Controller-Level Memory Repair for Multi-Die Systems
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Solution Overview
Problem
Memory devices face significant challenges due to the limited capacity of internal redundant memory portions, which can render an entire memory device unusable when all internal repair options are exhausted, leading to costly failures and reduced performance, especially in applications requiring large memory capacities.
Innovation Solution
Implementing controller-level memory repair by allowing a memory controller to remap memory accesses from a faulty memory die to a redundant memory portion on another die, effectively borrowing and sharing spare memory resources across memory dies to maintain full capacity and extend the lifespan of memory devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If internal redundant memory portions are used for repair, then memory reliability is improved, but the memory device becomes unusable when all internal repair options are exhausted
Solution Approach 1:
The patent combines redundant memory portions from multiple memory dies into a shared pool managed by the memory controller. Instead of each die having isolated redundant portions, the system merges them into a collective resource that can be allocated across any die needing repair, thereby extending overall repair capacity beyond individual die limitations.
Solution Approach 2:
The memory controller acts as an intermediary that manages the remapping process between faulty memory locations on one die and redundant memory portions on another die. This intermediary coordinates the repair operations and handles the complexity of cross-die remapping, enabling reliable repair while maintaining system adaptability.
2Quantity of substance
If memory capacity is increased, then application performance is improved, but the risk of faults increases
Solution Approach 1:
The system performs preliminary remapping operations to redirect memory accesses away from faulty locations before they cause failures. By proactively managing remapping and utilizing redundant portions across multiple dies, the system prepares repair paths in advance, allowing larger memory capacities to be deployed with reduced fault risk.
Data Source
AI summary
Described apparatuses and methods facilitate sharing redundant memory portions at a controller-level to enable memory repair between two or more memory blocks. Each memory die of multiple memory dies can include, for instance, multiple spare rows for use if a row of a memory array has a faulty bit. If a memory die has more faults than spare rows, the memory die cannot repair the additional faults. This document describes a controller that can inventory unrepaired faults and available spare rows across multiple memory dies. The controller can then “borrow” a spare row from a second memory die that has an available one and “share” the spare row with a first memory die that has a fault than it cannot repair. The controller can remap a memory access request targeting the row with the unrepaired fault in the first memory die to a spare row in the second memory die.