Projection optical system, exposure apparatus and method using the same
AssigneeCanon Kabushiki Kaisha
InventorsYuhei Sumiyoshi, Masayuki Suzuki
Life of this patent
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Abstract
A projection optical system includes an optical element that includes and locally uses a reflective or refractive area that is substantially axially symmetrical around an optical axis, the optical element being rotatable around the optical axis.
Claims19
A projection optical system comprising an optical element that includes and locally uses a reflective and/or refractive area that is substantially axially symmetrical around an optical axis of the optical element, said optical element being rotatable around the optical axis.
An exposure method comprising the steps of:
- evaluating a deterioration of a projection optical system for projecting, onto an object to be exposed, light from a mask which forms a pattern;
- selecting, based on a result of said evaluating step, at least one predetermined area on at least one optical element for correcting the deterioration of the projection optical system;
- and
- exposing the object to be exposed using the predetermined area.
An exposure apparatus comprising a projection optical system including an optical element that includes and locally uses a reflective and/or refractive area that is substantially axially symmetrical around an optical axis, said optical element being rotatable around the optical axis.
A device fabricating method comprising the steps of:
- exposing an object using an exposure apparatus;
- and
- performing a predetermined process for the exposed object,
- wherein an exposure apparatus includes a projection optical system including an optical element that includes and locally uses a reflective and/or refractive area that is substantially axially symmetrical around an optical axis, said optical element being rotatable around the optical axis.
Dependencies are inferred from the claim text.