Nonvolatile Memory Column Redundancy Defect Management

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional nonvolatile semiconductor memory devices face inefficiencies in defect recovery, particularly in managing defective columns within the memory cell array, which affects data storage and retrieval efficiency.

Innovation Solution

The implementation of a nonvolatile semiconductor memory device with a memory cell array divided into p areas, featuring a column redundancy area and a column substituting register that holds information to substitute defective user data columns with redundancy columns, allowing for efficient defect management by identifying and switching between global and local defective columns.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional defect management methods are used in nonvolatile semiconductor memory devices, then the device structure remains simple, but defect recovery efficiency is low and defective blocks are generated frequently

Engineering Contradiction:

Improvedefect recovery efficiencyVSAvoidmemory management structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The memory cell array is divided into multiple areas (first area, second area, etc.), with each area having its own dedicated redundancy columns. This segmentation allows defective columns to be managed at the area level rather than requiring global redundancy management, improving defect recovery efficiency while maintaining a structured but manageable system architecture

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Redundancy columns are pre-configured in each area before defects occur. When a defective column is detected, the system can immediately switch to using the pre-prepared redundancy columns in the same area, eliminating the need for complex real-time defect management and reducing the frequency of defective block generation

Inventive Principle:

Principle #10Preliminary action

2Reliability

If redundancy columns are used to substitute defective columns, then defective blocks are reduced, but the management of redundancy columns becomes complex

Engineering Contradiction:

ImproveyieldVSAvoidredundancy column management

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Each area is equipped with its own local redundancy columns specifically dedicated to that area. This local quality approach ensures that redundancy management is confined to small, manageable scopes within each area, reducing the overall complexity of redundancy column management while maintaining high yield through effective defect substitution

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The redundancy columns in each area can substitute any defective column within that same area, providing universal coverage for defect recovery within the local scope. This multi-functional capability allows a single set of redundancy columns to handle multiple potential defect scenarios, simplifying management compared to having dedicated backup columns for each specific defect type

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS8982623B2Nonvolatile semiconductor memory device

Publication Date: 2015.03.17 KIOXIA CORP

AI summary

A non-volatile semiconductor memory device has memory cell arrays, with the memory cells arranged in a matrix configuration and divided into p areas in the column direction, a column redundancy area arranged in a portion of the memory cell array and having redundancy columns that can substitute for defective user data columns, and a column substituting register that holds the column substituting information for substituting the defective user data columns of the selected area with the redundancy columns.