Laser-produced-plasma light source for EUV lithography

Abstract

The status of the next generation lithography laser produced plasma light source development at EUVA is presented. The light source is based on a Xenon jet target and a Nd:YAG driver laser. The laser, having a master oscillator power amplifier (MOPA) configuration, operates at 10 kHz repetition rate and generates an average output power of 1.5 kW. The fwhm pulsewidth is 6 ns. The EUV system currently delivers an average EUV source power of 9.1 W (2% bandwidth, 2π sr) with a conversion efficiency of 0.6 %. Based on the development it is concluded that solid-state Nd:YAG laser technology can be cost efficiently used to produce 10 W level EUV light sources. In order to generate an average power of 115 W for a future extreme ultraviolet (EUV) light source, however, the cost of a Nd:YAG based LPP source will be too high. Therefore RF-CO₂ laser technology will be used. The designed CO₂ driver laser system has a MOPA configuration. The oscillator has ns-order pulsewidth and the laser system operates at a repetition rate of 100 kHz. Due to its inert cleanliness Xenon droplets will be the target material.