Patent ID: 8450706

Claim:
An extreme ultraviolet light source apparatus for generating extreme ultraviolet light from plasma generated by irradiating a target with a laser beam, said apparatus comprising: a chamber in which the extreme ultraviolet light is generated; a target supply unit configured to supply the target into said chamber; a laser beam focusing mirror arranged in said chamber to focus the laser beam; a collector mirror having a reflection surface composed of a multilayer film and arranged in said chamber to collect and output the extreme ultraviolet light emitted from the plasma; a first shielding member including at least one metal selected from the group consisting of: silicon (Si), zirconium (Zr), molybdenum (Mo), lithium (Li), aluminum (Al), and an alloy including at least one of the metals, and arranged between said target supply unit and the plasma, said first shielding member being arranged apart from the reflection surface of said collector mirror; a second shielding member including at least one metal selected from the group consisting of: silicon (Si), zirconium (Zr), molybdenum (Mo), lithium (Li), aluminum (Al), and an allo including at least one of the metals, and arranged on an inner wall of said chamber; and a third shielding member including at least one metal selected from the group consisting of: silicon (Si), zirconium (Zr), molybdenum (Mo), lithium (Li), aluminum (Al), and an alloy including at least one of the metals, and arranged between said laser beam focusing mirror and the plasma.