A and method for fabricating a warpage-preventive circuit board is provided, wherein a plurality of conductive traces are formed on a surface of an electrically-insulative core layer, and a plurality of discontinuous dummy circuit regions are disposed on the surface of the electrically-insulative core layer at area free of the conductive traces, with adjacent dummy circuit regions being spaced apart by at least a chink. During a high-temperature fabrication process, the dummy circuit regions help reduce thermal stress and the chinks absorb thermal expansion of the dummy circuit regions, to thereby prevent warpage of the circuit board and cracks of a chip mounted on the circuit board, such that yield and reliability of fabricated semiconductor devices can be improved.