| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a synthetic quartz glass substrate having high flatness to perform fine drawing as well as having a substrate surface with less defect and minimal surface roughness, as a synthetic quartz glass substrate for a photomask used in a photolithography process or the like. <P>SOLUTION: In a synthetic glass substrate having a size of 6 inch squares, a surface thereof is inclined from an outer periphery of a central surface area of 132 mm squares toward an outer peripheral edge of the surface, the central surface area of 132 mm squares has a flatness of 50 nm or less, and a frame portion in a central surface area of 148 mm squares excluding the central surface area of 132 mm squares has a flatness of 150 nm or less. <P>COPYRIGHT: (C)2012,JPO&INPIT |
