Effect of aging mode on the IMC growth of SAC(305)/Cu solder joints during aging

Abstract

Abstract. Two different aging modes of continuous aging and interval aging were adopted to investigate the intermetallic compound (IMC) growth between Sn-3.0Ag-0.5Cu (SAC(305) )solder and Cu substrate. The morphologies of IMC layer are different during two different aging modes, and there is only one phase(Cu 6 Sn 5 phase) form during interval aging. Despite the different morphologies, the growth of IMC layers both follow diffusion control mode during two different aging styles, and the growth rate of IMC layer is slowlier over interval aging than that over continuous aging. In addition, it is illuminated the phenomenon of no Cu 3 Sn form during interval aging, this can be mainly explained by interval aging mode and diffusion growth mode, the free energy of system is not high enough to overcome the kinetic energy barrier and make the Cu 6 Sn 5 phase change into Cu 3 Sn. In a word, the reliability of SAC(305)/Cu solder joints can be improved during interval aging.