Collector optical system, light source unit, illumination optical apparatus, and exposure apparatus

摘要

A light source unit of EUV light is provided as a light source unit comprising a plasma light source (1) for emitting EUV light, a collective mirror (2) which has a reflecting surface of an ellipsoid of revolution and at a first focal point (1) of which the plasma light source is located, and an auxiliary collective mirror (4a,4b) which has a reflecting surface of a spherical surface and a spherical center of which is located as displaced from a position of the plasma light source.