Electrostatic fields and current-flow impact on whisker growth

Tin whisker growth is problematic due to the potential for short circuits in electronic devices. These devices are electrically active, generating electric fields, and transporting current. Controversy continues regarding the propensity for tin whiskers to grow more readily in the presence of an electrical bias, and other researchers have proposed that an electrical field can influence tin-whisker growth directions. The latter would exacerbate the problem of tin whiskers in electronic devices by potentially reducing the effective growth length required to induce electrical shorts. In this paper, we have developed a new test vehicle to examine the roles of electric field and current flow on the tendency to form tin whiskers. Parts have been exposed to various environmental conditions, similar to those proposed by the National Electronics Manufacturing Initiative (NEMI). In summary, the electrical fields used here, bias and current flow, do not significantly affect whisker growth. We will also present some analytical discussion regarding the potential of electromagnetic fields to influence whisker growth directions or deflections.