An investigation of the impact of a Ti barrier metal on the thermal stress field in passivated aluminium lines and vias in VLSI systems using finite element modelling approach

The impact of a thin barrier layer on the residual thermal stress in passivated aluminium lines and vias during the manufacture of multilevel structures was investigated using an advanced finite element approach. A chemical compound of aluminium and titanium was formed at the interface that prevented the transport of atoms and vacancies across the barrier layers. Results obtained for the double layer metalization structure showed that the titanium layers enhanced mechanical stability of the aluminium.