The invention provides a warpage-proof circuit board structure, including: an inner layer circuit board; at least one dielectric layer formed on at least one surface of the inner layer circuit board; at least one first groove formed in the at least one dielectric layer corresponding in position thereto; a solder mask formed on the surface of the dielectric layer, a second groove formed in the solder mask and corresponding in position to the first groove formed in the dielectric layer; and a metal frame formed in the first and second grooves and protruding from the surface of the solder mask, thereby strengthening the circuit board to prevent it from warping in thermal processing and further using the metal frame as a heat-dissipating means for the package structure.