Patent ID: 8558202

Claim:
An extreme ultraviolet light source apparatus for generating extreme ultraviolet light by irradiating a target material with a laser beam to turn the target material into plasma, said apparatus comprising: a chamber in which extreme ultraviolet light is generated; a target supply unit configured to supply droplets of a target material to a plasma emission point in said chamber; a laser unit configured to generate a first pulse laser beam and a second pulse laser beam; a laser emission control unit configured to control said laser unit to irradiate one of the droplets within said chamber with the first pulse laser beam when said one of the droplets reaches said plasma emission point to generate plasma, and then, irradiate neutral particles produced at plasma generation with the second pulse laser beam after said one of the droplets reaches said plasma emission point and before next one of the droplets reaches said plasma emission point to convert the neutral particles into ions; a collector mirror configured to collect the extreme ultraviolet light radiated from said plasma; and at least one of a magnetic field forming unit configured to form a magnetic field within said chamber and an electric field forming unit configured to form an electric field within said chamber so as to trap said ions.