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US 7,352,620 B2Granted
Non-volatile semiconductor device and method for automatically recovering erase failure in the device
AssigneeSpansion LLC
InventorMasaki Shingo
Life of this patent
Estimating the term…
Abstract
A spare sector is in a blank state beforehand. Each time the erasing is carried out in practical use, the number of erase pulses is counted or the presence/absence of overcurrent flowing when the erase pulse is being applied is monitored. A regular sector having long-erase failure thus detected is automatically replaced with a spare sector. In this manner, the long-erase failure can be recovered without erasing the spare sector after automatic redundancy with the spare sector.
Claims20
A semiconductor device comprising:
- electrically erasable/programmable regular sectors;
- at least one electrically erasable/programmable spare sector for the regular sectors;
- a decoder selecting one of the regular sectors in response to an erase command;
- a monitor circuit monitoring an erase performance of a selected regular sector during erasing;
- and
- a control circuit automatically selecting the spare sector for the selected regular sector when the selected regular sector has a degraded erase performance,
- the spare sector being initially in an erased state prior to selecting by the control circuit.
4 more elements
A redundant method for a non-volatile semiconductor memory comprising the steps of:
- erasing data stored in a regular sector selected by an erase command;
- monitoring an erase performance of a selected regular sector;
- and
- selecting a spare sector for the selected regular sector when the selected regular sector has a degraded erase performance,
- the spare sector being initially in an erased state prior to the step of selecting.
2 more elements
Dependencies are inferred from the claim text.