Wavefront aberration measurement method and projection exposure apparatus

摘要

The vicinity of an imaging position where the image of a pattern is formed via a projection optical system has another pattern. A projection exposure apparatus uses a light intensity distribution measurement unit for measuring the light intensity distribution of an image formed by a beam having passed through a phase shift pattern different from the pattern. The wavefront aberration of the projection optical system is calculated from changes in light intensity distribution obtained by the light intensity distribution measurement unit in synchronism with scan when the phase shift pattern is scanned in one or a plurality of directions perpendicular to the optical axis of the projection optical system.