A simple model for the mode I popcorn effect for IC packages

A simple model for the Mode I popcorn effect is presented here for packages with rectangular die pad (P-DSO). A package "stability parameter", relatin g to its moisture sensitivity, is derived from the popcorn model. It descri bes the critical factors for a robust package - molding compound properties and package, leadframe design for a given preconditioning and soldering pr ocess. Furthermore, nomograms generated from the model enable an easy estim ation of moisture sensitivity levels (between 1 and 5) of packages with dif ferent die pad sizes and molding compound underpad thicknesses and for diff erent soldering temperatures ranging from 220 degrees C to 260 degrees C (P b-free soldering). (C) 2000 Elsevier Science Ltd. All rights reserved.