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US 8,045,135 B2Granted
Lithographic apparatus with a fluid combining unit and related device manufacturing method
AssigneesASML Netherlands B.V., ASML Holding N.V.
InventorsJohannes Catharinus Hubertus Mulkens, Matthew Lipson, Harry Sewell, Louis John Markoya
Life of this patent
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Abstract
A system for tuning the refractive index of immersion liquid in an immersion lithographic apparatus is disclosed. Two or more immersion liquids of different refractive index are mixed together in order to achieve a desired refractive index. Further, the fluids may be conditioned and treated to maintain optical characteristics.
Claims18
A lithographic apparatus comprising:
- a first liquid supply system configured to provide a first liquid with a first refractive index greater than water at equal conditions;
- a second liquid supply system configured to provide a second liquid with a second refractive index which is lower than the first refractive index, the second liquid comprising one or more selected from the group:
- fluorinated hydrocarbon, fomblin, Krytox type oil, decalin, saturated monocyclic hydrocarbon, cyclohexane, fluorinated decalin or hydrocarbon;
- a combining unit configured to combine the first and second liquids to achieve a combined liquid with a refractive index lower than the first refractive index and closer to a desired refractive index than the first refractive index or the second refractive index and configured to control the combining the first and second liquids such that the combined liquid comprises 10% or less of the second liquid;
- and
- a refractive index measuring unit to measure the refractive index of the first liquid, of the combined liquid, or of both,
- wherein the combining unit is configured to achieve the refractive index of the combined liquid based on the measured refractive index of the first liquid, of the combined liquid, or of both.
4 more elements
A device manufacturing method comprising:
- combining a first liquid with a first refractive index greater than water at equal conditions with a second liquid with a second refractive index which is lower than the first refractive index in order to achieve a combined liquid with a refractive index lower than the first refractive index and closer to a desired refractive index than the first refractive index or the second refractive index, the second liquid comprising one or more selected from the group:
- fluorinated hydrocarbon, fomblin, Krytox type oil, decalin, saturated monocyclic hydrocarbon, cyclohexane, fluorinated decalin or hydrocarbon and the combined liquid comprising 10% or less of the second liquid;
- measuring the refractive index of the first liquid, of the combined liquid, or of both, wherein the combining is performed to achieve the refractive index of the combined liquid based on the measured refractive index of the first liquid, of the combined liquid, or of both;
- and
- projecting a patterned beam of radiation onto a substrate through the combined liquid, which liquid is provided between the substrate and a projection system used to project the patterned beam.
2 more elements
Dependencies are inferred from the claim text.