Abstract: A semiconductor package and a fabrication method thereof are disclosed. The fabrication method includes providing a carrier board; forming a plurality of metal bumps on the carrier board; covering on the carrier board a resist layer having openings for exposure of the metal bumps, the openings being smaller than the metal bumps in width such that a metal layer is formed in the openings, the metal layer having extension circuits and extension pads and bonding pads formed on respective ends of the extension circuits; removing the resist layer; electrically connecting at least one semiconductor chip to the bonding pads; forming an encapsulant on the carrier board to encapsulate the semiconductor chip; and removing the carrier board and the metal bumps to expose the metal layer.