Patent ID: 7352842

Claim:
An exposure apparatus comprising: an illumination optical system for illuminating a pattern of a mask, said illumination optical system including plural mirrors, and reflection points of the principal rays on the mirrors being arranged on a single plane; a projection optical system for projecting the pattern of the mask onto an object to be exposed; and an X-ray generator and introducing an X-ray to said illumination optical system, said X-ray generator comprising: a pair of plasma light sources having optical axes that form a single line; and a reflector, rotatably arranged between said pair of plasma light sources, for switching light sources and for reflecting the X-ray from one of said pair of plasma light sources to said illumination optical system, said reflector's rotational center being located on the line and equally distant from said pair of plasma light sources, wherein said pair of plasma light sources are the only plasma light sources in said X-ray generator, and wherein said pair of plasma light sources and said reflector are arranged so that an electric field vector of a polarized light component perpendicular to a plane that contains each optical axis of said pair of plasma light sources and a normal of a reflecting surface of said reflector corresponding to each optical axis can be perpendicular to a plane that contains reflection points of principal rays on the mirrors in said illumination optical system.