Practical assessment of tin whisker growth risk due to environmental temperature variations

Tin (Sn) whisker growth on semiconductor component leads with pure Sn or high Sn-content plating finishes remains to be a reliability concern for electronic system manufacturers. One of the driving forces for whisker growth is thermal stresses in the finishes induced by environmental temperature variations. These stresses are most significant when the leadframe material and the tin finishes have large differences in coefficient of thermal expansion (CTE) mismatch. As a result, excessive environmental temperature variations can increase the risk of whisker growth.