Wavefront measurement for EUV lithography system through Hartmann sensor

Abstract

Accurate wavefront aberration measurement are essential for next-generation Extreme Ultraviolet (EUV) Lithography. During the past years several accurate interferometric techniques have been developed, but these techniques have limitation. In this work we discuss a different technique based on the Hartmann Wavefront Sensor that requires no interferometry. We present a mathematical model of this system and describe our experimental setup which demonstrates the feasibility and advantages in terms of dynamic range and accuracy compared to interferometric techniques. © 2011 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE).