Manufacturing concerns when soldering with gold plated component leads or circuit board pads

Abstract

When manufacturing with either gold plated component leads or printed circuit board pads, one must be concerned with the amount of gold in the solder joint. Gold dissolves quickly in tin/lead solders, forming weak, brittle compounds, that when in high enough concentrations, adversely affect the solder joint fatigue life. This paper discusses the effects of gold in tin/lead solder, a qualification test with varying solder paste volumes, calculations for percent Au concentrations, a reliability test and its results, and suggested process controls or manufacturing safeguards.