Method for measuring an angularly resolved intensity distribution and projection exposure apparatus

Abstract

A method for measuring an angularly resolved intensity distribution in a reticle plane ( 24 ) of a projection exposure apparatus ( 10 ). The apparatus includes an illumination system ( 16 ), irradiating a reticle ( 22 ) arranged in the reticle plane ( 24 ) and having a first pupil plane ( 20 ). All planes of the projection exposure apparatus which are conjugate thereto are further pupil planes, and the reticle plane ( 24 ) and all planes which are conjugate thereto are field planes. The method includes: arranging a spatially resolving detection module ( 44 ) in the region of one of the field planes ( 24, 30 ) such that the detection module is at a smaller distance from this field plane than from the closest pupil plane ( 20 ), radiating electromagnetic radiation ( 21 ) onto an optical module ( 42 ) from the illumination system, and determining an angularly resolved intensity distribution of the radiation from a signal recorded by the detection module.

What is claimed is: 
     
         1 . A projection exposure apparatus for microlithography comprising a radiation source for generating exposure radiation, and an illumination system disposed downstream of the radiation source and configured for radiating the exposure radiation into a reticle plane of the projection exposure apparatus, wherein the illumination system comprises:
 a beam expanding optical unit for expanding a beam cross section of the exposure radiation from the radiation source,   a beam angle redistribution module for deflecting partial beams of the exposure radiation from the beam expanding optical unit,   a divergence amplification module for amplifying a divergence of the beam from the beam expanding optical unit, and   an exchanging device for exchanging at least one element of the beam angle redistribution module for the divergence amplification module.   
     
     
         2 . The projection exposure apparatus according to  claim 1 ,
 further comprising a projection lens for imaging mask structures from the reticle plane onto a wafer, a wafer stage for holding the wafer, and a system for measuring an illumination angle distribution in the reticle plane, wherein the system comprises a detector module arranged at the wafer stage and the detector module is arranged in a region of the conjugate pupil plane of the projection lens during the measuring.   
     
     
         3 . The projection exposure apparatus according to  claim 1 ,
 wherein the beam angle redistribution module comprises a diffractive optical element.   
     
     
         4 . The projection exposure apparatus according to  claim 1 ,
 wherein the divergence amplification module comprises a microlens element array.   
     
     
         5 . The projection exposure apparatus according to  claim 1 ,
 wherein the divergence amplification module comprises two microlens element arrays having different focal lengths.   
     
     
         6 . A method for measuring an angularly resolved intensity distribution in a reticle plane of a projection exposure apparatus for microlithography comprising
 an illumination system, which is configured for irradiating a reticle arranged in the reticle plane and has a first pupil plane, wherein all planes of the projection exposure apparatus which are conjugate with respect to the first pupil plane are further pupil planes, and the reticle plane and all planes which are conjugate with respect to the reticle plane are field planes, comprising:   arranging an optical module in a beam path of the projection exposure apparatus above the reticle plane,   arranging a spatially resolving detection module in a region of one of the field planes such that the detection module is at a smaller distance from the one field plane than from a closest one of the pupil planes,   radiating electromagnetic radiation onto the optical module with the illumination system, and   determining an angularly resolved intensity distribution of the radiated radiation from a signal recorded by the detection module.