Comparative characterization of chip to epoxy interfaces by molecular modeling and contact angle determination

An investigation of interfacial interaction has been performed between three epoxy molding compound materials and a native silicon dioxide layer (SiO2) usually found at chip surfaces. The epoxy materials were an industry oriented epoxy molding compound Epoxy Phenol Novolac (EPN), its filled variety EPNF (with silica particles) and a model aromatic epoxy1 (2 1 2). All systems are described in full in [1] and [2]. The free surfaces of the solid materials were experimentally analyzed by contact angle measurements of three different liquids (water, methylene-iodide (MI) and glycerol). Results are compared to interfacial energies obtained by analysis of the interfaces in bimaterial molecular models, yielding reasonable agreement. A qualitative prediction regarding the influence of water on the interfacial strength between chip and molding compound is attempted.