Memory Repair Strategy Handling for Post-Package Row Conflicts
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Solution Overview
Problem
Memory cells may fail during manufacture or use, necessitating repair, but existing methods do not effectively manage conflicts arising from repeated repairs of the same defective cell row, leading to data errors.
Innovation Solution
Invalidate the first repair strategy for a defective memory cell row repaired before packaging and configure a second repair strategy in a post-package repair mode to avoid conflicts, using a read-only memory (ROM) and content addressable memory (CAM) to manage repair strategies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a first repair strategy is applied to a defective memory cell row before packaging, then the defective cell row can be repaired, but conflicts arise when the same cell row is repaired again after packaging, leading to data errors
Solution Approach 1:
The patent applies preliminary action by checking whether a defective memory cell row has been previously repaired (before packaging) before applying a repair strategy after packaging. The control circuit queries the CAM to determine if the defective row exists in the repair record, and only applies the repair strategy if no prior repair is detected. This preliminary check prevents repair conflicts and ensures data integrity.
2Adaptability or versatility
If multiple repair strategies are stored for the same defective memory cell row, then repair flexibility is improved, but system complexity increases due to managing multiple strategies
Solution Approach 1:
The patent introduces an intermediary mechanism - a content addressable memory (CAM) table - to manage repair strategies. The CAM stores the mapping between defective row addresses and repair strategies, allowing the control circuit to efficiently query and retrieve the appropriate repair strategy based on the defective row address. This intermediary structure simplifies the management of multiple repair strategies by providing a centralized, addressable storage mechanism.
3Productivity
If repair strategies are not invalidated after use, then memory operations can proceed, but conflicts arise from applying outdated repair strategies to already-repaired cell rows
Solution Approach 1:
The patent implements feedback by having the control circuit query the CAM table before applying a repair strategy to check whether the defective memory cell row has already been repaired. This feedback mechanism provides real-time information about the repair status of each row, allowing the control circuit to make informed decisions about whether to apply a repair strategy. The feedback loop ensures that repair strategies are only applied when necessary, preventing conflicts and maintaining data integrity.
Data Source
AI summary
Examples of the present application provide operation methods of memories, memory devices and systems. In an example, an operation method includes: in response to a first defective memory cell row of a plurality of memory cell rows in the memory being repaired before packaging, invalidating, in a post-package repair mode, a first repair strategy for repairing the first defective memory cell row before packaging, and configuring a second repair strategy for repairing the first defective memory cell row and storing the second repair strategy.