Optical member of silica glass for transmitting fluorine excimer laser radiation and method for producing the same

摘要

A method for producing an optical silica glass member for transmitting F2 excimer laser radiation is known which comprises an optical silica glass for transmitting F2 excimer laser radiation formed of a transparent glass body prepared by depositing fine silica particles obtained by flame hydrolysis in gaseous phase of a compound containing silicon on a heat resistant base body and thereby forming a porous preform, followed by vitrifying the resulting porous preform into a transparent body in the temperature range of from 1,400 to 1,500 DEG C. In oder to improve the resistance against a F2 excimer laser radiation, it is suggested that the process further comprises between the production step of the porous preform and the vitrification step for obtaining the transparent glass body: a first step of performing heat treatment in a temperature range of from 800 to 1,200 DEG C under a mixed gaseous atmosphere of a chlorine-containing compound and oxygen; and a second step of performing heat treatment for doping fluorine after the first step above, in a temperature range of from 800 to 1,300 DEG C under a gaseous atmosphere of a compound containing fluorine atoms.