SEMICONDUCTOR DEVICE

PROBLEM TO BE SOLVED: To maintain high reliability, even when heating process such as a temperature cycle test is conducted, on a ball grid array(BGA) and a land grid array(LGA). SOLUTION: This semiconductor device is provided with a printed board 12, a semiconductor element 14 which is face-down bonded on the upper surface of the board 12, a stiffener 16 bonded to the board 12 via first adhesive agent 24 in which stiffener an aperture 30 where the semiconductor element 14 is positioned is formed, and a metal plate 18 which is arranged so as to cover the upper parts of the semiconductor element 14, and the stiffener 16 and bonded by using second adhesive agent. The stiffener 16 has rigidity, capable of preventing deformation due to the thermal expansion of the board 12 and deformation due to the thermal expansion of the metal plate 18 at heating.