A semiconductor structure is provided. The semiconductor structure including: a substrate, where the substrate includes a first region and a second region adjacent to the first region; a plurality of fins formed over the first region of the substrate; an isolation layer over the substrate between adjacent fins of the plurality of fins, where a top of the isolation layer is lower than a top surface of a fin of the plurality of fins, the isolation layer over the second region and the second region of the substrate together contain a power rail opening, and the substrate contains a through-hole at a bottom of the power rail opening; and a first metal layer in the power rail opening and the through-hole, where a back surface of the first metal layer is above a back surface of the substrate.