Read Disturb Management via Location-Based Refresh Windows
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Solution Overview
Problem
Existing memory sub-systems face issues with read disturb errors, particularly in NAND flash memory, due to biasing conditions and cross-coupling noise, which can lead to erroneous data sensing and reduced performance, especially in memory cells closer to the edge of a wafer where nonuniform process conditions exacerbate these issues.
Innovation Solution
The solution involves adjusting the window size for read disturb management based on the location and distance of memory dies from the center of the wafer, allowing for varying refresh frequencies and data sizes to maintain data accuracy without unnecessary resource expenditure, by determining the radius and region of each memory die and applying specific window sizes and refresh parameters accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If uniform refresh operations are applied to all memory dies, then data accuracy is maintained, but resource expenditure increases unnecessarily
Solution Approach 1:
The patent applies different refresh strategies to different memory die locations based on their specific characteristics. Memory dies closer to the wafer center receive different refresh parameters compared to those at the edges, optimizing resource usage while maintaining data accuracy where needed.
Solution Approach 2:
The patent changes refresh parameters (such as refresh frequency, window size, and data size) based on the location of memory dies within the wafer. By adjusting these parameters dynamically according to position, the system maintains reliability while reducing unnecessary resource expenditure in less problematic regions.
2Reliability
If refresh operations are performed frequently on all memory dies, then read disturb errors are reduced, but system performance and resource efficiency deteriorate
Solution Approach 1:
The patent implements location-specific refresh operations where memory dies at different wafer positions receive tailored refresh treatments. This localized approach reduces read disturb errors in vulnerable regions without subjecting all memory dies to excessive refresh operations that would degrade overall system performance.
Solution Approach 2:
The patent applies refresh operations selectively rather than uniformly across all memory dies. By performing partial refresh actions only where necessary based on location-based risk assessment, the system prevents read disturb errors without the performance penalty of excessive universal refreshing.
3Productivity
If larger window sizes are used for read disturb management, then fewer operations are needed, but data accuracy and error detection capability decrease
Solution Approach 1:
The patent adjusts window sizes based on memory die location, using smaller windows for dies closer to wafer edges where read disturb is more problematic and larger windows for central dies. This localized adaptation maintains error detection precision where needed while improving operation efficiency in less vulnerable regions.
Solution Approach 2:
The patent dynamically adjusts window sizes according to the specific location and characteristics of each memory die rather than using a fixed uniform size. This dynamic adaptation allows the system to optimize between operation efficiency and data accuracy based on real spatial variations in read disturb susceptibility.
Data Source
AI summary
An example system can include a memory device and a processing device. The memory device can include a group of memory cells. The processing device can be coupled to the memory device. The processing device can be configured to determine a distance of a memory die from a center of a memory component. The processing device can be configured to perform a read disturb operation on the memory die based on the determined distance use a first voltage window for a set of memory cells of the group of memory cells during a first time period.