Substrate for photomask, photomask blank and photomask

摘要

A substrate for photomask has a top surface and a back surface, the substrate being square in shape, an end surface formed along the thickness thereof and a chamfered surface formed on a perimeter edge region where the end surface and the top surface meet and another region where the end surface and the back surface meet, a size of the perimeter edge of the substrate is 300 mm or more on a side and the end surface and the chamfered surface each has a roughened surface having a surface roughness (Ra) ranging from 0.03 mum to 0.3 mum.