Immersion lithography system and method having an immersion fluid containment plate for submerging the substrate to be imaged in immersion fluid

• US 20070279608A1
• Filed: 09/20/2006
• Published: 12/06/2007
• Est. Priority Date: 06/06/2006
• Status: Active Grant

• Current Assignee: Nikon Corporation
• Original Assignee: Nikon Corporation
• Inventors: Coon, Derek, Poon, Alex Ka Tim, Kho, Leonard Wai Fung, Keswani, Gaurav
• Granted Patent: US 7,532,309 B2
• Time in Patent Office: Days
• US Class Current: 355/53
• CPC Class Codes: G03F 7/70341 Details of immersion lithography aspects, e.g. exposure media or control of immersion liquid supply chemical composition of immersion liquids G03F7/2041

Abstract

A lithography apparatus having a fluid confinement plate, which completely submerges the imaging surface of a substrate, is disclosed. The apparatus includes an imaging element defining an image and a stage configured to support the substrate. A projection optical system is provided to project the image defined by the imaging element onto the imaging surface of the substrate. A gap, filled with immersion fluid, is provided between the imaging surface of the substrate and the last optical element of the projection optical system. The fluid confinement plate, which is positioned within the gap between the last optical element and the substrate, is sufficiently sized so that the imaging surface is completely submerged in the immersion fluid. The fluid confinement plate includes a first surface facing the gap and opposing the imaging surface of the substrate. The first surface includes a droplet control element to control the formation of droplets forming on the first surface. In one embodiment, the droplet control element is a porous surface formed on the first surface. A vacuum is used to pull any excess immersion fluid through the porous region to prevent the formation of droplets. In a second embodiment, the droplet control element is a sloped surface that causes any immersion fluid on the first surface to flow toward to main body of immersion fluid in the gap.

Claims

1. An apparatus, comprising:

a stage configured to support a substrate having an imaging surface;

a projection optical system having a last optical element, which is configured to project an image onto the imaging surface of the substrate through an immersion liquid filled in a gap between the imaging surface of the substrate and the last optical element; and

a fluid confinement plate positioned within the gap between the last optical element and the imaging surface of the substrate so that the imaging surface is submerged in the immersion fluid, substantially preventing an atmosphere-fluid meniscus from forming on the imaging surface of the substrate,

the fluid confinement plate having a first surface facing the gap and opposing the imaging surface of the substrate, the first surface including a droplet control element to control the formation of droplets forming on the first surface.

2. The apparatus of claim 1, wherein the fluid confinement plate is sufficiently large to cover the entire substrate during scanning of the substrate by the stage.

3. The apparatus of claim 1, wherein the fluid confinement plate is not sufficiently large to cover the entire substrate during scanning of the substrate by the stage.

4. The apparatus of claim 1, wherein the stage further comprises a fluid recovery element provided in the stage adjacent the substrate when the substrate is supported by the stage.

5. The apparatus of claim 4, wherein the fluid recovery element substantially surrounds the periphery of the substrate when the substrate is positioned on the stage.

6. The apparatus of claim 4, wherein the fluid recovery element further comprises a porous element provided within in the stage and a vacuum to pull negative pressure through the porous element.

7. The apparatus of claim 1, wherein the fluid confinement plate further comprises one or more fluid inlets for supplying immersion fluid into the gap.

8. The apparatus of claim 7, wherein the one or more fluid inlets are located adjacent the last optical element of the projection optical system.

9. The apparatus of claim 1, wherein the fluid confinement plate further comprises an aperture so that the projection optical system can project the image onto the imaging surface of the substrate through the fluid confinement plate.

10. The apparatus of claim 9, wherein the aperture is recessed shaped to accommodate at least the last optical element of the projection optical system.

11. The apparatus of claim 1, wherein the first surface of the fluid confinement plate is made of or coated with a hydrophobic material.

12. The apparatus of claim 1, wherein the droplet control element comprises a porous region formed on the first surface of the fluid confinement plate, whereby the porous region is used to recover immersion fluid that has collected onto the first surface to substantially prevent the formation of droplets of immersion fluid on the first surface.

13. The apparatus of claim 12, further comprising a vacuum, coupled to the porous region, and configured to pull negative pressure through the porous region to recover the immersion fluid that has collected onto the first surface of the fluid confinement plate.

14. The apparatus of claim 1, wherein droplet control element comprises a sloped region formed on the first surface of the fluid confinement plate, the sloped region being sufficiently sloped to create a run off surface for the immersion fluid collected on the first surface to flow toward the immersion fluid in the gap to substantially prevent the formation of droplets on the first surface.

15. The apparatus of claim 6, wherein the porous element is substantially planar with a surface of the stage used to support the substrate.

16. A liquid immersion exposure apparatus in which a substrate is exposed to an exposure beam, the apparatus comprising:

an optical element through which the exposure beam passes;

a liquid confinement member having a surface;

a holding member configured to hold and move the substrate relative to the optical element and the liquid confinement member, the holding member being movable in a region so that the entire surface of the substrate can be positioned into the path of the exposure beam; and

a liquid recovery portion provided on the holding member and configured to recover a liquid which comes out from a gap between the surface of the substrate and the surface of the liquid confinement member;

wherein, the substrate on the holding member is opposite to the surface of the liquid confinement member or the end surface of the optical element or both, while the holding member is moved in the region.

17. The apparatus of claim 16, wherein the liquid recovery portion is disposed adjacent to the substrate held on the holding member.

18. The apparatus of claim 16, wherein the liquid recovery portion is disposed under the substrate held on the holding member.

19. The apparatus of claim 18, wherein the liquid recovery portion surrounds the substrate held on the holding member.

20. The apparatus of claim 18, wherein the liquid recovery portion has a porous material through which the liquid is recovered.

21. The apparatus of claim 16, wherein the liquid confinement member has a liquid supply passage from which the liquid is supplied.

22. The apparatus of claim 16, wherein the liquid confinement member has an aperture through which the exposure beam from the optical element passes, and the surface of the liquid confinement member is formed around the aperture of the liquid confinement member.

23. A device manufacturing method in which a substrate is exposed by using the exposure apparatus of claim 16.