A multi-scale approach for investigation of interfacial delamination in electronic packages

Interfacial delamination, due to the presence of dissimilar material systems, is one of the primary concerns in electronic package design. Continuum models such as J-integral have been developed to evaluate potential delamination by defining a pre-defined crack at selected interface in the package. The interface is modeled as a discontinuity across the mating material layer. However, at molecular level, the mating materials are held together by a force field which is prescribed by their chemical structures. Molecular dynamics (MD) simulation is an effective tool used to model such force fields. The MD model can be used to simulate the reaction of the interfacial force field under external loading and the result can be utilized to characterize the material properties at the interface. The material properties at the interface are not necessarily consistent with those of the bulk materials forming the interface. The present study is focused on incorporating material behavior at the interface derived from MD simulations into the continuum model. The MD simulations were conducted to construct the constitutive relation of interface under the external loading. The constitutive relations from MD simulations in the form of a traction-displacement plot were introduced into the cohesive zone model to study the constitutive response of interface under the external loading, which is traversed across the length scale from nanoscale to macroscale. (C) 2010 Elsevier Ltd. All rights reserved.