Method and apparatus for redundancy word line replacement in a repairable semiconductor memory device
US5963489A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | Mar 24, 1998 |
| Grant date | Oct 5, 1999 |
| Priority date | — |
| Expiry date | Mar 24, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11C29/848
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A method and apparatus for repairing a semiconductor memory device. A row redundancy replacement arrangement is provided to repair the memory device consisting of a first plurality of redundant true word lines and a second plurality of redundant complement word lines to simultaneously replace the same first number of first normal word lines and the same second number of the normal complement word lines. An address reordering scheme, preferably implemented as a word line selector circuit and controlled by redundancy control logic and address inputs, allows the redundant true (complement) word lines to replace the normal true (complement) word lines when making the repair. The redundancy replacement arrangement ensures that consistency of the bit map is maintained at all times, irrespective whether the memory device operates in a normal or in a redundancy mode. This approach introduces an added flexibility of incorporating the redundancy replacement without affecting the column access speed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.