Formation of Al3Ti during physical vapor deposition of titanium on aluminium

Summary form only given. In the classical approach of W plugs, a Ti / TiN barrier is usually deposited prior to via filling, in order to obtain low contact resistances and satisfactory adherence. Therefore titanium is deposited onto the underlayer aluminium line at the bottom of vias, enabling the formation of Al/sub 3/Ti at the Ti /Al interface. In this study, the kinetics of this chemical reaction have been investigated on full sheet Ti /Al sandwiches processed in a fast anneal chamber. Two characterization methods have been developed. The first one was based on full sheet resistance measurements and the second one on WDXRF spectroscopy. For both methods, a model of the thickness of the Al/sub 3/Ti layer formed versus annealing time and temperature was obtained using a centered composite design of experiments.