Exposure apparatus equipped with interferometer and exposure apparatus using the same
AssigneeCanon Kabushiki Kaisha
InventorYoshinori Ohsaki
Life of this patent
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Abstract
An exposure apparatus includes a projection optical system for projecting an exposure pattern, onto an object to be exposed, and a measuring apparatus for measuring, as an interference fringe, optical performance of the projection optical system, wherein the measuring apparatus includes an optical element having opposing first and second surfaces, wherein the first surface has a first measurement pattern, and the second surface has a second measurement pattern and is closer to the projection optical system than the first measurement pattern, and wherein the measuring apparatus introduces light into the projection optical system via first and second measurement patterns.
Claims10
An exposure apparatus comprising:
- a projection optical system for projecting an exposure pattern, onto an object to be exposed;
- and
- a measuring apparatus for measuring an interference fringe as an optical performance of said projection optical system,
- wherein said measuring apparatus includes an optical element having opposing first and second surfaces,
- wherein the first surface has a diffraction grating and the second surface has a plurality of openings and is closer to said projection optical system than the diffraction grating, and
- wherein said measuring apparatus measures the interference fringe being generated by lights of diffracted lights from the diffraction grating, each of which transmits on of a plurality of openings and said projection optical system.
Dependencies are inferred from the claim text.