International Business Machines Corporation
STEPPED TOP VIA FOR VIA RESISTANCE REDUCTION

Abstract:

Embodiments of the present invention are directed to fabrication methods and resulting interconnect structures having stepped top vias that reduce via resistance. In a non-limiting embodiment of the invention, a surface of a conductive line is recessed below a first dielectric layer. A second dielectric layer is formed on the recessed surface and an etch stop layer is formed over the structure. A first cavity is formed that exposes the recessed surface of the conductive line and sidewalls of the second dielectric layer. The first cavity includes a first width between sidewalls of the etch stop layer. The second dielectric layer is removed to define a second cavity having a second width greater than the first width. A stepped top via is formed on the recessed surface of the conductive line. The top via includes a top portion in the first cavity and a bottom portion in the second cavity.