| 摘要 |
The ability to repair defective cells in a memory array, by replacing those cells with redundant cells, is improved using a redundant memory line control circuit that employs two types of redundancy programming. Most, or all, redundant memory lines can be programmed while the memory array is in a wafer state by, e.g., cutting laser fuses. But at least one memory line can be programmed subsequent to device packaging ("post repair") using, e.g., commands that cut electric fuses. Preferably, the redundant memory line(s) that are reserved for post repair are selectable among the same redundant memory lines that can be programmed using laser fuses. This allows all redundant memory lines to be available for laser repair, if needed, but also allows a redundant memory line to be selected for post repair after it has been determined that that redundant memory line is defect-free. This increases the likelihood that a device will be repairable, and yet does not unnecessarily waste redundant memory lines by pre-dedicating them to laser or post repair.
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