Fluid handling structure, a lithographic apparatus and a device manufacturing method

Abstract

A fluid handling structure for a lithographic apparatus configured to contain immersion fluid to a region, the fluid handling structure having, at a boundary of a space: at least one gas knife opening in a radially outward direction of the space; and at least one gas supply opening in the radially outward direction of the at least gas knife opening relative to the space. The gas knife opening and the gas supply opening both provide substantially pure CO2 gas so as to provide a substantially pure CO2 gas environment adjacent to, and radially outward of, the space.

1 . An immersion system comprising a fluid handling structure configured to contain immersion fluid to a region, the fluid handling structure having, at a boundary of a space:
 at least one gas knife opening in a radially outward direction from the space; and   at least one gas supply opening in the radially outward direction from the at least one gas knife opening relative to the space; and the immersion system further comprising   a gas supply system configured to supply substantially pure CO 2  gas through the at least one gas knife opening and the at least one gas supply opening so as to provide an atmosphere of substantially pure CO 2  gas adjacent to, and radially outward of, the space.   
     
     
         2 . The immersion system of  claim 1 , wherein the gas exits the at least one gas knife opening at a first gas velocity and the gas exits the at least one gas supply opening at a second gas velocity, the first gas velocity being greater than the second gas velocity. 
     
     
         3 . The immersion system of  claim 1 , wherein the substantially pure CO 2  gas is humidified CO 2  gas. 
     
     
         4 . An immersion system comprising a fluid handling structure configured to contain immersion fluid to a region, the fluid handling structure having, at a boundary of a space:
 at least one gas knife opening in a radially outward direction from the space;   at least one gas supply opening in the radially outward direction from the at least one gas knife opening relative to the space; and   a gas supply system configured to supply gas through the at least one gas knife opening and the at least one gas supply opening, wherein gas exits the at least one gas knife opening at a higher gas velocity than gas exiting the at least one gas supply opening.   
     
     
         5 . The immersion system of  claim 1 , wherein the fluid handling structure comprises a meniscus controlling feature to resist passage of the immersion fluid in a radially outward direction from the space, the meniscus controlling feature being radially inward of the at least one gas knife opening. 
     
     
         6 . The immersion system of  claim 1 , wherein the gas exits the at least one gas knife opening at a first flow speed and the gas exits the at least one gas supply opening at a second flow speed, the first flow speed being greater than the second flow speed. 
     
     
         7 . The immersion system of  claim 1 , wherein the fluid handling structure comprises the gas supply system. 
     
     
         8 . The immersion system of  claim 1 , wherein the gas supply system comprises at least one gas source to provide gas to the at least one gas knife opening and the at least one gas supply opening. 
     
     
         9 . The immersion system of  claim 8 , wherein the gas supply system comprises a first path between a first gas source and the at least one gas knife opening and a second path between a second gas source and the at least one gas supply opening, wherein the second path comprises a flow restrictor section, and optionally, wherein the flow restrictor section is a bend and/or reduction in a flow-through area in the second path. 
     
     
         10 . The immersion system of  claim 9 , wherein the first gas source and the second gas source are the same gas source. 
     
     
         11 . The immersion system of  claim 1 , wherein the at least one gas knife opening and the at least one gas supply opening are on a surface of the fluid handling structure facing a substrate and/or a substrate table, wherein the at least one gas knife opening is closer to the substrate and/or substrate table than the at least one gas supply opening, and/or the at least one gas knife opening has a smaller surface area on the surface of the fluid handling structure than the at least one gas supply opening. 
     
     
         12 . The immersion system of  claim 1 , wherein the fluid handling structure is configured to dynamically control the amount of gas supplied to the gas knife opening by redirecting gas to the gas knife opening from the gas supply opening, or from the gas knife opening to the gas supply opening. 
     
     
         13 . A device manufacturing method comprising using the fluid handling structure of  claim 1  in a lithographic apparatus. 
     
     
         14 . A lithographic apparatus comprising an immersion system comprising the fluid handling structure of  claim 1 . 
     
     
         15 . A device manufacturing method comprising using the fluid handling structure of  claim 4  in a lithographic apparatus. 
     
     
         16 . A lithographic apparatus comprising an immersion system comprising the fluid handling structure of  claim 4 . 
     
     
         17 . A fluid handling structure configured to contain immersion fluid to a region, the fluid handling structure having, at a boundary of a space:
 at least one gas knife opening in a radially outward direction from the space; and   at least one gas supply opening in the radially outward direction from the at least one gas knife opening relative to the space, wherein   the at least one gas supply opening comprises a mesh, a sieve, porous material and/or array of holes.