Aerial image characterization for defects in an extreme-ultraviolet mask

Abstract

Simulation has been used to predict aerial images for masks with defect-free multilayer and with defect in multilayer. Mask defects are easily produced in an extreme-ultraviolet lithography mask fabrication process, because 80 Mo/Si multilayer films are stacked and each stack is made from 2 to 4 nm. In this case, the multilayer can be stacked with defects and with slightly different heights. It is difficult to achieve an aerial image which is desired. This paper discusses various image properties when there is no defect and when there are different kinds of defects in the multilayer. The results are calculated by using SOLID-EUV of Simga-C. A finite-difference time-domain algorithm is used, and the aerial images caused by defects in the multilayer, are also characterized.