The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 05, 2006
Filed:
Feb. 12, 2003
Daniel Krähmer, Aalen, DE;
Toralf Gruner, Aalen-Hofen, DE;
Wilhelm Ulrich, Aalen, DE;
Birgit Enkisch, Aalen, DE;
Michael Gerhard, Aalen, DE;
Martin Brunotte, Aalen, DE;
Christian Wagner, KS Eersel, NL;
Winfried Kaiser, Aalen, DE;
Manfred Maul, Aalen, DE;
Christof Zaczek, Heubach, DE;
Daniel Krähmer, Aalen, DE;
Toralf Gruner, Aalen-Hofen, DE;
Wilhelm Ulrich, Aalen, DE;
Birgit Enkisch, Aalen, DE;
Michael Gerhard, Aalen, DE;
Martin Brunotte, Aalen, DE;
Christian Wagner, KS Eersel, NL;
Winfried Kaiser, Aalen, DE;
Manfred Maul, Aalen, DE;
Christof Zaczek, Heubach, DE;
Carl Zeiss SMT AG, , DE;
Abstract
An objective for a microlithography projection system has at least one fluoride crystal lens. The effects of birefringence, which are detrimental to the image quality, are reduced if the lens axis of the crystal lens is oriented substantially perpendicular to the {100}-planes or {100}-equivalent crystallographic planes of the fluoride crystal. If two or more fluoride crystal lenses are used, they should have lens axes oriented in the (100)-, (111)-, or (110)-direction of the crystallographic structure, and they should be oriented at rotated positions relative to each other. The birefringence-related effects are further reduced by using groups of mutually rotated (100)-lenses in combination with groups of mutually rotated (111)- or (110)-lenses. A further improvement is also achieved by applying a compensation coating to at least one optical element of the objective.