Tetsuo Harada

EUV lithography has been used for high-volume manufacturing of semiconductor devices since 2019. An EUV lithography photomask is a reflection type with Mo/Si multilayer coatings. Since the EUV reflection phase is critical for printability, actinic (at-wavelength) inspection tools and microscopes were developed. In this report, we introduce an EUV specific issue of photomasks and EUV inspection tools for high-volume manufacturing. An EUV microscope is also important for EUV mask development. We made coherent EUV scatterometry microscopes to observe EUV phase images, which captured EUV diffraction from mask patterns without imaging optics. EUV phase images will be helpful for the development of high-contrast EUV masks.