Vacuum system for immersion photolithography

Abstract

A vacuum system for extracting a stream of a multi-phase fluid from a photo-lithography tool comprises a pumping arrangement for drawing the fluid from the tool, and an extraction tank located upstream from the pumping arrangement for separating the fluid drawn from the tool into gas and liquid phases. The pumping arrangement comprises a first pump for extracting gas from the tank, and a second pump for extracting liquid from the tank. In order to minimize any pressure fluctuations transmitted from the vacuum system back to the fluid within the tool, a pressure control system maintains a substantially constant pressure in the tank by regulating the amounts of liquid and gas within the tank.

1 .- 20 . (canceled) 
     
     
         21 . A lithographic apparatus, comprising:
 a projection device configured to project a radiation beam onto a substrate;   an inlet configured to provide a liquid to a space between the projection device and the substrate;   an outlet configured to remove at least part of the liquid as a multi-phase fluid;   a separator configured to receive the multi-phase fluid from the outlet, the separator configured to separate the fluid into gas and liquid phases;   a first opening at a first side of the separator, the first opening configured to allow the multi-phase fluid into a part of the separator; and   a second opening at a second side of the separator opposite to the first side, the second opening configured to exhaust separated gas from the separator.   
     
     
         22 . The apparatus of  claim 21 , further comprising a pump arrangement configured to draw the multi-phase fluid into the separator. 
     
     
         23 . The apparatus of  claim 21 , further comprising a pump arrangement configured to extract separated liquid, via a third opening, from the separator. 
     
     
         24 . The apparatus of  claim 21 , further comprising a control system configured to control a pressure within the separator by regulating the gas and/or liquid therein. 
     
     
         25 . The apparatus of  claim 21 , further comprising a control system configured to control flow of gas from the separator. 
     
     
         26 . The apparatus of  claim 21 , further comprising a control system configured to control an amount of liquid within the separator. 
     
     
         27 . The apparatus of  claim 21 , further comprising a flow restriction in a fluid path from the separator to a pump fluidly connected to the separator. 
     
     
         28 . The apparatus of  claim 21 , wherein the separator comprises a chamber having the first and second openings therein. 
     
     
         29 . The apparatus of  claim 21 , wherein the first opening is located at a different height than a third opening configured to exhaust separated liquid from the separator. 
     
     
         30 . The apparatus of  claim 29 , wherein the first opening is higher than the third opening. 
     
     
         31 . The apparatus of  claim 21 , further comprising a control system configured to control a level of liquid within the separator. 
     
     
         32 . A lithographic apparatus, comprising:
 a projection device configured to project a radiation beam onto a substrate;   an inlet configured to provide a liquid to a space between the projection device and the substrate;   an outlet configured to remove at least part of the liquid as a multi-phase fluid;   a separator configured to receive the multi-phase fluid from the outlet, the separator configured to separate the fluid into gas and liquid phases;   a first opening configured to allow the multi-phase fluid into a part of the separator; and   a second opening configured to exhaust separated liquid from the separator, the first opening being located at a different height than the second opening.   
     
     
         33 . The apparatus of  claim 32 , further comprising a pump arrangement configured to draw the multi-phase fluid into the separator. 
     
     
         34 . The apparatus of  claim 32 , further comprising a pump arrangement configured to extract separated liquid, via the second opening, from the separator. 
     
     
         35 . The apparatus of  claim 32 , further comprising a control system configured to control a pressure within the separator by regulating the gas and/or liquid therein. 
     
     
         36 . The apparatus of  claim 32 , further comprising a control system configured to control flow of gas from the separator. 
     
     
         37 . The apparatus of  claim 32 , further comprising a control system configured to control an amount of liquid within the separator. 
     
     
         38 . The apparatus of  claim 32 , further comprising a flow restriction in a fluid path from the separator to a pump fluidly connected to the separator. 
     
     
         39 . The apparatus of  claim 32 , wherein the separator comprises a chamber having the first and second openings therein. 
     
     
         40 . A lithographic apparatus, comprising:
 a projection device configured to project a radiation beam onto a radiation-sensitive substrate;   an inlet opening located above the stage, the inlet configured to provide a liquid to a space between the projection device and the substrate;   an outlet opening located above the stage, the outlet configured to remove at least part of the liquid as a multi-phase fluid;   a stage configured to support the substrate and moveable relative to the inlet and outlet;   a separator configured to receive the multi-phase fluid from the outlet, the separator configured to separate the fluid into gas and liquid phases;   a first opening at a first side of a chamber of the separator, the first opening configured to allow the multi-phase fluid into a part of the separator;   a second opening at a second side of the chamber opposite to the first side, the second opening configured to exhaust separated gas from the separator; and   a third opening configured to exhaust separated gas from the chamber, the second opening located at a different height than the second opening.