An interconnect arrangement and fabrication method are described. The interconnect arrangement includes an electrically conductive mount substrate, a dielectric layer formed on the mount substrate, and an electrically conductive interconnect formed on the dielectric layer. At least a portion of the dielectric layer under the interconnect contains a cavity. To fabricate the interconnect arrangement, a sacrificial layer is formed on the mount substrate and the interconnect layer is formed on the sacrificial layer. The interconnect layer and the sacrificial layer are structured to produce a structured interconnect on the structured sacrificial layer. A porous dielectric layer is formed on a surface of the mount substrate and of the structured interconnect as well as the sacrificial layer. The sacrificial layer is then removed to form the cavity under the interconnect.