Solder Joint Reliability: A Unified Thermo-Mechanical Model Approach

Due to an unprecedented pervasiveness of electronics in high performance applications, the dependability of mission critical equipment and systems, often solely depends on the reliability of underlying embedded electronic sub-systems. This includes reliability of the solder joints which are subject to fatigue failure over time in harsh operating environments replete with thermo-mechanical stresses. Fatigue behavior of the solder joints has been previously studied under the separate domains of microstructure evolution and non-linear plastic deformations. The proposed study captures the underlying physics of failure mechanisms to model the failure initiation and degradation phases to obtain a unified model characterizing the overall fatigue behavior over the two phases. The model development is followed by reliability analysis which takes into account the individual phases to establish the conditional relationship for a unified reliability model. The reliability analysis has been attempted using both the failure time and the damage accumulation approaches