External E-Fuse Array for Memory Chip Repair

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Solution Overview

Problem

Conventional memory systems face challenges in efficiently storing and transmitting repair information due to size and space limitations of E-fuse circuits, which restrict their application in memory devices, particularly in multi-chip packages.

Innovation Solution

A memory system architecture where a separate repair information storage chip, utilizing nonvolatile memories like E-fuse arrays, transmits repair data to multiple memory chips, eliminating the need for programming fuse circuits within the memory chips and allowing for defect replacement during initial operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If E-fuse circuits are used to store repair information in memory chips, then repair functionality can be achieved, but the size and space requirements increase due to the need for transistors and amplifiers

Engineering Contradiction:

Improverepair functionalityVSAvoidchip area

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

The patent extracts the E-fuse circuitry (transistors, amplifiers, and repair information storage) from individual memory chips and relocates it to a separate external device. This allows the memory chips to be smaller while the repair functionality is maintained in the external E-fuse array, resolving the contradiction between repair functionality and chip area.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The external E-fuse array serves multiple memory chips simultaneously, providing a universal repair solution. Instead of each memory chip having its own dedicated E-fuse circuit, a single external device can store and provide repair information for multiple chips, reducing total space requirements while maintaining repair functionality.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If laser fuses are used to store repair addresses, then repair operations can be performed, but the fuses cannot be programmed after wafer mounting

Engineering Contradiction:

Improverepair operation capabilityVSAvoidprogrammability timing

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent transitions from laser fuses (which can only be programmed before wafer mounting) to E-fuse circuits using transistors that can be programmed after wafer mounting. This parameter change in the fuse technology enables post-mounting programming capability while maintaining repair operation functionality.

Inventive Principle:

Principle #35Parameter changes

3Device complexity

If transistor size is increased to directly recognize E-fuse data, then sensing complexity is reduced, but the chip area increases

Engineering Contradiction:

Improvesensing operation complexityVSAvoidtransistor area

Core Design Contradiction:

Device complexityVSArea of stationary object

Solution Approach 1:

The patent extracts the E-fuse circuitry from individual memory chips and relocates it to a separate external device. This allows the memory chips to be smaller while the repair functionality is maintained in the external E-fuse array, resolving the contradiction between repair functionality and chip area.

Inventive Principle:

Principle #2Taking out (Extraction)

4Measurement precision

If amplifiers are provided for each E-fuse to sense current, then data recognition accuracy is improved, but the number of components and space requirements increase

Engineering Contradiction:

Improvedata recognition accuracyVSAvoidnumber of amplifiers

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent merges the amplification and data recognition functions into the external E-fuse array device. Instead of requiring separate amplifiers for each E-fuse, the external device consolidates these functions, reducing the total number of components while maintaining measurement precision through centralized signal processing.

Inventive Principle:

Principle #5Merging (Combining)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This solution enables efficient storage and transmission of repair information across multiple memory chips, reducing the complexity and size requirements of individual memory chips, facilitating effective repair operations without the need for additional amplifiers or enlarged transistors, thereby enhancing the reliability and efficiency of memory systems.

Implementation Method 1

a repair information storage chip including a nonvolatile memory configured to store repair information of the one or more memory chips

Methodology Applied

Scientific EffectNonvolatile memory storage:

Implementation Method 2

during an initial operation of the memory system, the repair information stored in the repair information storage chip is transmitted to the one or more memory chips

Methodology Applied

Scientific EffectData transmission:

Data Source

PatentUS9165620B2Memory system and operating method thereof

Publication Date: 2015.10.20 SK HYNIX INC

AI summary

A memory system includes one or more memory chips, and a repair information storage chip including a nonvolatile memory configured to store a repair information of the one or more memory chips, wherein during an initial operation of the memory system, the repair information stored in the repair information storage chip is transmitted to the one or more memory chips.