Moldflow simulation of an exposed pad leaded package

Abstract

A study has been conducted for epoxy mold compound filling for a 48 lead exposed pad package. The leadframe design contains a small gap feature where it is critical to evaluate void estimates. A modeling method is being discussed to accurately predict the flow front behavior and make void percentage estimates. With improved design, void percentage significantly goes down as predicted by models. The paper contains detailed methodology for creation of CAD model with standard leadframe drawing and final analysis using a defined gate area. Fill time contours shows significant improvement comparing two designs with 35 μm and 65 μm gap feature.