Erasing method of flash memory

Abstract

The invention provides an erasing method of a flash memory. The erasing method comprises the following steps: pre-programming a plurality of memory cells of the flash memory, wherein the first memory cells are arranged on a memory array composed of a plurality of row lines and a plurality of lines; erasing the programmed first memory cells; post-programming the erased first memory cells to repair the first memory cells which are excessively erased; and programming a plurality of second memory cells after post-programming the erased first memory cells, wherein the second memory cells are arranged on a first specific line of the memory array and the first specific line is arranged behind a final line corresponding to a final effective line address. According to the erasing method, the use states of the memory cells on the corresponding lines in the memory array are recorded by using the memory cells arranged on the extra lines, so that whether a selected section is a blank section or not can be rapidly judged.

Description

technical field [0001] The invention relates to an erasing method of a flash memory, in particular to an erasing method of a flash memory capable of quickly judging a blank section. Background technique [0002] When the flash memory stores data, specific data is written in through a program and erase mechanism. Generally speaking, the programming and erasing algorithms executed according to different command sheets may cause different problems, such as over erase. Taking the general erase program as an example, it mainly includes pre-program, erase and post-program steps, so as to ensure that each memory cell (memory cell) is at the logic level after the erase program. "1" state. When the memory repeatedly executes the erasing and programming procedures, as the number of writes increases, the execution time of the erasing procedure will gradually increase, which is used to repair the execution of the programming step in the entire erasing procedure after excessive erasing...

AI Technical Summary

Problems solved by technology

When an unexpected situation occurs, such as a sudden shutdown, the post-programming step may be interrupted, resulting in the incomplete execution of the post-programming step of the flash memory

Therefore, it takes a lot of time to verify the flash memory to find out the blank sector, so as to avoid any over-erased memory cells existing in the sector and cause read misjudgment

Images