Apparatus and method for maintaining immersion fluid in the gap under the projection lens during wafer exchange in an immersion lithography machine
An apparatus and method maintain immersion fluid in the gap adjacent to the projection lens during the exchange of a work piece in a lithography machine. The apparatus and method include an optical assembly that projects an image onto a work piece and a stage assembly including a work piece table that supports the work piece adjacent to the optical assembly. An environmental system is provided to supply and remove an immersion fluid from the gap between the optical assembly and the work piece on the stage assembly. After exposure of the work piece is complete, an exchange system removes the work piece and replaces it with a second work piece. An immersion fluid containment system maintains the immersion liquid in the gap during removal of the first work piece and replacement with the second work piece.
1. A lithographic projection apparatus comprising:
a substrate table on which a substrate is held;
a projection system, an immersion liquid being provided in a space between the projection system and the substrate; and
a shutter that keeps the projection system in contact with liquid, wherein:
the shutter is positionable on a side opposite the projection system such that liquid can be confined between the projection system and the shutter, and
the substrate table comprises a holding device that releasably holds the shutter to the substrate table.
2. An apparatus according to claim 1 , wherein the shutter keeps the projection system in contact with liquid when the substrate is moved away from under the projection system.
3. An apparatus according to claim 2 , wherein the shutter keeps the projection system in contact with liquid when the substrate, at least while on the substrate table, substantially comes out of contact with the liquid.
4. An apparatus according to claim 1 , wherein the holding device includes a vacuum clamp that attracts the shutter.
5. An apparatus according to claim 1 , further comprising an attachment device that releasably holds the shutter.
6. An apparatus according to claim 5 , wherein the attachment device holds the shutter, which is released from the holding device, opposite to the projection system.
7. An apparatus according to claim 5 , wherein the attachment device comprises a vacuum clamp that attracts the shutter.
8. An apparatus according to claim 1 , further comprising a liquid supply system to supply the immersion liquid.
9. An apparatus according to claim 1 , wherein the substrate table is moved so that the shutter is opposite to the projection system and the liquid is confined between the shutter and the projection system.
10. A device manufacturing method comprising:
providing an immersion liquid to a space between a projection system and a substrate;
maintaining the projection system in contact with liquid by positioning a shutter on a side opposite the projection system such that the liquid is confined between the projection system and the shutter; and
releasably holding the shutter on a substrate table.
11. A method according to claim 10 , wherein the shutter keeps the projection system in contact with liquid when the substrate is moved away from under the projection system.
12. A method according to claim 10 , wherein the shutter keeps the projection system in contact with liquid when the substrate, at least while on the substrate table, substantially comes out of contact with the liquid.
13. A method according to claim 10 , wherein the shutter is releasably held on the substrate table using vacuum.
14. A method according to claim 10 , further comprising releasably holding the shutter which is released from the substrate table.
15. A method according to claim 14 , wherein the shutter is releasably held, while being released from the substrate table, opposite to the projection system.
16. A method according to claim 15 , wherein the shutter is releasably held, while being released from the substrate table, opposite to the projection system using vacuum.
17. A method according to claim 10 , further comprising moving the substrate table so that the shutter is opposite to the projection system and the liquid is confined between the shutter and the projection system.
18. A method according to claim 10 , further comprising supplying the immersion liquid.
19. A method according to claim 10 , further comprising projecting a patterned beam of radiation, through the liquid, onto the substrate using the projection system.