Semiconductor device

Provided is a thin semiconductor device wherein warping is suppressed. A semiconductor element (3) is flip-mounted on a circuit board (2) so that an electrode (8) of the semiconductor element (3) and an electrode (7) of the circuit board (2) are electrically connected. On the surface of the semiconductor element (3) opposite to the circuit board (2), at least a warp suppressing layer (5) for suppressing warping of the semiconductor element (3), and a stress relaxing layer (4) for relaxing stress generated between the semiconductor element (3) and the warp suppressing layer (5) are formed. Thestress relaxing layer (4) has a spacer for ensuring a prescribed interval between the semiconductor element (3) and the warp suppressing layer (5). The Young's modulus of the stress relaxing layer (4) is lower than that of the warp suppressing layer (5), and the linear expansion coefficients of the stress relaxing layer (4) and the warp suppressing layer (5) are larger than the linear expansion coefficient of the semicond