Electrical Characteristics of Contacts Made With Anisotropic Conductive Adhesives: Current Density Distributions at the Contact

The electrical current density distribution at the contact between a spherical conducting particle and a flat conducting substrate was investigated using finite element analysis. As with a cylindrical constriction, the spherical particle shows non-uniform current distribution at the contact: the current is concentrated at the periphery of the contact. In practical applications, such as anisotropic conducting adhesives and ball grid arrays, the current concentration at periphery may have important implications.