摘要 |
When a synthetic quartz glass substrate is prepared from a synthetic quartz glass block, (I) the block has a hydrogen molecule concentration of 5x10<SUP>17</SUP>-1x10<SUP>19 </SUP>molecules/cm<SUP>3</SUP>, (II) the substrate has a hydrogen molecule concentration of 5x10<SUP>15</SUP>-5x10<SUP>17 </SUP>molecules/cm<SUP>3</SUP>, (III) the substrate has an in-plane variation of its internal transmittance at 193.4 nm which is up to 0.2%, and (IV) the substrate has an internal transmittance of at least 99.6% at 193.4 nm. The synthetic quartz glass substrate has a high transmittance and a uniform transmittance distribution, and is adapted for use with excimer lasers, particularly ArF excimer lasers.
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