| 摘要 |
In a non-volatile semiconductor memory device of a flash type for recording multivalue data into memory cells, a control is made such that a word line voltage is set in accordance with a distribution state of a threshold voltage at the time of verification of data after the writing, a precharge of a bit line is controlled in accordance with data latched in a latch circuit, whether a threshold value of the memory cell exceeds a voltage applied to word line or not is detected depending on whether a current sufficiently flows in the memory cell or not, a state of the latch circuit is specified by a detection output, and when data is sufficiently written, predetermined data is set into the latch circuit. At the time of reading, a control is made so that a word line voltage is set in accordance with the distribution state of the threshold voltage, the state of the latch circuit is specified depending on whether a current sufficiently flows in the memory cell or not, and the read data is set into the latch circuit. Thus, the number of elements constructing the latch circuit is reduced.
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