A Study of Highly Crosslinked Epoxy Molding Compound and its Interface with Copper Substrate by Molecular Dynamic Simulations

A novel Epoxy Molding Compound (EMC) with a crosslinked network structure was formed by curing tri-/tetra-functionalized EPN1180 with Bisphenol-A. A full atomistic model reflecting the network nature of the material was constructed by applying an iterative crosslinking algorithm to an amorphous cell with 3D periodic boundary condition containing the stoichiometric mixture of constitutive monomers. The geometry of the model was then optimized using the COMPASS force-field in Materials Studio [1]. The variation of system density and volume against temperature was simulated using a cooling down profile, which was employed to derive the glass transition temperature and coefficient of thermal expansion of the system. Furthermore, the Young's modulus and Poisson's ratio were calculated by uni-axial tensile molecular statics simulations. The material properties computed by molecular dynamics/mechanics simulations were in good agreement with experiment measurements. An epoxy resin/copper interface model was constructed and the interfacial adhesion energy was calculated as the energy difference between the total energy of the entire system and the sum of the energies of individual materials. The traction-displacement law of the interface was derived when the system was subjected to a molecular statics uni-axial tension. The work of separation and the peak traction, considered as the two key parameters required by cohesive zone finite element simulation, were extracted from the traction-displacement law.