US Patent 7375026 Local multilayered metallization

An interconnect comprises a trench and a number of metal layers above the trench. The trench has a depth and a width. The depth is greater than a critical depth, and the number of metal layers is a function of the width. In an alternate embodiment, a metallization structure having a trench including a metal layer and a second trench including a plurality of metal layers coupled to the metal layer is disclosed. The metal layer is highly conductive, and at least one of the plurality of metal layers is a metal layer that is capable of being reliably wire-bonded to a gold wire. The trench is narrower than the second trench, and at least one of the plurality of metal layers is copper or a copper alloy.