Coaxial Waveguide Plasma Generator for High Density Ionization
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Solution Overview
Problem
Conventional microwave plasma processing apparatuses face challenges in achieving high plasma density with a simplified structure and reduced manufacturing cost, as they often require complex designs and high electric power consumption, leading to uneven plasma formation and efficiency issues.
Innovation Solution
A microwave resonance plasma generating apparatus using a coaxial waveguide with an inner and outer electrode, where the outer electrode is shorter than the inner electrode, and a dielectric tube for insulation, operates with a magnetron at 2.45 GHz and less than 1 kW power, forming a plasma layer with high energy electrons and UV radiation to ionize gases efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a conventional ECR plasma processing apparatus uses an electromagnet to form a magnetic field for plasma generation, then plasma of high density can be obtained at relatively low pressure, but the electric power consumption increases significantly
Solution Approach 1:
The patent extracts and eliminates the electromagnet component from the plasma generation system. Instead of using an electromagnet to create a magnetic field for ECR plasma generation, the invention uses a simple waveguide structure that directs microwave energy to generate plasma without requiring a magnetic field, thereby removing the source of high power consumption
Solution Approach 2:
The patent replaces the electromagnetic field-based plasma generation mechanism (ECR requiring electromagnet) with a direct microwave heating mechanism. The waveguide structure directs microwave energy directly to the gas to generate plasma through dielectric heating, substituting the mechanical/electromagnetic field system with a simpler electromagnetic wave propagation system
2Quantity of substance
If a conventional ECR plasma processing apparatus uses multiple components including waveguide, horn antenna, and electromagnet, then plasma can be generated, but the structure becomes complicated and manufacturing cost increases
Solution Approach 1:
The patent merges multiple components (waveguide, horn antenna, and plasma generation chamber) into a single integrated waveguide structure. The waveguide itself serves as both the transmission medium and the plasma generation chamber, eliminating the need for separate horn antennas and complex positioning mechanisms
Solution Approach 2:
The waveguide structure performs multiple functions simultaneously: it transmits microwave energy, confines the electromagnetic field, and serves as the plasma generation chamber. This multi-functional design eliminates the need for separate dedicated components for each function, simplifying the overall system
3Productivity
If a conventional ECR plasma processing apparatus is designed for optimum ECR condition, then plasma producing efficiency is maximized, but process conditions become restricted and cannot be freely selected
Solution Approach 1:
The patent changes the fundamental operating parameters from ECR conditions (requiring specific magnetic field strength of about 875 Gauss) to microwave dielectric heating conditions. This parameter change allows operation at various microwave powers and pressures without being constrained by resonance conditions, providing flexibility in process condition selection while maintaining high plasma production efficiency
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 configuration enhances plasma density and efficiency while simplifying the apparatus structure and reducing manufacturing costs, allowing for flexible operation across various pressure ranges and applications, including plasma etching and deposition processes.
Implementation Method 1
the microwave can form a resonance mode in the resonance channel 15
Implementation Method 2
A microwave generating unit having an antenna which generates a microwave
Implementation Method 3
forming a plasma layer with high energy electrons and UV radiation to ionize gases efficiently
Implementation Method 4
The electrons to which the energy is applied collide against a gas in the resonance channel 15 to ionize the gas and thus to form plasma
Data Source
AI summary
A microwave resonance plasma generating apparatus, a plasma processing system having the same and a method of generating a microwave resonance plasma are provided. The apparatus includes a microwave generating unit which generates a microwave, and a plasma producing unit which produces electrons and photons of high energy using the microwave generated from the microwave generating unit. The plasma producing unit includes a coaxial waveguide having an inner electrode disposed adjacent to the microwave generating unit, an outer electrode connected to the microwave generating unit and disposed to coaxially surround a portion of the inner electrode, the outer electrode being shorter than the inner electrode, and a dielectric tube disposed between the inner electrode and the outer electrode to insulate between the inner electrode and the outer electrode. The coaxial waveguide utilizes a principle of “cut or truncated electrode of coaxial waveguide” and a resonance phenomenon of Langmiur.