A build-up layer packaging comprising a first ceramic substrate, a second ceramic substrate, and a circuit layer is provided. The first ceramic substrate has a through hole to dispose a die therein. The second ceramic substrate, attached to a common lower surface of the ceramic substrate and the die, further has a plurality of openings to expose the pads of the die. The openings are filled with plugs electrically connecting to the pads. The circuit layer is formed under the second ceramic substrate to transmit signals generated by the die outward.