Thermal test- and field cycling induced degradation and its FE-based prediction for different SAC solders

Abstract

A study of the performance of different Sn based solder alloys applied for large to small sized solder interconnects was undertaken. From the theoretical and experimental investigations on creep, fatigue and brittle fracture behaviors the paper focuses on the low cycle fatigue performance in test and field thermal environments. Special focus was put on a newly developed highly creep resistant solder alloy "Innolot" (SnAg3.8Cu0.7Bi3.0Sbl.4Ni0.2). In addition to results of previous studies on lead free materials, particularly their long- term durability and their microstructure-properties dependence was addressed. Phenomenological models based on finite element analyses including solder creep behaviors were applied to study the component and cyclic regime dependent creep straining and creep dissipation in several joints to assess solder failure. For this purpose, creep properties of several solders were measured for ball-type joint sized specimens.