Airgap Electronic Fuse Link for Uniform Low-Current Programming

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Solution Overview

Problem

Conventional electronic fuses suffer from low programming efficiency and resistance variations, leading to unacceptable inconsistencies between and within integrated circuits.

Innovation Solution

The structure and method of forming an electronic fuse include a semiconductor layer and silicide layer with an airgap between them, utilizing a second semiconductor layer with different composition for improved thermal isolation and uniformity, enhancing programming efficiency by controlling the electromigration effect.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a large programming current is passed through the fuse link to blow the fuse, then the fuse can be programmed, but the programming efficiency is low and resistance variations occur

Engineering Contradiction:
Improveprogramming efficiencyVSAvoidresistance uniformity
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent applies local quality by creating an airgap specifically at the fuse link location between the semiconductor layer and silicide layer, while maintaining direct contact in other regions. This localized structural modification concentrates the electromigration effect precisely where needed, improving programming efficiency while maintaining resistance uniformity across different fuses.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes the physical structure parameter by introducing an airgap, which alters the thermal and electrical properties locally. This structural parameter change enhances the electromigration effect during programming, allowing for more efficient and uniform fuse blowing across the integrated circuit.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If conventional electronic fuse structures are used, then the structure is simple, but programming efficiency is low and resistance variations are high

Engineering Contradiction:
Improveprogramming efficiencyVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the contact between semiconductor layer and silicide layer by introducing an airgap at the fuse link region. This segmentation creates a distinct programmed region separated from the terminal regions, allowing independent optimization of programming characteristics without affecting the overall device structure significantly.

Inventive Principle:
Principle #1Segmentation

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 approach improves programming efficiency, reduces resistance variations, and allows for a lower programming current with a smaller footprint, ensuring tighter control over resistance in programmed fuses.

Implementation Method 1

The fuse link includes an airgap between the semiconductor layer and the third portion of the silicide layer

Methodology Applied
Scientific EffectThermal isolation: Thermal Insulation

Implementation Method 2

A large programming current may cause an abrupt temperature increase in the fuse link that blows the fuse link as a result of electromigration

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 3

A large programming current may cause an abrupt temperature increase in the fuse link that blows the fuse link as a result of electromigration

Methodology Applied
Scientific EffectElectromigration:

Data Source

PatentEP4369397A1Electronic fuses with an airgap under the fuse link
Publication Date: 2024.05.15 GLOBALFOUNDRIES SINGAPORE PTE LTD
  • EP4369397A1 patent drawingFigure 1~2
  • EP4369397A1 patent drawingFigure 2A~2C
  • EP4369397A1 patent drawingFigure 3~3B

AI summary

Structures for an electronic fuse and methods of forming an electronic fuse. The structure comprises an electronic fuse including a first terminal, a second terminal, and a fuse link extending from the first terminal to the second terminal. The first terminal, the second terminal, and the fuse link each include a semiconductor layer and a silicide layer. The silicide layer includes a first portion on the first terminal, a second portion on the second terminal, and a third portion on the fuse link. The fuse link includes an airgap between the semiconductor layer and the third portion of the silicide layer.