System for interferometric fit testing

A system for the interferometric fit testing of a specimen having an aspherical surface in reflection, the specimen being a segment (footprint) of a rotationally symmetrical basic body (parent), comprising an interferometer and a diffractive optical element (DOE), wherein an optical axis of the interferometer in the beam direction behind the diffractive optical element and an axis of rotation of the basic body form an angle that differs from zero, the diffractive optical element being designed in such a way that the rays produced by the interferometer and falling into the diffractive optical element strike the specimen perpendicularly and from there run back in themselves and, to determine the non-rotationally symmetrical interferometer errors in the zeroth order of diffraction, a planar plate is provided as specimen.

A system for the interferometric fit testing of a specimen having an aspherical surface in reflection, the specimen being a segment (footprint) of a rotationally symmetrical basic body (parent), comprising an interferometer and a diffractive optical element (DOE), wherein an optical axis of the interferometer in the beam direction behind the diffractive optical element and an axis of rotation of the basic body form an angle that differs from zero, the diffractive optical element being designed in such a way that the rays produced by the interferometer and falling into the diffractive optical element strike the specimen perpendicularly and from there run back in themselves and, to determine the non-rotationally symmetrical interferometer errors in the zeroth order of diffraction, a spherical mirror is provided as specimen.

A system for the interferometric fit testing of a specimen having an aspherical surface in reflection, the specimen being a segment (footprint) of a rotationally symmetrical basic body (parent) for a mirror optical system in EUV-lithography, comprising an interferometer and a diffractive optical element (DOE), wherein an optical axis of the interferometer in the beam direction behind the diffractive optical element and an axis of rotation of the basic body form an angle that differs from zero, and the diffractive optical element being designed in such a way that rays produced by the interferometer and falling into the diffractive optical element strike the specimen perpendicularly and from there run back in themselves.