| 摘要 |
A glass composition for a photoetching mask is described, which comprises, all by mol, 55 to 70% SiO2, 7 to 11% Al2O3, 7 to 20% CaO, 3 to 13% MgO, 3 to 13% ZnO, 0.5 to 3% K2O or Na2O, 0 to 11% PbO and 0 to 3% ZrO2. This glass is free from defects such as pinholes, has a relatively low coefficient of thermal expansion and contains no air bubbles, and a photoetching mask composed of the glass composition.
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