Fluid handling structure, a lithographic apparatus and a device manufacturing method

1. A fluid handling system comprising:

a fluid handling structure configured to contain immersion fluid to a region, the fluid handling structure having, at a boundary of a space:

at least one gas knife opening outward from the space, and

at least one gas supply opening outward from the at least one gas knife opening relative to the space; and

a gas supply system configured to supply substantially pure CO 2 gas through the at least one gas knife opening and the at least one gas supply opening so as to provide an atmosphere of substantially pure CO 2 gas adjacent to, and outward of, the space, the gas supply system comprising at least one gas source, fluidly connected or connectable to the at least one gas knife opening and the at least one gas supply opening, to provide the substantially pure CO 2 gas to the at least one gas knife opening and the at least one gas supply opening.

2. The fluid handling system of claim 1 , wherein the gas supply system is configured to supply gas such that gas exits the at least one gas knife opening at a first gas velocity and the gas exits the at least one gas supply opening at a second gas velocity, the first gas velocity being greater than the second gas velocity.

3. The fluid handling system of claim 1 , wherein the gas supply system is further configured to supply the substantially pure CO 2 gas along with water vapor.

4. The fluid handling system of claim 1 , wherein the gas supply system is further configured to dynamically control gas supplied to the at least one gas knife opening and/or the at least one gas supply opening depending on a certain positional characteristic associated with the fluid handling structure.

5. A fluid handling system comprising:

a fluid handling structure configured to contain immersion fluid to a region, the fluid handling structure having, at a boundary of a space:

at least one gas knife opening outward from the space, and

at least one gas supply opening outward from the at least one gas knife opening relative to the space; and

a gas supply system configured to supply gas through the at least one gas knife opening and the at least one gas supply opening, wherein the gas supply system is configured to supply gas so that gas exits the at least one gas knife opening at a higher gas velocity than gas exiting the at least one gas supply opening and configured to dynamically control gas supplied to the at least one gas knife opening and/or at least one gas supply opening depending on a certain positional characteristic associated with the fluid handling structure.

6. The fluid handling system of claim 5 , wherein the fluid handling structure comprises a meniscus controlling feature to resist passage of the immersion fluid in a radially outward direction from the space, the meniscus controlling feature being inward of the at least one gas knife opening.

7. The fluid handling system of claim 5 , wherein the fluid handling structure comprises the gas supply system.

8. The fluid handling system of claim 5 , wherein the gas supply system comprises at least one gas source to provide gas to the at least one gas knife opening and the at least one gas supply opening.

9. The fluid handling system of claim 8 , wherein the gas supply system comprises a first path between a first gas source and the at least one gas knife opening and a second path between a second gas source and the at least one gas supply opening, wherein the second path comprises a flow restrictor section.

10. The fluid handling system of claim 9 , wherein the first gas source and the second gas source are the same gas source.

11. The fluid handling system of claim 5 , wherein the at least one gas knife opening and the at least one gas supply opening are on a surface of the fluid handling structure facing a substrate and/or a substrate table, wherein:

the at least one gas knife opening is closer to the substrate and/or substrate table than the at least one gas supply opening, and/or

the at least one gas knife opening has a smaller surface area on the surface of the fluid handling structure than the at least one gas supply opening.

12. The fluid handling system of claim 5 , wherein the fluid handling structure is configured to dynamically control the amount of gas supplied to the at least one gas knife opening by redirecting gas for the at least gas supply opening to the at least one gas knife opening, or for the at least one gas knife opening to the at least one gas supply opening.

13. The fluid handling system of claim 5 , wherein the characteristic comprises a location of the fluid handling structure, a direction of movement, a speed, and/or a velocity.

14. A device manufacturing method comprising projecting a projection beam of radiation via an immersion fluid onto a substrate in a lithographic apparatus comprising an immersion system, wherein the immersion system comprises a fluid handling structure configured to contain the immersion fluid to a region, the fluid handling structure having, at a boundary of a space:

at least one gas knife opening outward from the space; and

at least one gas supply opening outward from the at least one gas knife opening relative to the space; and

the method comprising supplying substantially pure CO 2 gas through the at least one gas knife opening and the at least one gas supply opening so as to provide an atmosphere of substantially pure CO 2 gas adjacent to, and outward of, the space, or

the method comprising supplying gas through the at least one gas knife opening and the at least one gas supply opening, wherein gas exits the at least one gas knife opening at a higher gas velocity than gas exiting the at least one gas supply opening, and dynamically controlling gas supplied to the at least one gas knife opening and/or at least one gas supply opening depending on a certain positional characteristic associated with the fluid handling structure.

15. The method of claim 14 , comprising the supplying gas through the at least one gas knife opening and the at least one gas supply opening, wherein gas exits the at least one gas knife opening at a higher gas velocity than gas exiting the at least one gas supply opening, and dynamically controlling gas supplied to the at least one gas knife opening and/or at least one gas supply opening depending on a certain positional characteristic associated with the fluid handling structure.

16. The method of claim 14 , comprising the supplying substantially pure CO 2 gas through the at least one gas knife opening and the at least one gas supply opening so as to provide an atmosphere of substantially pure CO 2 gas adjacent to, and outward of, the space.

17. A lithographic apparatus comprising an immersion system comprising a fluid handling structure configured to contain immersion fluid to a region, the fluid handling structure having, at a boundary of a space:

at least one gas knife opening outward from the space; and

at least one gas supply opening outward from the at least one gas knife opening relative to the space; and

the immersion system further comprising:

a gas supply system configured to supply substantially pure CO 2 gas through the at least one gas knife opening and the at least one gas supply opening so as to provide an atmosphere of substantially pure CO 2 gas adjacent to, and outward of, the space, or

a gas supply system configured to supply gas through the at least one gas knife opening and the at least one gas supply opening, wherein the gas supply system is configured to supply gas so that gas exits the at least one gas knife opening at a higher gas velocity than gas exiting the at least one gas supply opening and configured to dynamically control gas supplied to the at least one gas knife opening and/or the at least one gas supply opening depending on a certain positional characteristic associated with the fluid handling structure.

18. The lithographic apparatus of claim 17 , comprising the gas supply system configured to supply gas through the at least one gas knife opening and the at least one gas supply opening, wherein the gas supply system is configured to supply gas so that gas exits the at least one gas knife opening at a higher gas velocity than gas exiting the at least one gas supply opening and configured to dynamically control gas supplied to the at least one gas knife opening and/or the at least one gas supply opening depending on a certain characteristic associated with the fluid handling structure.

19. The lithographic apparatus of claim 18 , wherein the characteristic comprises a location of the fluid handling structure, a direction of movement, a speed, and/or a velocity.

20. A fluid handling structure configured to contain immersion fluid to a region, the fluid handling structure having, at a boundary of a space:

at least one gas knife opening in outward from the space; and

at least one gas supply opening outward from the at least one gas knife opening relative to the space, wherein the at least one gas supply opening comprises a mesh, a sieve, porous material and/or array of holes; and

a gas supply system configured to supply gas through the at least one gas knife opening and the at least one gas supply opening, wherein the gas supply system is configured to supply gas so that gas exits the at least one gas knife opening at a higher gas velocity than gas exiting the at least one gas supply opening and configured to dynamically control gas supplied to the at least one gas knife opening and/or the at least one gas supply opening depending on a certain positional characteristic associated with the fluid handling structure.