Projection optical system, exposure apparatus, and exposure method

Abstract

An immersion projection optical system having, for example, a catadioptric and off-axis structure, reduces the portion of an image space filled with liquid (immersion 5 liquid), The projection optical system, which projects a reduced image of a first plane onto a second plane through the liquid, includes a refractive optical element (Lp) arranged nearest to the second plane. The refractive optical element includes a light emitting surface (Lpb) shaped to be substantially symmetric with respect to two axial directions (XY axes) perpendicular to each other on the second plane. The light emitting surface has a central axis (Lpba) that substantially coincides with a central axis of a circle corresponding to a circumference of a light entering surface (Lpa) of the refractive optical element. The central axis of the light emitting surface is decentered in one of the two axial directions (Y˜axis) from an optical axis (AX).

What is claimed: 
     
         1 . A projection optical system for projecting an image of a first plane onto a second plane through a liquid, the projection optical system comprising:
 a refractive optical element arranged nearest to the second plane;   wherein the refractive optical element includes a light emitting surface shaped to be rotationally asymmetric with respect to an optical axis of the projection optical system in accordance with the shape of an effective projection region formed on the second plane.