A semiconductor device includes: an insulating substrate including an insulating plate and a circuit board on the insulating plate; a semiconductor chip having an electrode on a front surface thereof, a back of the semiconductor chip being fixed to the circuit board; a printed circuit board that faces the circuit board and the front surface of the semiconductor chip; and one or more conductive posts each having one end connected via solder to the circuit board or to the electrode on the semiconductor chip, another end connected to the printed circuit board, and one or more grooves that extend from said one end of the conductive post that contacts the solder to said another end of the conductive post connected to the printed circuit board.