Elevated metal-to-metal antifuse structures and fabrication processes.

摘要

A metal-to-metal antifuse structure includes a pedestal structure in an underlying insulating layer upon which a lower conductive antifuse electrode is formed. An inter-metal dielectric layer is formed and planarized, having a differential thickness between the on-pedestal and off-pedestal regions. An antifuse cell opening is formed in the inter-metal dielectric over the pedestal region. A suitable antifuse material is deposited in the cell opening and an upper electrode is formed over the antifuse material. Another metal-to-metal antifuse structure includes a conductive lower electrode for an antifuse formed over an underlying insulating layer. An antifuse dielectric material is then formed over the lower electrode and an antifuse cell opening is formed in the antifuse dielectric material. A layer of antifuse material is then formed in the antifuse cell opening and an upper antifuse electrode is formed over the antifuse material. The upper antifuse electrode is then patterned and an etching step is used to remove the unprotected portions of the upper antifuse electrode and the antifuse material. An inter-metal dielectric layer is then formed and planarized and an antifuse cell opening is etched therein down to the upper antifuse electrode. An upper metal interconnect layer is formed over the inter-metal dielectric layer and in contact with the upper antifuse electrode.