抄録
In the development of extreme ultraviolet (EUV) lithography source using laser-produced plasma (LPP), it is important to investigate the optimum wavelength of the driver laser to obtain the high conversion efficiency. We have proposed the EUV generation pumped by CO2 laser-produced plasma. In this article, we show the characteristics of EUV emission from gas and solid Xe irradiated by a TEA CO2 laser. The conversion efficiency to 13.5 nm was ∼0.2 %. This value is comparable to those of Nd: YAG LPP with Xe in early works. In order to gain insight into the difference between the CO2 LPP and Nd:YAG LPP, we investigated the emission characteristics from Nd: YAG LPP and CO2 LPP with solid tin under the same experimental setup. As the results, we confirmed that the conversion efficiency of CO2 LPP is comparable to that of Nd: YAG LPP. The conversion efficiency was estimated to be 2 % in maximum.
