US Patent 9666562 3D integrated circuit

A three-dimensional integrated circuit (3D-IC) architecture incorporates multiple layers, each layer including at least one die and at least one switch to connect the dies on the different layers. In some aspects, a power distribution network (PDN) is routed from a first layer through the switches to supply power to at least one other layer, thereby reducing routing congestion on the layers. The switches can be placed around the periphery of an IC package to improve heat dissipation (e.g., by improving heat transfer from the center to the edge of the IC package). The switches can be used for routing test signals and/or other signals between layers, thereby improving test functionality and/or fault recovery.