Method for correcting a reflective optical element for a wavelength range of 5 nm to 20 nm

摘要

The present invention is a method of correcting a reflective optical element having a multilayer system on a substrate for a wavelength range of 5 nm to 20 nm, wherein the multilayer system has at least two different real parts of the refractive index at wavelengths in the extreme ultraviolet wavelength range. A method wherein two different materials have alternating layers. The method includes measuring a reflectance distribution over a surface of the multilayer system, and comparing the measured reflectance distribution to a target distribution of reflectance over the surface of the multilayer system, having a measured reflectance that exceeds the target reflectance. Determining one or more partial surfaces and irradiating one or more partial surfaces with ions or electrons.