LED Failure Localization Method due to Thermal Shock and Residual Stress Impact

LEDs and electronic components are taking a more important part in automotive lighting systems. With the increasing need of size reduction and higher flux performances, thermal and electronic reliability are important to maintain by deploying a validated pre-sizing tool to reduce long simulation times and assure a quick design validation in a project.In this paper, we present a new simulation method to predict the thermo mechanical fatigue of solder joints in a complex 3D stack up LED. Solder joints are essential to the assemuly of components on a substrate. Yet, thermal cycles are identified as a primary cause of solderjoint breaking. The aim is to analyze the damage caused by the thermal expansion effect during reflow of the solders and thermal shock cycling on the stack up by Hutchinson's 1966 model and 3D simulation. The predicted damages are compared to microstructure analysis done by SEM.