METHOD FOR REDUCING OXYGEN COMPONENT AND CARBON COMPONENT IN FLUORIDE

摘要

A method for reducing an oxygen component and a carbon component in a fluoride which comprises subjecting the fluoride to a fluorine gas treatment wherein the fluoride is contacted with a gas containing a fluorine gas. The utilization of the method allows, for example, the reduction of the amount of a scavenger to be added at the deoxidation step in a single crystal preparation process. The method can be used for reducing an oxygen component and a carbon component contained in a high purity fluoride such as calcium fluoride or barium fluoride which is a material for a stepper lens for an ArF or F2 excimer laser used, for example, in an exposure system in a photolithography process for manufacturing a semiconductor device or contained in a rare earth fluoride such as ytterbium fluoride or cerium fluoride which is used as a material for an optical fiber or a coating.