| 摘要 |
A method for testing flash memory device is provided to screen the sub - leakage fail by lowering the sensing point, so increasing the reliability of the device. Electric charge within the bit line is discharged before reading a memory cell, and a page buffer is set to the initial state. The drain selection transistor within the cell string, and the gate arrow signal of the memory cell transistor and source selection transistor are applied. A low signal is supplied to the drain selection transistor within the cell string, source selection transistor and a memory cell transistor. A bit line(BLe) which are selected for data sensing is pre-charged, and pass voltage is applied to the source selection line of the NAND string. A memory cell is evaluated by supplying low level is supplied as the bit line select signal. The evaluation time is sets up in order to enough discharge electric charges. The transistors and latch of the page buffer are appropriately controlled and state of the memory cell is monitored.
|
