Illumination system with variable adjustment of the illumination

Abstract

An illumination system comprises (a) a first optical element upon which a light beam impinges, where the first optical element has first raster elements that partition said light beam into light channels; (b) a second optical element that receives said light channels, where the second optical element has a second raster elements; (c) an object plane that receives said light channels via said second optical element; and (d) an exit pupil that is provided with an illumination via said object plane. The system is characterized by an assignment of a member of said first raster elements and a member of said second raster elements to each of said light channels to provide a continuous beam path from said first optical element to said object plane for each of said plurality of light channels. The assignment is changeable to provide an adjustment of said illumination in said exit pupil.

1 . Illumination system for wavelengths ≦193 nm, particularly for EUV lithography, with
 a light source   an object plane   an exit pupil   a first optical element with raster elements, which is illuminated by the light source and which divides the light beam impinging from light source into light channels   a second optical element with raster elements, wherein each light channel which is formed by the raster element of the first optical element is assigned to a raster element of the second element, wherein   the raster elements of the first optical element and of the second optical element are each assigned to light channels, and the raster elements are configured or arranged such that a continuous beam path from light source to object plane results for each light channel, characterized in that   the assignment can be manipulated such that, by assigning the raster elements of the first to the second optical elements, a predetermined illumination is adjusted in the exit pupil of the illumination system.