Double side transistors on same silicon wafer

Abstract

An apparatus and method for efficiently increasing semiconductor chip functionality in a particular area. A semiconductor fabrication process (or process) grows a silicon substrate layer, and forms multiple p-type and n-type transistors along a front side surface of the silicon substrate layer. The process flips the silicon substrate layer and removes silicon substrate leaving a particular thickness of the silicon substrate layer. The process forms multiple p-type and n-type transistors along the back side surface of the silicon substrate layer, and forms metal layers that connect terminals of the transistors formed along the back side surface to particular signals. The process forms through silicon vias (TSVs) that traverse through the silicon substrate layer. The process again flips the silicon substrate layer, and forms metal layers that connect terminals of the transistors formed along the front side surface to particular signals.