The Extreme Ultraviolet Lithography System Development Association (EUVA) started an extreme ultraviolet (EUV) light source development project for EUV lithography. Both, laser produced plasma (LPP) sources and gas discharge produced plasma (DPP) sources are developed in this project. The development status of the laser produced plasma EUV light source is reported including the xenon jet system and the 500-W laser system. Laser parameter optimization, for example laser pulse energy, pulse width and laser spot size, is ongoing to improve the conversion efficiency and EUV output power. A maxium conversion efficiency of 0.53% is obtained with a 50-μm diameter target. The EUV output stability is analyzed based on spatial fluctuations of the Xe jet and the laser beam. In addition, a Xe ion exposure measurement has been started to investigate the collector mirror damage mechanism.
"EUV light source development in Japan", Proc. SPIE 5063, Fourth International Symposium on Laser Precision Microfabrication, (18 November 2003); doi: 10.1117/12.540548; https://doi.org/10.1117/12.540548