A micromechanics model for electrical conduction in isotropically conductive adhesives during curing

A 3-D electrical conduction model for isotropically conductive adhesives with spherical particles was developed to simulate the curing process. A microstructure model of a conductive adhesive block was generated to describe the positions and connections of the conductive fillers. The bulk resistance of the conductive adhesive is mainly contributed by the contact resistances between connected particles. The contact resistance consists of constriction resistance and tunnel resistance, which depend on contact load, filler material properties and contact areas. A finite element analysis of a representative volume element was conducted to simulate the process of shrinkage caused by the curing process of the polymer matrix. The resulted contact radius was incorporated in the calculation of contact resistances between conductive particles, the bulk resistance was then calculated of the resistor network formed by all particle connections. The result of bulk resistivity change with respect to shrinkage was presented and compared with experimental results.