Patent ID: 8355201
Filing Date: 2013-01-15
Classification: G02B,G03F

Abstract:
1. A catadioptric projection objective for imaging a pattern provided in an object plane of the projection objective onto an image plane of the projection objective comprising: a first, refractive objective part for imaging the pattern provided in the object plane into a first intermediate image; a second objective part including at least one concave mirror for imaging the first intermediate image into a second intermediate image; a third, refractive objective part for imaging the second intermediate imaging onto the image plane; wherein the projection objective includes at least one double asphere having a first aspheric surface and a second aspheric surface immediately adjacent to the first aspheric surface, the double asphere being formed by facing adjacent aspheric surfaces of two consecutive lenses; wherein a first concave mirror having a first continuous mirror surface and at least one second concave mirror having a second continuous mirror surface are arranged in the second objective part; pupil surfaces are formed between the object plane and the first intermediate image, between the first and the second intermediate images and between the second intermediate image and the image plane; and all concave mirrors are arranged optically remote from a pupil surface.