Patent ID: 8170078

Claim:
A lithography system comprising: a laser system configured to operate at an output pulse repetition rate of up to 12 kHz, the laser system comprising: a seed laser oscillator producing an output comprising a laser output light beam of pulses, the seed laser oscillator comprising a first gas discharge laser chamber; and a laser amplification stage containing an amplifying gain medium in a second gas discharge laser chamber receiving the output of the seed laser oscillator and amplifying the output of the seed laser oscillator to a pulse energy of ≧1 mJ to form a laser system output comprising a laser output light beam of pulses, the laser amplification stage comprising: a regenerative closed loop optical cavity defined in part by a partially reflecting optical element through which the seed laser oscillator output light beam is injected, and a beam de-magnification stage and a beam expansion stage within the optical cavity, wherein the beam de-magnification stage is configured to de-magnify the laser beam as the laser beam travels from the partially reflecting optical element toward the amplifying gain medium and the beam expansion stage is configured to expand the laser beam as the laser beam travels from the amplifying gain medium toward the partially reflecting optical element; and a photolithography tool that receives the laser system output.