Reliability of Electronic Assemblies Under Mechanical Shock Loading

Abstract

The emphasis of this chapter is placed on describing the loading condition under drop testing of electronic devices and the analysis of the failure modes and mechanisms of high-density component boards under mechanical shock loading conditions. The failure modes and mechanisms under drop impact loading are markedly different from those typically observed in thermally cycled component boards. Reliability of different material combinations under the tests is reported, and the associated failure modes and mechanisms are discussed. Because the reliability of electronic assemblies under mechanical shock loading is highly dependent on the ability of intermetallic layers to withstand the stresses produced during drop impacts, the formation and properties of different interfacial regions are discussed in detail. Furthermore, it is shown that alloying and impurity elements can have strong effects on the intermetallic layers in the solder interconnections and the drop reliability of component boards.