Patent ID: 9056785
Filing Date: 2015-06-16
Classification: B29C,C03B,C03C,Y02P

Abstract:
1. A method for preparing a synthetic quartz glass for forming nanoimprint molds, comprising the steps of subjecting a silicon-providing feedstock to flame hydrolysis in an oxyhydrogen flame to produce fine particles consisting of silica, depositing the silica fine particles on a rotating quartz glass target while concurrently melting and vitrifying them, thereby forming a synthetic quartz glass ingot, shaping, annealing, and effecting dehydrogenation treatment by holding at a temperature of at least 600° C. and a pressure of up to 5 Pa for a time of at least 12 hours, thereby obtaining a synthetic quartz glass having an OH group concentration of 300 to 489 ppm and a Raman peak attributable to hydrogen molecule equal to or less than the detection limit which is a hydrogen molecule concentration of up to 8.5×10