Leading Indicators of Failure for Prognostication of Leaded and Lead-Free Electronics in Harsh Environments

In this paper, a methodology for prognostication-of-electronics has been developed for assessment of residual life in deployed electronic components, and the determination of damage-state in absence of macro-indicators of failure. Proxies for leading indicators-of-failure have been identified and correlated with damage progression under thermomechanical loads. Examples of proxies include micro-structural evolution characterized by average phase size and intermetallic growth rate in solder interconnects. Validity of damage proxies has been investigated for both 63Sn37Pb leaded and SnAgCu lead-free electronics. Structures examined include plastic ball grid array format electronic and MEMS packages and discrete devices assembled with FR4-06 laminates. The focus of the research presented in this paper is on interrogation of the aged material's damage state and enhancing the understanding of damage progression. Instead of life prediction of new components, the research is aimed at the development of damage relationships for determination of residual life of aged electronics and the assessment of design margins. The prognostic indicators presented in this paper can be used for health monitoring of electronic assemblies.