Electrochemical Migration Characteristics of Ag-Plated Cu Powders in Conductive Thick Film

Abstract

Silver electrochemical migration results in the degradation of surface insulation resistance, and has been attributed to the dendritic bridge between adjacent conductors. In this paper, the electrochemical migration behavior of both Ag-plated Cu powder and pure silver powder in conductive thick film (CTF) are investigated. By Electrochemical migration test (water drop+ DC bias method), and the SEM and XRD examinations, it was found that the silver electrochemical migration in CTF was minimized when the Ag-plated Cu powder substitute silver powder in CTF. This is ascribed to the galvanic coupling effect that plays an important role in the migration inhibition. As sacrifice anode copper restrains the cathodic silver from dissolving in solution so as to decreases the probability of dendritic growth.