Lithographic apparatus and device manufacturing method

Abstract

A lithographic projection apparatus is disclosed for use with an immersion liquid positioned between the projection system and a substrate. Several methods and mechanism are disclosed to protect components of the projection system, substrate table and a liquid confinement system. These include providing a protective coating on a final element of the projection system as well as providing one or more sacrificial bodies upstream of the components. A two component final optical element of CaF2 is also disclosed.

1 - 55 . (canceled) 
     
     
         56 . An exposure apparatus, comprising:
 a projection optical system configured to project radiation patterned by a patterning device onto an object, the projection optical system comprising an optical element closest to the object through which the radiation is projected onto the object, the optical element having a bottom surface and an oblique side surface, and wherein the bottom surface of the optical element has a smaller cross-sectional width than that of a surface on the patterning device side of the optical element; and   a liquid confinement member configured to at least partly constrain liquid within a space between the optical element and the object, the liquid confinement member having a surface facing the side surface of the optical element, wherein a gap between the surface of the liquid confinement member and the side surface of the optical element allows liquid to flow therein to contact the side surface of the optical element.   
     
     
         57 . The exposure apparatus of  claim 56 , wherein the liquid confinement member comprises an opening configured to supply the liquid to between the optical element and the object, the opening located underneath the optical element. 
     
     
         58 . The exposure apparatus of  claim 56 , wherein the projection optical system is a catadioptric optical system. 
     
     
         59 . The exposure apparatus of  claim 56 , wherein the side surface has a protective coating arranged to have the liquid in contact therewith. 
     
     
         60 . The exposure apparatus of  claim 56 , wherein the surface on the patterning device side of the optical element is curved. 
     
     
         61 . The exposure apparatus of  claim 56 , wherein the surface on the patterning device side of the optical element is hemispherical. 
     
     
         62 . The exposure apparatus of  claim 56 , wherein the optical element comprises CaF 2 . 
     
     
         63 . The exposure apparatus of  claim 56 , wherein the liquid confinement member comprises:
 an opening configured to supply the liquid to between the optical element and the object,   an outlet configured to recover at least some of the liquid,   wherein a distance between the outlet and an optical axis of the optical element is longer than a distance between the opening and the optical axis.   
     
     
         64 . An exposure apparatus comprising:
 a projection optical system configured to project radiation patterned by a patterning device onto an object, the projection optical system comprising an optical element closest to the object through which the radiation is projected onto the object, the optical element having a bottom surface and an oblique side surface; and   a liquid confinement member configured to at least partly constrain liquid within a space between the optical element and the object, the liquid confinement member comprising an opening configured to supply the liquid to between the optical element and the object, wherein the opening is located below the optical element and within an outer periphery of the optical element.   
     
     
         65 . The exposure apparatus of  claim 64 , wherein the liquid confinement member has a surface facing the side surface of the optical element, wherein a gap between the surface of the liquid confinement member and the side surface of the optical element allows liquid to flow therein to contact the side surface of the optical element. 
     
     
         66 . The exposure apparatus of  claim 64 , wherein the projection optical system is a catadioptric optical system. 
     
     
         67 . The exposure apparatus of  claim 64 , wherein the side surface has a protective coating arranged to have the liquid in contact therewith. 
     
     
         68 . The exposure apparatus of  claim 64 , wherein a surface on the patterning device side of the optical element is curved. 
     
     
         69 . The exposure apparatus of  claim 64 , wherein a surface on the patterning device side of the optical element is hemispherical. 
     
     
         70 . The exposure apparatus of  claim 64 , wherein the optical element comprises CaF 2 . 
     
     
         71 . The exposure apparatus of  claim 64 , further comprising an outlet configured to recover at least some of the liquid, wherein a distance between the outlet and an optical axis of the optical element is longer than a distance between the opening and the optical axis. 
     
     
         72 . A device fabrication method comprising:
 at least partly constraining liquid within a space between an optical element of a projection optical system and an object using a liquid confinement member, the liquid confinement member having a surface facing an oblique side surface of the optical element, wherein a gap between the surface of the liquid confinement member and the side surface of the optical element allows liquid to flow therein to contact the side surface of the optical element; and   projecting radiation patterned by a patterning device onto the object, the radiation projected via a bottom surface of the optical element,   wherein the bottom surface of the optical element has a smaller cross-sectional width than that of a surface on the patterning device side of the optical element.   
     
     
         73 . The method of  claim 72 , further comprising supplying the liquid to between the optical element and the object using an opening of the liquid confinement member, the opening located underneath the optical element. 
     
     
         74 . The method of  claim 72 , wherein the projection optical system is a catadioptric optical system. 
     
     
         75 . The method of  claim 72 , wherein the side surface has a protective coating arranged to have the liquid in contact therewith.