| 摘要 |
PROBLEM TO BE SOLVED: To surely prevent fluctuations of a threshold voltage of a memory transistor for maintaining erase data in EEPROM's having a NAND type memory cell. SOLUTION: When a program voltage Vpgm is supplied to a word line WL2 to page-program, a second pass voltage Vpass 2 lower than a first pass voltage Vpass 1 is supplied to adjacent word lines WL1, WL3. When Vcc is supplied to a bit line BL1 and a memory transistor M21 is a cell for storing erase data, both memory transistors M11, M31 adjacent to the memory transistor M21 are unconductively connected in accordance with capacitance coupling of a word line voltage. Therefore, a local step-up voltage by a program voltage is charged in the memory transistor M21, and a change in a threshold voltage is surely prevented. |
