| 摘要 |
PURPOSE:To produce quartz glass which has extremely little Ti impurities and excellent in the transmittance of ultraviolet light by using both alkylsilicate and high-purity ultrafine powdery silica as a raw material and adopting a sol-gel process as the producing method. CONSTITUTION:After mixing ethylsilicate of 0.02ppm Ti content, pure water and hydrochloric acid and violently stirring the mixture, ultrafine powdery silica of 0.01ppm Ti content is slowly added and this mixture is fully stirred to make it a sol soln. and thereafter the sol soln. is regulated to 4.3pH by aq. ammonia and left at rest, allowed to gel and aged in a thermostatic chamber at 30 deg.C. After drying this wet gel to obtain dry gel, it is sintered to produce quartz glass and this is subjected to high temp. treatment at 1,780 deg.C for 10min. the obtained quartz glass has extremely small amount of <=0.05ppm Ti or Ti compd. of impurities, >=90% transmittance for ultraviolet light having 200nm wavelength and excellent performance as the substrate of a photomask for an IC. |
