Patent ID: 6850436

Claim:
A non-volatile semiconductor device including memory blocks and a controller for performing the control of operation of the memory blocks upon receipt of an address and a command, the non-volatile semiconductor storage device comprising: a redundant memory block provided for redundancy in the case where deficient erasure occurs inside of the memory block; a register for storing therein an input address; a redundancy judging circuit for outputting an address stored in the register and an address stored inside of the redundant memory block as a redundant address with respect to the address stored in the register in the case where a deficient erasure status representing deficient erasure is output from the memory block when an erasure command is input into the memory block; and redundant address storage means for storing therein the address and the redundant address; wherein the address is replaced with the redundant address stored in the redundant address storage means when the address input into the controller is the address stored in the redundant address storage means, and memory operation is performed.