Dual stage lithographic apparatus and device manufacturing method

Abstract

The invention relates to a dual stage lithographic apparatus, wherein two substrate stages are constructed and arranged for mutual cooperation in order to perform a joint scan movement. The joint scan movement brings the lithographic apparatus from a first configuration, wherein immersion liquid is confined between a first substrate held by the first stage of the stages and a projection system of the apparatus, to a second configuration, wherein the immersion liquid is confined between a second substrate held by the second stage of the two stages and the projection system, such that during the joint scan movement the liquid is essentially confined within the space with respect to the projection system.

The invention claimed is: 
     
       1. A lithographic apparatus comprising:
 a support constructed to support a patterning device, the patterning device being capable of imparting a radiation beam with a pattern in its cross-section to form a patterned radiation beam;   a measuring system configured to measure characteristics of substrates in a metrology station of the apparatus;   a projection system configured to project the patterned radiation beam onto a substrate in an exposure station of the apparatus;   a liquid confinement system configured to at least partly confine liquid in a space between the projection system and the substrate;   a positioning system and at least two substrate stages, each stage constructed to hold a substrates, wherein the positioning system is constructed to move the stages between the metrology station and the exposure station, and wherein the positioning system is constructed to position one of the stages holding a substrate during exposure in the exposure station on the basis of at least one measured characteristic of that substrate;   wherein the stages are constructed and arranged for mutual cooperation in order to perform a joint scan movement to bring the lithographic apparatus from a first situation, wherein the liquid is confined between a first substrate held by a first stage of the two stages and the projection system, towards a second situation, wherein the liquid is confined between a second substrate held by a second stage of the two stages and the projection system, such that during the joint scan movement the liquid is essentially confined within the space with respect to the projection system.   
     
     
       2. The lithographic apparatus according to  claim 1 , wherein each of the first stage and second stage has an immersion cross edge at or near a side of the stage which is constructed and arranged to cooperate with an immersion cross edge of another stage during the joint scan movement. 
     
     
       3. The lithographic apparatus according to  claim 2 , wherein each immersion cross edge comprises an essentially plane surface. 
     
     
       4. The lithographic apparatus according to  claim 2 , wherein the positioning system is constructed and arranged to position the respective stages during their joint scan movement such that surfaces of their respective immersion cross edges remain at an essentially mutual constant distance, wherein the distance is in the range of zero to about 1 millimeter, wherein a preferred distance is about 0.1 millimeter. 
     
     
       5. The lithographic apparatus according to  claim 2 , wherein at least one of the respective stages is provided with a channel system having an opening in a surface of the immersion cross edge of the stage, wherein the channel system is constructed and arranged to generate a flow of gas and/or liquid along the immersion cross edge during the joint scan movement. 
     
     
       6. The lithographic apparatus according to  claim 2 , wherein at least one of the respective stages is provided with a liquid gutter under its immersion cross edge, wherein the liquid gutter is capable of catching liquid possibly dripped along the immersion cross edge. 
     
     
       7. The lithographic apparatus according to  claim 2 , wherein at least one of the respective stages is provided with an interferometer-mirror near the immersion cross edge, wherein the interferometer-mirror is staggered with respect to the immersion cross edge and preferably placed in a niche of the stage in order to protect the interferometer-mirror. 
     
     
       8. The lithographic apparatus according to  claim 6 , wherein at least one of the respective stages is provided with an interferometer-mirror near the immersion cross edge, wherein the interferometer-mirror is placed at a level below that of the liquid gutter in order to protect the interferometer-mirror. 
     
     
       9. The lithographic apparatus according to  claim 1 , further comprising an exposure station situated between a first metrology station and a second metrology station such that alternately substrates measured by the first metrology station and substrates measured by the second metrology station may be fed towards the exposure station. 
     
     
       10. The lithographic apparatus according to  claim 1 , further comprising a base frame configured to carry a metro frame which supports the measuring system and the projection system, wherein the metro frame is dynamically isolated from the base frame, and wherein the measuring system comprises at least one encoder plate configured to cooperate with an encoder head placed at one of the stages to measure the position of that stage. 
     
     
       11. The lithographic apparatus according to  claim 10 , wherein the at least one encoder plate extends in the exposure station and the metrology station. 
     
     
       12. The lithographic apparatus according to  claim 10 , further comprising a machine frame which is preferably separated from the base frame, wherein the machine frame is provided with a first part of a planar motor to cooperate with respective second parts of the planar motor in the respective stages, wherein the positioning system is constructed and arranged to control the planar motor in order to position the respective stages between the metrology station and the exposure station. 
     
     
       13. The lithographic apparatus according to  claim 10 , further comprising a machine frame which is preferably separated from the base frame, wherein the machine frame has two essentially parallel guides extending in a first direction in a horizontal plane, wherein each guide is coupled to an element which can be moved along the guide by means of a motor, and wherein each element is coupled to a stage of the respective stages by means of a motor to move that stage in a second direction directed in the horizontal plane and perpendicular to the first direction, wherein the positioning system is constructed and arranged to control the motors in order to move the stage in the plane. 
     
