Electromigration Analysis and Electro-Thermo-Mechanical Design for Package-on-Package (POP)

摘要

An electro-thermo coupling finite element model is developed to investigate the electromigration and electro-thermo-mechanical effects on electronic packaging. Sn4.0Ag0.6Cu (SAC405) solder ball are commonly used on POP package in this research. Current density arising in the Copper trace above SAC405 solder ball implies the hot spot where results in an electromigration along the current direction. Finite element predictions reveal the peak electro-thermo-mechanical effective stress is located at the regions where electromigration potentially occurred. Current crowding, temperature distribution and electro-thermo induced effective stress distribution are predicted. A submodel scheme is applied for evaluation of equivalent life time of solder ball. Reliability analysis on electro-thermo-mechanical for SAC405 solder ball is evaluated.