Patent ID: 10928733

Abstract:
An illumination optical unit for projection lithography illuminates an object field with illumination light along an illumination beam path. The arrangement of field facets of a field facet mirror and also of pupil facets of a pupil facet mirror is such that an illumination channel is guided over each of them. The field facet mirror images a light source image along in each case one illumination channel onto one of the pupil facets. The pupil facet mirror superimposedly images of the field facets into the object field. The illumination optical unit is designed for the settable specification of a spatial resolution of an illumination light illumination of an entrance pupil of a projection optical unit arranged downstream of the object field in the illumination light beam path. The result of this is an illumination optical unit with which illumination light can be used efficiently for high-contrast imaging of the structures to be projected.