Computer processing of electron microscope cross sections of multilayer mirrors.

A method is developed for determining interface profiles of extreme ultraviolet- (EUV-) layered synthetic microstructures (LSM’s). It is based on computer processing digitized LSM electron micrographs. This study was carried out on a tungsten/carbon multilayer. Interfacial roughness has been characterized by means of two statistical parameters, i.e., the root mean square (rms) roughness height and the autocorrelation length σ. Additionally, knowledge of interface profiles should enable one to study more accurately the structural behavior of the stack, from the substrate to the top, and, in turn, help one better understand its EUV optical properties.