Projection exposure apparatus and method having a positional deviation

Abstract

A projection exposure apparatus includes an illumination optical system for illuminating a plurality of partial areas on a mask. A plurality of projection optical systems each project images of the partial areas thus illuminated onto a photosensitive substrate. A mask table holds the mask. A position detector detects a position of the mask table. A substrate table holds the photosensitive substrate. A plurality of first reference marks are provided on the mask table; each of the plurality of first reference marks are disposed at a position corresponding to each of the plurality of projection optical systems. A plurality of second reference marks are provided on the substrate table; the second reference marks are substantially conjugate with the first reference marks with respect to the projection optical systems and are in a predetermined positional relation with the first reference marks in in-plane directions of the mask and the photosensitive substrate. A positional deviation detector detects positional deviations between the first reference marks and second reference marks when light beams from the illumination optical system are radiated onto the plurality of first reference marks to project the plurality of first reference marks through the projection optical systems onto the plurality of second reference marks. A correcting device corrects imaging characteristics of the projection optical systems, based on the positional deviations. The first reference marks can comprise a single aperture of a plurality of apertures. A reverse-type aperture may be employed. The positional deviation detector may include a single photodetector or a plurality of photodetectors.