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Title:
PROJECTION OBJECTIVE HAVING MIRROR ELEMENTS WITH REFLECTIVE COATINGS
Document Type and Number:
Japanese Patent JP2013157636
Kind Code:
A
Abstract:

To provide optical systems having mirror elements with reflective coatings for use with short wavelength radiation in a photolithography apparatus.

An optical system includes a plurality of elements arranged to image radiation at a wavelength λ from an object field in an object surface to an image field in an image surface. The elements include mirror elements having a reflective surface formed by a reflective coating positioned at a path of radiation. At least one of the mirror elements has a rotationally asymmetrical reflective surface deviating from a best-fit rotationally symmetric reflective surface by about λ or more at one or more locations. The elements include an apodization correction element effective to correct a spatial intensity distribution in an exit pupil of the optical system relative to the optical system without the apodization correcting element. The apodization correction element can be effective to increase symmetry of the spatial intensity distribution in the exit pupil relative to the optical system without the apodization correcting element.


Inventors:
CHAN DANNY
HANS-JUERGEN MANN
SASCHA MIGURA
Application Number:
JP2013097906A
Publication Date:
August 15, 2013
Filing Date:
May 07, 2013
Export Citation:
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Assignee:
ZEISS CARL SMT GMBH
International Classes:
H01L21/027; G02B7/02; G02B19/00; G03F7/20
Domestic Patent References:
JP2006128697A2006-05-18
JP2009508150A2009-02-26
JPH09326347A1997-12-16
JP2003177319A2003-06-27
JP2006059889A2006-03-02
JP2006058023A2006-03-02
JP2006128321A2006-05-18
JP2006128697A2006-05-18
JP2009508150A2009-02-26
JPH09326347A1997-12-16
JP2003177319A2003-06-27
JP2006059889A2006-03-02
JP2006058023A2006-03-02
JP2006128321A2006-05-18
Foreign References:
WO2005119369A12005-12-15
WO2007031271A12007-03-22
Attorney, Agent or Firm:
Koichi Tsujii
Sadao Kumakura
Fumiaki Otsuka
Takaki Nishijima
Hiroyuki Suda
Hiroshi Uesugi