Reliability study of planarized aluminum metallization

This work investigates the reliability issues associated with an aluminum process, called the Al-plug process, that results in the complete filling of submicron contacts and vias. It has been demonstrated that the Al-plug process is a viable means of filling high aspect ratio vias and contacts for submicron geometries and can be used without degrading device reliability. It also has been experimentally determined that the film´s microstructural parameters such as surface roughness, grain size, Si nodules and hillock formation are improved over the conventionally deposited Al-Si-Cu film. Both electromigration and stress-induced migration data also indicate that the Al-plug metal film is highly reliable. The planarity of the Al-Si-Cu lines in vias and over steps is excellent compared to that of a standard metal process