Soldering flux and solder paste composition

摘要

A soldering flux contains a base resin and an activating agent. The soldering flux contains, as the activating agent, an oxygen-containing heterocyclic compound having at least one carboxyl group in a molecule. A solder paste composition contains the abovementioned soldering flux and the solder alloy powder. These enable exhibition of excellent wettability to lead-free metals and plating, irrespective of the type of the metals.