Non-real time reprogramming of non-volatile memory to achieve tighter distribution of threshold voltages
US7633802B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Dec 29, 2008 |
| Grant date | Dec 15, 2009 |
| Priority date | — |
| Expiry date | Dec 29, 2028 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11C2216/14
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A set of non-volatile storage elements undergoes initial programming, after which a reprogramming, with higher verify levels, is performed in non-real time, such as when a control enters a standby mode, when no other read or write tasks are pending. The reprogramming can program pages in the set one at a time, stopping at a page boundary when another read or write task is pending, and restarting when the control become available again. Status flags can be provided to identify whether a page and/or the set has completed the reprogramming. In another aspect, a higher pass voltage is applied to unselected word lines during the reprogramming. In another aspect, an error count is determined using a default set of read voltages, and an alternative set of read voltages is selected if the count exceeds a threshold.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.