Integrated Copper Fuse with Diffusion Barrier for ESD and Over-Voltage Protection

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Solution Overview

Problem

Conventional fuses have inherent resistance, limited lifetime, and time lag, which can lead to false activation during short high-current pulses, failing to adequately protect both the power source and electronic devices from over-currents and over-voltages, requiring separate surge devices and frequent replacements.

Innovation Solution

An integrated circuit combining an over-current protection circuit and an over-voltage protection circuit, with a conductive metal track protected by diffusion layers to prevent oxidation, ensuring immediate protection without lag time and reducing the need for separate diode and fuse replacements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional fuse is used for over-current protection, then the power source and electronic equipment are protected from excess currents, but the fuse has inherent resistance, limited lifetime, and time lag that cause false activation during short high-current pulses and fail to provide immediate protection

Engineering Contradiction:
Improveprotection reliabilityVSAvoidlag time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent combines a fuse and a surge diode into a single integrated device. The fuse provides over-current protection while the surge diode provides over-voltage protection and eliminates lag time by clamping voltage spikes immediately. This merging resolves the contradiction by providing both reliable protection and immediate response without the time lag inherent in conventional fuses.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The integrated device uses composite material structures, including a copper conductive layer protected by diffusion barriers (tungsten silicide or titanium nitride). This composite structure provides both electrical conductivity and protection against oxidation and diffusion, extending the lifetime of the conductive material while maintaining reliable protection function.

Inventive Principle:
Principle #40Composite materials

2Reliability

If a diode is added for over-voltage protection, then the powered device is protected against excess voltage, but the diode and fuse must be replaced separately when damaged, increasing maintenance complexity

Engineering Contradiction:
Improveover-voltage protectionVSAvoidreplacement complexity
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

The patent integrates the surge diode and fuse into a single device, so that when either component fails, the entire integrated device is replaced as one unit. This eliminates the need to test and replace components separately, significantly simplifying repair procedures while maintaining both over-current and over-voltage protection functions.

Inventive Principle:
Principle #5Merging (Combining)

3Loss of energy

If copper is used as the conductive material for low resistance, then the inner resistance of the fuse is reduced, but copper is susceptible to oxidation and diffusion that degrade the metal over time

Engineering Contradiction:
Improveinner resistanceVSAvoidlifetime
Core Design Contradiction:
Loss of energyVSDuration of action of stationary object

Solution Approach 1:

The patent uses a composite material structure where a copper conductive layer is protected by diffusion barrier layers (tungsten silicide or titanium nitride). The copper provides low electrical resistance while the diffusion barriers protect against oxidation and metal diffusion, thereby extending the lifetime of the conductive material while maintaining low energy loss.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The diffusion barrier layers create an inert environment for the copper conductive layer, preventing oxidation and diffusion by blocking exposure to oxygen and other reactive substances. This protects the copper from degradation while maintaining its low-resistance electrical properties throughout the device's operational lifetime.

Inventive Principle:
Principle #39Inert atmosphere (Inert environment)

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

The integrated solution provides efficient and immediate protection against both over-currents and over-voltages, extending the lifetime of the conductive material and simplifying replacements by integrating both protection functions into a single device.

Implementation Method 1

Metal is susceptible to oxidation, which degrades the metal. Therefore, the conductive material of the instant disclosure is provided with a diffusion-protector.

Methodology Applied
Scientific EffectOxidation: Oxidation

Implementation Method 2

the conductive material of the instant disclosure is provided with a diffusion-protector

Methodology Applied
Scientific EffectDiffusion: Diffusion

Data Source

PatentEP2562812B1Integrated copper fuse combined with esd/over-voltage/reverse polarity protection
Publication Date: 2018.10.03 NEXPERIA BV
  • EP2562812B1 patent drawingFigure 1
  • EP2562812B1 patent drawingFigure 2
  • EP2562812B1 patent drawingFigure 3

AI summary

In one embodiment, an integrated circuit, and method of manufacturing thereof, is provided. The integrated circuit contains an over-voltage protection element and an over-current protection element. The integrated circuit operates to provide enhanced and efficient ESD functionality. The over-current element of the instant disclosure includes a diffusion protection layer to enhance the lifetime of the over-current element and improve functionality.