Abstract:

This paper presents a design-of-experiments study on the effect of annealing and simulated reflow on tin whisker growth. Copper, brass, and alloy 42 coupons plated with either bright or matte tin were subjected to one of three elevated temperature exposures. After the elevated temperature exposures, specimens along with a set of control specimens were then kept in room ambient conditions and monitored periodically using an environmentally scanning electron microscope. Surface observations up to 16 months of room ambient exposure revealed that tin whiskers formed on the surfaces of each specimen. However, various differences in whisker growth between the matte¨C and bright tin-plated specimens were observed. Columnar-type whiskers grown on the matte tin plated specimens were initiated from one grain at the surface, as opposed to the growth on bright tin which were independent from the surface morphology. Maximum length and length distribution data for matte and bright tin plating for the various exposures are presented. The result of this study shows annealing to be effective in reducing the maximum length of whiskers, particularly on bright finished coupons.

Complete article is available to CALCE Consortium Members.

© IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.