Measuring method and apparatus using shearing interferometry, exposure method and apparatus using the same, and device manufacturing method
AssigneeCanon Kabushiki Kaisha
InventorMasanobu Hasegawa
Life of this patent
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Abstract
A measuring apparatus for irradiating measuring light and for measuring optical performance of a target optical system includes a barrel for housing the target optical system, the barrel being rotatable around an optical axis of the target optical system, and an illumination optical system for introducing the measuring light into the barrel, the illumination optical system being movable along a direction perpendicular to the optical axis of the target optical system. The measuring apparatus controls an illumination area of the measuring light in the target optical system using a polar coordinate determined by a rotational angle of the barrel and a moving amount of the illumination optical system.
Claims8
A measuring apparatus comprising:
- a first mask having a pinhole for generating a spherical wave as measuring light;
- a second mask provided subsequent to said first mask in a light traveling direction, said second mask having two pairs of selecting windows that allow the measuring light that has passed a target optical system to transmit through the selecting windows;
- and
- a two-dimensional light divider, located between said first and second masks, for two-dimensionally dividing incident light into two pairs of ±1st order lights,
- wherein the two pairs of selecting windows in the second mask are arranged at a position where each of the two pairs of ±1st order lights passes through simultaneously and
- wherein said measuring apparatus calculates optical performance of the target optical system from an interference fringe formed by a shearing interference between each measuring light that has passed the selecting windows.
Dependencies are inferred from the claim text.