Memory Sub-System Retirement via Fail Bit Count Monitoring

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Solution Overview

Problem

Existing memory sub-system retirement determination methods are oversimplified and do not effectively monitor the performance of a large number of memory cells, leading to premature retirement or continued operation beyond recommended lifespan, lacking real-time data integrity monitoring.

Innovation Solution

Implementing a memory sub-system fail bit count component that monitors error parameter values such as fail bit count and codeword error rate, allowing for real-time retirement determination based on statistical boundaries and write cycles, enabling component-level retirement decisions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If simplified retirement determination methods are used, then device complexity is reduced, but measurement precision and reliability of retirement determination deteriorate

Engineering Contradiction:
Improveretirement determination method complexityVSAvoidretirement determination accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent segments the retirement determination process into distinct components: monitoring error parameter values (fail bit count, codeword error rate), comparing against statistical boundaries, and making retirement decisions at component level. This segmentation allows for precise monitoring without requiring complex overall system redesign.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements continuous feedback by monitoring error parameter values during write cycles and comparing them against statistical boundaries. This feedback mechanism enables real-time assessment of memory component health and accurate determination of retirement timing based on actual performance data.

Inventive Principle:
Principle #23Feedback

2Reliability

If real-time error parameter monitoring is implemented, then reliability of retirement determination is improved, but device complexity increases

Engineering Contradiction:
Improveretirement determination reliabilityVSAvoidmonitoring system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The memory sub-system performs self-monitoring by tracking its own error parameter values (fail bit count, codeword error rate) during normal write cycles. This self-service approach enables reliable retirement determination without requiring external monitoring systems, thus improving reliability while minimizing added complexity.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The monitoring mechanism serves multiple functions: it tracks error rates, compares against statistical boundaries, determines component health status, and guides retirement decisions. This multi-functionality reduces the need for separate specialized systems, thereby improving reliability without proportionally increasing complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Reliability

If statistical boundaries and error parameter monitoring are used, then data integrity is improved, but loss of time in retirement determination increases

Engineering Contradiction:
Improvedata integrityVSAvoidretirement determination time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The error parameter monitoring operates continuously during normal write cycles without interrupting memory operations. This continuous monitoring ensures data integrity is maintained while avoiding time loss, as the retirement determination is based on accumulated real-time data rather than periodic assessments.

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The system establishes statistical boundaries and monitoring thresholds in advance before actual retirement determination is needed. This preliminary action prepares the framework for quick real-time assessment, ensuring data integrity through pre-defined criteria while minimizing determination time when retirement decisions are actually required.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentUS20220050618A1Memory sub-system retirement determination
Publication Date: 2022.02.17 MICRON TECHNOLOGY INC
  • US20220050618A1 patent drawing
  • US20220050618A1 patent drawing
  • US20220050618A1 patent drawing

AI summary

A method includes performing a quantity of write cycles on memory components. The method can further include monitoring codewords, and, for each of the codewords including a first error parameter value, determining a second error parameter value. The method can further include determining a probability that each of the codewords is associated with a particular one of the second error parameter values at the first error parameter value and determining a quantity of each of the codewords that are associated with each of the determined probabilities. The method can further include determining a statistical boundary of the quantity of each of the codewords and determining a correlation between the quantity of write cycles performed and the corresponding determined statistical boundary of the quantity of each of the codewords.