Appeal No. 1996-2284
Application No. 08/228,889
Supplemental Answer. Consequently, we are reversing the
rejection of claims
2-4 based on Mitome.
The rejection based on Kosugi and Sakamoto
Kosugi's system corrects any detected misalignment
between two alignment marks on the reticle and two
corresponding alignment marks on the wafer by adjusting the
position of the wafer. The alignment marks on the reticle are
cross-shaped transparent areas 32 (Fig. 3B). Light projected
through these areas produces cross-shaped latent images in
corresponding light-sensitive alignment areas 35 (Fig. 6A) on
the wafer. Figure 1 shows an alignment optical system C,
including a movable mirror 27 and an image pickup tube 29, for
detecting the position of the latent image within one of the
two wafer alignment areas 35. Mirror 27 is in the solid-line
position during formation of the latent images and in the
dashed-line position during scanning of the latent image by
image pickup tube 29 (col. 7, lines 32-45). Kosugi explains
that a second optical alignment system C (not shown) is
required to detect the position of the latent image in the
other of the two wafer alignment areas 35 (col. 5, lines
12
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