Liquid immersion type exposure apparatus
AssigneeCanon Kabushiki Kaisha
InventorTakashi Nakamura
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Abstract
Disclosed is a liquid immersion type exposure apparatus specifically arranged to maintain a liquid film between an exposure substrate and a terminal end portion of a projection optical system. In one preferred form, the liquid immersion type exposure apparatus includes a projection optical system for projecting a pattern of a mask onto a substrate, a liquid film forming system for forming a liquid film in a predetermined region between the projection optical system and the substrate, and a sensor for detecting disappearance of at least a portion of the liquid film in the predetermined region.
Claims7
A liquid immersion type exposure apparatus, comprising:
- a projection optical system for projecting a pattern of a mask onto a substrate;
- a liquid film forming system for forming a liquid film in a predetermined region between said projection optical system and the substrate;
- and
- a sensor for detecting disappearance of at least a portion of the liquid film in said predetermined region, said sensor having a light providing element and a light receiving element mounted on a barrel of said projection optical system, wherein light from said light providing element is received by said light receiving element after being repeatedly reflected inside the liquid film.
Dependencies are inferred from the claim text.