Optical element and projection exposure apparatus based on use of the optical element

Abstract

A liquid immersion exposure apparatus includes a projection optical system (PL) which projects an image of a pattern onto a substrate (W) and a unit ( 5 ) which supplies a liquid ( 7 ) between an optical element ( 4 ) at the end of the projection optical system (PL) and the substrate (W). A corrosion-resistant film composed of an oxide is formed on the surface of the optical element ( 4 ) to prevent corrosion by the liquid ( 7 ). Consequently, a desired performance of the projection optical system can be secured for a long time even where a full field exposure in the step-and-repeat manner or a scanning exposure in the step-and-scan manner is performed in a liquid-immersion state.

1 . A lithographic projection apparatus arranged to project a pattern from a patterning device onto a substrate using a projection system and having a liquid supply system configured to at least partly fill a space between the projection system and the substrate with a liquid, wherein an element of the projection system through which the pattern is projected has, on a surface configured to be in contact with the liquid, a protective coating which is substantially insoluble in the liquid.  
   
   
       2 . The apparatus according to  claim 1 , wherein the protective coating has a thickness equal to or greater than 5 mn.  
   
   
       3 . The apparatus according to  claim 1 , wherein the protective coating has a thickness less than or equal to 500 nm  
   
   
       4 . The apparatus according to  claim 1 , wherein the protective coating is a metal, a metal oxide or nitride, CaF 2 , SiO, SiO 2  or any combination of these materials.  
   
   
       5 .- 7 . (canceled)  
   
   
       8 . The apparatus according to  claim 1 , wherein the protective coating has two distinct layers.  
   
   
       9 .- 32 . (canceled)  
   
   
       33 . A device manufacturing method comprising projecting a patterned beam of radiation onto a substrate through a liquid provided in a space between an element of a projection system and the substrate, wherein a surface of the element in contact with the liquid comprises a protective coating which is substantially insoluble in the liquid.  
   
   
       34 . The method according to  claim 33 , wherein the protective coating has a thickness in the range of from 5 nm to 500 nm.  
   
   
       35 . The method according to  claim 33 , wherein the protective coating is a metal, a metal oxide or nitride, CaF 2 , SiO, SiO 2  or any combination of these materials.  
   
   
       36 . The method according to  claim 33 , wherein the protective coating is a fused silica plate having a thickness in the range of from 50 μm to 5 mm.  
   
   
       37 . The method according to  claim 36 , wherein the fused silica plate is attached to the element by contact bonding without glue.  
   
   
       38 . The method according to  claim 33 , wherein the protective coating has two distinct layers.  
   
   
       39 .- 55 . (canceled)  
   
   
       56 . A lens adapted for illumination by a predetermined wavelength of light during liquid immersion photolithography, the lens comprising: a transparent substrate; and a layer of anti-corrosion coating (ACC) formed proximate to the transparent substrate, wherein the ACC is positioned between a liquid used during the liquid immersion photolithography and the transparent substrate to protect the transparent substrate from the liquid.  
   
   
       57 . The lens of  claim 56 , wherein the transparent substrate is CaF 2 .  
   
   
       58 .- 60 . (canceled)  
   
   
       61 . The lens of  claim 56 , wherein the ACC is SiO 2 .  
   
   
       62 .- 64 . (canceled)  
   
   
       65 . The lens of  claim 56 , wherein the predetermined wavelength of light is centered at 248 nm.  
   
   
       66 . The lens of  claim 56 , wherein the predetermined wavelength of light is centered at 193 nm.  
   
   
       67 . (canceled)  
   
   
       68 . The lens of  claim 56 , wherein the ACC has a thickness less than 1000 μm.  
   
   
       69 . The lens of  claim 56 , wherein a fluctuation of surface flatness of the ACC is less than half of the predetermined wavelength of light.  
   
   
       70 .- 89 . (canceled)