Microwave Plasma Device Microstrip Line Gas Flow Control

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Solution Overview

Problem

Conventional plasma processing techniques face challenges in generating stable, wide-width plasma jets under intermediate and high pressures, requiring expensive high-vacuum devices and struggling with electrode deterioration, filamentous discharge, and difficulty in upsizing plasma generators.

Innovation Solution

A microwave plasma processing device with a dielectric substrate, microstrip line, and ground conductor configuration that includes a tapered portion, gas flow widening portion, and nozzle to generate plasma under varying pressures, using a microstrip line for efficient microwave power transmission and gas flow management.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If a conventional waveguide is used for microwave transmission, then microwave power can be transmitted, but the device size and cost increase

Engineering Contradiction:
Improvemicrowave power transmissionVSAvoiddevice size
Core Design Contradiction:
PowerVSArea of stationary object

Solution Approach 1:

The patent extracts the microwave transmission function from the conventional waveguide structure and implements it using a microstrip line configuration. The microstrip line consists of a signal conductor and ground conductor separated by a dielectric substrate, which provides the necessary microwave transmission capability while occupying significantly less space than a traditional waveguide structure.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent employs a thin dielectric substrate to support the microstrip line configuration. This thin-film approach enables compact microwave transmission, replacing the bulky metal waveguide with a planar structure that achieves the same electromagnetic wave guidance function with minimal thickness and area.

Inventive Principle:
Principle #30Flexible shells and thin films

2Power

If a conventional waveguide is used for microwave transmission, then microwave power can be transmitted, but manufacturing cost increases

Engineering Contradiction:
Improvemicrowave power transmissionVSAvoidmanufacturing cost
Core Design Contradiction:
PowerVSEase of manufacture

Solution Approach 1:

The patent extracts the microwave transmission function from the expensive conventional waveguide and implements it using a microstrip line configuration. The microstrip line consists of a signal conductor and ground conductor separated by a dielectric substrate, which provides the necessary microwave transmission capability while occupying significantly less space than a traditional waveguide structure.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the expensive, complex waveguide structure with a simpler, cheaper microstrip line configuration that can be manufactured using standard PCB fabrication techniques. The dielectric substrate and conductor layers can be produced cost-effectively through conventional printing and lamination processes, making the overall device more economical.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Power

If DC arc discharge or DC pulse discharge is used to generate plasma jet, then plasma can be generated, but electrode deterioration occurs

Engineering Contradiction:
Improveplasma generationVSAvoidelectrode life
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The patent replaces the mechanical contact-based DC arc discharge or DC pulse discharge method with a microwave-induced plasma generation method. By using electromagnetic fields at microwave frequency to excite the gas and generate plasma, the invention eliminates the need for physical electrodes, thereby avoiding electrode deterioration and extending system reliability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces microwave electromagnetic fields as an intermediary to generate plasma without direct electrode contact. The microwave energy couples to the gas molecules, causing ionization and plasma formation through electromagnetic interaction rather than direct electrical contact, thus preventing electrode wear and contamination.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Power

If dielectric barrier discharge is used to generate plasma jet, then plasma can be generated, but filamentous discharge occurs and high-density radicals cannot be generated

Engineering Contradiction:
Improveplasma generationVSAvoiddischarge uniformity
Core Design Contradiction:
PowerVSStability of the object's composition

Solution Approach 1:

The patent replaces the dielectric barrier discharge method with microwave-induced plasma generation. The microwave electromagnetic fields provide uniform energy distribution throughout the gas volume, creating a stable and uniform plasma without the filamentous discharge patterns characteristic of dielectric barrier discharge. This results in consistent plasma properties and uniform radical generation.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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

Stably generates wide-width plasma jets under low, intermediate, and high pressures, enabling large-area surface processing, such as etching, ashing, and CVD, with reduced operational costs and increased efficiency.

Implementation Method 1

generation of a plasma jet through microwave discharge provides following advantages

Methodology Applied
Scientific EffectMicrowave discharge: Electromagnetic Induction

Implementation Method 2

configured to generate plasma with microwave power

Methodology Applied
Scientific EffectPlasma: Plasma

Implementation Method 3

a microstrip line for microwave power transmission

Methodology Applied
Scientific EffectMicrowave power transmission: Electromagnetic Induction

Implementation Method 4

a gas flow widening portion configured to supply a wide-width gas flow having a uniform flow velocity

Methodology Applied
Scientific EffectGas flow: Convection

Data Source

PatentEP3041324B1Microwave plasma processing device
Publication Date: 2020.05.13 NATIONAL INSTITUTE OF ADVANCED INDUSTRIAL SCIENCE & TECHNOLOGY
  • EP3041324B1 patent drawingFigure 1~2
  • EP3041324B1 patent drawingFigure 3~4
  • EP3041324B1 patent drawingFigure 5~6

AI summary

To provide microwave excitation plasma processing device capable of generating wide-width plasma jet having high uniformity, high density, and low temperature even under intermediate pressure and high pressure. The microwave plasma processing device includes: dielectric substrate; tapered portion provided in one end portion of the dielectric substrate, the tapered portion being shaped so that thickness of the dielectric substrate becomes gradually smaller; microstrip line; ground conductor; microwave input portion; gas input port configured to input gas into the dielectric substrate; plasma generating portion; gas flow widening portion provided inside the dielectric substrate and configured to supply wide-width gas flow having uniform flow velocity to the plasma generating portion, the gas flow widening portion being formed to make a gas flow width wider as the gas flow advances; gas flow channel configured to supply the gas to the gas flow widening portion; and nozzle for blowing plasma.