| 摘要 |
PROBLEM TO BE SOLVED: To bring a saturated hydrocarbon suitable for an immersion exposure liquid excellent in transmissivity in a far-ultraviolet region to be treated with sulfuric acid in an amount less than the amount conventionally used. SOLUTION: The method for producing saturated hydrocarbons by a sulfuric acid cleaning treatment to reduce absorbance includes, succeeding to a first sulfuric acid cleaning treatment process, a second sulfuric acid cleaning treatment process carried out at a cleaning treatment temperature 10°C less than that of the first sulfuric acid treatment process. In the production method, the absorbance of the saturated hydrocarbon treated in the second sulfuric acid cleaning treatment process is≤0.10 per 1 cm optical path length of the liquid in 193 nm wave length and the saturated hydrocarbon is an alicyclic saturated hydrocarbon. COPYRIGHT: (C)2007,JPO&INPIT
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