Lithographic apparatus and device manufacturing method
AssigneeASML Netherlands B.V.
InventorChristian Wagner
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Abstract
A final element of a projection system of an immersion lithographic apparatus is configured for a liquid having a refractive index greater than a refractive index of the final element. In an embodiment, the final element comprises a convex meniscus shaped lens. Such a final element enables the effective numerical aperture of the lithographic apparatus to be increased and reduce total internal reflection of the projected beam as it passes through the final element to the liquid.
Claims20
A lithographic projection apparatus arranged to project a patterned beam of radiation from a patterning device onto a substrate, the apparatus comprising:
- a projection system configured to project the patterned beam of radiation onto the substrate, the projection system comprising a final element adjacent the substrate and configured to focus the patterned beam of radiation through a liquid onto the substrate;
- and
- a liquid supply system configured to supply a liquid to a space between the final element and the substrate, the liquid having a refractive index greater than a refractive index of the final element.
A device manufacturing method, comprising:
- supplying a liquid to a space between a final element of a projection system and a substrate, the liquid having a refractive index greater than a refractive index of the final element, the final element positioned adjacent the substrate and configured to focus a patterned beam of radiation through a liquid onto the substrate;
- and
- projecting a patterned beam of radiation, using the final element, through the liquid onto the substrate.
Dependencies are inferred from the claim text.