Programming of drain side word line to reduce program disturb and charge loss

摘要

Techniques are provided for programming the memory cells of a drain-side edge word line of a set of word lines before programming memory cells of any other word line of the set. Pass voltages applied to the other word lines act as stress pulses which redistribute holes in the charge-trapping material of the memory cells of the other word lines to reduce short-term charge loss and downshifting of the threshold voltage. Additionally, one or more initial program voltages used for the drain-side edge word line are relatively low and also act as stress pulses. The memory cells of the drain-side edge word line are programmed to a narrower Vth window than the memory cells of the other word lines. This compensates for a higher level of program disturb of erased state memory cells of the drain-side edge word line due to reduced channel boosting.