Patent ID: 7884921

Claim:
An illumination optical apparatus, used in a projection exposure apparatus which projects and exposes a pattern arranged in a reticle plane to a second plane, which supplies the reticle plane with illumination light from a light source, the illumination optical apparatus comprising: a relay optical system, arranged between the light source and the reticle plane, which forms a third plane optically conjugate with the reticle plane between the light source and the reticle plane, the relay optical system being located between the third plane and the reticle plane; an optical path combiner, arranged in an optical path between the light source and the reticle plane, for combining a first light beam from the light source and a second light beam different from the first light beam such that the first and second light beams illuminate the reticle plane closely to each other; and a field stop that is arranged at a position at which the third plane is located or at a light source side position in the optical path that is optically conjugate with the third plane, the field stop including a first movable blind arranged in an optical path of the first light beam, and a second movable blind arranged in an optical path of the second light beam; a first preliminary relay optical system arranged in an optical path between the first movable blind and the third plane; and a second preliminary relay optical system arranged in an optical path between the second movable blind and the third plane, wherein the optical path combiner includes a first region corresponding to the first light beam and a second region, separated from the first region, corresponding to the second light beam; a boundary between the first and second regions is arranged on or near the third plane; and the optical axes of the relay optical system, the first preliminary relay optical system and the second preliminary relay optical system intersect.