A comparison of alloy-surface finish combinations considering different component package types and their impact on soldering reliability

Reliability specifications for solder joints, as well as for all electronic components, have become a fundamental feature in the qualification of an electronic product. The relevance of these reliability features increases if new components or materials are considered. In this research activity, an accelerated thermal test on customized electronic boards was implemented for an early reliability evaluation; we therefore proposed a study on the reliability behaviour of a solder joint by considering different surface finishes, and several component packages. A comparative study was carried out through the application of statistical methods. To this end, Weibull distributed data and non-linear mixed models were evaluated. More precisely, Weibull random-effects models were applied to compare different combinations of surface finishes, (e.g. Hot Air Solder Leveling, Electroless Nickel Immersion Gold, Immersion Tin) and alloys, (e.g. tin-silver-copper, tin-lead), connected to four types of components, also to evaluate how the type of package or the geometry of the joint may affect the reliability of the soldering. Therefore, the aim of this research is a statistical study of the reliability of solder alloys subjected to thermal aging tests by also taking different surface finishes of the printed circuit boards and different types of packaging into account. The study was carried out with two-by-two comparisons of alloy-surface finishes. By evaluating the statistical results, the tin-silver-copper alloy, with the considered finishes, demonstrates a higher reliability with respect to the boards soldered by the traditional combination of soldering alloy and surface finish.