Effect of Extreme Environment on Interfacial IMC Growth and Fracture Behavior of SAC305/Cu solder joints

With the development trend of miniaturization of microelectronic packaging, the solder joints may serve at a very complex environment, contains electrical current, heat, and mechanical stress. In this article, the effects of extreme environment on interfacial intermetallic compounds (IMC) growth and fracture behavior of the SAC305/Cu samples were investigated. The thickness of IMC gradually increased and shear strength decreased during the aging process at 100 °C, -196 °C and 150 °C. Moreover, the thickness of the interfacial IMCs showed a linear function with t
^1/2
when stored at 100 °C and 150 °C. After 960 h of aging, the morphology of interfacial IMC at -196 °C changed to columnar, and the morphology of interfacial IMC at 150 °C and 100 °C changed to planar. The fracture behavior was dominated by ductile fracture at 100 °C. Numerous bulk-like Cu6Sn5 compounds could be observed on the fracture layer when the SAC305/Cu samples get stored for 720 h at 150 °C or -196 °C. Thus, the fracture behavior had become ductile-brittle mixed fracture at this time. The fracture location also moved from matrix to matrix/IMC layer interface. The research results provide some general design guidelines and concepts for optimization of performance of the SAC305/Cu solder joints in extreme environment.