Airgap Fuse Link Structure for Uniform eFuse Programming

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Solution Overview

Problem

Conventional electronic fuses suffer from low programming efficiency and resistance variations, leading to unacceptable variations between fuses in the same integrated circuit or among different circuits.

Innovation Solution

The electronic fuse structure includes a fuse link with an airgap between a semiconductor layer and a silicide layer, enhancing thermal isolation and programming efficiency, and is formed using selective etching and silicidation processes to improve control over silicide thickness and uniformity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional electronic fuse structure is used, then manufacturing is simpler, but programming efficiency is low and resistance variations are high

Engineering Contradiction:

Improveprogramming efficiencyVSAvoidresistance uniformity

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The fuse link is segmented into distinct semiconductor layer and silicide layer portions, with the silicide layer divided into first, second, and third portions. This segmentation allows different regions to serve different functions: the first and second silicide portions provide low-resistance contacts, while the third silicide portion forms the programmable fuse link with controlled resistance characteristics, improving both programming efficiency and resistance uniformity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the fuse structure are assigned different material compositions and properties. The silicide layer has varying thickness and composition across different portions, with the third portion having specific characteristics optimized for programmability. This local differentiation enables precise control over programming current distribution and resistance characteristics, resolving the contradiction between programming efficiency and resistance uniformity.

Inventive Principle:

Principle #3Local quality

2Speed

If higher programming current is used, then programming speed increases, but resistance variations between fuses increase

Engineering Contradiction:

Improveprogramming speedVSAvoidresistance uniformity

Core Design Contradiction:

SpeedVSManufacturing precision

Solution Approach 1:

The structure enables control of programming parameters through the layered design. The specific thickness and composition of the third silicide portion, along with the overall fuse link geometry, are optimized to achieve uniform current distribution during programming. This allows high programming speeds while maintaining resistance uniformity across different fuse instances through precise parameter control.

Inventive Principle:

Principle #35Parameter changes

3Ease of manufacture

If uniform silicide layer is used, then manufacturing is easier, but thermal isolation and programming control are insufficient

Engineering Contradiction:

Improvesilicide layer fabricationVSAvoidprogramming control

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The silicide layer is segmented into multiple portions with different functions. The first and second portions provide robust low-resistance contacts that are easier to manufacture, while the third portion is specifically designed for programmability. This segmentation maintains manufacturing simplicity for the contact regions while enabling precise programming control in the fuse link region.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The silicide layer exhibits local quality variations, with different thickness and composition in different portions. The third silicide portion has optimized characteristics for thermal isolation and programming control, while maintaining compatibility with standard manufacturing processes. This local differentiation achieves both manufacturing ease and programming reliability.

Inventive Principle:

Principle #3Local quality

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 airgap provides efficient thermal isolation, allowing for lower programming currents and reduced resistance variations, resulting in tighter control over programmed states and consistent performance across fuses.

Implementation Method 1

The airgap provides efficient thermal isolation, allowing for lower programming currents and reduced resistance variations

Methodology Applied

Scientific EffectThermal isolation: Thermal Insulation

Implementation Method 2

formed using selective etching and silicidation processes

Methodology Applied

Scientific EffectSelective etching:

Implementation Method 3

formed using selective etching and silicidation processes

Methodology Applied

Scientific EffectSilicidation:

Data Source

PatentUS12581942B2Electronic fuses with an airgap under the fuse link

Publication Date: 2026.03.17 GLOBALFOUNDRIES SINGAPORE PTE LTD

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.