Memory Cell Refresh Selection for Read Disturb Errors

Solution Overview

Problem

Memory systems perform unnecessary read disturb refresh operations due to indiscriminate error detection, leading to decreased performance and increased power consumption.

Innovation Solution

The memory system differentiates between read disturb errors and other types of errors by determining the quantity of cells with threshold voltages above a reference threshold, selectively performing read disturb refresh operations only when the difference exceeds a threshold, and employing alternative maintenance operations for other errors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If read disturb refresh operations are performed indiscriminately to correct all errors, then error correction is improved, but system performance decreases and power consumption increases

Engineering Contradiction:

Improveerror correctionVSAvoidsystem performance

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent applies local quality by differentiating between read disturb errors and other types of errors (such as slow charge loss) based on specific characteristics of affected memory cells. The system determines whether to perform read disturb refresh operations by evaluating the threshold voltage distributions and error metrics of specific cell sets, thereby applying the appropriate maintenance operation only where needed rather than indiscriminately across all cells.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The system dynamically adjusts its behavior by monitoring error metrics and threshold voltage distributions over time. It determines whether read disturb refresh operations are necessary by comparing current error conditions against thresholds and by evaluating changes in threshold voltage distributions, allowing the system to adaptively select between different maintenance operations based on real-time conditions.

Inventive Principle:

Principle #15Dynamics

2Reliability

If read disturb refresh operations are performed indiscriminately to correct all errors, then error correction is improved, but power consumption increases

Engineering Contradiction:

Improveerror correctionVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent applies local quality by differentiating between read disturb errors and other types of errors (such as slow charge loss) based on specific characteristics of affected memory cells. The system determines whether to perform read disturb refresh operations by evaluating the threshold voltage distributions and error metrics of specific cell sets, thereby applying the appropriate maintenance operation only where needed rather than indiscriminately across all cells.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The system dynamically adjusts its behavior by monitoring error metrics and threshold voltage distributions over time. It determines whether read disturb refresh operations are necessary by comparing current error conditions against thresholds and by evaluating changes in threshold voltage distributions, allowing the system to adaptively select between different maintenance operations based on real-time conditions.

Inventive Principle:

Principle #15Dynamics

3Reliability

If indiscriminate error detection and refresh operations are performed, then error correction is improved, but operational complexity increases

Engineering Contradiction:

Improveerror correctionVSAvoidoperational complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies segmentation by dividing memory cells into different sets based on their threshold voltage distributions and error characteristics. The system performs error scans on specific sets of cells and evaluates whether read disturb refresh operations are necessary for each set, thereby managing complexity through structured organization rather than treating all cells uniformly.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by differentiating between read disturb errors and other types of errors (such as slow charge loss) based on specific characteristics of affected memory cells. The system determines whether to perform read disturb refresh operations by evaluating the threshold voltage distributions and error metrics of specific cell sets, thereby applying the appropriate maintenance operation only where needed rather than indiscriminately across all cells.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS20260031160A1Selective read disturb refresh operations in a memory system

Publication Date: 2026.01.29 MICRON TECHNOLOGY INC

AI summary

Methods, systems, and devices for selective read disturb refresh operations in a memory system are described. A memory system may determine, for a set of memory cells, a first quantity of memory cells of the set of memory cells that are associated with having a threshold voltage greater than a reference threshold voltage. The memory system may read the set of memory cells, in response to an error metric for the set of cells satisfying a threshold error metric, to determine a second quantity of memory cells of the set of memory cells that have a threshold voltage greater than the reference threshold voltage. And the memory system may determine whether to perform a refresh operation on the set of memory cells in accordance with a difference between the first quantity of memory cells and the second quantity of memory cells.