Illuminating apparatus and projection exposure apparatus provided with such an illuminating apparatus

A projection exposure apparatus projecting a first object illuminated by an illuminating apparatus onto a second object through a projection optical system, said illuminating apparatus including the following:

• light source means to supply parallel light beams;
• multiple light beam formation means to form a plurality of secondary light sources by the parallel light beams from said light source means;
• and
• a condensing optical system to condense the light beams from said plural secondary light sources to illuminate an area to be irradiated in a superposed manner,
• said multiple light beam formation means including a first optical integrator which forms a given number of secondary light sources, and a second optical integrator which is arranged replaceably with said first optical integrator and forms substantially the same number of second light sources as the first optical integrator,
• said area to be irradiated being illuminated with a first aperture number when said first optical integrator is installed in the illuminating light path, and
• said area to be irradiated being illuminated with a second aperture number which differs from said first aperture number when said second optical integrator is installed in said light path.

A projection exposure apparatus projecting a first object illuminated by an illuminating apparatus onto a second object through a projection optical system, said illuminating apparatus including the following:

• light source means to supply parallel light beams;
• multiple light beam formation means to form a plurality of secondary light sources by the parallel light beams from said light source means;
• and
• a condensing optical system to condense the light beams from said plural secondary light sources to illuminate an area to be irradiated in a superposed manner,
• said multiple light beam formation means including a first optical integrator and a second optical integrator which are replaceable with each other,
• said first and second optical integrators forming substantially the same numbers of secondary light sources and having the aperture numbers which differ from each other on the emission sides,
• said condensing optical system including a first lens system having a first focal length, and a second lens system having a second focal length which differs from said first focal length,
• said first object being illuminated with a first aperture number when said first optical integrator is installed in the illuminating light path of said first optical integrator,
• said first object being illuminated with a second aperture number which differs from said first aperture number when said second optical integrator is installed in said light path, and
• said area to be irradiated being illuminated with a second aperture number which differs from said first aperture number when said second optical integrator.