•Christoph Eberl¹, Ralph Spolenak², Oliver Kraft³, Franz Kubat⁴, Anton Leidl⁴ und Eduard Arzt^1,2
2Max-Planck Institut f/ür Metallforschung Stuttgart
³Forschungszentrum Karlsruhe
⁴EPCOS AG
¹Institut f/ür Metallkunde der Universit/ät Stuttgart

We present a novel pop-out mechanism of high cycle damage formation in thin metal films. Quantitative post test analysis as a function of testing time, power density and temperature revealed a direct correlation between extrusion density and film performance. The effect of alloying, though in general beneficial, will be critically assessed. The kind of damage observed will be examined in the light of the local mechanical stress state. A combination of measurement for thermal stresses (substrate curvature, X-ray diffraction) and finite element as well as P-Matrix based modelling allowed the complete stress tensor to be determined. The mechanistic insight obtained in this way will be a key element in life-time prediction of devices undergoing a large number of loading cycles.