| 主权项 |
1. An illumination optical unit configured to guide illumination light toward an object field in which a lithography mask is arrangeable and displaceable along an object displacement direction, the illumination optical unit comprising:
a field facet mirror comprising a multiplicity of individual mirrors which are switchable between at least two tilting positions and which provide individual-mirror illumination channels for guiding illumination light partial beams toward the object field during use of the illumination optical unit; and a pupil facet mirror downstream of the field facet mirror along a beam path of the illumination light through the illumination optical unit, the pupil facet mirror comprising a plurality of stationary pupil facets configured so that, during use of the illumination optical unit, each pupil facet contributes to at least sectional superimposed imaging of a group of the individual mirrors of the field facet mirror into the object field via a group-mirror illumination channel, wherein:
a pupil facet is assigned to a corresponding group of the individual mirrors that are to be imaged;an individual-mirror group that is completely imageable into the object field has a nominal number of individual mirrors;a number of the pupil facets, on which illumination light is impingeable simultaneously via the individual-mirror groups, multiplied by the nominal number of the individual mirrors per individual-mirror group, yields a number of individual mirrors that is greater than an actual number of the individual mirrors on the field facet mirror; andan assignment of the individual mirrors to the individual-mirror groups is such that, during use of the illumination optical unit, the assignment is used to correct a dependence of an illumination light intensity integrated along the object displacement direction on an object field height perpendicular to the object displacement direction. |
