Microstructural modeling and electronic interconnect reliability

Initial development of microstructurally accurate finite element models of the soldered joints of electronic surface mount components is described. These models allow for the presence of lead and tin‐rich phases and copper‐tin intermetallic layers within the joints. The effect of these features on the strain distributions within the joints is shown. These strain distributions can be used to predict fatigue lives. This is demonstrated for homogeneous solder joints for which excellent correlation was shown between predicted lives and those measured experimentally by thermal cycling of actual components.