PROJECTION ALIGNER AND ALIGNING METHOD, AND METHOD FOR FABRICATING CIRCUIT

摘要

PROBLEM TO BE SOLVED: To enhance the depth of focus and the resolution. SOLUTION: In the projection aligner for projecting a pattern on a projection original plate onto a substrate with exposing light from an illumination optical system through a projection optical system, the illumination optical system comprises means for forming a secondary ring light source by the exposing light from a light source means, and a condenser optical system for condensing the light beam from the ring light source forming means onto the projection original plate. The ratio of the inside diameter of the secondary ring light source to the outside diameter thereof is referred to ring ratio, and the ring light source forming means comprises a ring ratio selecting means for a switching between a secondary light source having a first ring ratio and a secondary light source having a second ring ratio different from the first ring ratio.