| 摘要 |
PURPOSE:To make it possible to obtain a homogeneous and large-sized, quartz glass plate of a uniform ultraviolte-ray transmittivity, by processing the flat bar or the pipe below by cutting after fusing the fused quartz ingot again to mold it into the flat bar or the pipe. CONSTITUTION:In production of the large-sized quartz plate for photomask substrate for production of an LSI and so on, fused quartz ingot is melted at >=1,900 deg.C and is molded into a flat bar or a pipe. Next, it is cut with prescribed dimensions and is polished to obtain a quartz glass plate. The quartz plate obtained in this manner has no fusion striae and strain, so that the quartz plate suitable as a substrate of photomask can be produced efficiently. |
