Growth and shear strength of intermetallic compounds in Sn-Ag-Cu solder joints

The growth evolution of intermetallic compounds and shear properties of various Sn-Ag-Cu solder joints were investigated by thermal cycling test. The numbers of thermal cycling tests were 0, 200, 400, 600, 800 cycles. Polyhedron particles composited of (Cu_1-xNi_x)₆Sn₅ were observed after 400 thermal cycles and found in bulk solder away from the IMC layers after much more thermal cycles. Meanwhile, cracks are observed in the interfacial IMC layers after thermal cycling experiment. The shear strength of solder joints decreased with increasing the cycles of thermal cycling test.