Patent ID: 8759804

Claim:
A chamber apparatus which has an obscuration region and is used with an external apparatus, the chamber apparatus comprising: a chamber in which extreme ultraviolet light is generated; a collector mirror configured for reflecting and collecting an extreme ultraviolet light generated in the chamber, the collector mirror having a through-hole and two notches, the through-hole being located at a center of a reflecting surface of the collector mirror and penetrating the collector mirror from a reflective side of the collector mirror to a back side of the collector mirror, each of the two notches being a cut in an edge of the collector mirror, the two notches being symmetrically-located with respect to the center of the reflection surface of the collector mirror; a support configured for supporting the collector mirror in the chamber; and an output port provided to the chamber for allowing the extreme ultraviolet light reflected and collected by the collector mirror to be introduced therethrough into the external apparatus, wherein the support supports the collector mirror so that the two notches of the collector mirror are located at positions corresponding to the obscuration region.