Circuit structure with non-migrating silver contacts

Abstract

An integrated circuit assembly that prevents silver migration by providing conductive rims around oxidizable silver contacts that contact a substrate. Typically the silver contacts are supported by respective metal pads on the substrate with a contact potential existing at each contact-pad junction. In many applications an electrical circuit transmits electrical signals via the contacts to produce potential differences between the contacts and create electrical fields at their surfaces. The conductive rims have a work function that is sufficiently small to reduce the electric fields and contact potentials so as to inhibit the ionization of the oxidized contacts' surfaces and prevent silver migration across the metal pads and the substrate.