The use of undulator radiation for atto-wavelength interferometry of EUV lithography optics

摘要

At present a program is underway to develop tunable interferometry for extreme ultraviolet (EUV) lithographic optics, with a goal of achieving good wavefront accuracy. Recent tests of a 10X Schwarzschild optic, having Mo-Si coated surfaces optimized for peak reflectivity at 13.4 nm, indicate a wavefront error which would give near-diffraction limited performance.