Patent ID: 7393722

Claim:
A method for fabricating a reprogrammable metal-to-metal antifuse, comprising: planarizing an insulating layer and a tungsten plug; forming a lower Ti barrier layer over said insulating layer and said tungsten plug; forming a lower adhesion-promoting layer over said lower Ti barrier layer, said lower adhesion-promoting layer selected from the group comprising Si x C y and Si x N y ; forming an antifuse material layer over said lower adhesion-promoting layer, wherein said antifuse material layer is selected from the group comprising amorphous carbon, amorphous carbon doped with at least one of hydrogen and fluorine, and amorphous silicon carbide; forming an upper adhesion-promoting layer over said antifuse material layer, said upper adhesion-promoting layer selected from the group comprising Si x C y and Si x N y ; forming an upper Ti barrier metal layer over said antifuse material layer; forming an oxide or tungsten hardmask layer over said barrier metal layer; forming a layer of photoresist over said hardmask layer; defining said hardmask layer; removing said photoresist; defining a shape of a stack for said antifuse by etching said upper Ti barrier layer, said upper adhesion-promoting layer, said antifuse material layer, said lower adhesion-promoting layer, and said lower Ti barrier metal layer using said hardmask layer as a mask; forming an insulating layer over said stack; forming an aperture in said insulating layer; forming a metal interconnect layer over said insulating layer and in said aperture; forming a second masking layer over said metal interconnect layer; and defining said metal interconnect layer.