Mechanical Characterization of SAC305 and SnPb36Ag2 BGA Assemblies Under Static Flexural Loading

Static bending-induced solder joints damage is a main reliability concern for aerospace and military industries whose Printed Circuit Board Assemblies (PCBAs) are required to remain functional under flexural loading. In order dissipate heat in an equipment, it common install thermal gap pads on electronic packages. When compressing during the fixture process, PCBA can bend therefore crack if deflection too important. This paper reports durability of 96.5Sn-3.0Ag-0.5Cu (SAC305) 62Sn-36Pb-2Ag (SnPb36Ag2) Ball Grid Array (BGA) assemblies static loading at -55°C, 20°C 125°C. As equipment be stored high temperature prolonged durations, some SAC305 test vehicles were also aged 125°C 192 hours. For each configuration, bending tests conducted ramp-rate 2 mm/min central displacement-to-failure was measured. Finite Element Modeling (FEM) analysis considering global-local approach transfer function between local PCB strain near critical determined configuration. The results give necessary data designers assess whether specific design subjected risk or not.