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

• US 7,532,309 B2
• Filed: 09/20/2006
• Issued: 05/12/2009
• 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
• Primary Examiner(s): RUTLEDGE, DELLA J
• Application Number:
  US11/523,595
• Publication Number:
  US 20070279608A1
• Time in Patent Office: 965 Days
• Field of Search: 355/53, 355/67, 355/72, 355/75, 355/30, 355/71, 378/34, 378/35, 250/492.2
• US Class Current: 355/67
• 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 includes a fluid confinement plate which can completely submerge the imaging surface of a substrate. A gap, filled with immersion fluid, is provided between the imaging surface of the substrate and the last optical element of a 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.

Claims

1. An apparatus, comprising:

a stage which supports a substrate having an imaging surface;

a projection optical system having a last optical element, which projects 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 adjacent to the imaging surface of the substrate so that the imaging surface is submerged in the immersion liquid, the fluid confinement plate is sufficiently large to cover an area larger than an area of the imaging surface of the substrate so as to completely submerge the imaging surface of the substrate, substantially preventing an atmosphere-liquid meniscus from forming on the imaging surface of the substrate,

the fluid confinement plate having a first surface 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 stage further comprises a fluid recovery element provided in the stage adjacent the substrate when the substrate is supported by the stage.

4. The apparatus of claim 3, wherein the fluid recovery element substantially surrounds the periphery of the substrate when the substrate is positioned on the stage.

5. The apparatus of claim 3, wherein the fluid recovery element further comprises a porous element provided in the stage, the porous element being connected to a vacuum source.

6. The apparatus of claim 1, wherein the fluid confinement plate further comprises one or more liquid inlets from which the immersion liquid is supplied into the gap.

7. The apparatus of claim 6, wherein the one or more liquid inlets are located adjacent the last optical element of the projection optical system.

8. 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.

9. The apparatus of claim 8, wherein the aperture is recessed shaped to accommodate at least the last optical element of the projection optical system.

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

11. 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 liquid that has collected onto the first surface to substantially prevent the formation of droplets of the immersion liquid on the first surface.

12. The apparatus of claim 11, wherein the porous region is connected to a vacuum source to recover the immersion liquid that has collected onto the first surface of the fluid confinement plate.

13. The apparatus of claim 1, wherein the 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 liquid collected on the first surface to flow toward the immersion liquid in the gap to substantially prevent the formation of droplets on the first surface.

14. The apparatus of claim 5, wherein the porous element is substantially planar with a surface of the stage used to support the substrate.

15. A liquid immersion exposure apparatus in which an imaging surface of 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 which holds the substrate and moves the substrate relative to the optical element and the liquid confinement member, the holding member being movable in a region so that the entire imaging surface of the substrate can be positioned into the path of the exposure beam; and

a liquid recovery portion provided on the holding member, which recovers a liquid that comes out from a gap between the imaging surface of the substrate and the surface of the liquid confinement member;

wherein the liquid confinement member is sufficiently large that the entire imaging surface of 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, an entire time while the holding member is moved within the entire region.

16. The apparatus of claim 15, wherein the liquid recovery portion is disposed adjacent to the substrate held on the holding member.

17. The apparatus of claim 15, wherein the liquid recovery portion is disposed below the substrate held on the holding member such that an undersurface of at least a peripheral portion of the substrate directly communicates with the liquid recovery portion.

18. The apparatus of claim 17, wherein the liquid recovery portion surrounds the substrate held on the holding member.

19. The apparatus of claim 17, wherein the liquid recovery portion has a porous material through which the liquid is recovered.

20. The apparatus of claim 15, wherein the liquid confinement member has a liquid supply passage from which the liquid is supplied.

21. The apparatus of claim 15, 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.

22. A device manufacturing method comprising:

exposing a substrate through the optical element of the liquid immersion exposure apparatus according to claim 15; and

developing the exposed substrate.