| 主权项 |
1. An exposure apparatus that irradiates a pattern formed on an original plate with light emitted from an illumination system to thereby expose an image of the pattern on a substrate via a projection optical system, the exposure apparatus comprising:
a light shielding plate that is arranged on a plane conjugate to a substrate plane serving as an object plane of the projection optical system in the illumination system, includes a circular-arc overlapping a circular borderline, which defines a region whereupon the image on the substrate is formed, on an inner side of an outer periphery of the substrate at an edge, and shields against light to prevent the light from entering an outer peripheral region outside the circular borderline on the substrate; a first driving unit that rotationally drives the light shielding plate about an axis parallel to an optical axis of the illumination system; a second driving unit that linearly drives the light shielding plate within a plane perpendicular to the optical axis; a detecting unit that detects a light-shielding position at which light is shielded by the light shielding plate; and a control unit that stores a light-shielding position at reference time point and light-shielding positions prior to and after change of the light shielding plate when the light shielding plate is changed after the reference time point, and calculates a variation amount of the light-shielding position based on a light-shielding position detected by the detecting unit at any time point after the light shielding plate is changed, a light-shielding position at the reference time point, and the difference between light-shielding positions before and after the light shielding plate is changed. |
