Catadioptric imaging system and a projection exposure apparatus provided with said imaging system

A catadioptric imaging apparatus for forming a reduced image of a first plane onto a second plane, comprising:

• a first imaging optical system of dioptric type;
• a second imaging optical system of catadioptric type;
• wherein
• the first imaging optical system comprises in the order from the first plane, a first lens group having a positive refracting power, an aperture stop, and a second lens group having a positive refracting power, for forming a primary image of the first plane;
• the second imaging optical system comprises a primary mirror having a front surface reflecting surface formed in a concave form and a first radiation transmitting portion at the center thereof, a secondary mirror having a reflecting surface with a second radiation transmitting portion at the center thereof, and a lens component provided adjacently to the secondary mirror on a side of the primary mirror to have a negative refracting power, for forming a secondary reduced image of the first plane based on the radiation from the primary image;
• the lens component provided adjacently to the secondary mirror is the only refracting optical member in an optical path between the primary mirror and the secondary mirror;
• the radiation from the primary image passes through the first radiation transmitting portion of the primary mirror and the lens component to be reflected by the secondary mirror, the radiation reflected by the secondary mirror passes through the lens component to be reflected by the primary mirror, and the radiation reflected by the primary mirror passes through the lens component and the second radiation transmitting portion of the secondary mirror to form the secondary image;
• and
• all of the refracting optical members in the catadioptric imaging apparatus are made of optical materials having the same refractive index.