Dielectric Front Base Plasma Chamber for Thermal Stress Reduction

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Solution Overview

Problem

High-performance plasma devices face thermal and mechanical stress issues due to high microwave powers, leading to limited operational capacity and environmental concerns, as existing cooling methods are ineffective in managing heat distribution and chemical attacks on ceramic or glass discharge chambers.

Innovation Solution

A plasma device design featuring a dielectric gas discharge chamber with electromagnetic waves coupled selectively into a dielectric front base, allowing for even surface cooling and minimizing mechanical stress through controlled heat dissipation, using a coaxial line with coupling pins that reduce reflection and impedance jumps, and optionally incorporating inductive coupling or waveguide feeds.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If high microwave powers are used to generate plasma, then plasma generation efficiency is improved, but thermal load on the discharge chamber increases exponentially

Engineering Contradiction:
Improvemicrowave powerVSAvoidthermal load
Core Design Contradiction:
PowerVSTemperature

Solution Approach 1:

The discharge chamber is segmented into a front base (through which microwaves enter) and side walls (which form the discharge space). This segmentation allows selective cooling of the front base while the side walls are exposed to plasma, separating the thermal management function from the plasma generation function.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A coupling pin acts as an intermediary element, transmitting microwave energy from the waveguide into the front base of the discharge chamber. This intermediary structure manages the interface between the waveguide and discharge chamber, allowing controlled energy transfer while maintaining thermal management capabilities.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Temperature

If the discharge chamber is encased with water cooling devices, then cooling effectiveness is improved, but microwave penetration into the discharge chamber is prevented

Engineering Contradiction:
Improvecooling effectivenessVSAvoidmicrowave penetration
Core Design Contradiction:
TemperatureVSUse of energy by moving object

Solution Approach 1:

The discharge chamber is divided into a front base and side walls, with the front base being the only portion through which microwaves enter. This segmentation allows the front base to be cooled while maintaining microwave penetration, as the side walls forming the discharge space are not encased with cooling devices.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Cooling is applied locally to the front base rather than uniformly to the entire discharge chamber. The front base has cooling channels for heat dissipation, while the side walls are designed to be exposed to plasma for efficient cooling through plasma contact, creating different thermal management zones.

Inventive Principle:
Principle #3Local quality

3Object-affected harmful factors

If the discharge chamber is made of brittle ceramic or glass, then chemical attack resistance is improved, but mechanical stress from thermal loads causes cracks

Engineering Contradiction:
Improvechemical attack resistanceVSAvoidmechanical stress resistance
Core Design Contradiction:
Object-affected harmful factorsVSStrength

Solution Approach 1:

The discharge chamber is segmented into a front base and side walls, with the front base bearing the thermal load from microwave entry and the side walls forming the plasma-exposed discharge space. This segmentation allows the front base to be designed for thermal management while the side walls are optimized for chemical resistance and plasma interaction.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different portions of the discharge chamber have different material properties and cooling requirements. The front base is designed with cooling channels and is the entry point for microwaves, while the side walls are exposed to plasma for cooling and are optimized for chemical resistance. This local differentiation reduces overall mechanical stress.

Inventive Principle:
Principle #3Local quality

4Temperature

If cooling is applied to the discharge chamber, then thermal load management is improved, but uneven cooling causes large mechanical stresses

Engineering Contradiction:
Improvethermal load managementVSAvoidmechanical stress
Core Design Contradiction:
TemperatureVSStress or pressure

Solution Approach 1:

The discharge chamber is segmented into a front base and side walls, with the front base being the only portion through which microwaves enter and where cooling channels are located. The side walls are exposed to plasma for cooling. This segmentation creates a controlled thermal gradient that reduces uneven stress distribution compared to uniform cooling of the entire chamber.

Inventive Principle:
Principle #1Segmentation

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 solution enables high-power plasma generation with extended service life by evenly distributing heat and reducing mechanical stress, enhancing the environmental compatibility and productivity of plasma devices, particularly in semiconductor processes.

Implementation Method 1

electromagnetic waves can be coupled into the front base

Methodology Applied
Scientific EffectElectromagnetic wave coupling: Electromagnetic Induction

Implementation Method 2

generating excited and/or ionized particles in a plasma from a process gas

Methodology Applied
Scientific EffectPlasma generation: Plasma

Implementation Method 3

the dielectric forms a frontal base, from which side walls, which also consist of dielectric, extend to form the gas discharge space

Methodology Applied
Scientific EffectDielectric heating: Dielectric Heating

Data Source

PatentEP1819208B1Device and method for creating activated and/or ionised particles in a plasma
Publication Date: 2015.10.14 MUEGGE
  • EP1819208B1 patent drawingFigure 1~2
  • EP1819208B1 patent drawingFigure 3~4
  • EP1819208B1 patent drawingFigure 5~6

AI summary

The invention relates to a device for generating excited and/or ionized particles in a plasma from a process gas, comprising a generator for generating an electromagnetic wave, a waveguide, and a gas discharge chamber with a gas discharge space in which the excited and/or ionized particles are formed, and with a dielectric in which the gas discharge space is formed, wherein the gas discharge chamber is arranged within the waveguide. To enable the use of the highest possible microwave power while simultaneously achieving a long service life, the dielectric forms an end-face base from which side walls extend, forming the gas discharge space. Furthermore, the electromagnetic wave can be coupled into the end-face base.