Effect of Environmental Conditions on Tin (Sn) Whisker Growth

Abstract

This research focuses on tin whisker growth under two different environmental conditions namely hygrothermal and a salt solution. Tin coated brass coupons were used for this study to analyze the growth of tin whiskers over time. Their growth rates were examined periodically using optical and scanning electron microscopy. The physical characteristics of the tin whiskers were identified for each environmental condition. It was discovered that submersion of tin coated brass substrates in 5% salt solution considerably increased the density (number of whiskers per unit area), and the length of the whiskers. In addition, it was found that the geometry and aspect ratio of tin whiskers were different for each environment.

Microscopic Analysis of Tin Whisker Growth on Tin Plated Copper Microchip Leads.

“…Their growths are a current challenge in the aerospace, defense and high performance electronics industry as the reliability of electronics is in question due to the formation of bridging short circuits between two whiskers in high impedance electrical equipment. [1] They can grow spontaneously at room temperature with a diameter of a few microns and an elongation of up to few millimeters. The growth mechanisms have been discussed by many researchers resulting in a number of hypotheses.…”

“…Other growth mechanisms include residual stresses, externally applied stresses, stored energy, surface energy effects, thermal expansion mismatch, corrosion, electroplating, etc. [1][2][3].…”