Patent ID: 7277330

Claim:
A nonvolatile semiconductor memory device comprising: a plurality of normal memory cells each storing data of one bit in a nonvolatile mannner; a plurality of spare memory cells each used in place of a defective memory cell when the defective memory cell is present in said plurality of normal memory cells, and constituted so that two spare memory cells store data of one bit as a whole; a control circuit, in accordance with an external access, selecting a first memory cell group corresponding to an address signal from among said plurality of normal memory cells and selecting a second memory cell group from among said plurality of spare memory cells in parallel to selection of said first memory cell group; and a select and amplification section selecting a read memory cell group in accordance with said address signal from among said first and second memory cell groups, and amplifying and outputting the data held in said read memory cell group, wherein said plurality of normal memory cells are arranged in rows and columns, and said nonvolatile semiconductor memory device further comprising: a plurality of word lines provided along said rows of said plurality of normal memory cells; a plurality of bit lines provided along said columns of said plurality of normal memory cells; a plurality of reference memory cells provided adjacent to a region in which said plurality of normal memory cells are arranged, arranged to form columns along a column direction of said plurality of normal memory cells, and each holding a reference value for determining a read value when the data is read from each of said normal memory cells; first and second data lines, one of the first and second data lines being connected to one of said plurality of normal memory cells and the other being connected to one of said plurality of reference memory cells; and third and fourth data lines connected to first and second spare memory cells, among said plurality of spare memory cells, forming a pair and storing predetermined data of one bit as the pair.