RF Plasma Vacuum Coating for Filling High-Aspect-Ratio Indentations

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Solution Overview

Problem

Vacuum-process coating of substrates with indentations such as pinholes, vias, and trenches poses challenges in ensuring complete coverage without leaving hollow spaces, as existing methods like sputter deposition and HIPIMS-sputtering face limitations in directional control and efficiency.

Innovation Solution

A vacuum layer deposition apparatus utilizing an Rf plasma source with a larger second electrode surface relative to a first electrode surface, generating a directional acceleration of positively charged particles towards the substrate, combined with a substrate holder on ground potential to avoid arcing and facilitate efficient coating of indentations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If sputter deposition with RF bias is used to coat substrates with indentations, then coating coverage is improved, but directional control and coating efficiency deteriorate

Engineering Contradiction:

Improvecoating coverageVSAvoidcoating efficiency

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The invention changes the electrical parameters by operating the substrate holder at ground potential instead of negative bias, and uses RF-powered plasma to generate positive ion flux. This parameter change enables both complete coverage of indentations and high coating efficiency through enhanced directional transport of positively charged particles.

Inventive Principle:

Principle #35Parameter changes

2Manufacturing precision

If HIPIMS-sputtering with pulsed DC is used to coat substrates with indentations, then coating coverage is improved, but directional control and efficiency deteriorate

Engineering Contradiction:

Improvecoating coverageVSAvoidcoating efficiency

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

Inventive Principle:

Principle #35Parameter changes

3Manufacturing precision

If substrate holder is biased negatively to attract positive ions, then coating coverage of indentations is improved, but arcing occurs and process stability deteriorates

Engineering Contradiction:

Improvecoating coverageVSAvoidprocess stability

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The invention inverts the conventional approach by operating the substrate holder at ground potential instead of negative bias. This inversion eliminates arcing while still achieving complete coverage of indentations through RF-powered positive ion generation and directional acceleration.

Inventive Principle:

Principle #13The other way round (Inversion)

4Device complexity

If conventional plasma deposition is used, then coating process is simple, but directional control of particles deteriorates

Engineering Contradiction:

Improveprocess simplicityVSAvoiddirectional control

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The invention introduces RF-powered plasma generation while maintaining the substrate holder at ground potential. This parameter change enhances directional control of positively charged particles through electric field acceleration without significantly increasing device complexity, as it utilizes standard RF power supplies and plasma generation techniques.

Inventive Principle:

Principle #35Parameter changes

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 apparatus effectively coats indentations by directing positively charged particles to fill them completely, avoiding hollow spaces and enhancing coating efficiency, particularly for substrates with high aspect ratios.

Implementation Method 1

an Rf plasma source which comprises: a first electrode electrically operationally Rf-connectable or electrically operationally Rf-connected to a first tap of a Rf generator; a second electrode electrically operationally Rf-connectable or electrically operationally Rf-connected to a second tap of the Rf-generator

Methodology Applied

Scientific EffectRf plasma: Plasma

Implementation Method 2

generating a directional acceleration of positively charged particles towards the substrate

Methodology Applied

Scientific EffectDirectional acceleration of positively charged particles: Electric Field

Implementation Method 3

Vacuum layer deposition apparatus and method of depositing a layer on a substrate

Methodology Applied

Scientific EffectVacuum layer deposition: Physical Vapour Deposition

Data Source

PatentUS12595550B2Vacuum layer deposition apparatus and method of depositing a layer on a substrate, especially on a substrate comprising indentations in the surface to be coated

Publication Date: 2026.04.07 EVATEC AG

AI summary

A vacuum layer deposition apparatus includes a vacuum coating chamber with an inner space; a material source to generate electrically positively charged particles of a material to be deposited on a substrate in said inner space; a substrate holder with an extended metal or dielectric material surface exposed to said inner space; and a Rf plasma source comprising: first and second electrodes Rf-connectable or Rf-connected to first and second taps of a Rf generator, respectively. Said first and second electrodes include first and second electrode surfaces, respectively, of metal or of a dielectric material which are freely exposed to said inner space. Said extended surface of said substrate holder is at least a part of said first electrode surface and said second electrode surface is larger than said first electrode surface by at least a factor of 1.5. A method includes vacuum-process depositing a layer on a substrate.