MEASURING ILLUMINATION OPTICAL UNIT FOR GUIDING ILLUMINATION LIGHT INTO AN OBJECT FIELD OF A PROJECTION EXPOSURE SYSTEM FOR EUV LITHOGRAPHY

摘要

A measuring illumination optical unit is used to guide illumination light (3) into an object field of a projection exposure system for EUV lithography, in which a lithography mask can be arranged. A field facet mirror of the illumination optical unit has a plurality of field facets (7, 7') and a pupil facet mirror of the illumination optical unit has a plurality of pupil facets (11). The latter are used for superimposed imaging of field facet images (12) of the field facets (7) into the object field. A field facet imaging channel (12a) of the illumination light (3) is guided via one field facet (7) and one pupil facet (11). A field stop (29) is used to define a field boundary of an illumination field (31) in an object plane (17) in which the object field is arranged. The illumination field (31) has a larger extension along a field dimension (y) than one of the field facet images (12). At least some of the field facets (7') have tilting actuators (7a) which ensure that the illumination light (3) is guided via different field facets (7, 7') and one and the same pupil facet (11) into the illumination field (31). The result is a measuring illumination optical unit with which full illumination of an illumination field is possible, which field has a larger extension along a field dimension than a field facet image in the object plane.