GOLD OR GOLD-ALLOY MATERIAL FOR THIN FILM DEPOSITION AND ITS MANUFACTURING METHOD, AND HEARTH INGOT USING THE GOLD OR GOLD ALLOY AND ITS MANUFACTURING METHOD

摘要

PROBLEM TO BE SOLVED: To provide a gold or gold-alloy material for thin film deposition in which impurities contained in the inner part and impurities adhering to the external surface are minimized and its manufacturing method and also to provide a hearth ingot and its manufacturing method. SOLUTION: The gold or gold-alloy material for thin film deposition is composed of gold of =4N purity and the proportion of gold exceeds 50% by mole ratio, and further, the content of volatile metallic impurities is made to =1 wt.ppm and the content of hydrogen and nitrogen is made to =1 wt.ppm, respectively, and also oxygen content is made to =5 wt.ppm. This material can be manufactured by heating and melting the gold of =4N by the zone melting and refining process in a high vacuum of =110-3 Pa. Moreover, the hearth ingot has a shape where at least a part of the casting surface of the upper surface is constituted of a smooth melting surface and the central part 1 of the upper surface is swollen and becomes higher than the rim 2 of the upper surface.