Non-Volatile Memory Plane Isolation for Word Line Leak Detection

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Solution Overview

Problem

Word line shorts in non-volatile memory systems cause voltage leaks, leading to programming failures across multiple planes and unnecessary retirement of memory locations, slowing down the programming process.

Innovation Solution

Implement a testing mechanism to identify and isolate planes with voltage leaks before programming, allowing concurrent programming only in leak-free planes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If concurrent programming is performed for multiple planes to increase efficiency, then programming speed is improved, but programming failures occur across all planes when one plane has a word line short

Engineering Contradiction:

Improveprogramming speedVSAvoidprogramming success rate

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The memory system segments the multiple planes into independent programming groups. Planes are tested individually for word line shorts, and only planes without shorts are grouped together for concurrent programming. This segmentation prevents a fault in one plane from affecting other planes, resolving the contradiction between concurrent programming efficiency and reliability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system performs preliminary testing of each plane for word line shorts before initiating concurrent programming operations. By detecting and isolating faulty planes in advance, the system ensures that only healthy planes participate in concurrent programming, thereby maintaining both high programming speed and high success rate.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If all planes are tested and retired when one plane has a word line short, then reliability is maintained, but too many memory locations are retired unnecessarily

Engineering Contradiction:

Improvememory reliabilityVSAvoidusable memory capacity

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

Instead of retiring all planes when a short is detected, the system segments the planes and isolates only the faulty plane(s). Healthy planes continue to be used for storage operations, maximizing usable memory capacity while maintaining reliability through selective isolation of defective components.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system applies local quality control by identifying and isolating only the specific plane(s) with word line shorts, rather than applying a global retirement policy to all planes. This localized approach preserves usable memory in healthy planes while ensuring reliability by excluding faulty planes from operations.

Inventive Principle:

Principle #3Local quality

3Reliability

If reprogramming is performed for all planes when one plane fails, then data integrity is maintained, but programming time increases significantly

Engineering Contradiction:

Improvedata integrityVSAvoidprogramming time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The system segments planes into faulty and healthy groups, allowing successful planes to complete programming without reprogramming. Only planes with detected word line shorts require reprogramming or retirement, significantly reducing the time loss compared to reprogramming all planes, while still maintaining data integrity through selective handling of faulty planes.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS12462888B2Non-volatile memory with neighbor plane program disturb avoidance

Publication Date: 2025.11.04 SANDISK TECHNOLOGIES LLC

AI summary

A non-volatile memory system tests for a voltage leak in any of multiple planes using a voltage being ramped up on selected word lines in the multiple planes. If no voltage leak is detected, then the system concurrently programs data into memory cells connected to the selected word lines in the multiple planes. If a voltage leak is detected in any of the planes, then the system separately tests each plane for the voltage leak at its respective selected word line in order to determine which plane is the source of the voltage leak, and then concurrently programs data into memory cells connected to the selected word lines in planes without the detected voltage leak while isolating the plane with the detected voltage leak.