Solder joint structure, soldering method, and electronic-component manufacturing apparatus using the same structure and the method

摘要

A structure of solder joint structure formed of zinc-based lead-free solder having excellent characteristics is disclosed. Between a first lead-free solder layer and a soldering pad, the following layers are formed: a tin-copper alloy layer formed on the pad; a first alloy layer formed of second lead-free layer of which main ingredients are tin and silver; and a second alloy layer formed between the first alloy layer and the first lead-free solder. This structure allows forming the solder joint structure formed of zinc-based lead-free solder having high joint strength.