Patent Number: 
Section: abstract

In a projection exposure apparatus used in lithography process for transferring a predetermined pattern formed on a reflection type mask onto a photosensitive substrate, the reflection mask and the substrate are moved relative to each other by a scanning driver, and the illumination optical system located between a radiation light source and the reflection mask includes a field stop located near a position conjugate with the reflection mask. In another embodiment a scanning driver changes the positional relationship between the reflection mask and the projection optical system, or/and between the substrate and the projection optical system. In another embodiment an image of the field stop is formed on the reflection mask by a relay optical system, preferably a catoptric system, forming the predetermined pattern. The projection optical system located between the reflection mask and the substrate directs the light reflected from the mask to the substrate, and illuminance distribution of the light on the exposure area of the substrate is adjustable by changing the position of reflection optical elements located along the optical path of the radiation light in the illumination optical system.