Process for Annealing Contamination-Sensitive Metal Films
Original Publication Date: 1985-Jul-01
Included in the Prior Art Database: 2005-Feb-19
This article describes a new technique for protecting impurity- sensitive metal films of very large-scale integrated-circuit (VLSI) devices. These metal films are usually disposed and thermally cycled to obtain desired electrical and microstructural properties. Present methods of thermal treatment do not protect the film satisfactorily from contamination by impurities in ambient gases, which degrades film properties and quality. The present invention protects semiconductor metal films from impurity penetration by the application of a final layer of metal, such as titanium, zirconium, or hafnium. After the layer is patterned, the device is annealed in nitrogen so that its conductive layer also acts as a diffusion barrier, preventing adverse interaction with other metals and keeping out impurities.