Spare Column Remap Storage for Memory Repair

Solution Overview

Problem

Memory devices face limitations in repairing failed memory cells due to insufficient spare columns, where the number of spare columns is less than the number of core columns with failed memory cells, leading to incomplete repair of all failed units.

Innovation Solution

A memory device with a data storage region and spare column remap storage, where column address information of repaired main columns is stored across multiple storage units, allowing for virtual allocation of remapped addresses to facilitate efficient repair even when the number of spare columns is insufficient.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the number of spare columns is increased to repair all failed memory cells, then the repair capability is improved, but the device complexity and fabrication difficulty increase

Engineering Contradiction:

Improverepair capabilityVSAvoiddevice complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the functionality of multiple spare columns across different sub-arrays by implementing a remapping mechanism. When a main column in one sub-array fails, it can be remapped to a spare column in another sub-array through the spare column remap storage. This combining approach allows the system to utilize spare columns from multiple sub-arrays collectively, thereby increasing the total repair capability without adding more spare columns to each individual sub-array, thus avoiding increased device complexity.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The spare columns are designed to serve multiple functions across different sub-arrays. A spare column in one sub-array can be used to repair failed columns in the same sub-array or in other sub-arrays through the remapping mechanism. This multi-functionality allows the same physical spare column resources to serve multiple repair purposes, increasing repair capability without proportionally increasing the number of spare columns needed.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If the number of spare columns is increased to repair all failed memory cells, then the repair capability is improved, but the manufacturing cost increases

Engineering Contradiction:

Improverepair capabilityVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent merges the functionality of multiple spare columns across different sub-arrays by implementing a remapping mechanism. When a main column in one sub-array fails, it can be remapped to a spare column in another sub-array through the spare column remap storage. This combining approach allows the system to utilize spare columns from multiple sub-arrays collectively, thereby increasing the total repair capability without adding more spare columns to each individual sub-array, thus avoiding increased device complexity.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The spare columns are designed to serve multiple functions across different sub-arrays. A spare column in one sub-array can be used to repair failed columns in the same sub-array or in other sub-arrays through the remapping mechanism. This multi-functionality allows the same physical spare column resources to serve multiple repair purposes, increasing repair capability without proportionally increasing the number of spare columns needed.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Device complexity

If traditional BISR scheme is used with limited spare columns, then the device complexity is reduced, but the repair completeness deteriorates

Engineering Contradiction:

Improvedevice complexityVSAvoidrepair completeness

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent introduces a new dimension to the traditional BISR scheme by implementing a remapping mechanism that operates across the dimension of sub-array boundaries. Instead of being confined to repairing failed columns within the same sub-array, the system can remap failed columns to spare columns in other sub-arrays. This dimensional expansion allows the system to achieve complete repair coverage without proportionally increasing the number of spare columns in each sub-array, thus maintaining relatively low device complexity while improving repair completeness.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent introduces an intermediary mechanism (the remapping logic and spare column remap storage) that mediates between failed main columns and spare columns. This intermediary layer enables the system to dynamically determine the optimal mapping between failed columns and available spare columns across multiple sub-arrays, achieving complete repair coverage without requiring a direct 1:1 correspondence between failed columns and spare columns in each sub-array.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS11200962B2Memory devices having spare column remap storages and methods of remapping column addresses in the memory devices

Publication Date: 2021.12.14 SK HYNIX INC

AI summary

A memory device includes a data storage region and a spare column remap storage. The data storage region includes a plurality of sub-arrays, and each of the plurality of sub-arrays has a plurality of main columns and a plurality of spare columns. The spare column remap storage includes a plurality of storage units storing column address information of a repaired main column of one of the plurality of sub-arrays and address information of a repaired main column of another of the plurality of sub-arrays into at least one of the plurality of storage units included in the spare column remap storage.