| 摘要 |
PURPOSE: An erasing method of a flash memory is provided to prevent a program fail by verifying the addresses of a cell after executing a post program about all bit lines of a sector at which an erase has been performed. CONSTITUTION: When there is an erase order(S310), a program about a pertinent address is performed(S330), and the pertinent address is verified(S340). An existing of a fail is decided according to a result of the verification(S350). On the occasion of fail, when the present value of a fail-counter is not a maximum value(MAX)(S352), the value of the fail counter is increased(S353), and the pre program step is performed(S330). On the occasion of no fail, when the present verified address is a final address, the fail counter and the address are reset(S370), and the pertinent address is erased(S380), because the per program is finished. After this, the erase of the pertinent address is verified(S390), and the erased pertinent address is verified(S390) in order to decide whether the fail exists or not. When there is the fail, it is decided whether the present value of the fail counter is the maximum value(S401). If the present value of the fail counter is not the maximum value, the present value of the fail counter is increased(S402), and the erase step is performed(S380). If the present value of the fail counter is the maximum value, a fail set-up is performed(S352).
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