Reliability improvement of aluminium-based contact and interconnect systems for VLSI applications by grain structure modification

Abstract The reliability of narrow aluminium-based metal lines has become an essential factor in very large scale integration integrated circuits (VLSI ICs). After theoretical considerations, a new developed experimental procedure is presented. This so-called cold deposition with immediate in-situ annealing leads to a modified metal system of high reliability, resulting in enhancement of the lifetime. Mechanical stress and electromigration as driving forces for void formation are examined. It is shown how an intentional change of Al-alloy microstructure significantly improves metallization reliability.