     
       14. A lithographic product with a lithographic apparatus according to  claim 1 . 
     
     
       15. A lithographic apparatus, comprising:
 a first movable stage configured to hold a substrate;   a second stage movable with respect to the first stage;   a projection system configured to image a pattern onto the substrate;   a liquid confinement structure configured to at least partly confine a liquid in a space between a final element of the projection system and the substrate, the first stage, and/or the second stage;   an encoder system comprising an encoder plate and an encoder head cooperating with the encoder plate, the encoder system configured to measure a position of the first stage and/or of the second stage in at least a first direction and the encoder system configured to provide radiation to or from a respective surface of the first and/or second stage to measure the position of respectively the first and/or second stage, the respective surface facing toward the projection system; and   a positioning system configured to control movement of the first stage and the second stage together relative to the liquid confinement structure such that liquid in the liquid confinement structure is transferred from being confined by the substrate, or the first stage, or both, to being confined by the second stage, the liquid crossing a first edge of the first stage and an opposing second edge of the second stage.   
     
     
       16. The lithographic apparatus of claim 15, further comprising a frame supporting at least part of the encoder system, the frame dynamically isolated from the first and second movable stages. 
     
     
       17. The lithographic apparatus of claim 16, wherein the frame further supports the projection system. 
     
     
       18. The lithographic apparatus of claim 16, wherein the projection system is dynamically isolated from the frame. 
     
     
       19. The lithographic apparatus of claim 15, further comprising an interferometer system configured to measure a position of the first stage and/or of the second stage in at least the first direction. 
     
     
       20. The lithographic apparatus of claim 15, further comprising an exposure station in which the substrate of the first stage is exposed by the projection system and a metrology station in which measurements are made using the second stage, wherein at least part of the encoder system extends into both the exposure and measurement stations. 
     
     
       21. The lithographic apparatus of claim 15, wherein the positioning system is configured to control the movement of the first and second stages together such that a gap between the first and second edges passes under the liquid in the liquid confinement structure and further comprising a fluid extraction channel in or on the first stage, the second stage, or both, the fluid extraction channel constructed and arranged to collect immersion liquid flowing into the gap during the movement of the first and second stages. 
     
     
       22. The lithographic apparatus of claim 15, further comprising a channel in the first stage, in the second stage, or in both, that is in fluid communication with an opening defined by a surface of the respective stage, the channel constructed and arranged to generate a fluid flow along the respective first and/or second edge, the fluid flow including liquid from the liquid confinement structure. 
     
     
       23. A device manufacturing method, comprising:
 at least partly confining liquid in a space between a projection system and a first stage, a substrate supported by the first stage, or both; and   measuring a position of the first stage and/or of a second movable stage using an encoder system comprising an encoder plate and an encoder head cooperating with the encoder plate, the measuring using the encoder system comprising providing radiation to or from a respective surface of the first and/or second stage to measure the position of respectively the first and/or second stage, the respective surface facing toward the projection system; and   jointly moving the first stage with the second stage such that confinement of liquid in the space by the first stage, the substrate, or both, is replaced by confinement of liquid in the space by the second stage.   
     
     
       24. The method of claim 23, further comprising supporting at least part of the encoder system using a frame, the frame dynamically isolated from the first and second movable stages. 
     
     
       25. The method of claim 24, wherein the frame further supports the projection system. 
     
     
       26. The method of claim 24, wherein the projection system is dynamically isolated from the frame. 
     
     
       27. The method of claim 23, further comprising measuring a position of the first stage and/or of the second stage in at least the first direction using an interferometer system. 
     
     
       28. The method of claim 23, further comprising an exposure station in which the substrate of the first stage is exposed by the projection system and a metrology station in which measurements are made using the second stage, wherein at least part of the encoder system extends into both the exposure and measurement stations. 
     
     
       29. The method of claim 23, wherein the jointly moving comprises moving the first and second stages such that a gap between respective opposing edges of the first and second stages passes under the confined liquid and further comprising collecting immersion liquid flowing into the gap during the movement of the first and second stages using a fluid extraction channel in or on the first stage, the second stage, or both. 
     
     
       30. The method of claim 23, further comprising generating a fluid flow, including at some of the liquid, along a first edge of the first stage and/or a second edge of the second stage using a channel in the first stage, in the second stage, or in both, that is in fluid communication with an opening defined by a surface of the respective stage. 
     
     
       31. A lithographic apparatus, comprising:
 a first movable stage configured to hold a substrate;   a second stage movable with respect to the first stage;   a projection system configured to image a pattern onto the substrate;   a liquid confinement system configured to at least partly confine a liquid in a space between a final element of the projection system and the substrate, the first stage, and/or the second stage;   an optical encoder system configured to measure a position of at least the first stage in at least a first direction, the encoder system comprising a first part located above the first stage and a second part located in or on the first stage, the second part facing upwardly toward the first part; and   a positioning system configured to control movement of the first stage and the second stage together relative to the liquid confinement system such that liquid in the liquid confinement structure is transferred from being confined by the substrate, or the first stage, or both, to being confined by the second stage, the liquid crossing an edge of the first stage and an opposing edge of the second stage.   
     
     
       32. The lithographic apparatus of claim 31, further comprising a frame supporting the first part of the encoder system, the frame dynamically isolated from the first and second movable stages. 
     
     
       33. The lithographic apparatus of claim 32, wherein the projection system is dynamically isolated from the frame. 
     
     
       34. The lithographic apparatus of claim 31, further comprising an interferometer system configured to measure a position of the first stage and/or of the second stage in at least the first direction.