Comparative analysis of reliability between dual-row and conventional QFN packages

The reliability of novel Quad Flat No-Lead (QFN) package design with multi-row lead fingers has not been well analyzed yet. The thermal characterization, warpage performance and board level solder joint reliability of dual-row and conventional QFN packages are investigated in this paper for comparison. Flotherm Computational Fluid Dynamics (CFD) software is employed to predict the package thermal performance. Warpage performance is studied by FE modeling, and correlates with analytical results from Timoshenko´s bi-layer beam model. In board level solder joint reliability comparison study, 3D-Quarter finite element (FE) model, steady-state creep hyperbolic sine constitutive model for SnAgCu solder and Zhu´s energy based fatigue model are used. The results show that thermal performance and board level solder joint fatigue life of conventional QFN are slightly greater than that of dual-row QFN. Warpage results based on bi-layer beam theory basically agree with FE modeling results.