Method for correcting a reflective optical element for the wavelength range between 5 nm and 20 nm

Abstract

A method for correcting a reflective optical element for the wavelength range between 5 nm and 20 nm, which includes a multilayer system on a substrate. The multilayer system has layers consisting of at least two alternately arranged different materials with a different real component of the refractive index for a wavelength in the extreme ultraviolet wavelength range. The method includes: measuring the reflectivity distribution over the surface of the multilayer system; comparing the measured reflectivity distribution to a nominal distribution of the reflectivity over the surface of the multilayer system, determining at least one partial surface having a measured reflectivity above the nominal reflectivity; and irradiating the at least one partial surface with ions or electrons.

Dependencies are inferred from the claim text.