DRAM Bank Redundancy Sharing Across Planes for Yield Recovery
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Solution Overview
Problem
In dynamic random access memory (DRAM) manufacturing, the uneven distribution of defective memory cells in different planes leads to an imbalance in the availability of redundancy resources, resulting in situations where one plane lacks sufficient redundancy to replace defective memory resources, affecting yield and flexibility of replacement.
Innovation Solution
A memory architecture where each bank comprises two planes, allowing defective memory resources in one plane to be replaced by redundant resources from the other plane, with a higher priority given to intra-plane replacements over inter-plane replacements, enhancing resource sharing and yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fixed redundancy resources are provided in each plane, then each plane can independently replace defective memory resources, but redundancy resources become unevenly distributed and one plane may lack sufficient redundancy when defects occur
Solution Approach 1:
The patent implements a universal redundancy resource pool that can serve multiple planes. The redundancy management circuit allows redundancy resources to be dynamically allocated across different planes based on actual defect distribution, enabling one plane to borrow redundancy resources from another plane when needed. This multi-functional redundancy system resolves the contradiction by making redundancy resources adaptable to different planes' needs while maintaining reliable replacement capability.
Solution Approach 2:
The patent introduces dynamic redundancy allocation where the redundancy management circuit can flexibly assign redundancy resources to different planes based on real-time defect detection. Instead of fixed per-plane redundancy, the system dynamically adjusts redundancy assignment, allowing planes with fewer defects to share their spare resources with planes experiencing higher defect rates, thus balancing reliability and adaptability.
2Productivity
If redundancy resources are shared across planes, then resource utilization improves and yield increases, but replacement priority conflicts arise between intra-plane and inter-plane replacements
Solution Approach 1:
The patent implements preliminary defect detection and classification before final replacement decisions. The redundancy management circuit first identifies defective memory resources and then pre-evaluates replacement options, establishing a priority framework that favors intra-plane replacements. This preliminary action simplifies subsequent replacement control by pre-resolving priority conflicts, allowing the system to efficiently manage shared redundancy resources across planes while maintaining high yield.
Solution Approach 2:
The patent introduces a redundancy management circuit as an intermediary between memory planes and redundancy resources. This intermediary component handles the complex priority arbitration between intra-plane and inter-plane replacements, shielding the rest of the system from complexity. The circuit automatically applies replacement priority rules, managing shared redundancy allocation without requiring complex external control logic.
Data Source
AI summary
A memory and an electronic device are provided in the present application. The memory includes a bank. The bank includes two planes. Each of the two planes includes a plurality of memory resources and a plurality of redundant replacement resources. A bad memory resource of one of the two planes is capable of being replaced by the redundant replacement resource of an other of the two planes for performing a normal Read/Write operation. A first priority level of replacing the bad memory resource in the one of the two planes by the redundant replacement resource in a same plane is greater than a second priority level of replacing the bad memory resource by the redundant replacement resource in a different plane of the two planes.