A simple model for the mode II popcorn effect in thin plastic IC packages

A simple model for the mode II popcorn effect is presented here for thin packages, e.g. TSSOP, TQFP. A package "stability parameter", relating to its moisture sensitivity, is derived from the popcorn model. It describes the critical factors for a robust package die-attach, mold compound properties and package, die and lead frame design for a given preconditioning and soldering process. Furthermore, nomograms generated from the model enable an easy estimation of the moisture sensitivity level of products with different die sizes for a given die pad size and package configuration for soldering temperatures up to 260/spl deg/C (Pb-free soldering).