Delamination and Cracking Effects in Quad Flat Package

In this research, the delamination issue in the Quad Flat Package (QFP) after molding and post-mold cure processes is investigated through experiments and simulation modeling. The delamination failure is occurred at the interface between the Cu pad and the molding compound. The resulting interfacial delamination failure weakens the structural strength of the package and adversely affects the electronic device reliability. In the present study, the delamination failure in QFP under the reflow process is analyzed and the underlying mechanisms are investigated using different types of pad design and geometric parameters. The simulation modeling can predict the most of delamination failures in the QFP. However, the delamination failure in QFP is subject to some uncertainties Specifically, as Cu oxidation gradually increases under the reflow process and plasma, this results in the formation of a non-uniform oxide layer on the Cu frame surface. These uncertainty factors influence the delamination failure index, limiting the accuracy of the QFP module delamination failure prediction model. The purpose of this research was to improve the shear stress and the von-Mises stress of Cu pad by discussing the pad design, the die arrangement, and the structure design in the QFP.