Two-Dimensional Spare Memory Structure for Defect Repair
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Solution Overview
Problem
Existing methods for repairing large-scaled memories using spare memory units are inadequate, as one-dimensional structures cannot effectively repair two-dimensional defects, and two-dimensional structures struggle with defects that form clusters in row and column directions.
Innovation Solution
A method and system that utilize a spare memory with multiple units, a built-in self-test circuit, a built-in self-repair circuit, and a spare memory redundancy analysis table to allocate and manage spare memory units for effective defect coverage, allowing for the removal of unqualified permutations and allocation of additional units as needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a one-dimensional spare memory structure is used, then the device complexity is reduced, but the ability to repair two-dimensional defects is insufficient
Solution Approach 1:
The patent transitions from traditional one-dimensional spare memory structures to a two-dimensional spare memory structure with row and column spares. This dimensional change enables the system to effectively repair two-dimensional defects in large-scaled memories by providing repair paths in both row and column directions, thereby improving defect repair capability while maintaining reasonable device complexity.
2Reliability
If a two-dimensional spare memory structure is used, then the ability to repair two-dimensional defects is improved, but defects forming clusters in row and column directions cannot be effectively repaired
Solution Approach 1:
The patent implements a dynamic defect repair method that adaptively selects repair strategies based on defect patterns. When defects form clusters, the system dynamically adjusts the repair approach by utilizing the interconnection between row and column spares, allowing flexible handling of various defect configurations including clustered defects, thereby improving adaptability while maintaining high repair capability.
3Reliability
If multiple spare memory units are allocated, then the defect coverage is improved, but the chip area is increased
Solution Approach 1:
The patent merges row spare memory and column spare memory into an integrated two-dimensional spare memory structure. This merging allows the system to achieve comprehensive defect coverage for both row and column defects using a unified spare memory resource, thereby improving defect coverage while avoiding the need for separate spare memory blocks that would increase chip area.
Solution Approach 2:
The two-dimensional spare memory structure serves multiple functions simultaneously: it can repair row defects, column defects, and clustered defects through a single unified structure. This multi-functionality eliminates the need for separate dedicated spare memory blocks for different defect types, optimizing chip area utilization while maintaining comprehensive defect coverage.
Data Source
AI summary
A method for repairing a main memory comprises the steps of: utilizing a spare memory to repair a main memory, wherein the spare memory includes a plurality of spare memory units; allocating a spare memory unit; determining whether available permutations of the allocated spare memory unit cover a newly found defect in the main memory; removing permutations of the spare memory unit failing to cover newly found defects in the main memory; and allocating another spare memory unit to repair the newly found defects if available permutations of the allocated spare memory unit fails to cover the newly found defects.