| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a liquid immersion projection optical system which can assure a large image side numerical aperture of, for example, about 1.7 and good image forming performance. <P>SOLUTION: The liquid immersion projection optical system which forms an image of a first plane (R) on a second plane (W), has an optical element (Lb) of which surface on a side of the first plane can contact with a gas and surface on a side of the second plane can contact with a liquid (Lm). The liquid which can contact with the surface of the optical element on the side of the second plane has a refractive index larger than 1.5 for using light, when a refractive index of the gas in the liquid immersion objective optical system for the using light is 1. When Rb is a curvature radius of the surface of the optical element on the side of the first plane, Eb is an effective diameter of the surface of the optical element on the side of the first plane, and Nb is a refractive index of an optical material forming the optical element for the using light, the relation of 3.2<Nb×Eb/¾Rb¾<4.0 is satisfied. <P>COPYRIGHT: (C)2008,JPO&INPIT |
