Reliability and prediction of Sn36Pb2Ag solder joints under thermal aging test

Abstract

Abstract In this work, the capacitor solder joints were aged at 50 °C, 75 °C, 100 °C, 125, and 150 °C from 100 h to 1000 h. The intermetallic compounds (IMCs) layer growth of Sn36Pb2Ag on hot air solder leveled (HASL) pad and electroless nickel/immersion gold (ENIG) pad was measured. Based on the empirical power-law of the IMC growth and the Arrhenius relationship between diffusion coefficient and aging temperature, a method to predict the IMC growth at a selected temperature was developed. The mechanical property of capacitor solder joints after thermal aging was investigated through the shear test. Through analysis of the fracture surface, the mixed fracture mode of ductile and brittle was exhibited. The porous structure of the Cu coating on the capacitor electrode was determined to be the origin of the crack.