Block and page level bad bit line and bits screening methods for program algorithm
US8880964B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 19, 2012 |
| Grant date | Nov 4, 2014 |
| Priority date | — |
| Expiry date | Jan 15, 2033 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11C2029/1204
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A programming process evaluates NAND strings of a block to detect a defective NAND string, e.g., a NAND string with a defective storage element. Status bits can be stored which identify the defective NAND string. Original data which is to be written in the NAND string is modified so that programming of the defective NAND string does not occur. For example, a bit of write data which requires a storage element in the defective NAND string to be programmed to a higher data state is modified (e.g., flipped) so that no programming of the storage element is required. Subsequently, when a read operation is performed, the flipped bits are flipped back to their original value, such as by using error correction code decoding. In an erase process, a count of defective NAND strings is made and used to adjust a pass condition of a verify test.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.