Stacking Yield Prediction of Package-on-Package Considering the Statistical Distributions of Top/Bottom Package Warpages and Solder Ball Heights

A comprehensive stochastic model is proposed to predict PoP stacking yield loss based on the non-contact open. The model takes into account all pad locations at the stacking interface while considering the statistical variations of warpages as well as solder ball heights. The goal is achieved by employing three statistical approaches including (1) uncertainty propagation (UP) analysis by advanced approximation integration method called eigenvector dimension reduction (EDR), (2) stress-strength interference (SSI) model, and (3) probability of the union of events. Theoretical development of the proposed stochastic model is presented first. Implementation of the proposed model for a PoP assembly is followed.