Surface mounting semiconductor device and semiconductor mounting component

摘要

A surface mounting semiconductor device or a mounting component includes a metallic carbonate coating on a mounting surface which may be a plated layer of a metal easy to solder on which an outer lead or the like is to be mounted so that the oxidation of the mounting surface of the outer leads during storage is reliability prevented. Upon mounting the semiconductor device to the circuit board with solder, the heat added causes the metallic carbonate coating to decompose, to evolve CO3, and leave active metal, significantly improving solder wettability, so that a reliable solder joint is obtained. Since CO3 is evolved in the gaseous state, it does not stay on the metal surface, eliminating the need for cleaning after the treatment. Because solder wettability is significantly improved, molten solder cannot flow from the side of the soldered joint to bridge outer leads and terminals.