SEMICONDUCTOR PACKAGE AND SEMICONDUCTOR DEVICE

PROBLEM TO BE SOLVED: To provide a semiconductor package of a structure, where the thermal conductivity of a package is increased and the heat resistance of the package can be reduced and at the same time, the packaging strength of the packaging surface of the package can be increased, and a semiconductor device. SOLUTION: A radiating material 12 is mounted on a base substrate 11, and an LSI chip 13 is mounted on the material 12. Pads on the chip 13 and pads on the substrate 11 are connected with each other via bonding wires 14. Through-holes 16 connected with the material 12 are formed in the substrate 11 and solder balls 18 connected with the holes 16 are formed on the backside of the substrate 11. The substrate 11 is mounted on a mounting substrate 19 through the balls 18 and through holes 21 connected with the balls 18, and moreover, a conducting layer 22 connected with the holes 21 are formed in the substrate 19.