| US 7,495,780 B2 | ||
| Position measurement apparatus, imaging apparatus, exposure apparatus, and Device manufacturing method | ||
| Nozomu Hayashi, Utsunomiya (Japan) | ||
| Assigned to Canon Kabushiki Kaisha, Tokyo (Japan) | ||
| Filed on Nov. 15, 2007, as Appl. No. 11/940,975. | ||
| Claims priority of application No. 2006-341055 (JP), filed on Dec. 19, 2006. | ||
| Prior Publication US 2008/0144047 A1, Jun. 19, 2008 | ||
| Int. Cl. G01B 11/14 (2006.01); G01B 11/00 (2006.01) | ||
| U.S. Cl. 356—620 [356/614; 356/400; 356/401] | 2 Claims |
| 1. An exposure apparatus that performs a relative alignment between a reticle and a substrate and exposes a pattern of the
reticle onto the substrate, the exposure apparatus comprising:
a movable stage that carries one of the reticle and the substrate; and
a position measurement apparatus that measures a position of at least one of the reticle and the substrate, the position measurement
apparatus including,
an illumination unit configured to emit light toward a mark that indicates the position of the reticle or the substrate;
a light intensity measurement unit configured to measure an intensity of the light;
an imaging unit configured to capture an image of the mark;
a stage position measurement unit configured to measure a position of the stage; and
a signal waveform correction unit configured to correct a signal waveform output from the imaging unit based on a change in
stage position and a change in illumination light intensity during a period of time the imaging unit captures the image of
the mark.
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