US Patent 7145635 Exposure method and apparatus

An exposure apparatus includes a projection optical system for projecting a pattern on a mask onto an object to be exposed, a final surface of the projection optical system and a surface of the object immersed in a fluid, and a plane-parallel plate arranged between the projection optical system and the object. The plane-parallel plate includes a first surface and a second surface that serves as a back surface of the first surface and opposes to the object. Both the first and second surfaces are immersed in the fluid and the plane-parallel plate has an antireflection coating that is designed according to an incident light at an angle corresponding to a numerical aperture of the projection optical system.