METAL-TO-METAL ANTIFUSE EMPLOYING CARBON-CONTAINING ANTIFUSE MATERIAL

摘要

A metal-to-metal antifuse (22) is disposed between two metal interconnect layers in an integrated circuit. An insulating layer (18) is disposed above a lower metal interconnect layer (16). The insulating layer includes a via formed therethrough containing a tungsten plug (20) in electrical contact with the lower metal interconnect layer. The tungsten plug forms a lower electrode of the antifuse. The upper surface of the tungsten plug is planarized with the upper surface of the insulating layer. In a first embodiment, an antifuse material layer (22) comprising amorphous carbon, amorphous carbon doped with hydrogen or fluorine, or amorphous silicon carbide is disposed above the upper surface of the tungsten plug. A layer of a barrier metal (24) disposed over the antifuse material layer forms an upper electrode of the antifuse. An oxide (28) or tungsten hard mask provides high etch selectivity and the possibility to etch barrier metals without affecting the dielectric constant value and mechanical properties of the antifuse material. In a second embodiment, a layer of barrier material is disposed between the top surface of the tungsten plug and the antifuse material layer. An adhesion-promoting layer may be used where amorphous carbon is used as the antifuse material layer.