Nonvolatile semiconductor memory device having a plurality of blocks provided on a plurality of electrically isolated wells

摘要

The inventive DINOR flash memory includes a plurality of blocks, a spare block and a spare word line block, which are formed on a plurality of electrically isolated P-type wells. When a word line-to-well short-circuit takes place in a certain block and another block is selected, the block causing the word line-to-well short-circuit is brought into a non-selected state. Thus, no leakage takes place in the block causing the word line-to-well short-circuit, to exert no bad influence on the selected block.