| 摘要 |
PROBLEM TO BE SOLVED: To provide a method of soldering a printed board for obtaining a solder-joined part having excellent temperature cycle characteristics.SOLUTION: The method of soldering a printed board is provided in which in order to suppress development of cracks caused by formation of a hard solder structure in a surface portion of a solder fillet, soldering is performed by flow soldering using a solder alloy containing 0.5-0.8 mass% Cu, 0.04-0.08 mass% Ni, 0.05-0.09 mass% Sb, 0.001-0.05 mass% one or more kinds of elements selected from a group consisting of P and Ge in total, and the balance comprising Sn. |
