Abstract: In a semiconductor device constructed of bare chips stacked together and improved in reliability in connection and in yield in production, used therein is the wiring built-in insulation film assuming a linearly elongated shape containing a series of, for example, five unit films linearly arranged. Each of the unit films corresponds to each of the chips. The film is bent through an angle of approximately 180 degrees at every unit film alternately to the right and the left in a zigzag manner so that each of the chips is packaged in each of the unit films, whereby all the chips are stacked together in the direction of thickness dimensions of the chips through the film having its end portion fixed to the lowermost one of the chips in a manner such that all the chips are wrapped up in the film to form the semiconductor device.