Stress and Electromigration in Thin Film Metallisation

Abstract

ABSTRACTThis paper reviews the experimentally established relationship between electromigration and mechanical stress in thin films. A model will be described which calculates the development of stress around sites of electromigration flux divergence in a metallisation track and it is shown how the model can be used to predict the time before electromigration damage occurs. The effect of passivation on the stress state within a metal track is discussed and the behaviour of metallisation under pulsed current testing is interpreted in terms of mechanical stress generation and relaxation.