Three-dimensional (3d) interconnect structures employing via layer conductive structures in via layers and related fabrication methods

Abstract

Three-dimensional (3D) interconnect structures employing via layer conductive structures in via layers are disclosed. The via layer conductive structures in a signal path in an interconnect structure are disposed in respective via layers adjacent to metal lines in metal layers. The via layer conductive structures increase the conductive cross-sections of signal paths between devices in an integrated circuit (IC) or to/from an external contact. The via layer conductive structures provide one or both of supplementing the height dimensions of metal lines and electrically coupling metal lines in the same or different metal layers to increase the conductive cross-section of a signal path. The increased conductive cross-section reduces current-resistance (IR) drop of signals and increases signal speed. As metal track pitches are reduced in size, signal path resistance increases. The via layer conductive structures are provided to reduce or avoid an even greater increase in resistance in the signal paths.