Re‐calibration of Engelmaier's Model for Leadless, Lead‐free Solder Attachments

In this paper, the solder attachment fatigue model created by Werner Engelmaier is re-calibrated in order to make it applicable in conjunction with leadless, lead-free solder attachments. Sn3.8Ag0.7Cu solder attached ball-grid-array components are addressed to three thermal cycling test profiles. Based on the results, both physical and statistical parameters are obtained and compared with the values relevant to tin–lead solder assemblies. The validity of the statistical distribution selection (two-parameter Weibull) is studied. Acceleration factors correlating different test profiles are obtained, and they are found to be only weakly dependent on the test vehicle type. Copyright © 2006 John Wiley & Sons, Ltd.