Fish & Richardson P.C.
Catadioptric projection objective including an aspherized plate
A catadioptric projection objective for imaging a pattern onto an image plane includes: a first objective part for imaging the pattern into a first intermediate image; a second objective part for imaging the first intermediate image into a second intermediate image; and a third objective part for imaging the second intermediate image onto the image plane. A first concave mirror having a continuous mirror surface and a second concave mirror having a continuous mirror surface are upstream of the second intermediate image. A pupil surface is formed between the object plane and the first intermediate image, between the first and the second intermediate image, and between the second intermediate image and the image plane. A plate having essentially parallel plate surfaces is positioned in the first objective part near the pupil surface. At least one plate surface is aspherized to correct for aberrations.
Carl Zeiss SMT GmbH
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G02B G02B G03F G02B G02B G02B G02B
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David Aurelian Wilhelm Hans-Juergen Rudolf M. Alexander
Shafer Dodoc Ulrich Mann Von Buenau Epple