A Methodology for Fatigue Prediction of Electronic Components Under Random Vibration Load

In modern automotive control modules, mechanical failures of surface mounted electronic components such as microprocessors, crystals, capacitors, transformers, inductors, and ball grid array packages, etc., are major roadblocks to design cycle time and product reliability. This paper presents a general methodology of failure analysis and fatigue prediction of these electronic components under automotive vibration environments. Mechanical performance of these packages is studied through finite element modeling approach for given vibration environments in automotive application. The vibration simulation provides system characteristics such as modal shapes and transfer functions, and dynamic responses including displacements, accelerations, and stresses. The system level model is correlated through vibration experiments. Using the results of vibration simulation, fatigue life is predicted based on cumulative damage analysis and material durability information. Detailed model of solder/lead joints is built to correlate the system level model and obtain solder stresses. Predicted failure mechanism of the leads agrees with the experiment observation. On the test vehicle with multiple components, one of the 160-pin gull-wing lead plastic quad flat packages was chosen as an example to illustrate the approach of failure analysis and fatigue life prediction.