Development of High-Peak and High-Average-Power LD Pumped Solid-State Laser System for EUV Generation

Abstract

We are developing a 5kW (5kHz, 1J, 1-10ns) solid state laser system for EUV lithography. The Laser system is constructed by the fiber oscillator, regenerative amplifier and three amplifier stages. The output power is achieved at 955W, 10kHz, 7ns. The main amplifier modules are pumped with high power density over 400 W/cm. The thermal lens effect is not sphere, and includes high order phase aberrations. The phase aberration disturbs the propagation of the laser light. In addition, the spectral shift of the fluorescence is caused by rising the temperature of the laser medium.