Method and device for narrowing memory erase unit threshold range

Abstract

The invention discloses a method and a device used for narrowing the memory erase unit threshold range. In the device, a weak erase comparison module determines whether thresholds of various memory units all lower than a weak erase comparison threshold; a pre-erase comparison module determines whether thresholds of various memory units all higher than a pre-erase comparison threshold; a weak erase operation module carries out weak erase upon areas of memory units with thresholds larger than the weak erase comparison threshold; an erase verification unit determines whether thresholds of various memory units all larger than an erase verification reference threshold; a weak writing operation module carries out a writing operation upon the memory units with thresholds smaller than that of the pre-erase comparison threshold unit; an erase operation module carries out erase upon various memory units, and determines whether the thresholds of erased memory units are larger than an over-erase reference threshold; if a threshold of an erased memory unit is smaller than the over-erase reference threshold, the threshold of the memory unit is corrected, such that the corrected threshold of the memory unit is larger than the over-erase reference threshold.

Description

technical field [0001] The invention relates to the field of memory, in particular to a method and a device for converging the threshold range of memory erasing units. Background technique [0002] With the continuous improvement of erasing speed requirements, erasing verification also requires more precision, and it is necessary to effectively control the convergence of the erasing unit threshold to avoid increasing the erasing time due to the divergence of the erasing unit threshold. A single erasure verification standard cannot meet these requirements. [0003] figure 1 It is a schematic diagram of a storage cell array of a memory in the related art; such as figure 1 As shown, due to the capacitive coupling between the write word lines (wl), the voltage of the word line will change. This will affect the accuracy of the read and write operations of the array, which puts forward higher requirements on the threshold distribution of memory cells, especially higher requirem...

AI Technical Summary

Problems solved by technology

It is difficult to effectively converge the threshold range of the erasing unit, and a large amount of time overhead ...

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