PoP assembly reliability test and assessment under random vibration loading

Abstract

This paper investigates the reliability of the Package-on-Package (PoP) under random vibration loading by experimental tests and FEM simulations. An event detector was used to monitor the PoP failure times under random vibration. A finite element model of the PoP assembly model was built in ANSYS, and the natural frequencies and modes were calculated and verified by experimental model test. The results showed that the bottom package soon failed under random vibration loading, and the top package failed after a long period of time, the reliability of top package is better than the bottom package under vibration loading. The dye-pry and cross-section tests indicated that the outermost corner bottom solder joint is the critical solder joint for the PoP. Over 80% of the failed solder joints of the bottom package fractured on the component side, brittle failure (IMC crack) and ductile failure (bulk crack) were discovered under vibration loading. The stress characteristics of PoP solder joints obtained from FEM simulations are consistent with the experimental results.