Patent ID: 8045135
Filing Date: 2011-10-25
Classification: G03F,H01L

Abstract:
1. 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.