A semiconductor assembly includes an anti-warping controller, a semiconductor device, a balance layer and a first routing circuitry positioned within a through opening of a stiffener and a second routing circuitry positioned outside of the through opening of the stiffener and electrically connected to the first routing circuitry and a vertical connecting element of the stiffener. The mechanical robustness of the stiffener and the anti-warping controller can prevent the assembly from warping, whereas the vertical connecting element of the stiffener provides electrical connection between two opposite sides of the stiffener. The first routing circuitry can enlarge the pad size and pitch of the semiconductor device, whereas the second routing circuitry not only provides further fan-out wiring structure, but also mechanically binds the first routing circuitry with the stiffener.