Abstract: Positional discrepancies of images of segmental areas, which are caused by stretching of a substrate in the Y direction, are corrected by changing magnifications of respective projection optical systems and inclinations of parallel plane glass pieces with respect optical axes. After that, positional discrepancies of the images after the correction are accurately detected by using a calibration system for the projection optical systems. Thus it is possible to confirm whether or not the positional discrepancies are accurately corrected. If the correction is insufficient as a result of the confirmation, at least one of correction of the magnifications of the respective projection optical systems and shift of the images projected through the respective projection optical systems onto the substrate is executed again so that amounts of the positional discrepancies are sufficiently small.

Abstract: To improve the focus accuracy during alignment and to improve the alignment accuracy even if a substrate has warpage, during alignment, an approximate focus plane is obtained by using only the detection results at focus points of focus sensors located near the ends of a substrate, close to alignment points, and without using the detection results at focus points of two central focus sensors. The auto-focus operation is performed by using the above operation results. As a result, a substrate is driven so as to be adjusted to the approximate focus plane during alignment.