Title:
光リソグラフィー用光学部材及びその評価方法
Document Type and Number:
Japanese Patent JP3741208
Kind Code:
B2
Abstract:
A method for evaluating an optical member for photolithography composed of a fluoride crystal comprises a step of measuring a crystal plane orientation of the optical member, and a step of specifying a twin region on the basis of a result of the measurement. The twin region in an effective region of an optical element is specified as a total area of a region obtained by projection onto a plane perpendicular to an optical axis of the optical element. It is judged that the optical member is usable when the total area is not more than 10 % of an effective diametric area or a partial diametric area of the optical element. The obtained optical element has satisfactory image formation characteristics because of less birefringence.
Inventors:
Shigeru Sakuma
Application Number:
JP2001363584A
Publication Date:
February 01, 2006
Filing Date:
November 29, 2001
Export Citation:
Assignee:
NIKON CORPORATION
International Classes:
C30B11/00; G01N23/205; G02B1/02; G02B1/11; G02B5/26; G03F7/20; H01L21/027
Foreign References:
| EP1154046A1 | ||||
| EP1130136A1 |
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