PURPOSE: To prevent solder from wetting up, improve soldering strength between a substrate and a package, and increase the reliability in the temperature cycle after substrate mounting, by providing the wide width part of a lead frame with a through hole.

CONSTITUTION: The wide width part 11 of an outer lead part is provided with a through hole 12. When a plastic lidded chip carrier PLCC 16, for example, is fixed on a mounting substrate 17 by applying solder 18, the heat dissipation capability of the wide width part 11 is increased, temperature rise is restrained, and the area of the wide width part 11 is reduced by an amount of the hole 12. Thereby, solder can be prevented from wetting up from a narrow width part 13 to the wide width part 11, and the decrease of solder quantity between the narrow width part 13 and the mounting substrate 17 can be restrained. Consequently, the soldering strength can be improved as compared with the conventional method, and the reliability in the temperature cycle test after substrate mounting can be maintained.