Lithographic apparatus and device manufacturing method

Abstract

In an immersion lithographic apparatus, bubble formation in immersion liquid is reduced or prevented by reducing a gap size or area on a substrate table and/or covering the gap.

1 .- 20 . (canceled) 
     
     
         21 . A lithographic projection apparatus arranged to project a radiation beam, through a liquid, onto a radiation-sensitive surface of a substrate, the apparatus comprising a movable table configured to hold an object, the object comprising (i) a sensor, (ii) a substrate, (iii) a closing plate, or (iv) any combination of (i)-(iii), the movable table comprising a plate thereon, wherein a gap between the plate and the object, when held by the movable table, is less than or equal to about 0.5 mm. 
     
     
         22 . The apparatus of  claim 21 , wherein the gap between the object and the plate is less than or equal to 0.3 mm. 
     
     
         23 . The apparatus of  claim 21 , wherein the gap between the object and the plate is less than or equal to 0.1 mm. 
     
     
         24 . The apparatus of  claim 21 , wherein the object is a substrate having a radiation-sensitive material layer. 
     
     
         25 . The apparatus of  claim 21 , wherein the object is easily removable from the movable table. 
     
     
         26 . The apparatus of  claim 21 , wherein the plate is movable with respect to the object and the movable table. 
     
     
         27 . A device manufacturing method, comprising:
 supplying a liquid between an object and a final optical element of a projection system of a lithographic projection apparatus, wherein the object is held on a movable table having a plate thereon, the object comprising (i) a sensor, (ii) a substrate, (iii) a closing plate, or (iv) any combination of (i)-(iii), wherein a gap between the plate and the object is less than or equal to about 0.5 mm; and   projecting a radiation beam, through the liquid, onto a radiation-sensitive surface of a substrate.   
     
     
         28 . The method of  claim 27 , wherein the gap between the object and the plate is less than or equal to 0.3 mm. 
     
     
         29 . The method of  claim 27 , wherein the gap between the object and the plate is less than or equal to 0.1 mm. 
     
     
         30 . The method of  claim 27 , wherein the object is a substrate having a radiation-sensitive material layer. 
     
     
         31 . The method of  claim 27 , further comprising easily removing the object from the movable table. 
     
     
         32 . The method of  claim 27 , further comprising moving the plate with respect to the object and the movable table. 
     
     
         33 . A lithographic projection apparatus arranged to project a radiation beam onto an object held on a movable table through an immersion liquid which is confined to a space by a barrier member, the object comprising at least one selected from the following: a sensor, a substrate, a closing plate or other object in or on the movable table, wherein the apparatus comprises a cover plate to contact the object and a top surface of the movable table and bridge a gap between the object and the top surface of the movable table, the cover plate being stretchable and having a hole in its interior. 
     
     
         34 . The apparatus of  claim 33 , wherein the cover plate has a thickness selected from the range of 5 to 50 microns. 
     
     
         35 . The apparatus of  claim 33 , wherein the cover plate comprises an adhesive to adhere the cover plate to the object, the movable table, or both. 
     
     
         36 . The apparatus of  claim 33 , wherein the cover plate comprises plastic. 
     
     
         37 . The apparatus of  claim 33 , wherein the cover plate comprises metal. 
     
     
         38 . The apparatus of  claim 33 , wherein the object is a substrate having a radiation-sensitive material layer. 
     
     
         39 . The apparatus of  claim 33 , further comprising an actuator to move the cover plate with respect to the object and the movable table.