Low cycle fatigue of aluminium thin films on vibrating silicon MEMS cantilevers: Highly accelerated stress test and finite element modelling

摘要

We present a novel, highly accelerated stress test method that addresses disruption of metallisation layers in standard microelectronic components, a major reliability risk. This failure mode typically arises from large time-dependent temperature gradients due to strong cyclic current pulses. The test vehicle behind is a Silicon-based micro-cantilever beam with aluminium (Al) metallisation meander on top. By resonant excitation of the beam the metallisation is exposed to disruption via large cyclic plastic strains. Decoupling strain from temperature, a few million cycles can be reached within short time. Degradation of the metallisation reflects in measurable increase of resistance across the meander lines. Furthermore we characterise the progress of disruption by means of several failure imaging techniques. Our test method principally paves the way towards Health Monitoring concepts that allow tracking the integrity of microelectronic components subject to harsh application and environmental conditions.