Development of a high-power EUV irradiation tool in a hydrogen atmosphere

Abstract

Abstract Extreme ultraviolet (EUV) lithography has recently been utilized as a high-volume manufacturing technology for advanced semiconductors. An EUV mirror can be easily contaminated in the existence of a residual hydrocarbon vapor gas inside an exposure chamber in a vacuum environment, which reduces the reflectance of the Mo/Si multilayer coating. To reduce this carbon contamination, hydrogen gas is introduced at a pressure of a few pascals in the EUV scanner. However, during this process, the multilayer may be damaged by hydrogen. In addition, the multilayer surface can become oxidized by residual water vapor in the vacuum chamber. Therefore, an EUV irradiation tool in hydrogen and water vapor atmospheres was developed and installed at BL-09 of the NewSUBARU synchrotron light facility to evaluate the cleaning effect and irradiation durability of the Mo/Si multilayer. The EUV irradiation intensity increased up to 6 W cm−2, and the hydrogen pressure reached 70 Pa.