Patent ID: 6727978
Filing Date: 2004-04-27
Classification: G03F

Abstract:
A projection exposure apparatus for exposing a photosensitive substrate with a pattern formed on a circular mask having a rectangular pattern area by projection through a projection optical system, comprising:an illumination optical system for illuminating the circular mask; a mask stage; a stage for moving the photosensitive substrate two-dimensionally; a prealignment stage for pre-aligning the circular mask for its orientation, the prealignment stage comprising a detecting means for detecting an orientational error of the circular mask from a predetermined orientation on the prealignment stage, a rotatable means for rotating the circular mask on the prealignment stage, and a control means for controlling the rotatable means on the basis of the orientational error so that the circular mask has the predetermined orientation; and a transport means for transporting the circular mask from the prealignment stage to the mask stage while maintaining a pre-aligned orientation of the circular mask.