Lithographic apparatus and device manufacturing method

Abstract

In an immersion lithography apparatus, ultrasonic waves are used to atomize liquid on a surface of the substrate.

1 .- 25 . (canceled) 
     
     
         26 . A lithographic projection apparatus, comprising:
 a movable table;   a projection system configured to project a patterned radiation beam onto a target portion of a substrate;   a liquid supply system comprising an inlet to provide liquid in a space between the projection system and the table and an outlet to remove liquid from the space; and   an ultrasonic waves generator having an ultrasonic wave emitting surface located outward of the outlet relative to a path of the patterned radiation beam through the space, to impart ultrasonic waves to liquid on a surface located outward of the outlet relative to the path.   
     
     
         27 . The apparatus according to  claim 26 , wherein the liquid supply system comprises a liquid confinement structure, located above the table, to at least partly confine liquid in the space, the liquid confinement structure having the inlet and the outlet. 
     
     
         28 . The apparatus according to  claim 26 , further comprising a gas inlet located outward of the outlet relative to the path to supply a flow of gas to the surface. 
     
     
         29 . The apparatus according to  claim 26 , further comprising a sensor configured to detect material on the surface. 
     
     
         30 . The apparatus according to  claim 26 , further comprising a control system configured to control the ultrasonic waves generator depending on whether the sensor detects material on the surface. 
     
     
         31 . The apparatus according to  claim 26 , wherein the ultrasonic waves generator is configured to emit ultrasonic waves having a frequency in the range of 1 to 50 MHz. 
     
     
         32 . The apparatus according to  claim 26 , wherein the ultrasonic waves generator is configured to emit the ultrasonic beam into a gaseous medium. 
     
     
         33 . A device manufacturing method, comprising:
 providing liquid to a space between a projection system and a movable table;   removing liquid from the space using an outlet;   projecting a patterned beam of radiation using the projection system through liquid onto a substrate; and   imparting ultrasonic waves to liquid located outward of the outlet relative to the path of the patterned radiation beam through the space using an ultrasonic wave emitting surface located outward of the outlet relative to the path.   
     
     
         34 . The method according to  claim 33 , comprising at least partly confining liquid in the space using a liquid confinement structure located above the substrate and comprising providing and removing liquid using the liquid confinement structure. 
     
     
         35 . The method according to  claim 33 , further comprising supplying a flow of gas to the surface using a gas inlet located outward of the outlet relative to the path. 
     
     
         36 . The method according to  claim 33 , further comprising detecting material on the surface using a sensor. 
     
     
         37 . The method according to  claim 33 , further comprising controlling the imparting of the ultrasonic waves depending on whether material is detected on the surface. 
     
     
         38 . The method according to  claim 33 , wherein the ultrasonic waves have a frequency in the range of 1 to 50 MHz. 
     
     
         39 . The method according to  claim 33 , wherein imparting ultrasonic waves comprises emitting the ultrasonic waves into a gaseous medium. 
     
     
         40 . A device manufacturing method, comprising:
 projecting a patterned beam of radiation onto a substrate through a liquid in a space adjacent the substrate;   at least partly confining the liquid in the space using a liquid confinement structure; and   imparting ultrasonic waves to remove material from a surface using an ultrasonic transducer located in or on the liquid confinement structure, wherein the ultrasonic waves emitting surface of the ultrasonic transducer is non-perpendicular to a top surface of the substrate.   
     
     
         41 . The method according to  claim 40 , further comprising supplying a flow of gas to the surface. 
     
     
         42 . The method according to  claim 40 , further comprising detecting material on the surface using a sensor. 
     
     
         43 . The method according to  claim 42 , further comprising controlling the imparting of the ultrasonic waves depending on whether material is detected on the surface. 
     
     
         44 . The method according to  claim 40 , wherein imparting ultrasonic waves comprises emitting the ultrasonic waves into a gaseous medium. 
     
     
         45 . The method according to  claim 40 , wherein the ultrasonic waves have a frequency in the range of 1 to 50 MHz.