Structures of a system on chip and methods of forming a system on chip are disclosed. In one embodiment, a method of fabricating the system on chip includes forming a through substrate opening from a back surface of a substrate, the through substrate opening disposed between a first and a second region, the first region comprising devices for RF circuitry and the second region comprising devices for other circuitry. The method further includes forming patterns for redistribution lines on a photo resist layer, the photo resist layer disposed under the back surface, and filling the through substrate opening and the patterns for redistribution lines with a conductive material.