Laser-produced plasma source development for EUV lithography

Abstract

Summary form only given. We are developing a laser produced plasma light source for high volume manufacturing (HVM) EUV lithography1. The light source is based on a high power, high repetition rate C02 laser system, a tin droplet target and a magnetic plasma guiding for collector mirror protection. This approach enables cost-effective high-conversion efficiency and EUV power scaling. The laser system is a master oscillator power amplifier (MOPA) configuration. We have achieved a maximum average laser output power of more than 10 kW at 100 kHz and 20 ns pulse by a single laser beam with good beam quality. EUV in-band power and out-of-band characteristics are measuring with high power C02 laser and Sn droplet target configuration. This light source is scalable to more than 200 W EUV in-band power based on a 20-kW C02 laser. Collector mirror life can be extended by using droplet target and magnetic plasma guiding. Effectiveness of the magnetic plasma guiding is examined by monitoring the motion of fast Sn ion in a large vacuum chamber. The ion flux from a Sn plasma was confined along the magnetic axis with a maximum magnetic flux density of 2 T. The development status of the source system and its performance including EUV characteristics will be described in detail. Relevant topics of HVM sources including the future light source development will be outlined. A part of this work was supported by the New Energy and Industrial Technology Development Organization (NEDO), Japan.