The effect of pretinning on the solderability of copper

Abstract

The reliability and integrity of pretinned, copper-clad printed circuit boards are serious concerns in the manufacture of electronic devices. The nature of wetting during the soldering of copper is critical in the reliability of these solder joints. Some preliminary experiments on the solderability of pretinned copper suggest that pretinning with a lead-rich solder, such as 95Pb-5Sn, is preferred to pretinning with a eutectic solder, because the latter can develop exposed intermetallics during aging or baking that wet poorly.