Effect of external stresses by bending on Sn whiskers formation and growth on immersion Sn surface finish

• Main Authors: Fadil, Nor Akmal, Yusof, Siti Zahira, A. B. Kahar, Mohamad Nawawi, Abu Bakar, TutyAsma
• Format: Conference or Workshop Item
• Published: 2015
• Subjects: TJ Mechanical engineering and machinery
• Online Access: http://eprints.utm.my/id/eprint/63451/; http://www.akademiabaru.com/conference.html

Deposited tin (Sn) layers used as lead-free solderable finish on the semiconductor devices are known to form whiskers. These whiskers are single crystal of tin that spontaneously grows from the surface of tin within weeks to years. Thus, they can cause shorts and the failure of a whole electronic circuit. In this research, the effect of external stresses applied by bending on the Sn whiskers formation and growth was investigated on immersion Sn surface finish. The plating time was 10 minutes to produce 1.4 µm coating thickness on the copper substrate and exposed for 1, 4, and 8 weeks under the environment of 30°C/60%.RH for bended and non-bended samples. It was found that the non-bended Sn surface has uniform Sn whiskers distributed on the entire surface. Unlike the non- bended Sn surface, the Sn whiskers has been formed more and grown longer at lower stresses region of the bended surface than higher stresses region based on the micrograph observed by field emission scanning electron microscopy (FESEM).