Projection exposure apparatus

Abstract

A projection exposure apparatus having an illuminating system for irradiating a mask, which has a pattern, with illuminating light for exposure, and a projection optical system for projecting an image of the mask pattern onto a photosensitive substrate with predetermined image-forming characteristics under the illuminating light. The apparatus is provided with an optical filter changing member for selecting one of a plurality of optical filters that change at least one of optical characteristics of light from the mask by respective amounts which are different from each other. The optical characteristics include an amplitude distribution, a phase distribution and a condition of polarization. The optical filter changing member further disposes the selected optical filter on a pupil plane in the projection optical system or on a plane in the neighborhood of the pupil plane. The apparatus is further provided with a correcting member-changing member for selecting one of a plurality of image-forming characteristic correcting members that correct the image-forming characteristics of the projection optical system by respective amounts which are different from each other in accordance with the optical filter selected by the optical filter changing member, and for disposing the selected image-forming characteristic correcting member between the mask and the substrate.

Dependencies are inferred from the claim text.