Yukio Tanigaki

Stress migration resistance and contact characterization of Al–Pd–Si interconnects for very large scale integrations

Stress‐induced migration resistance and contacts to silicon of Al–0.3%Pd–1%Si interconnections for submicron process integrated circuit devices have been investigated and compared to Al–0.5%Cu–1%Si. Using creep tests, Pd has been found to be an excellent additional element to Al for reducing grain boundary diffusion. Palladium improved the stress‐induced migration resistance and reduced void and hillock formation in Al–Si conductors. Aluminum palladium precipitates in Al–Pd–Si alloys were found to be formed at higher temperatures than aluminum copper compounds and may be the reason for the improvements. The contact resistance of Al–Pd–Si was found to be similar to that of Al–Cu–Si. The reliability and yield data from 1.2 μm ROM test devices using Al–Pd–Si conductors is better than that of Al–Cu–Si conductors.

Effects of Si on electromigration of Al–Cu–Si/TiN layered metallization

This work investigates electromigration (EM) in Al‐1 wt %Si, Al‐1 wt %Si‐0.5 wt % Cu and Al‐0.5 wt % Cu films with TiN barrier metals. The EM resistance of the Al‐0.5 wt % Cu layered metallization was found to be higher than that of the Al‐1 wt % Si‐0.5 wt % Cu layered metallization. The electromigration test results show that the reaction between Al films and underlying TiN layer degrades the electromigration performance of the Al‐1 wt % Si, Al‐1 wt % Si‐0.5 wt % Cu films. The reaction kinetics between Al alloys and TiN layers was studied by transmission electron microscopy and by investigating the resistance rise mechanism. Si was found to enhance thin intermetallic compound formation between the Al alloys and TiN on samples annealed at 450 °C.

Photochemical Characterization of the Surface Oxide Films of Al‐Pd‐Si and Al‐Si

The effect of Pd addition to the Al alloy on the photoelectrochemical response is described. The oxide films are characterized by photoelectrochemical methods. The addition of Pd decreases the photocurrent during illumination. The properties of the surface oxide films on thin Al‐Pd‐Si and Al‐Si alloy films are discussed. The surface oxide film property is related to the increased corrosion resistance of Al‐Pd‐Si. A model of the aluminum oxide film structure on the Al‐Pd‐Si film is also proposed.