Bidirectional Current Control for Semiconductor Joint Layer Electromigration

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Solution Overview

Problem

Existing technologies for suppressing electromigration (EM) in semiconductor devices require additional metal layers, increasing costs and complexity due to directional current flow, which complicates the process.

Innovation Solution

A controller is used to manage the imbalance between forward and reverse current EM progression indices by adjusting the temperature and frequency of current flow through joint layers, canceling out excessive EM without the need for additional metal layers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an extra metal layer is added to suppress EM progression, then the reliability of the joint layer is improved, but the manufacturing cost and device complexity increase

Engineering Contradiction:
Improvejoint layer stabilityVSAvoidnumber of metal layers
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the harmful EM effect from the system by applying a reverse current that opposes the forward current. By calculating the EM progression indices and applying compensating reverse current, the harmful ion migration is canceled out without adding any physical metal layers, thus maintaining reliability while avoiding increased complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the electrical parameters (current direction and magnitude) to suppress EM progression. By dynamically adjusting the reverse current based on calculated EM progression indices, the system compensates for EM effects through parameter modulation rather than structural modification, eliminating the need for additional metal layers.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If different metal types are used for different current directions, then the EM suppression effectiveness is improved, but the manufacturing process complexity increases

Engineering Contradiction:
ImproveEM suppression effectivenessVSAvoidmanufacturing process simplicity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent makes the existing joint layer perform multiple functions: it serves as both the electrical connection layer and the EM suppression layer. By applying reverse current through the same joint layer structure, the patent eliminates the need for different metal types for different current directions, simplifying the manufacturing process while maintaining EM suppression effectiveness.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The joint layer suppresses its own EM progression by utilizing reverse current applied through itself. The system calculates the EM progression index and applies compensating current through the same joint layer, making the layer self-correcting without requiring external specialized components or complex multi-metal structures.

Inventive Principle:
Principle #25Self-service

3Reliability

If reverse current is applied to accelerate EM cancellation, then the reliability is improved, but the energy consumption increases

Engineering Contradiction:
Improvejoint layer stabilityVSAvoidenergy for current control
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent applies reverse current only to the extent necessary for EM cancellation. By calculating the EM progression index and applying proportional reverse current, the system avoids excessive energy consumption while achieving sufficient EM suppression. The reverse current is applied partially, only during periods when forward current has created EM imbalance.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The patent implements a feedback control mechanism where the EM progression index is continuously calculated based on forward current characteristics, and reverse current is applied in response to this feedback. This closed-loop control ensures that energy is consumed only when and to the extent that EM suppression is actually needed, optimizing the balance between reliability and energy consumption.

Inventive Principle:
Principle #23Feedback

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 effectively reduces EM progression in semiconductor devices by balancing forward and reverse current EM indices, maintaining stability and reducing costs by eliminating the need for extra metal layers.

Implementation Method 1

When current flows through the joint layer, a phenomenon occurs in which ions forming the joint layer are moved. In the present disclosure, this phenomenon is called electromigration, and is abbreviated as EM.

Methodology Applied
Scientific EffectElectromigration:

Implementation Method 2

The high potential electrode 16 is connected via a high potential joint layer 20 to an unillustrated high potential electric conductor, and the low potential electrode 18 is connected via a low potential joint layer 22 to an unillustrated low potential electric conductor.

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentUS10044352B2Electronic equipment and automobile mounting the same
Publication Date: 2018.08.07 TOYOTA JIDOSHA KK

AI summary

An electronic equipment is provided with a semiconductor device including an electrode joined to an electric conductor via a joint layer, a calculator and a controller. The semiconductor device is configured to pass current bidirectionally. The calculator is configured to calculate an imbalance EM progression index. The imbalance EM progression index is a difference between a forward current EM progression index and a reverse current EM progression index. The controller is configured to: adopt a condition to accelerate an increase rate of the reverse current EM progression index in at least a part of an excessive forward current EM period; and adopt a condition to accelerate an increase rate of the forward current EM progression index in at least a part of an excessive reverse current EM period.