| 摘要 |
PROBLEM TO BE SOLVED: To prevent breakdown of a comb-type pattern formed on the surface of a lithium tantalate (LT) substrate and cracking of the LT substrate by preventing spark generated by the accumulation of electric charges on the substrate surface; and to prevent that the light transmitted through the LT substrate reflects on the rear surface of the substrate and returns to the surface, and thereby, the resolution of the comb-type pattern is reduced in a photolithographic process. SOLUTION: In a method for manufacturing the LT substrate from an LT crystal, after growing the crystal, an LT crystal in an ingot form is embedded in carbon powder, or is placed in a carbon vessel, and heat treatment is performed at a maintained temperature of 650-1,650°C for at least 4 hours. COPYRIGHT: (C)2005,JPO&NCIPI
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