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The first in this series on tin whiskers, Tin Whiskers – Clarity First (SMT Magazine, May 2013), has set the stage for subsequent topics in this series, including this month’s focus, along with these upcoming titles: Tin Whiskers - Potential Impact and Concerns; Tin Whiskers - Contributing Factors, Tin Whiskers - Plausible Theory; Tin Whiskers - Impact of Testing Conditions; and lastly, Tin Whiskers - Preventive and Mitigating Measures.
The metal whisker phenomenon was discovered in the late 1940s. Telephone companies reported that telephone line failures caused by electric short were traced to those fibrous hairy whiskers. These whiskers were found to have grown from the tin plating on capacitor plates, which perhaps was one of the first formal reports on tin whiskers.
Tin whisker reflects its coined name. It has long been recognized to be associated with electroplated tin coating and most likely occurs with pure tin. Its appearance resembles whiskers. However, whiskers can also form in a wide range of shapes and sizes, such as fibrous filament-like spiral, nodule, column, and mound. Tin whiskers are often single crystals and electrically conductive. They are normally brittle in nature, but can be rendered ductile when very long and thin.
Read the full column here.
Editor's Note: This column originally appeared in the September 2013 issue of SMT Magazine.