Reliability of Ball Grid Array Subjected to Temperature Cycling

This study established a simulation model for reliability of Ball Grid Array (BGA) IC package subjected to temperature cycling. COMSOL Multiphysics software was used to established a simulation model and this study used Garofalo-Arrheniuss Law creep equation and Modified Coffin-Manson equation to estimate fatigue life of chip subjected to temperature cycling test (TCT). Since the thermal expansion coefficients between the materials are mismatch, chip would occur warpage. The solder ball of peripheral edge was cracked firstly, and the estimated error of solder ball life is 15.7% compared with experimental value. This study could find out the position where the solder ball first cracked which was not the position of maximum stress but was the position of the maximum strain range.