A fabrication method of a semiconductor package includes the steps of: forming a release layer on a carrier having concave portions; disposing chips on the release layer in the concave portions of the carrier; forming an encapsulant on the chips and the release layer; forming a bonding layer on the encapsulant; removing the release layer and the carrier so as to expose the active surfaces of the chips; and forming a circuit structure on the encapsulant and the chips. Since the release layer is only slightly adhesive to the chips and the encapsulant, the present invention avoids warpage of the overall structure during a thermal cycle caused by incompatible CTEs.