A method of making a stackable semiconductor assembly that includes a semiconductor device, a heat spreader, an adhesive, a terminal, a plated through-hole and build-up circuitry is disclosed. The heat spreader includes a bump, a base and a flange. The bump defines a cavity. The semiconductor device is mounted on the bump at the cavity, electrically connected to the build-up circuitry and thermally connected to the bump. The bump extends from the base into an opening in the adhesive, the base extends vertically from the bump opposite the cavity and the flange extends laterally from the bump at the cavity entrance. The build-up circuitry provides signal routing for the semiconductor device. The plated through-hole provides signal routing between the build-up circuitry and the terminal. The heat spreader provides heat dissipation for the semiconductor device.