Semiconductor Memory Bad Block Detection and Replacement
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Solution Overview
Problem
Semiconductor memory devices face challenges in detecting and addressing growing bad blocks, which can lead to instability and performance issues over time, as existing technologies lack efficient methods for proactive identification and replacement of defective memory blocks during operations.
Innovation Solution
The semiconductor memory device incorporates a memory cell array with normal and replacement blocks, a CAM block, and a control logic that performs a growing bad block check operation to identify defective blocks and automatically replace them, ensuring stability and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a semiconductor memory device operates without proactive bad block detection, then the device complexity is reduced, but the reliability deteriorates due to undetected growing bad blocks causing instability
Solution Approach 1:
The patent performs a growing bad block check operation before executing the actual program operation. The control logic identifies potential bad blocks in advance by attempting to program dummy data and verifying the programming result, then replaces detected bad blocks with replacement blocks before normal operation. This preliminary detection and replacement prevents reliability issues during actual use.
Solution Approach 2:
The semiconductor memory device performs self-diagnosis and self-repair through automatic bad block detection and replacement. The control logic autonomously identifies growing bad blocks during the programming process and replaces them with spare replacement blocks without requiring external intervention, enabling the device to maintain its own reliability.
2Reliability
If a growing bad block check operation is performed before every program operation, then the reliability is improved, but the productivity deteriorates due to additional operation time
Solution Approach 1:
The patent performs a simplified growing bad block check operation that programs dummy data to a target block and verifies the programming result, without performing complete programming verification. This partial check detects growing bad blocks with sufficient reliability while minimizing the time overhead compared to full programming operations.
Solution Approach 2:
The control logic continuously monitors for growing bad blocks during normal operation by performing check operations between programming tasks. This continuous monitoring approach detects bad blocks early while maintaining overall system productivity through efficient resource utilization and minimal interruption to normal programming operations.
3Reliability
If replacement blocks are maintained for bad block replacement, then the reliability is improved, but the device complexity increases due to additional block management
Solution Approach 1:
The replacement blocks serve multiple functions: they act as spare blocks for replacing growing bad blocks, and can also be used as normal memory blocks when not needed for replacement. The control logic dynamically assigns replacement blocks to either backup or normal storage functions based on system needs, maximizing resource utilization while maintaining reliability.
Data Source
AI summary
The present technology relates to a semiconductor memory device and a method of operating the semiconductor memory device. The semiconductor memory device includes a memory cell array including a plurality of memory blocks, which are assigned as a plurality of normal blocks, a plurality of first replacement blocks, a plurality of second replacement blocks, a first CAM block, and a second CAM block, a peripheral circuit configured to perform an erase operation and a program operation on the plurality of memory blocks, and a control logic configured to control the peripheral circuit to perform a growing bad block check operation on a target block during the program operation on a selected target block among the normal memory blocks.