Fatigue Life Analysis of Laser Solder Joints

Laser soldering could be used in medical devices for component interconnection.  The assembling process or implant environment may put forces on those solder joints.  Because of the low melting temperature, solder materials can exhibit room or body temperature creep, which causes reliability concerns. 

In this study, the creep and fatigue performance of eutectic solder is evaluated through numerical modeling and testing.  There are a variety of material models for solder and their main features are compared.  Finite Element models were developed to study the fatigue life of solder joints under constant or cyclic load.  It's interesting that FEA predictions vary dramatically among different material models.  Experimental testing was then conducted to help select and verify the solder FEA model.  The selected model is then applied in sensitivity studies to understand the effect of temperature and frequency on solder performance.  This developed modeling framework would guide the future design and testing related to laser solder joints.