PURPOSE: To simply obtain highly reliable chip carrier wherein soft errors are not generated by α rays, by arranging an α rays shielding plate, at the part of a substrate which part faces an IC.

CONSTITUTION: A substrate 1 has a plurality of pads 2 on the upper surface and plurality of I/O bumps 3 on the lower surface, and the pads 2 and the bumps 3 are connected by using inner wirings 4. An α-ray shielding plate 6 is fixed to the part of the substrate 1 which part faces an IC 5, by using adhesive agent 10 or the like. Said plate 6 is, e.g. a film of polyimide resin in which radioactive elements of uranium and thorium as impurities are little. The IC 5 having a plurality of leads 7 is mounted on the substrate 1, after the leads 7 are shaped into a specified figure. The leads 7 and the pads 2 are connected by gold-gold thermocompression bonding method or the like. A cap 8 is bonded to the IC 5 by using adhesive agent 9. The cap 8 is bonded to also the substrate 1 by suing adhesive agent 11, and seals the IC 5. Since the α-ray shielding plate 6 is present on the substrate 1 surface facing the circuit surface existing on the lower surface of the IC 5, the α rays generated by the substrate 1 are cut off, and soft errors are not generated in the IC 5 by the α rays.