Patent ID: 8730455
Filing Date: 2014-05-20
Classification: G03B,G03F

Abstract:
1. An illumination system for a microlithographic projection exposure step-and-scan apparatus, comprising the following components arranged along a light propagation direction: a light source, a first optical raster element that extends in or in close proximity of a pupil plane of the illumination system and includes an array of parallel elongated first micro-lenses extending along a first direction which is at least substantially perpendicular to a scan direction of the projection exposure apparatus, a second optical raster element that extends in or in close proximity of a second pupil plane of the illumination system, which is not necessarily different from the first pupil plane, and includes an array of parallel elongated second micro-lenses extending along a second direction which is at least substantially parallel to the scan direction, a third optical raster element positioned at least substantially in a focal plane of the second micro-lenses and including an array of parallel elongated third micro-lenses that extend along the second direction, said second micro-lenses and third micro-lenses having curved surfaces that are facing each other, and a fourth optical raster element positioned at least substantially in a focal plane of the first micro-lenses and including an array of parallel elongated fourth micro-lenses that extend along the first direction.