Collector mirror assembly and extreme ultraviolet light source device using said collector mirror assembly

Abstract

A deterioration of the collector performance in an extreme ultraviolet light source device due to a heat deformation of the collector mirror assembly is to be prevented. The collector mirror assembly used in the extreme ultraviolet light source device comprises a plurality of reflective shellswith different diameters which are shaped as ellipsoids of revolution or hyperboloids of revolution, wherein the reflective shellsare arranged in a nested shape and the ends thereof are held by a holding structure. A cooling channel, through which a cooling medium flows is mounted at the reflective shellin the axial direction of the reflective shell on the face being the back side of the reflective surface. This cooling channel acts as a reinforcement material and is able to suppress a heat deformation of the reflective shell. By using molybdenum as the material for the reflective shells, the heat deformation can be suppressed even further, and by providing cooling channels in the holding structure, the collector mirror assembly can be cooled even more efficiently and a heat deformation thereof can be suppressed.