Tilt induced polarization rotation and its importance in high-NA EUV lithography

A projection imaging system for EUV lithography uses a number of mirrors to guide light from an object plane onto an image plane. To avoid obstruction of the reflected light by the mirrors, the mirrors must be tilted by various angles with respect to each other. Light reflected from a tilted mirror undergoes a polarization rotation which is different for different points on the mirror. In this paper, the phenomenon of tilt induced polarization rotation and its importance in present and future generations of high-NA EUV lithography is discussed.