Fluid handling structure, lithographic apparatus and device manufacturing method
A fluid handling structure is disclosed in which measures are taken to increase the speed at which meniscus breakdown occurs. Measures include the shape of a plurality of fluid extraction openings and the shape and density of a plurality of fluid supply openings in the fluid handling structure.
1. A fluid handling structure for a lithographic apparatus, the fluid handling structure having a plurality of openings arranged, in plan, in a cornered shape, the fluid handling structure configured such that the openings are directed towards a substrate and/or a substrate table configured to support the substrate, when the substrate and/or the substrate table are provided, wherein
the cornered shape has a side with a negative radius.
2. The fluid handling structure of claim 1 , wherein the cornered shape has four corners and four sides, each side having a negative radius of curvature.
3. The fluid handling structure of claim 1 , wherein the cornered shape has a side with a negative radius and the cornered shape has at least one smoothly curved corner.
4. The fluid handling structure of claim 1 , wherein the cornered shape has a side with a negative radius that changes direction continuously along at least part of its length, and/or the cornered shape has a corner with a radius selected from the range of 0.05-4.0 mm.
5. The fluid handling structure of claim 1 , wherein the cornered shape has at least one smoothly curved corner.
6. The fluid handling structure of claim 5 , wherein the smoothly curved corner has a radius selected from the range of 0.5-4.0 mm.
7. The fluid handling structure of claim 1 , wherein the openings are inlets for the passage of gas and/or liquid into the fluid handling structure.
8. The fluid handling structure of claim 1 , wherein the openings are outlets for the passage of fluid out of the fluid handling structure.
9. The fluid handling structure of claim 1 , wherein a line intersecting the openings is smooth.
10. The fluid handling structure of claim 1 , wherein an opening is present at the apex of at least one corner of the cornered shape.
11. The fluid handling structure of claim 1 , wherein the openings surround a space to which the fluid handling structure is arranged to supply fluid.
12. The fluid handling structure of claim 1 , wherein at least one corner of the cornered shape has an angle selected from the range of 60 to 90 degrees.
13. The fluid handling structure of claim 1 , wherein the cornered shape comprises eight corners.
14. The fluid handling structure of claim 1 , wherein a line defined by the openings and defining the cornered shape is continuous and has a continuously changing direction.
15. A lithographic apparatus, comprising:
a fluid handling structure having a plurality of openings arranged, in plan, in a cornered shape, the fluid handling structure configured such that the openings are directed towards a substrate and/or a substrate table configured to support the substrate, when the substrate and/or the substrate table are provided, wherein
a) the cornered shape has a side with a negative radius; and/of and
b) the cornered shape has a corner with a radius selected from the range of 0.05-4.0 mm.
16. The lithographic apparatus of claim 15 , wherein, when scanning or stepping motion is performed, at least one corner of the cornered shape points in a scanning or in a stepping direction.
17. A fluid handling structure for a lithographic apparatus, the fluid handling structure having a plurality of fluid extraction openings arranged, in plan, in a first cornered shape, and a plurality of fluid supply openings arranged, in plan, in a second cornered shape, the fluid extraction openings and fluid supply openings being directed towards a substrate and/or a substrate table configured to support the substrate, when the substrate and/or the substrate table are provided, the first and second cornered shapes being substantially similar, wherein a fluid extraction opening is present at the apex of at least one corner of the first cornered shape and/or a fluid supply opening is present at the apex of at least one corner of the second cornered shape, wherein the fluid supply openings are more closely spaced near a corner than elsewhere.
18. A device manufacturing method, comprising:
providing a fluid between a projection system and a substrate; and
retrieving liquid from between the substrate and the projection system by applying an under pressure to a plurality of openings in a fluid handling structure, the openings being arranged, in plan, in a cornered shape around the fluid between the projection system and the substrate, wherein
the cornered shape has a side with a negative radius.
19. A fluid handing structure for a lithographic apparatus, the fluid handling structure having a plurality of fluid extraction openings arranged, in plan, in a first cornered shape, and a plurality of fluid supply openings arranged, in plan, in a second cornered shape, the fluid extraction openings and fluid supply openings being directed towards a substrate and/or a substrate table configured to support the substrate, when the substrate and/or the substrate table are provided, the first and second cornered shapes being substantially similar and the first cornered shape and/or the second cornered shape having a side with a negative radius,
wherein a corner of the first cornered shape, or of the second cornered shape, or of both, is configured to be aligned with a direction of relative motion between the fluid handling structure and the substrate table, such that the two sides of the corner are at a non-zero angle with respect to the direction of relative motion, when there is relative motion between the fluid handling structure and the substrate table.