To solve the problem that a semiconductor device is treated as a defective product even if a main LSI chip is non-defective because the sub-LSI in failure cannot be solely replaced when only the sub-LSI chip fails.

This device is provided with the main LSI chip A having a built-in changeover switch 2 and a plurality of sub-LSI chips B1, B2. All the terminals of the sub-LSI chips B1, B2 are connected to the main LSI chip A, input signals into the sub-LSI chips B1, B2, and output signals from the sub-LSI chips B1, B2 are transmitted via the main LSI chip A, and paths of these signals are controlled by the changeover switch 2 of the main LSI chip A.

COPYRIGHT: (C)2006,JPO&NCIPI