Patent Number: 
Section: abstract

Laser light emitted from a high output laser light source is condensed by a condenser lens to form a condensed point. Xenon (Xe) gas or the like as a target is injected from a nozzle to the condensed point to generate Extreme Ultra Violate (EUV) light, and then the generated EUV light is condensed by a condenser mirror. A transmission filter having a predetermined transmittance with respect to the EUV light is disposed between the condenser mirror and a reflecting mirror, and scattering particles mixed in the EUV light are adsorbed by the transmission filter. The EUV light passing through the transmission filter is deviated by the reflecting mirror, a illuminance distribution of the EUV light is uniformalized by fly eye mirrors, thereafter the EUV light is condensed by another condenser mirror, and then exposure is effected using the condensed EUV light as an exposure beam.