There is provided a system-in-package (SiP), which includes a substrate obtained by cutting a wafer for each unit system; one or more first electronic devices mounted on the substrate by a heat radiation plate; a plurality of interlayer dielectrics sequentially formed on the substrate; and one or more second electronic devices buried between or in the interlayer dielectrics on the substrate. A heat sink may be additionally attached to the bottom surface of the substrate. In this case, a thermal conduction path including heat pipes connecting the heat radiation plate on the substrate and the heat sink is formed. In the SiP, various types of devices are buried at a wafer level, so that a more integrated semiconductor device is implemented corresponding to demand for a fine pitch. Further, the heat radiation of a device required in high-speed operation and high heat generation is maximized due to the multi-stepped heat radiation structure, and thus the operation of the device is more stabilized.