Abstract: The present invention relates to a compound semiconductor integrated circuit chip having a front and/or back surface metal layer used for electrical connection to an external circuit. The compound semiconductor integrated circuit chip (first chip) comprises a substrate, an electronic device layer, and a dielectric layer. A first metal layer is formed on the front side of the dielectric layer, and a third metal layer is formed on the back side of the substrate. The first and third metal layer are made essentially of Cu and used for the connection to other electronic circuits. A second chip may be mounted on the first chip with electrical connection made with the first or the third metal layer that extends over the electronic device in the first chip in the three-dimensional manner to make the electrical connection between the two chips having connection nodes away from each other.