US Patent 7851346 Bonding metallurgy for three-dimensional interconnect

A method provides a first substrate with a conductive pad and disposes layers of Cu, TaN, and AlCu, respectively, forming a conductive stack on the conductive pad. The AlCu layer of the first substrate is bonded to a through substrate via (TSV) structure of a second substrate, wherein a conductive path is formed from the conductive pad of the first substrate to the TSV structure of the second substrate.