed.
Appellants’ arguments in response (Br. 7) initially direct attention to
that portion of the Specification (10:18 through 11:7) which discusses
various optical techniques for measuring properties of a resist, one of which
optical techniques being, but not limited to, scatterometry. Appellants’
arguments further make reference to the Raymond reference (Handbook of
Silicon Semiconductor Metrology, page 480) which, in Appellants’ view,
discloses that scatterometry, when used to measure periodic features such as
those in determining overlay, can be termed diffractometry or diffraction
reflectometry.
It is our view, however, that, to whatever extent Appellants are
arguing that Raymond supports the position that scatterometry necessarily
means that diffraction efficiency is measured, we do not find such arguments
to be persuasive. In the first instance, there is no evidence presented from
Appellants that would support the conclusion that measuring diffraction is
equivalent to measuring diffraction efficiency. Secondly, we agree with the
Examiner (Answer 4) that Raymond, at best, merely discloses that
scatterometry may be used to measure diffraction efficiency, not that
scatterometry necessarily requires the measurement of diffraction efficiency,
let alone that detection and analysis of diffraction efficiency is required
when measuring overlay as claimed.
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Last modified: September 9, 2013