An extensive investigation of the four point bending test for interface characterization

This paper focuses on metal-polymer interfaces that cover a wide range of all critical interfaces in the micro-electronic industry. Interface characterization is performed for two types of copper/epoxy molding compound (EMC) interfaces on a four point bending setup. The force-displacement curves for the type 1 interface show a clear force plateau indicating steady delamination propagation along the interface. The interface properties for this measurement can be calculated analytically from the steady-state part of the curve. Transient calculations on a 2D plane strain finite element model including cohesive zone elements show that the effect of intrinsic thermal stresses due to processing on the resulting force-displacement curve is apparent. The force-displacement curves for the type 2 samples do not show a clear force plateau. The deformation of the samples clearly shows this can be attributed to non-linear effects that are not considered in the analytical stead-state solution. The influence of the main contributors to nonlinear behavior, such as plasticity, large deformations, and contact at the supports is investigated. The quantification of these effects by FE analysis results in a better understanding of the force-displacement curve for the type 2 samples.