Dependence of Tin Whisker Growth on Copper and Oxygen Content on the Surface of Tin-Rich Lead Free Alloys

The introduction of lead-free technology into electronics has intensified concern over tin whiskers phenomenon. Tin whiskers are crystals growing from the alloy surface as the result of compressive stress relaxation. This paper presents the dependence of tin whisker growth on copper and oxygen surface content. The observations and measurements were done using scanning electron microscopy with energy-dispersive X-ray spectroscopy. The results show that whisker growth is strongly related to increased copper and oxygen surface content in whisker neighborhood.