Production of fluoride crystal for use in e.g., various optical elements, by dehydrating raw material of fluoride by heating crucible for accommodating raw material of fluoride, and exhausting inside gas of the crucible

摘要

Production of fluoride crystal involves dehydrating a raw material of fluoride by heating a crucible adapted to accommodate raw material of fluoride in it and having an exhaust mechanism for exhausting an inside gas of the crucible; and exhausting, in the dehydrating step, an inside gas of the crucible by use of the exhaust mechanism. Independent claims are included for the following: (a) A crystal producing apparatus comprising a process chamber for producing fluoride crystal; a pressure detecting unit for detecting a pressure of the process chamber; a crucible accommodated in the process chamber and adapted to accommodate a raw material in it; and a control unit for controlling the gas exhaust through the exhaust mechanism, on the basis of the pressure of the process chamber detected by the pressure detecting unit; (b) An exposure apparatus in which one of ultraviolet light, deep ultraviolet light, and vacuum ultraviolet light is used as exposure light, and where exposure light is projected on a workpiece through an optical system including an optical element to expose the workpiece with the exposure light;and (c) A device manufacturing method comprising exposing a workpiece using the exposure apparatus.