Investigation of adhesion properties of Cu-EMC interface by molecular dynamic simulation

Cu-EMC (copper-epoxy molding compound) interface is known to be the weakest joint in the electronic packages, which causes delamination during reliability test. A prime reason is the lack of adhesion between Cu and epoxy compound. To solve the problem, self-assembly monolayer (SAM) is used to improve adhesion of copper-epoxy system. This paper focuses on simulation of adhesion in Cu-SAM-EMC system. In this study, molecular models of bi-material system, which consists of SAM and Cu, were built to evaluate the adhesion force of the Cu-SAM system. Interfacial energy density was derived from molecular dynamics (MD) simulation. The newly developed condensed phase optimization molecular potentials for atomistic simulation studies (COMPASS) force field enables prediction of adhesive strength of bi-material system in organic-metal oxide interface. The MD results were compared against shear load obtained from button shear tests. It has been illustrated that MD can provide a reasonable qualitatively prediction of the relative interfacial strength of the selected SAM samples. It is concluded that MD is an effective tool in screening SAM candidates.