Apparatus and method for maintaining immersion fluid in the gap under the projection lens during wafer exchange in an immersion lithography machine

Abstract

A liquid immersion lithography apparatus and method expose a substrate with an optical beam via an optical assembly and liquid by (i) arranging a stage opposite to the optical assembly such that the liquid is maintained in a local space under the optical assembly, the stage having an upper surface and a surface of a pad member and being configured to support the substrate within the upper surface; and (ii) moving the upper surface and the surface of the pad member in a movement relative to the optical assembly in a state in which the upper surface and the surface of the pad member are adjacent to and substantially coplanar with each other so that the surface of the pad member is arranged opposite to the optical assembly in place of the upper surface while the liquid is maintained in the local space under the optical assembly.

What is claimed is: 
     
         1 . A liquid immersion lithography apparatus comprising:
 an optical assembly configured such that a substrate is exposed with an optical beam via the optical assembly and liquid; and   a stage having an upper surface and a surface of a pad member such that a relative movement between the upper surface and the surface of the pad member is allowed, and being configured to support the substrate within the upper surface and in a recessed portion on the upper surface, the upper surface or the surface of the pad member being arranged to support the liquid to maintain the liquid in a local space under the optical assembly when the upper surface or the surface of the pad member is arranged facing to the optical assembly, wherein   when the substrate is in the recessed portion on the upper surface, the upper surface surrounds the substrate, and a part of the upper surface is arranged between the surface of the pad member and a surface of the substrate, and   the upper surface and the surface of the pad member are movable in a movement relative to the optical assembly in a state in which the upper surface and the surface of the pad member are adjacent to and substantially coplanar with each other so that the surface of the pad member is arranged facing the optical assembly in place of the upper surface while the liquid is maintained in the local space under the optical assembly.   
     
     
         2 . The apparatus according to  claim 1 , wherein, in the movement relative to the optical assembly, the surface of the pad member is arranged outside the upper surface. 
     
     
         3 . The apparatus according to  claim 1 , further comprising a different stage that is different from the stage, the different stage also having an upper surface and being configured to support a substrate within the upper surface,
 wherein the upper surface of the stage, the surface of the pad member and the upper surface of the different stage are movable in a movement relative to the optical assembly such that a supported position of the liquid maintained in the local space under the optical assembly is changed from the upper surface of the stage to the upper surface of the different stage via the surface of the pad member.   
     
     
         4 . The apparatus according to  claim 3 , wherein the stage and the different stage are each configured to support the substrate such that a surface of the substrate and the upper surface are substantially coplanar. 
     
     
         5 . The apparatus according to  claim 4 , wherein, after the movement relative to the optical assembly, the liquid maintained in the local space under the optical assembly is supported by the different stage, and a different process from the exposure process for the substrate is performed with the stage at an area away from under the optical assembly. 
     
     
         6 . The apparatus according to  claim 5 , further comprising an exchange system configured to exchange the substrate at the stage. 
     
     
         7 . The apparatus according to  claim 5 , further comprising an alignment system configured to align the substrate at the stage. 
     
     
         8 . The apparatus according to  claim 1 , wherein at least one of the upper surface and the surface of the pad member are movable in at least one of directions including a direction for adjusting relative angle and a vertical direction, so that the upper surface and the surface of the pad member are substantially coplanar. 
     
     
         9 . The apparatus according to  claim 1 , wherein the upper surface and the surface of the pad member are movable relative to the optical assembly while the upper surface and the surface of the pad member are in a close state so that contact between the optical assembly and the liquid is able to be maintained. 
     
     
         10 . The apparatus according to  claim 1 , wherein the upper surface and the surface of the pad member are movable relative to the optical assembly while the upper surface and the surface of the pad member are in a close state such that the upper surface and the surface of the pad member form a substantially continuous surface. 
     
     
         11 . A liquid immersion lithography method for exposing a substrate with an optical beam via an optical assembly and liquid, the method comprising:
 arranging a stage opposite to the optical assembly such that the liquid is maintained in a local space under the optical assembly, the stage having an upper surface and a surface of a pad member and being configured to support the substrate within the upper surface; and   moving the upper surface and the surface of the pad member in a movement relative to the optical assembly in a state in which the upper surface and the surface of the pad member are adjacent to and substantially coplanar with each other so that the surface of the pad member is arranged opposite to the optical assembly in place of the upper surface while the liquid is maintained in the local space under the optical assembly.   
     
     
         12 . The method according to  claim 11 , wherein, in the movement relative to the optical assembly, the surface of the pad member is arranged outside the upper surface. 
     
     
         13 . The method according to  claim 11 , wherein
 a different stage, which is different from the stage, is provided, the different stage also having an upper surface and being configured to support a substrate within the upper surface, and   the upper surface of the stage, the surface of the pad member and the upper surface of the different stage are moved in a movement relative to the optical assembly such that a supported position of the liquid maintained in the local space under the optical assembly is changed from the upper surface of the stage to the upper surface of the different stage via the surface of the pad member.   
     
     
         14 . The method according to  claim 13 , wherein the stage and the different stage are each configured to support the substrate such that a surface of the substrate and the upper surface are substantially coplanar. 
     
     
         15 . The method according to  claim 14 , wherein, after the movement relative to the optical assembly, the liquid maintained in the local space under the optical assembly is supported by the different stage, and a different process from the exposure process for the substrate is performed with the stage at an area away from under the optical assembly. 
     
     
         16 . The method according to  claim 15 , wherein the different process comprises at least one of a loading process and an unloading process for the substrate. 
     
     
         17 . The method according to  claim 15 , wherein the different process comprises at least one of an alignment process for the substrate and an exchange process of the substrate. 
     
     
         18 . The method according to  claim 11 , wherein at least one of the upper surface and the surface of the pad member are moved in at least one of directions including a direction for adjusting relative angle and a vertical direction, so that the upper surface and the surface of the pad member are substantially coplanar. 
     
     
         19 . The method according to  claim 11 , wherein the upper surface and the surface of the pad member are moved relative to the optical assembly while the upper surface and the surface of the pad member are in a close state so that contact between the optical assembly and the liquid is able to be maintained. 
     
     
         20 . The method according to  claim 11 , wherein the upper surface and the surface of the pad member are moved relative to the optical assembly while the upper surface and the surface of the pad member are in a close state such that the upper surface and the surface of the pad member form a substantially continuous surface. 
     
     
         21 . A device fabricating method comprising:
 exposing a substrate by use of the liquid immersion lithography apparatus of  claim 1 ; and   developing the exposed substrate.   
     
     
         22 . A device fabricating method comprising:
 exposing a substrate by use of the liquid immersion lithography method of  claim 11 ; and   developing the exposed substrate.