Physical properties of low temperature solders and die attach materials

The properties at the temperature range of -55/spl deg/C to 180/spl deg/C of several common solders used in electronic packaging are analyzed for mechanical properties (elastic modulus, yield point, ultimate tensile strength (UTS), and creep) and physical properties (microstructure and thermal expansion coefficient). Numerous experimental methods are utilized and correlated. The finite element method is used to model thermal stresses (thermal fatigue) induced by the mismatched coefficient of thermal expansion using all the results obtained in this work. Some preliminary data are presented together with previous data obtained in our laboratories for the Au-Sn eutectic alloy.