Tin Whisker Mitigation Technologies for Sn-based Surface Finishes on Electronic Assemblies and Microelectronic Devices

The impact of metal whisker growth on the reliability of electronics has been exacerbated by environmentally-driven efforts to eliminate lead from tin plating and solders. Even exempt applications, such as military, are affected due to process, logistic and economic supplier realities. It is generally acknowledged in research that the whisker growth mechanism is still not fully understood and that test methods, especially accelerated ones, do not correlate well with field experience. Foresite, Inc., a consultant, laboratory and test equipment development company specializes in the identification, mitigation, removal and prevention of detrimental, process-related residues on electronic assemblies. Foresite research indicates a correlation between ionic residue levels and whisker growth, given prerequisite conditions, such as stress. The Phase I goal is to identify and rank tin whisker nucleation and growth factors by teaming the process residue expertise of Terry Munson, Foresite President, with the whisker research expertise of Prof. Carol Handwerker, Materials Science, Purdue University and the plating process expertise of Dennis Fritz, Senior Engineer, SAIC. An accelerated test for the proclivity of a sample to grow whiskers [using introduced, controlled contamination(?)] will be developed in Phase II. Ultimately, mitigation protocol(s) and, perhaps, whisker test equipment will result.