Interfacial Delamination Propagation in Multi-Layered High-Density Wiring Electronic Packaging Structures

One of the most common failure modes in multi-layered electronic packaging structures is interfacial delamination. The objective of this research is to examine the possibilities of interfacial delamination in a next-generation electronic packaging structure under thermal loading. A sophisticated analytical model has been developed to determine energy release rate and stress intensity factor for delamination propagation. The model takes into consideration the temperature-dependent material properties as well as direction-dependent material properties. Although delamination between two adjacent layers is studied, the model takes into consideration the effect of all dielectric, metallization, and substrate layers in the multi-layered structure. Assuming that an initial delamination exists between the base layer and the Copper metallization layer, the present work studies the propagation of delamination. In the analytical model, the base layer is modeled as an orthotropic thermo-elastic material. Copper and the polymer dielectric materials are modeled as isotropic thermo-elastic material. For the Copper/base layer interface, the variation of bimaterial constant (ε) with temperature is obtained through the analytical model. The effect of some key parameters, such as materials Young’s modulus, coefficient of thermal expansion, and the base layer thickness on energy release rate is presented. Design recommendations for improved thermo-mechanical reliability are proposed.