MOUNTED STRUCTURE AND MOTOR

摘要

A mounted structure (1) wherein an electronic component (5) is surface-mounted on a wiring board (2) with solder (4). The solder is an Sn-Ag-Bi-In-based solder comprising 0.1 to 5 wt% of Bi, more than 3 wt% and less than 9 wt% of In, and a balance of Sn, Ag, and unavoidable impurities. The linear expansion coefficient of the wiring board is no more than 13 ppm/K in all directions. Due to this, the mounted structure using this lead-free solder is suppressed in the occurrence of cracks at solder joint portions caused by 1000 cycle heat shock testing at -40 to 150°C.