Semiconductor device

A semiconductor device, comprising:

• a base having front layers provided on respective sides of a core layer formed by a printed circuit board;
• and
• a semiconductor chip mounted on said base,
• wherein said semiconductor chip is joined to one of said front layers using a joining member,
• the other front layer of said front layers has a plurality of external terminals arranged thereon,
• said core layer has a plurality of through-holes formed therein to electrically connect said semiconductor chip to said plurality of external terminals, and
• said plurality of external terminals comprise external signal terminals, external power terminals, and external ground terminals,
• said plurality of through-holes include signal through-holes electrically connecting said external signal terminals and said semiconductor chip together, power through-holes electrically connecting said external power terminals and said semiconductor chip together, ground through-holes electrically connecting said external power terminals and said semiconductor chip together, and additional through-holes electrically connecting said external ground terminals and said semiconductor chip together or said external ground terminals and said semiconductor chip together, and
• the number of said plurality of through-holes is larger than that of said plurality of external terminals by the number of said additional through-holes.