Statistics of electric conductance through anisotropically conductive adhesive

We have investigated the electric conductance between two contacts electrically interconnected by an anisotropically conductive adhesive (ACA). It is first demonstrated that as compared with the symmetric equipotential profile of a point contact between two half infinitely large conducting materials, the spatial distribution of the equipotential profile becomes deformed when the contact is close to the edge of the conducting material. The electric potentials of two contacts also redistribute when the two contacts are brought together in nearby vicinity. By simulating the metal fillers spatial distributions in an ACA, we have shown that the spatial uniformity of the electric conduction between two contacts depends on the number of metal particles that interconnect the two contacts. Increasing the number of metal fillers on the contact pad improves the uniformity of the electric conduction. It however also increases the constriction resistances due to fellow particles so that the total conductance does not increase in the additive manner.