A Damage Evolution Model for Thermal Fatigue Analysis of Solder Joints

Abstract

Thermal fatigue of solder joints is critical to the performance and reliability of electronic components. It is well known that the fatigue life of solder joints is rather difficult to be estimated because of the complicated material behaviors and solder joint geometry. Conventional life prediction methods such as Coffin-Manson equation or its modifications usually over-estimate the thermal fatigue life. The main reason for this phenomenon is that the material properties are assumed constant during thermal cycling. In this paper, a damage evolution model is introduced for predicting the thermal fatigue life of solder joints. This method not only considers the degradation of material properties in the solder, but also saves substantial computational effort. In the present study, a damage function is determined by the hysteresis loops of creep shear stress-strain of solder joints in a double-beam specimen. The proposed model is then applied to investigate the solder joint reliability of a 272 PBGA package and a bottom-leaded plastic (BLP) package for model verification. The results from the present analysis seem to be encouraging. [S1043-7398(00)01003-3]