Cross-Plane DRAM Redundancy for Uneven Defect Repair
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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 one plane having insufficient redundancy to replace defective cells while the other has excess, affecting yield and flexibility of replacement.
Innovation Solution
A memory design where redundant replacement resources from different planes can be shared, allowing a bad memory resource in one plane to be replaced by a redundant resource from another plane, with a priority mechanism to optimize resource utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fixed number of redundancy resources are provided in each plane, then each plane has dedicated backup resources, but the distribution of defective memory cells is uneven across planes leading to waste of redundancy resources
Solution Approach 1:
The patent makes redundancy resources universal by enabling them to serve multiple planes. The first redundancy resource in the first plane can replace defective memory resources in either the first plane or the second plane, transforming plane-specific redundancy into cross-plane redundancy. This multi-functionality resolves the contradiction by allowing the same redundancy resource to adapt to defects in different planes, improving both reliability coverage and resource flexibility.
Solution Approach 2:
The patent merges the redundancy resource pools of multiple planes by establishing cross-plane replacement capability. Instead of maintaining separate, isolated redundancy resources for each plane, the system combines them into a shared resource pool where redundancy resources from one plane can substitute for defective resources in another plane, optimizing overall resource utilization.
2Device complexity
If redundancy resources are confined to same plane replacement, then replacement logic is simple, but yield is reduced due to insufficient redundancy coverage when one plane has more defects
Solution Approach 1:
The patent extends the functionality of redundancy resources to operate across multiple planes. The replacement control logic, while slightly more complex, enables a redundancy resource to be activated for defects in either its native plane or the other plane, thereby increasing the effective coverage of redundancy resources and improving memory yield without excessive complexity increase.
Solution Approach 2:
The patent introduces dynamic replacement capability where the target plane for redundancy replacement is not fixed but can be selected based on where defects occur. The system dynamically determines whether to use same-plane or cross-plane redundancy resources, allowing flexible adaptation to different defect distributions and improving yield while maintaining manageable complexity through systematic control methods.
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 the other of the two planes for performing a normal Read/Write operation. By the above-mentioned way, the redundant replacement resources in different planes are capable of being shared, thereby improving the flexibility of redundancy and the yield of the memory.