US Patent 11670563 Thermally enhanced FCBGA package

A semiconductor device has a heat spreader with an opening formed through the heat spreader. The heat spreader is disposed over a substrate with a semiconductor die disposed on the substrate in the opening. A thermally conductive material, e.g., adhesive or an elastomer plug, is disposed in the opening between the heat spreader and semiconductor die. A conductive layer is formed over the substrate, heat spreader, and thermally conductive material.