| 摘要 |
PURPOSE:To prevent contamination of a silicon wafer by heating a silica gel obtained by a sol-gel method to provide cristobalite, pulverizing the resultant cristobalite, forming the obtained powder into a tubular shape, thermally fusing the tube, pulverizing the fused tube and converting the resultant powder into synthetic quartz glass. CONSTITUTION:A solution of an aloxysilane, such as tetramethoxysilane or tetraethoxysilane, is hydrolyzed to form a sol, which is then heated at 30-60 deg.C, gelatinized and dried at 50-70 deg.C. The obtained dried gel is subsequently heated stepwise to 1000-1600 deg.C at 10-100 deg.C/hr heating rate and transformed into cristobalite, which is then pulverized in a ball mill, etc., preferably sieved to regulate the particle diameter to 50-250 mesh average particle diameter. The glass powder is then formed into a tubular shape by a tube forming method, etc., and thermally fused. The resultant powder is subsequently converted into synthetic quartz glass with <=0.1ppm content of metallic impurities, such as Na, K, Li or Cu, and >=10<13>P viscosity value at 1200 deg.C and excellent in devitrification resistance. |
