Comparative research of mirror systems for extreme ultraviolet lithography illuminator

Illuminator is one of the important components of extreme ultraviolet lithography system. Industrial extreme ultraviolet lithography illuminator uses two compound eyes and relay system, which can realize variety of illumination modes. But the manufacture and assembly of compound eyes are difficult. Therefore, we would like to design illuminators, which use such as Offner-relay system, quad elliptical mirrors, or other mirror systems. These systems do not have more complex surfaces, easier to assembly. Analyze advantages and disadvantages of these systems, and then discuss the possibility of using these systems in industrial extreme ultraviolet lithography.