Present status of laser-produced plasma EUV light source

The development status of key technologies for a HVM laser-produced plasma EUV light source is presented. This includes the high-power RF-excited CO 2 laser, the Sn droplet target and the collector mirror lifetime enhancement technology. In this paper, we mainly discuss countermeasures for Sn ions and neutrals which cause mirror reflectivity degradation. The effectiveness of ion mitigation by a strong magnetic field was measured. We also observed that Sn neutrals were removed by etching gases and that the etching process did not degrade the effectiveness of the ion mitigation by the magnetic field. A part of this work was supported by the New Energy and Industrial Technology Development Organization (NEDO), Japan.