| 摘要 |
PURPOSE:To obtain high-purity quartz glass, having improved heat resistance and suitable as jigs for producing semiconductors, by oxidizing a silicon compound in the vapor phase, depositing the oxidized compound on a substrate, crystallizing the deposited glass and heating the crystallized glass at a high temperature. CONSTITUTION:A silane expressed by the formula (R is H or monofunctional hydrocarbon group; X is halogen or alkoxy; n is 0 or an integer 1-4) is gasified, burned in a flame, e.g. oxyhydrogen flame, etc., and subjected to hydrolytic and thermal oxidation reactions to deposit the generated sintered porous glass material in the form of glass on a synthetic quartz glass substrate, etc. The resultant deposited quartz glass is then dipped in an aqueous solution of an alkaline compound, e.g. NaOH, as a crystallization accelerator, dried and crystallized while heating at 1,100-1,200 deg.C to give a cristobalite crystal, which is then heated at about 1,100 deg.C in a halogen gas stream, etc., for about 10hr to evaporate the alkali component and reduce the residual amount thereof to <=0.05ppm. The resultant crystal is further heat-treated at a high temperature above the melting point of the cristobalite and vitrified. |
