E-fuse Structure with Stress Dielectrics for Low-Voltage Programming

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Solution Overview

Problem

Laser fuses are limited by their programming depth and require expensive equipment and long programming times, making them unsuitable for post-fabrication customization and optimization of semiconductor chips, while e-fuses lack efficient mechanisms for resistance ratio enhancement.

Innovation Solution

The e-fuse structure incorporates a fuse part with depletion and accumulation regions, dielectrics applying compressive and tensile stresses, and a program current that leverages electromigration, thermomigration, and stress-migration to reduce programming voltage and current, and area requirements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If laser fuses are used for programming, then programming can be performed before chip encapsulation, but programming requires expensive laser equipment and long programming time

Engineering Contradiction:

Improveprogramming timeVSAvoidprogramming equipment

Core Design Contradiction:

Loss of timeVSDevice complexity

Solution Approach 1:

The patent replaces the laser-based mechanical/optical system with an electrical field-based system. The e-fuse structure uses electric field-induced electromigration and stress migration to achieve fuse breaking, substituting expensive laser equipment with standard electrical testing equipment for programming.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the programming mechanism from optical (laser) to electrical (electric field). By applying voltage to create electromigration and stress migration effects, the fuse part breaks through electrical means rather than thermal means, enabling faster and cheaper programming.

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If laser fuses are disposed at or near the exposed surface, then laser programming is possible, but post-fabrication customization and optimization cannot be performed

Engineering Contradiction:

Improvepost-fabrication customizationVSAvoidfuse position

Core Design Contradiction:

Adaptability or versatilityVSShape

Solution Approach 1:

The e-fuse structure can be programmed both before and after chip encapsulation, providing universal programming capability. The electrical programming method works regardless of the fuse's position in the chip structure, enabling both pre-fabrication and post-fabrication customization and optimization.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Reliability

If conventional e-fuse structures are used without stress dielectrics, then structure is simpler, but resistance ratio enhancement is insufficient

Engineering Contradiction:

Improveresistance ratioVSAvoiddielectric structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies different types of stress dielectrics to different regions of the fuse part. Compressive stress dielectric is applied to the depletion region while tensile stress dielectric is applied to the accumulation region, creating local quality differences that enhance the resistance ratio through targeted stress migration effects.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent uses composite dielectric structures combining different stress characteristics. By integrating compressive and tensile stress dielectrics in specific configurations, the structure leverages multiple material properties to enhance electromigration and stress migration effects, improving resistance ratio beyond what single-material structures could achieve.

Inventive Principle:

Principle #40Composite materials

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 configuration allows for efficient programming of e-fuses at lower voltages and currents, enabling post-fabrication customization and optimization with reduced sensing circuit area, enhancing resistance ratio and programming efficiency.

Implementation Method 1

The migration effect is generated by electromigration and thermomirgration

Methodology Applied

Scientific EffectElectromigration:

Implementation Method 2

The migration effect is generated by electromigration and thermomirgration

Methodology Applied

Scientific EffectThermomigration:

Implementation Method 3

a first dielectric applies a larger compressive stress to the fuse part than does the second dielectric

Methodology Applied

Scientific EffectCompressive stress:

Implementation Method 4

a second stress dielectric contacting the accumulation region of the fuse part and formed of at least one of materials applying a tensile stress to the fuse part

Methodology Applied

Scientific EffectTensile stress:

Data Source

PatentUS8471354B2E-fuse structure of semiconductor device

Publication Date: 2013.06.25 SAMSUNG ELECTRONICS CO LTD

AI summary

An e-fuse structure includes an anode, a cathode, a fuse part connecting the anode and the cathode to each other, and a dielectric contacting the fuse part. The dielectric is configured to apply a stress to the fuse part, where the stress constructively acting on a migration effect of atoms constituting the fuse part. The migration effect is generated by electromigration and thermomirgration.