Laser produced EUV light source development for HVM

Abstract

We develop a laser produced plasma light source for high volume manufacturing (HVM) EUV lithography. The light source is based on a short pulse, high power, high repetition rate CO₂ master oscillator power amplifier (MOPA) laser system and a Tin droplet target. A maximum conversion efficiency of 4.5% was measured for a CO₂ laser driven Sn plasma having a narrow spectrum at 13.5 nm. In addition, low debris generation was observed. The CO₂ MOPA laser system is based on commercial high power cw CO₂ lasers. We achieve an average laser power of 3 kW at 100 kHz with a single laser beam that has very good beam quality. In a first step, a 50-W light source is developing. Based on a 10-kW CO₂ laser this light source is scalable to more than 100 W EUV in-band power.