Bonding Structure Diffusion Liner Oxidation Resistance

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Solution Overview

Problem

Conventional metal bonding structures in semiconductor devices face issues such as oxidation, high contact resistance, stress-induced voiding, and electromigration, especially as feature sizes decrease and integration increases, leading to reliability concerns.

Innovation Solution

A bonding structure with a diffusion liner layer composed of the same metal components as the bonding elements, but with different concentrations, is formed at the exposed surfaces to enhance resistance to oxidation and electromigration, and an adhesive layer is used to fill gaps between substrates for improved bonding integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If metal bonding elements are used to connect substrates, then electrical connectivity is achieved, but oxidation and electromigration occur leading to reliability degradation

Engineering Contradiction:

Improvebonding structure reliabilityVSAvoidoxidation and electromigration damage

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A diffusion liner layer is introduced as an intermediary between the metal bonding elements and the ambient environment. This liner layer acts as a protective mediator that prevents direct interaction between the metal bonding elements and harmful environmental factors such as oxygen and stress, thereby eliminating oxidation and stress-induced voiding while maintaining electrical connectivity.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The bonding structure is transformed into a composite material system consisting of multiple layers with different properties: the metal bonding elements provide electrical conductivity, while the diffusion liner layer provides protective properties. This composite structure combines the advantages of different materials to simultaneously achieve electrical connectivity and resistance to oxidation and electromigration.

Inventive Principle:

Principle #40Composite materials

2Reliability

If copper is used for conductive lines and bonding, then electrical connectivity is achieved, but nonconductive oxide film formation increases contact resistance

Engineering Contradiction:

Improvecontact resistanceVSAvoidnonconductive oxide film formation

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The diffusion liner layer serves as a protective intermediary that prevents oxygen from reaching the copper bonding elements. By blocking the oxidation pathway, the liner layer prevents the formation of nonconductive oxide films on the copper surface, thereby maintaining low contact resistance and ensuring reliable electrical connectivity.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Productivity

If feature size of bonding pad or contact is reduced, then integration density increases, but oxidation and electromigration problems become more significant

Engineering Contradiction:

Improveintegration densityVSAvoidoxidation and electromigration severity

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The diffusion liner layer provides a protective intermediary function that becomes increasingly important as feature sizes are reduced. The liner layer completely encapsulates the metal bonding elements, preventing direct exposure to environmental factors. This protection is particularly critical for miniaturized structures where the surface-to-volume ratio is higher, making them more susceptible to oxidation and electromigration.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

A thin film diffusion liner layer is applied to cover and protect the metal bonding elements. This thin film provides effective protection against oxidation and electromigration while occupying minimal space, thereby enabling continued reduction of feature sizes and improvement of integration density without compromising reliability.

Inventive Principle:

Principle #30Flexible shells and thin films

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 diffusion liner layer effectively prevents damage from ambient interactions and mitigates stress-induced voiding and electromigration, significantly enhancing the reliability of the bonding structure and the final device.

Implementation Method 1

the resistance to oxidation, electromigration and stress-induced voiding is improved

Methodology Applied

Scientific EffectOxidation resistance: Oxidation

Implementation Method 2

the resistance to oxidation, electromigration and stress-induced voiding is improved

Methodology Applied

Scientific EffectElectromigration resistance:

Implementation Method 3

the resistance to oxidation, electromigration and stress-induced voiding is improved

Methodology Applied

Scientific EffectStress-induced voiding resistance:

Data Source

PatentUS9931813B2Bonding structure and method of fabricating the same

Publication Date: 2018.04.03 IND TECH RES INST

AI summary

A bonding structure and a method of fabricating the same are provided. A first substrate having a first bonding element and a second substrate having a second bonding element are provided, wherein at least one of the first bonding element and the second bonding element is formed with an alloy. A bonding process is performed to bond the first bonding element with the second bonding element, wherein a diffusion liner is generated at the exposed, non-bonded surface of the bonding structure.