Disclosed is an illumination system for illuminating an illumination region
with uniform illuminance, wherein the light intensity gravity center of light impinging
on the illumination region is registered with the center of light rays. The illumination
system includes a first reflection type integrator, a first condensing mirror system
for superposing light beams from the first reflection type integrator one upon
another on the surface to be illuminated, a second reflection type integrator disposed
between the light source and said first reflection type integrator, and a second
condensing mirror system for superposing light beams from the second reflection
type integrator one upon another on the first reflection type integrator. Also
disclosed is an exposure apparatus having such illumination system, and a device
manufacturing method using the same.
