A semiconductor device comprises a substrate (30) having a plurality of holes (36) and having wiring patterns (32) on one side and part of wiring patterns (32) overlying the holes (36) horizontally; a semiconductor chip (10) having a plurality of electrodes (12) and arranged on the other side of the substrate (30) with the electrodes (12) corresponding to the holes; and conductors arranged through the holes (36) to connect the electrodes (12) and the wiring patterns (32) electrically.