RESIDUAL STRESS DEVELOPMENT IN CU THIN FILMS WITH AND WITHOUT AlN PASSIVATION BY CYCLIC PLANE BENDING

Abstract

Since the thin film technology is applied to micro-machines, MEMS (micro electro-mechanical system), optical devices and others, the evaluation of mechanical properties in thin films becomes to be important. On the other hand, there are differences in mechanical properties between bulk materials and thin films, but studies in this field have not yet been made enough. The present paper reports on the evaluation of the mechanical properties of Cu thin films with and without AlN passivation layer. Specimens with different thickness of Cu film were subjected to cyclic plane bending fatigue test. Residual stresses developed in the Cu films were measured in a sequence of bending cycles using X-ray diffraction method in order to understand the effect of film thickness and passivation layer on mechanical properties of Cu thin films.