Abstract: A method is provided for fabricating a via contact structure contacting a single-crystal semiconductor diffusion region at a top surface of a substrate. In such method, a first layer is formed in contact with the diffusion region at the top surface, the first layer consisting essentially of a silicide of a first metal. A dielectric region is formed to overlie the first layer. An opening is etched in the dielectric region extending through the first layer to the diffusion region. A second layer is formed to line the opening, the second layer including a second metal. Thereafter, a conductor is deposited within the opening over the second layer, and the substrate is heated to cause the second metal to form a silicide at the top surface.

Abstract: Silicide is protected during MC RIE etch by first forming an oxide film over the silicide and, after performing MC RIE etch, etching the oxide film. The oxide film is formed from a film of alloyed metal-silicon (M-Si) on the layer of silicide, then wet etching the metal-silicon. An ozone plasma treatment process can be an option to densify the oxide film. The oxide film may be etched by oxide RIE or wet etch, using 500:1 DHF.

Abstract: A via contact is provided to a diffusion region at a top surface of a substrate which includes a single-crystal semiconductor region. The via contact includes a first layer which consists essentially of a silicide of a first metal in contact with the diffusion region at the top surface. A dielectric region overlies the first layer, the dielectric region having an outer surface and an opening extending from the outer surface to the top surface of the substrate. A second layer lines the opening and contacts the top surface of the substrate in the opening, the second layer including a second metal which lines a sidewall of the opening and a silicide of the second metal which is self-aligned to the top surface of the substrate in the opening. A diffusion barrier layer overlies the second layer within the opening. A third layer including a third metal overlies the diffusion barrier layer and fills the opening.