Tin whisker electrical short circuit characteristics - Part II

Karim J. Courey, Shihab S. Asfour, Arzu Onar, Jon A. Bayliss, Lawrence L. Ludwig, Maria Clara Wright

Research output: Contribution to journalArticlepeer-review

5 Scopus citations


Existing risk simulations make the assumption that when a free tin whisker has bridged two adjacent exposed electrical conductors, the result is an electrical short circuit. This conservative assumption is made because shorting is a random event that has an unknown probability associated with it. Note however that due to contact resistance, electrical shorts may not occur at lower voltage levels. In our first paper, we developed an empirical probability model for tin whisker shorting. In this paper, we develop a more comprehensive empirical model using a refined experiment with a larger sample size, in which we studied the effect of varying voltage on the breakdown of the contact resistance which leads to a short circuit. From the resulting data, we estimated the probability distribution of an electrical short, as a function of voltage. In addition, the unexpected polycrystalline structure seen in the focused ion beam (FIB) cross section in the first experiment was confirmed in this experiment using transmission electron microscopy (TEM). The FIB was also used to cross section two card guides to facilitate the measurement of the grain size of each card guide's tin plating to determine its finish.

Original languageEnglish (US)
Pages (from-to)41-48
Number of pages8
JournalIEEE Transactions on Electronics Packaging Manufacturing
Issue number1
StatePublished - 2009


  • Contact resistance
  • Focused ion beam (FIB)
  • Short circuit
  • Tin whiskers
  • Transmission electron microscopy (TEM)

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Industrial and Manufacturing Engineering


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