Projection exposure apparatus

A projection exposure apparatus comprising:

• a light source for producing illumination light;
• a condenser lens for condensing the illumination light emanating from said light source onto a mask including a circuit pattern;
• a projection lens having a pupil with a diameter, said projection lens for condensing the illumination light that has passed through the mask onto a surface of a wafer;
• and
• an aperture member disposed between said light source and said condenser lens and having a transmission area with an outer diameter for shaping the light emanating from said light source and a light blocking area at a central portion of said transmission area, the outer diameter of said transmission area of said aperture member being set such that a ratio .sigma. of an outer diameter of an effective light source to the diameter of the pupil of said projection lens is 0.6.+-.0.3 while a ratio of said light blocking area to the transmission area is 60.+-.35%.