Board-level solder intermetallic strength measurements using mini-Charpy shock testing and FEM calibration

A modified Charpy impact testing tool is used for the characterization of brittle fractures at the solder - board finish transition. The application of an accelerometer on the hammer allows to extract additional impact parameters which characterize the fracture behavior. By combining the experimental results with FEM (Finite Element Modelling) simulations, the stress distribution inside and at the surroundings of the solder connection can be derived at the onset of fracture. This method provides an estimated Cu-Sn intermetallic/ intermetallic interface fracture strength in the order of 100MPa.