APERTURE FOR SLANT INCIDENT ILLUMINATION AND PROJECTION EXPOSURE DEVICE UTILIZING APPERTURE THEREOF

PROBLEM TO BE SOLVED: To provide an aperture whose light intensity is improved by forming a light transmissive area to a shape like a prism so that incident light may be diffracted by the edge part of a condenser lens. SOLUTION: It is desirable that the aperture is provided with a 1st light shielding central area 40 for interrupting straight advancing component among the incident light, a ring-shaped light transmissive area 42 surrounding the 1st light shielding area 40 and a 2nd light shielding area 44 surrounding the light transmissive area 42. The radius σ2 of the 1st light shielding are 40 is made smaller and the radius σ1 of the light transmissive area 42 is made larger. The light transmissive area 42 is formed into a prism shape so that the transmitted light may be diffracted by the edge part of the condenser lens for the stepper. The 1st light shielding area 40 is made thicker than the 2nd light shielding area, or the 1st area 40 is made as thick as the 2nd area 44. It is possible to form a part of the light transmissive area 42 into a prism shape.