PURPOSE: To conduct a selective burn-in at low cost wherein optionally determined burn-in conditions are applied to only memory IC chips and no influence is given to the other peripheral circuits.

CONSTITUTION: This method includes a process wherein first connection points 6a-6c, 7a-7c which are led out from a DRAM chip 3 and second connection points 4a-4c, 5a-5c which are electrically separated from the first connection points and which are led out from a CPU chip 2, a peripheral circuit, are installed on an MCM board 1 and a burn-in is conducted with the DRAM chip 3 and the CPU chip 2 being separated and a process wherein when this device is proved good by the result of the burn-in, the first and the second connection points are electrically connected.