Method and apparatus for defect repair in NAND memory device
US9558852B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 15, 2015 |
| Grant date | Jan 31, 2017 |
| Priority date | — |
| Expiry date | Apr 15, 2035 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11C2029/4402
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
System and method of selecting defective columns in NAND memory devices for repair. After locating the defective blocks and defective columns in a NAND memory device, a weight value is calculated for each defective block by dividing a total number of defective blocks that would be inherently repaired as a result of repairing the respective defective block by a number of defective data columns in the respective defective block. A defective block with the greatest weight value is selected for repair in which the defective columns in the selected block are substituted by redundant columns. Other defective blocks with defective columns having the same column addresses with the defective columns in the selected defective block are automatically selected for repair as well. Remaining defective columns are selected for repair by iteratively updating weight values and selecting a defective block that has the greatest weight value among the remaining defective blocks.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.