Patent ID: 7969556

Claim:
An illumination optical system for microlithography for guiding an illumination light bundle from a radiation source to an object field in an object plane, the illumination optical system comprising: a field facet mirror with a plurality of field facets arranged to define predetermined illumination conditions in the object field, a following optical system arranged downstream of the field facet mirror, the following optical system being configured to transfer the illumination light into the object field, wherein the following optical system has a pupil facet mirror with a plurality of pupil facets, the field facets being in each case individually associated with the pupil facets so fractions of the illumination light bundle, which impinge on one of the field facets are guided onward via the associated pupil facet to the object field, wherein at least some of the field facets are divided into individual mirrors, which predetermine individual mirror illumination channels to guide sub-fractions of the illumination light bundle impinging on the individual mirrors, wherein the individual mirrors each have a mirror face arranged so that the individual mirror illumination channels in the object field illuminate object field portions which are smaller than the object field, wherein at least some of the individual mirrors are configured as individual correction mirrors, wherein the individual correction mirrors are configured to be tiltable between at least two tilting positions including a basic tilting position and a correction illumination position, wherein in the basic tilting position of the individual correction mirrors, an illumination of a central region of the object field takes place using a basic individual mirror illumination channel of the individual correction mirrors, and in the correction tilting position of the individual correction mirrors, an illumination of a surrounding region of the object field takes place using an individual correction mirror illumination channel of the individual correction mirrors, the surrounding region of the object field being adjacent to the central region in the object plane.