EVALUATION OF PRESSURE-INDUCED TIN WHISKER FORMATION
Authors: Tadahiro Shibutani, Ph.D. et al. Date Published: 6/21/2007
Abstract: This paper presents a fundamental assessment of pressureinduced tin whisker formation along with a creep-based tin whisker model developed to explain the experimental data. We also show that certain creep properties can be used as a tin whisker screen for plating finishes. For the assessment of electronics components, qualification of stress evolution in the plating was performed by using finite element analysis (FEA). Analysis of ball indentation test for tin reflow Sn-2Ag, and Sn-2Bi showed higher stresses corresponded to longer whisker formation in connectors. Double-layered plating consisting of semi-bright and matte tin copper was also assessed for tin whisker formation and was found to mitigate pressure-induced tin whiskers in connectors. Stress evolution in the plating reveals that multiaxial residual stresses decrease as a function of.
Keywords: tin whisker, pressure, creep, nanoindentation, finite element analysis