Principles of certification of aspherical mirrors for an EUV lithography lens at a wavelength of 13.5 nm

Abstract The study is devoted to modification of the lens of an EUV lithographer and the method of certification of the aspherical mirrors of the lens without using a wavefront corrector. A lens aberration pattern is reconstructed from the interference pattern of fronts that passed through the lens...
Ausführliche Beschreibung

Abstract The study is devoted to modification of the lens of an EUV lithographer and the method of certification of the aspherical mirrors of the lens without using a wavefront corrector. A lens aberration pattern is reconstructed from the interference pattern of fronts that passed through the lens and the reference. This pattern contains information about the surface deformations of both aspherical mirrors. A procedure for determining the pattern of each mirrors by turning one of the mirrors and solving systems of linear equations is proposed. Ausführliche Beschreibung