Image Degradation from Surface Scatter in EUV Optics

Abstract

Synchrotron-based 13 nm measurements of scatter from individual mirrors and an assembled imaging system for Extreme Ultraviolet Lithography have been compared to a model of image formation in the presence of scatter. The theory uses a Power Spectral Density description of the constituent optics to describe modifications to the image due to scatter. Reasonable agreement between measurements and theory was obtained for both individual mirrors and the assembled system.