Development of CO2 laser produced Xe plasma EUV light source for microlithography

摘要

A CO2 laser driven Xe droplet plasma is presented as a light source for EUV lithography. A short-pulse TEA CO2 master oscillator power amplifier system and a pre-pulse Nd:YAG laser were used for initial experiment with 0.6% of CE from a Xe jet. A target technology is developed for high average power experiments based on a Xe droplet at 100kHz. Magnetic field ion mitigation is shown to work well in the pre-pulsed plasma combined with a CO2 laser main pulse. This result is very promising with respect to collector mirror lifetime extension by magnetic field mitigation. A master oscillator power amplifier (MOPA) CO2 laser system is under development with a few kW and 100 kHz repetition rate with less than 15ns laser pulse width using a waveguide Q-switched CO2 laser oscillator and RF-excited fast axial flow CO2 laser amplifiers.