| 摘要 |
A nonvolatile semiconductor memory according to the present invention includes a memory cell array including a plurality of electrically writable memory cells; a plurality of word lines and a plurality of bit lines connected to the plurality of memory cells; and a data reading and programming control section for, when performing 4-value data programming, read or erasure with respect to at least one of the plurality of memory cells, selecting and applying a voltage to a corresponding word line and a corresponding bit line among the plurality of word lines and the plurality of bit lines; wherein the data reading and programming control section includes an adjacent memory cell data reading section for reading, at a reading voltage of a predetermined reading voltage level, whether or not data is programmed in a lower page of a second memory cell adjacent to a first memory cell in the memory cell array, and generating adjacent memory cell state data which represents a data state of the second memory cell; an adjacent memory cell data memory section for storing the adjacent memory cell state data generated by the adjacent memory cell data reading section; a reading voltage level control section for defining a plurality of predetermined reading voltage verify levels for reading data from the first memory cell based on the adjacent memory cell state data; a data reading section for reading the data from the first memory cell at a plurality of reading voltages corresponding to the plurality of predetermined reading voltage verify levels; and a data determining section for determining which data of 4-value data is programmed in the first memory cell based on the data which is read by the data reading section.
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