Board level reliability test of MPBGA assembly

The purpose of this paper is to investigate the solder joint performance of MPBGA (Multi-package BGA) under board level reliability test. Temperature cyclic test (TCT), bending cyclic test and drop test are conducted to evaluate the fatigue life and bonding strength of solder joints of this package. For TCT, LFBGA which is at the top of MPBGA is found to show a poorer solder joint performance than PBGA (at the bottom of MPBGA). However, it exhibits opposite result after underfill is applied between solder joints of LFBGA. For bending cyclic test and drop test, failure is found to occur at the solder joints of PBGA. Additionally, failure analysis (FA) is also conducted to find the root cause of electrical failure at each reliability test. All the test results and FA results are reported in this paper.