Lithographic apparatus and device manufacturing method

Abstract

A lithographic apparatus is disclosed wherein a liquid supply system is configured to at least partly fill a region between a substrate and a projection system of the lithographic apparatus with a liquid and having a liquid confinement structure fixed in a plane substantially perpendicular to an optical axis of the projection system and configured to cooperate with a substrate table configured to hold the substrate in order to restrict the liquid to a region above an upper surface of the substrate table so that a side of the substrate to be exposed is substantially covered in the liquid during exposure.

1 . A lithographic apparatus, comprising:
 a substrate table constructed to hold a substrate to be exposed;   a projection system configured to project a patterned radiation beam onto a target portion on a side of the substrate to be exposed;   a liquid supply system configured to at least partly fill a region between the substrate and the projection system with a liquid; and   a liquid confinement structure fixed in a plane substantially perpendicular to an optical axis of the projection system and configured to cooperate with the substrate table in order to restrict the liquid to a region above an upper surface of the substrate table so that a side of the substrate to be exposed is substantially covered in the liquid during exposure.   
     
     
         2 . The apparatus according to  claim 1 , wherein a portion of the liquid confinement structure extends further towards the substrate than any part of a final element of the projection system. 
     
     
         3 . The apparatus according to  claim 1 , wherein the substrate table comprises:
 a substrate seat configured to hold the substrate; and   a sealing projection surrounding the substrate seat in a plane substantially perpendicular to the optical axis and configured to cooperate with the liquid confinement structure so as to substantially prevent liquid from escaping from the region between the substrate and the projection system.   
     
     
         4 . The apparatus according to  claim 3 , wherein the sealing projection comprises a gas seal configured to substantially prevent flow of liquid through a gap between a surface of the liquid confinement structure and the sealing projection. 
     
     
         5 . The apparatus according to  claim 4 , wherein the gas seal is arranged to produce a flow of gas within the gap that is directed substantially towards the optical axis in such a way as to at least partially confine the liquid. 
     
     
         6 . The apparatus according to  claim 1 , wherein:
 the liquid confinement structure comprises a gas seal, and   the substrate table comprises a sealing zone arranged to cooperate with the gas seal so as to substantially prevent liquid from escaping from the region between the substrate and the projection system.   
     
     
         7 . A lithographic apparatus, comprising:
 a projection system configured to project a patterned radiation beam onto a target portion of a substrate;   a liquid supply system configured to at least partly fill a region between the substrate and the projection system with a liquid; and   a saturated gas supply system configured to provide substantially saturated gas to a surface of the substrate not covered by liquid.   
     
     
         8 . The apparatus according to  claim 7 , further comprising a liquid confinement structure fixed in a plane substantially perpendicular to an optical axis of the projection system and configured to contain the liquid, the liquid confinement structure comprising an extension structure extending substantially radially with respect to the optical axis from the liquid confinement structure. 
     
     
         9 . The apparatus according to  claim 8 , wherein the extension structure is arranged to cooperate with a vapor sealing projection, forming part of a substrate table configured to hold the substrate, so as to substantially contain the substantially saturated gas. 
     
     
         10 . The apparatus according to  claim 9 , wherein the extension structure and the vapor sealing projection are configured to contain the substantially saturated gas in a region delimited by the substrate table, the substrate, the liquid when provided to the region, the liquid confinement structure, the extension structure and the vapor sealing projection. 
     
     
         11 . The apparatus according to  claim 9 , wherein the vapor sealing projection comprises a gas seal configured to substantially prevent flow of substantially saturated gas through a gap between a surface of the extension structure and the vapor sealing projection. 
     
     
         12 . The apparatus according to  claim 7 , wherein the saturated gas supply system comprises a saturated gas preparer configured to make substantially saturated gas from the liquid. 
     
     
         13 . The apparatus according to  claim 7 , wherein the liquid supply system is configured to supply liquid to a region covering only a localized portion of the substrate at any one time. 
     
     
         14 . A lithographic apparatus, comprising:
 a substrate table configured to hold a substrate to be exposed;   a projection system configured to project a patterned radiation beam onto a target portion on a side of the substrate to be exposed;   a liquid supply system configured to at least partly fill a region between the substrate and the projection system with a liquid;   a first confinement structure fixed in a plane substantially perpendicular to an optical axis of the projection system and configured to cooperate with the substrate table in order to restrict the liquid to a region above an upper surface of the substrate table; and   a second confinement structure fixed in a plane substantially perpendicular to an optical axis of the projection system and configured to cooperate with the substrate table in order to restrict substantially saturated gas to a region above an upper surface of the substrate table,   wherein the first and second confinement structures and the substrate table are arranged so that a side of the substrate to be exposed is entirely covered with substantially saturated gas except for an area covered with liquid during exposure.   
     
     
         15 . The apparatus according to  claim 14 , wherein the substrate table comprises a vapor sealing projection arranged to cooperate with the second confinement structure so as to substantially contain the substantially saturated gas. 
     
     
         16 . The apparatus according to  claim 15 , wherein the second confinement structure and the vapor sealing projection are configured to contain the substantially saturated gas in a region delimited by the substrate table, the substrate, the liquid when provided to the region, the first confinement structure, the second confinement structure and the vapor sealing projection. 
     
     
         17 . The apparatus according to  claim 15 , wherein the vapor sealing projection comprises a gas seal configured to substantially prevent flow of substantially saturated gas through a gap between a surface of the second confinement structure and the vapor sealing projection. 
     
     
         18 . The apparatus according to  claim 14 , wherein the liquid supply system is configured to supply liquid to a region covering only a localized portion of the substrate at any one time. 
     
     
         19 . The apparatus according to  claim 14 , further comprising a saturated gas supply system configured to provide substantially saturated gas to a surface of the substrate not covered by liquid. 
     
     
         20 . A lithographic apparatus, comprising:
 a substrate table configured to hold a substrate to be exposed;   a projection system configured to project a patterned radiation beam onto a target portion of a substrate;   a liquid supply system configured to at least partly fill a region between the substrate and the projection system with a liquid;   a saturated gas supply system configured to provide substantially saturated gas to a surface of the substrate not covered by liquid;   a first confinement structure fixed in a plane substantially perpendicular to an optical axis of the projection system and configured to contain the liquid; and   a second confinement structure fixed in a plane substantially perpendicular to an optical axis of the projection system and configured to cooperate with the substrate table in order to restrict substantially saturated gas to a region above an upper surface of the substrate table,   wherein the first and second confinement structures and the substrate table are arranged so that aside of the substrate to be exposed is entirely covered with substantially saturated gas except for an area covered with liquid during exposure.   
     
     
         21 .- 42 . (canceled)