Nonvolatile Memory Sub-Block Segmentation for Wasted Region Reduction
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Solution Overview
Problem
In three-dimensional flash memory devices, the increasing number of string select lines and word lines leads to a wasted region in memory blocks where metadata is stored, as the size of metadata does not increase proportionally, resulting in inefficient use of memory space.
Innovation Solution
The implementation of a nonvolatile memory device with sub-blocks defined by unique string select lines and word lines within a physical block, where data is programmed in specific sub-blocks without sharing these lines, and vacant blocks are defined to minimize wasted space, allowing for efficient data storage and partial erasing of sub-blocks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the number of string select lines and word lines is increased to expand memory block size, then the storage capacity is improved, but the wasted region in memory blocks increases due to fixed metadata size
Solution Approach 1:
The memory block is divided into multiple sub-blocks, where each sub-block can be independently managed. This segmentation allows the memory block to be efficiently utilized by storing metadata in dedicated sub-blocks while using other sub-blocks for data storage, thereby reducing wasted regions as memory block size increases.
Solution Approach 2:
The patent introduces a new organizational dimension by creating sub-blocks with unique string select line and word line combinations within a physical block. This dimensional reorganization enables more flexible space utilization and reduces waste by allowing independent management of metadata and data storage areas.
2Ease of operation
If metadata is stored in designated memory blocks separate from general data, then data organization is improved, but the efficiency of memory space utilization deteriorates due to fixed metadata size
Solution Approach 1:
By segmenting the memory block into multiple sub-blocks, the patent maintains separate storage areas for metadata and general data while improving space utilization. Each sub-block can be independently allocated, allowing efficient use of memory space even as the overall block size increases.
Solution Approach 2:
The sub-block structure enables multi-functionality where each sub-block can serve different purposes (metadata storage, data storage, or vacant) depending on the operation requirements. This universal approach allows the same physical block to efficiently handle both metadata and data storage needs.
3Loss of substance
If sub-blocks are defined with unique string select lines and word lines, then wasted region is reduced, but the device complexity increases
Solution Approach 1:
The patent divides the memory block into sub-blocks with unique string select line and word line combinations, reducing wasted regions through better space utilization. While this segmentation increases structural complexity, it enables more efficient memory management and reduced waste.
Solution Approach 2:
The sub-block structure provides dynamic flexibility in memory management, allowing the system to adaptively allocate space for metadata and data. This dynamic approach reduces wasted regions by enabling fine-grained control over memory allocation, justifying the increased device complexity.
Data Source
AI summary
A nonvolatile memory includes a first sub-block defined by a first string select line and a first word line; a second sub-block defined by a second string select line different from the first string select line and a second word line different from the first word line; a first vacant block defined by the first string select line and the second word line; and a second vacant block defined by the second string select line and the first word line. First data is programmed in the first sub-block with, second data is programmed in the second sub-block, and no data is programmed in the first vacant block and the second vacant block.