Programming method for flash memory capable of compensating reduction of read margin between states due to high temperature stress

摘要

A programming method of a flash memory device having a plurality of memory cells for storing multi-bit data indicating one of a plurality of states. The programming method includes programming selected memory cells using multi-bit data to have one of the states; detecting programmed memory cells arranged within a predetermined region of threshold voltage distribution each corresponding to at least two of the states, wherein predetermined regions of the respective at least two states are selected by one of a first verify voltage and a read voltage and a second verify voltage, the first verify voltage being lower than the second verify voltage and higher than the read voltage; and simultaneously programming detected memory cells of the at least two states to have a threshold voltage being equivalent to or higher than the second verify voltage corresponding to each of the states.