Research on thermal impact properties of single solder joint by RTC

Research under the condition of thermal shock fine pitch flip chip micro solder joint crack initiation and propagation, through the observation of crack growth path, and connecting with the cumulative plastic strain energy density and the distribution of strain on the solder joints, analysis of crack growth mechanism results show that the crack formation in the solder joint lateral, located in nickel welding plate boundary and the IMC and solder matrix on the boundary between; Cracks with the increase of cycling times, into the nickel solder in a nearby solder matrix, extend in the direction of the welding plate in parallel, the cumulative plastic strain energy density and distribution of the strain on the solder joint and crack propagation in the same direction of crack growth mechanism discussion, the IMC and micro solder joints between the community and in double stress concentration condition, so the micro cracks easily in the solder joints and on the boundary between IMC and initiation; With the increase of cycle times, the plastic deformation of the solder matrix increases, and the high plastic solder region provides conditions for crack propagation.