ILLUMINATION OPTICAL SYSTEM PROVIDED WITH NESTED CONDENSER

摘要

PROBLEM TO BE SOLVED: To provide such an illumination optical system provided with a nested condenser that can prevent substance or ray damageable to an optical component from entering an illumination system on the downstream side of the condenser. SOLUTION: This illumination optical system includes an object plane and a plane conjugated to the object plane and is for wavelengths of 193 nm or less. A first collector unit 3 is provided between the object plane and the conjugated plane 200, and at least one second collector unit 300 is provided on the downstream side of the conjugated plane. The first collector unit 3 focuses a beam bundle of rays from the object plane in the conjugated plane, and at least one of the collector units 3 and 300 is provided with at least one reflection mirror shell. The beam bundle of rays from the object plane strikes the reflection mirror shell at an angle of incidence less than 20°relative to a surface tangent of the reflection mirror shell. COPYRIGHT: (C)2003,JPO