PVD Target Non-Reactive Cap Layer Oxidation Prevention

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Solution Overview

Problem

Highly reactive physical vapor deposition (PVD) targets, such as Magnesium Oxide (MgO) and Lanthanum (La), quickly absorb water or oxidize when exposed to air, requiring a lengthy burn-in time for cleanup, which reduces tool utilization and affects coating purity and consistency.

Innovation Solution

A PVD target with a non-reactive cap layer, such as titanium oxide (TiO2) or aluminum oxide (Al2O3), is used to protect the reactive source material from oxidation, allowing for a sacrificial cap to be formed and removed in an oxygen-free environment, reducing the need for extensive cleanup processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a highly reactive PVD target is exposed to air for installation and operation, then the target can be easily handled and installed, but the target quickly absorbs water or oxidizes, requiring lengthy clean-up time

Engineering Contradiction:

Improveease of handling and installationVSAvoidclean-up time

Core Design Contradiction:

Ease of operationVSLoss of time

Solution Approach 1:

A non-reactive cap layer is pre-formed on the highly reactive PVD target surface before the target is exposed to air. This preliminary protective action prevents oxidation and water absorption during handling, installation, and storage, eliminating the need for lengthy clean-up processes while maintaining ease of operation

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

A non-reactive intermediate layer (cap layer) is introduced between the highly reactive target material and the oxygen-containing atmosphere. This intermediary layer acts as a barrier that prevents direct contact between reactive species and air, allowing the target to be handled freely without oxidation

Inventive Principle:

Principle #24Intermediary (Mediator)

2Manufacturing precision

If a lengthy clean-up process is performed to remove oxidation and water from the target surface, then high purity coatings can be achieved, but tool utilization is significantly reduced

Engineering Contradiction:

Improvecoating purityVSAvoidtool utilization

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The non-reactive cap layer is formed in advance to prevent oxidation and water absorption before they occur. By performing the protective action preliminarily rather than requiring corrective clean-up afterward, the system achieves both high coating purity and maximum tool utilization

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The potentially harmful oxidation and water absorption processes are converted into a beneficial preventive measure. The cap layer undergoes controlled formation (in some cases deliberate oxidation) to create a protective barrier that prevents further degradation, transforming what would be a harmful process into a protective mechanism

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Manufacturing precision

If the target is kept in an oxygen-free environment to prevent oxidation, then coating quality is maintained, but the complexity of the system increases

Engineering Contradiction:

Improvecoating quality consistencyVSAvoidsystem complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

Instead of requiring complex oxygen-free environments, a simple non-reactive cap layer serves as an intermediary barrier. This passive protective layer maintains coating quality consistency through straightforward handling and installation procedures without necessitating elaborate environmental controls

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The cap layer acts as a disposable protective element that can be easily handled and installed. Its temporary nature allows for simple handling procedures while the layer performs its protective function, after which it is removed during the deposition process without affecting the final coating quality

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

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 significantly reduces the clean-up time needed for PVD targets, enhancing tool utilization and ensuring high-purity, consistent coatings by preventing oxygen and water absorption, thus improving the manufacturing process for electrical devices.

Implementation Method 1

The non-reactive cap layer is a barrier obstructing the diffusion of oxygen containing species to the body of the PVD target

Methodology Applied

Scientific EffectDiffusion barrier: Diffusion Barrier

Implementation Method 2

By protecting the body of the target from being exposed to oxygen, the sacrificial non-reactive cap limits the absorption of oxygen and water by the body of the target

Methodology Applied

Scientific EffectAbsorption: Absorption (physical)

Implementation Method 3

bombarding the non-reactive cap layer of the PVD target with first energetic particles to remove the non-reactive cap layer

Methodology Applied

Scientific EffectSputtering: Sputtering

Data Source

PatentUS11299801B2Structure and method to fabricate highly reactive physical vapor deposition target

Publication Date: 2022.04.12 INTERNATIONAL BUSINESS MACHINE CORPORATION

AI summary

A physical vapor deposition (PVD) target that includes a body composed of material that is reactive with an oxygen containing atmosphere; and a non-reactive cap layer encapsulating at least a sputter surface of the body. The non-reactive cap layer is a barrier obstructing the diffusion of oxygen containing species to the body of the PVD target.