Numerical simulation on thermal fatigue behavior of CuCGA soldered joints

The constitutive equation of Sn3.9Ag0.6Cu and 63Sn37Pb were established based on creep law, and the stress-strain distribution of soldered joints in copper column grid array(CuCGA) devices was analyzed under the loadings of different temperature cycles.Results indicate that no matter how the change of temperature cycle range, the maximum creep strain is located in the soldered joint where the location from the device center is foremost, in which the stress concentration is found and cracks appear, therefore, the corner soldered joint is the most fragile area in the whole device.Creep strain of Sn3.9Ag0.6Cu soldered joints is smaller than that of 63Sn37Pb soldered joints.Lower stress and creep strain are exhibited for both Sn3.9Ag0.6Cu and 63Sn37Pb when the temperature cycles range is shortened.Sn3.9Ag0.6Cu soldered joints show higher thermal fatigue life than 63Sn37Pb soldered joints under the same temperature cycle.