Flash Memory Block Endurance Prediction via Machine Learning

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Solution Overview

Problem

Flash memory devices experience varying rates of failed bits over time, leading to reduced performance and eventual device failure, as older cells are more prone to errors due to manufacturing variances and usage factors, which existing error correction mechanisms can only partially mitigate.

Innovation Solution

An endurance prediction system using a neural network machine learning algorithm processes historical data to correlate current block characteristics with future endurance metrics, allowing for the modification of operation parameters to optimize performance and lifespan by distributing writes and garbage collection based on predicted block endurance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If error correction mechanisms are used to mitigate failed bits, then device reliability is improved, but device complexity increases

Engineering Contradiction:
Improvedevice reliabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system performs preliminary action by predicting block endurance characteristics before failures occur. The machine learning model analyzes historical data and current block characteristics to forecast which blocks are likely to fail, allowing the system to proactively redistribute data and perform garbage collection on at-risk blocks before they actually fail, thus maintaining reliability without needing complex real-time error correction mechanisms

Inventive Principle:
Principle #10Preliminary action

2Duration of action of stationary object

If uniform write distribution is applied across all blocks, then device lifespan is extended, but performance deteriorates due to not accounting for individual block variances

Engineering Contradiction:
Improvedevice lifespanVSAvoidperformance
Core Design Contradiction:
Duration of action of stationary objectVSProductivity

Solution Approach 1:

The system applies local quality by treating each block individually based on its predicted endurance characteristics. Instead of uniform treatment, the machine learning model generates block-specific endurance predictions, and the system adapts its write distribution strategy for each block according to its predicted lifespan. High-endurance blocks receive more write operations while low-endurance blocks are protected, optimizing both overall device lifespan and performance

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The system implements dynamics by continuously updating block endurance predictions based on changing block characteristics and usage patterns. The machine learning model re-evaluates block states over time, allowing the write distribution strategy to dynamically adapt as blocks age and their endurance characteristics change, thereby extending device lifespan while maintaining performance

Inventive Principle:
Principle #15Dynamics

3Productivity

If aggressive write operations are performed to improve performance, then productivity increases, but block endurance deteriorates accelerating device failure

Engineering Contradiction:
Improvewrite speedVSAvoidblock endurance
Core Design Contradiction:
ProductivityVSDuration of action of stationary object

Solution Approach 1:

The system applies parameter changes by adjusting write operation parameters based on predicted block endurance. The machine learning model provides endurance predictions that inform the selection of appropriate write parameters for each block. For blocks with lower predicted endurance, the system uses more conservative write parameters that reduce stress on the block, while blocks with high predicted endurance can tolerate more aggressive write operations, thus maintaining productivity without accelerating device failure

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS11049009B2Identifying memory block write endurance using machine learning
Publication Date: 2021.06.29 SANDISK TECHNOLOGIES LLC
  • US11049009B2 patent drawing
  • US11049009B2 patent drawing
  • US11049009B2 patent drawing

AI summary

Systems and methods are described for predicting an endurance of groups of memory cells within a memory device, based on current characteristics of the cells. The endurance may be predicted by processing historical information regarding operation of memory devices according to a machine learning algorithm, such as a neural network algorithm, to generate correlation information between characteristics of groups of memory calls at a first time and an endurance metric at a second time. The correlation information can be applied to current characteristics of a group of memory cells to predict a future endurance of that group. Operating parameters of a memory device may be modified at a per-block level based on predicted block endurances to increase the speed of a device, the longevity of a device, or both.