Aging study on interfacial microstructure and solder-ball shear strength of a wafer-level chip-size package with Au/Ni metallization on a Cu pad

[[abstract]]The growth of the intermetallic compounds (IMC) layer and the shear-strength degradation of the eutectic Sn-Pb solder that was reflowed on a Cu pad with an Au/Ni metallization during aging at 150°C was examined. It was shown that first two IMC layers, Au0.5Ni0.5Sn 4 and Ni3Sn4, were observed at the solder/Ni interface after 150°C isothermal-aging treatment over 720 h. The Ni 3Sn4 layer was observed at the solder/Ni interface and the Au0.5Ni0.5Sn4 layer was found at the solder/Ni3Sn4 interface. Au0.5Ni 0.5Sn4 layer grows with time and dominates the thickness of the IMC layer.[[fileno]]2020233010004[[department]]動機