Immersion fluid containment system and method for immersion lithogtraphy
AssigneeNikon Corporation
InventorMichael Sogard
Life of this patent
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Abstract
A ferrofluid is provided adjacent to the immersion area between a projection optical system (PL) and substrate and receives a magnetic force so as to form a ferrofluidic seal (100) adjacent to the immersion area so as to inhibit immersion liquid from escaping from the gap between the projection optical system and substrate. The ferrofluid can be a fluid having a colloidal suspension of ferromagnetic particles in it.
Claims74
A fluid control system for immersion lithography in which a portion of a surface located in an immersion area is exposed to irradiation while an immersion liquid is supplied to a gap disposed between an optical member and the portion of the surface located in the immersion area, the fluid control system comprising:
- a ferrofluidic seal located adjacent to the immersion area and that is formed from a ferrofluid that is different from the immersion fluid.
An immersion lithography apparatus for transferring an image to a substrate, the apparatus comprising:
- a projection optical system that projects the image onto the substrate;
- a substrate stage that holds the substrate;
- an immersion fluid supply system that supplies an immersion fluid to a portion of a surface of the substrate located in an immersion area that is between the substrate and a last optical element of the projection optical system;
- and
- a ferrofluidic seal located adjacent to the immersion area and that is formed from a ferrofluid that is different from the immersion fluid.
A method of retaining immersion fluid in an immersion area during an immersion lithography process in which a portion of a surface located in the immersion area is exposed to irradiation while the immersion liquid is supplied to a gap disposed between an optical member and the portion of the surface located in the immersion area, the method comprising:
- forming a ferrofluidic seal adjacent to the immersion area, the ferrofluidic seal being formed from a ferrofluid that is different from the immersion fluid.
Dependencies are inferred from the claim text.