| 摘要 |
PROBLEM TO BE SOLVED: To make a solder wet well against a substrate by reducing oxygen content in a molten solder alloy which is mainly composed of zinc and tin so as to restrain generation of dross. SOLUTION: A solder alloy mainly composed of zinc and tin is heated to form a molten metal, and the oxygen content in the molten metal is reduced so as to restrain generation of dross. Then, a jointed member, on the surface of which the metal having wettability against the solder alloy is formed, is brought into contact with the surface of the molten metal, so as to form a solder layer on the surface of the metal. Generation of dross depends on the oxygen content in the molten solder, and when the oxygen content exceeds 50 ppm, the dross is surely generated. For reducing the dross, it is effective that oxygen scavenger chosen from, for example, Mn, Al, In, Si, Fe, Ge, P, C, N, B, H, and ammonium is added to the molten metal.
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