Patent ID: 7405970

Claim:
A non-volatile semiconductor memory device comprising: a plurality of electrically data rewritable non-volatile semiconductor memory cells; a memory cell array in which a plurality of the memory cells or memory cell units are arranged in matrix, the memory cell unit including at least one of the memory cells; a plurality of word lines connected to gates of the memory cells; a write circuit configured to write data in a plurality of selected memory cells in the memory cells, the write circuit writes a data in the plurality of selected memory cells by supplying a write voltage and a write control voltage to the plurality of selected memory cells, a first memory cell included in the memory cells; a second memory cell included in the memory cells; and a third memory cell included in the memory cells, gates of the first memory cell, the second memory cell and the third memory cells being connected to a first word line, wherein there are plurality of distributions of threshold value of the memory cells, the plurality of distributions of threshold value includes a first distribution of threshold value and a second distribution of threshold value, the second distribution of threshold value has higher threshold values than the first distribution of threshold value, the write voltage is divided into plurality of pulses, the write voltage increases with a stepwise increment of predetermined voltage per pulse in two or more ones of the plurality of pulses, a first write control voltage, a second control voltage and a third write control voltage are respectively supplied to the first memory cell, the second memory cell and the third memory cell while at least one pulse of the write voltage is supplied to a first word line, all of the first memory cell, the second memory cell and the third memory cell are included in the second distribution of threshold value after the plurality of pulses are supplied to the first word line, and the first write control voltage, the second control voltage and the third control voltage are different one another.