Flash memory section and method for erasing flash memory cluster

Abstract

A flash memory group erasing method includes the following steps: (a) applying erasing pulses to a first subset of a flash memory group. (b) performing soft programmed validation or strictly soft programmed validation on the first subset above. (c) Repeat steps (a) and (b) until the first preset condition is true. (d) performing erase validation on the second subset of the memory groups. (e) Steps (a) to (d) are repeated until the second preset condition is true. Finally, (f) repair the bit line leakage phenomenon of the third subset of the above-mentioned memory groups by slow programming and applying erase pulses.

Description

technical field [0001] The present invention relates to a flash memory, and in particular to a method for erasing a flash memory area and a method for erasing a flash memory group (METHOD FOR ERASING A FLASH MEMORY SECTORAND METHOD FOR ERASING A FLASH MEMORY GROUP). Background technique [0002] Every time a flash memory cell is erased, it is always possible to lower the threshold voltage of the memory cell. The so-called over-erase refers to the condition of bit line leakage in the flash memory cell. If a memory cell that has been over-erased is erased again, deep over-erase may occur. Because deep over-erasing cannot be repaired, it should be avoided if possible. [0003] figure 1 It is a flow chart of a conventional method for erasing a flash memory group. A flash memory group is a collection of multiple flash memory sectors. In step 110, an erase pulse (ERS pulse, that is, an erase pulse) is applied to a memory group to simultaneously erase all memory areas of the m...

AI Technical Summary

Problems solved by technology

However, some memory areas may leak electricity every time, and need to be repaired every time

This situation will waste a lot of time

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