METROLOGY FOR EXTREME ULTRAVIOLET LIGHT SOURCE

摘要

An extreme ultraviolet light system includes a drive laser system that produces an amplified light beam; a target material delivery system configured to produce a target material at a target location; a beam delivery system configured to receive the amplified light beam emitted from the drive laser system and to direct the amplified light beam toward the target location; and a metrology system. The beam delivery system includes converging lens configured and arranged to focus the amplified light beam at the target location. The metrology system includes a light collection system configured to collect a portion of the amplified light beam reflected from the converging lens and a portion of a guide laser beam reflected from the converging lens. The light collection system includes a dichroic optical device configured to optically separate the portions.