Patent ID: 9067814
Filing Date: 2015-06-30
Classification: C03B,Y02P

Abstract:
1. A method of producing a synthetic quartz glass for excimer laser, comprising the steps of: depositing on a target silica particulates in a vacuum sintering furnace to form a porous silica base material; vitrifying the porous silica base material to obtain a vitrified material; and subjecting the vitrified material to hot forming, an annealing treatment and a hydrogen doping treatment, so that the synthetic quartz glass suitable for use in an excimer laser is produced, wherein the silica particulates have been obtained by subjecting a silica raw material to vapor-phase hydrolysis or oxidative decomposition in an oxyhydrogen flame, and the vitrification of the porous silica base material comprises steps of: (a) holding a vacuum pressure at or below 20.0 Pa in a temperature range from 400° C., inclusive, to 900° C., exclusive; (b) holding a vacuum pressure at or below 10.0 Pa in a temperature range from 900° C., inclusive, to 1100° C., exclusive; and (c) holding a vacuum pressure at or below 3.0 Pa in a temperature range from 1100° C. to a transparent-vitrification temperature, wherein the porous silica base material is held in a temperature range from 150° C. to 350° C. for a period of time from 30 minutes to 6 hours, prior to the step (a).