Appeal No. 1996-2284
Application No. 08/228,889
consideration by a Group Director (MPEP § 1002.02(c), para.
3a) (7th ed. July 1998) rather than an appealable matter for
consideration by this board.
The invention
The invention relates to the correction of alignment
errors occurring within the lens portion of a lithographic
system as a result of environmental changes, such as changes
in temperature or atmospheric pressure. In contrast to prior
art systems which correct alignment errors between reference
marks on a reticle and reference marks on a wafer, the
disclosed invention corrects errors in the positions of the
reticle reference marks in the output image of the lens
without regard to the positions of any reference marks on a
wafer. Referring to Figure 1 as filed, this is accomplished
with the use of folding mirrors (65, 67) and detectors (59,
61), which are attached by mounting brackets 63 to a metrology
plate 49 that is "mounted on the lens system itself, slightly
below it" (Specification as filed at 3, lines 24-25). By
means of an "Amendment after Final Rejection" received
3
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