Birch, Stewart, Kolasch & Birch, LLP
Large-size synthetic quartz glass substrate, evaluation method, and manufacturing method
A large-size synthetic quartz glass substrate has a diagonal length of at least 1,000 mm. Provided that an effective range is defined on the substrate surface, and the effective range is partitioned into a plurality of evaluation regions such that the evaluation regions partly overlap each other, a flatness in each evaluation region is up to 3 μm. From the quartz glass substrate having a high flatness and a minimal local gradient within the substrate surface, a large-size photomask is prepared.
SHIN-ETSU CHEMICAL CO., LTD.
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C03C G03F B24B G01B C03C C03C
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Daijitsu Masaki Yoko Atsushi
Harada Takeuchi Ishitsuka Watabe