Multi-Plane Flash Memory Block Management with Reserve Fields
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Solution Overview
Problem
Multi-plane semiconductor memory devices face challenges in efficiently detecting and replacing bad blocks, which can affect the reliability and performance of flash memory due to the complexity of simultaneous operations across multiple planes.
Innovation Solution
A block management method that utilizes a reserve field and a data field with a control module to conduct operations such as replacing blocks within a multi-plane operation group, including single and multiple replacement modes, to ensure reliable data storage and improved performance by determining the availability of free blocks for replacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multi-plane structure is used to enable simultaneous flash operations on multiple blocks, then programming speed and productivity are improved, but device complexity and difficulty of detecting and measuring bad blocks increase
Solution Approach 1:
The patent divides the multi-plane memory structure into distinct data fields and reserve fields, with each plane containing multiple blocks organized in a segmented manner. This segmentation allows independent management of data storage and bad block replacement, simplifying the control of simultaneous operations across planes while maintaining high programming speed.
Solution Approach 2:
The patent introduces a reserve field as an intermediary structure that contains replacement blocks specifically designated for bad block replacement. This intermediary layer mediates between the data field and the control logic, enabling automatic bad block management without increasing the complexity of the simultaneous multi-plane operations control.
2Productivity
If multi-plane structure is used to enable simultaneous flash operations on multiple blocks, then programming speed is improved, but reliability of bad block detection and replacement deteriorates
Solution Approach 1:
The patent pre-organizes replacement blocks within the reserve field before bad blocks occur. This preliminary arrangement of replacement resources ensures that when bad blocks are detected during multi-plane operations, reliable replacement can be executed immediately without disrupting the simultaneous programming operations across multiple planes.
Solution Approach 2:
The patent implements a self-managing bad block replacement mechanism where the system automatically detects bad blocks and performs replacement using pre-designated blocks from the reserve field, without requiring external intervention. This self-service approach maintains reliability while preserving the benefits of simultaneous multi-plane operations.
3Reliability
If reserve field is allocated for bad block replacement in multi-plane structure, then reliability is improved, but available data storage capacity is reduced
Solution Approach 1:
The patent dynamically adjusts the allocation and usage of the reserve field based on the actual occurrence of bad blocks. Instead of permanently dedicating fixed portions of memory to reserve blocks, the system modifies the operational parameters of the reserve field, using it actively only when bad block replacement is needed, thereby maximizing data storage capacity while maintaining data integrity.
Solution Approach 2:
The patent enables the recovery and reuse of blocks from the reserve field after they have been used for bad block replacement. Once a replacement block has successfully replaced a bad block, the system can recover and reutilize the replacement block for future data storage or replacement purposes, optimizing the utilization of available memory capacity while ensuring data reliability.
Data Source
AI summary
A semiconductor memory device includes adjacent planes and a control module. The adjacent planes include a reserve field and a data field having multiple blocks. The blocks of each of the reserve and data fields are successively arranged over the adjacent planes to form a multi-plane operation group. The control module is configured to control the adjacent planes to conduct a first operation or a second operation in accordance with whether the reserve field includes free blocks corresponding to a unit of the multi-plane operation group. The first operation includes replacing blocks of the data field with free blocks of the reserve field in the unit of the multi-plane operation group. The second operation includes replacing one block of the data field with one free block of the reserve field.