Patent ID: 6897942

Claim:
An illumination apparatus provided in an exposure apparatus which exposes an object with an illumination beam via a mask to illuminate with the illumination beam an area on a predetermined plane on which a pattern surface of the mask is placed, comprising: an illumination optical system provided on an optical path through which the illumination beam passes, that includes a plurality of optical members arranged along an optical axis substantially perpendicular to the predetermined plane of which the area is illuminated via the plurality of optical members with the illumination beam having any one of plural intensity distributions different from each other on a pupil plane of the illumination optical system; and a shaping optical system provided on the optical path in the illumination optical system to shape the plural intensity distributions of which one has an increased intensity portion apart from the optical axis relative to a portion of the one intensity distribution on the optical axis, that includes prisms provided on the optical axis, of which at least one is movable in a direction along the optical axis and between which an interval in the direction is variable by the at least one prism to change the one intensity distribution.