An IC chip and overhang portions are stuck to tape by an adhesive agent layer having elasticity. A plurality of solder balls are attached to the tape. By soldering the solder balls to a printed board, a semiconductor device is mounted. In the case where a temperature cycle has been caused, thermal stress occurs between the IC chip and the printed board or between the hangover portion and the printed board because of a difference in coefficient of thermal expansion between the IC chip or the hangover portion and the printed board. However, this thermal stress is absorbed by the elasticity of the adhesive agent layer. As a result, little thermal stress is applied to solder balls. Even if the above described temperature cycle is repeated, therefore, the solder balls are electrically connected to the printed board stably over a long period of time. In addition, the area of the tape is widened by the area of the hangover portions. Accordingly, a larger number of solder balls can be attached to the tape without reducing the size of each of the solder balls.