Diffusion barriers have been used in electronics manufacturing for several decades. Nevertheless, at SEM Lab, Inc. we occasionally see cases where no barrier layer is used when perhaps it should be. The addition of a plating step to create a diffusion barrier adds cost to the end product. This is the likely reason that we find cases where no barrier layer is used. However, the cost of the diffusion barrier may well be offset by improved soldering process quality and solder joint reliablity.
This document attempts to chronicle the reason for using diffusion barriers, and identifies opportunities for applications where they have apparently been overlooked. This paper is a series of examples illustrating the use of diffusion barriers in electronics manufacturing.