| CPC G11C 16/3459 (2013.01) [G11C 16/08 (2013.01); G11C 16/3468 (2013.01)] | 20 Claims |
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1. A method of programming memory cells of a memory device to a plurality of program states, the method comprising, for a target program state of the plurality of program states:
(a) selecting one or more of the memory cells to be programmed to the target program state, the selected memory cells being connected to a selected word line;
(b) applying one or more program pulses to the selected memory cells;
(c) performing a first verification operation of verifying the selected memory cells as programmed to at least the target program state, the verified selected memory cells being identified as programmed-passed memory cells, the first verification operation comprising providing a first verify voltage to the selected memory cells;
(d) after the first verification operation is passed for all of the selected memory cells, performing a second verification operation of detecting fail cells among the programmed-passed memory cells, the second verification operation comprising providing an over-bit verify voltage to the programmed-passed memory cells; and
(e) comparing a number of detected fail cells to a reference value to determine whether a program operation should be terminated,
wherein the over-bit verify voltage provided to the programmed-passed memory cells in the second verification operation comprises a verify voltage corresponding to a subsequent program state to the target program state,
wherein a first voltage is applied to an unselected word line during the first verification operation,
wherein a second voltage is applied to the unselected word line during the second verification operation, and
wherein the first voltage and the second voltage are different from each other.
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