US Patent 9543257 3DIC interconnect devices and methods of forming same

An interconnect device and a method of forming the interconnect device are provided. Two integrated circuits are bonded together. A first opening is formed through one of the substrates. One or more dielectric films are formed along sidewalls of the first opening. A second opening is formed extending from the first opening to pads in the integrated circuits, while using some of the pads as hard masks. The first opening and the second opening are filled with a conductive material to form a conductive plug.