Coaxial Waveguide Plasma Device With Adjustable Stubs
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Solution Overview
Problem
Existing plasma devices with coaxial waveguides struggle to control the distribution of microwave power to multiple rods, leading to non-uniform plasma generation due to positional displacement of the inner conductor, which affects the intensity and uniformity of the microwave field.
Innovation Solution
A plasma device with a coaxial waveguide featuring branching sections and conductive stubs that can be inserted or removed to adjust the gap between the inner and outer conductors, allowing for controlled distribution of microwave power to center and edge rods, thereby regulating the plasma generation rate and uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the inner conductor is positionally displaced with respect to the center of the outer conductor, then the structure is simpler, but the microwave intensity becomes nonuniform
Solution Approach 1:
The patent applies local quality by providing different gap widths at different radial positions. Specifically, the gap between the inner conductor and outer conductor is made nonuniform, with a first gap width in a first radial direction and a second gap width in a second radial direction. This local variation in gap width compensates for the positional displacement of the inner conductor, ensuring uniform microwave intensity distribution across the plasma generation region despite the simplified asymmetric structure.
2Manufacturing precision
If a stub member is provided to relieve adverse effects, then the microwave intensity uniformity is improved, but the device complexity increases
Solution Approach 1:
The patent merges the function of the stub member into the gap structure itself. Instead of adding a separate stub component to adjust for displacement, the gap between the inner and outer conductors is designed with different widths at different radial positions. This integrated approach achieves the same microwave intensity uniformity effect as a stub member would provide, but without the additional structural complexity of a separate adjustable component.
3Productivity
If multiple rods are used to generate plasma, then the plasma generation capability is improved, but the control over microwave power distribution to each rod is lost
Solution Approach 1:
The patent applies local quality by positioning the multiple rods at different radial locations where they experience different microwave field intensities due to the nonuniform gap structure. The rods are strategically placed in regions with different gap widths, allowing each rod to receive an appropriate amount of microwave power for plasma generation. This enables effective plasma generation across multiple rods while maintaining control over the power distribution through the designed gap geometry.
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 adjustable stubs enable precise control over the plasma distribution, improving the uniformity of the electric field intensities and plasma density, enhancing the consistency of substrate treatment processes such as film formation and etching.
Implementation Method 1
a microwave is provided from the coaxial waveguide into the dielectric. That is, the microwave introduced from a microwave introduction part of the coaxial waveguide is transmitted through a branch structure of the coaxial waveguide
Implementation Method 2
An electric field that is generated through the dielectrics of the rods causes plasma to be generated
Data Source
AI summary
Examples of a plasma device includes a coaxial waveguide having an inner conductor and an outer conductor enclosing the inner conductor with a first gap provided between the outer conductor and the inner conductor, the coaxial waveguide having a shape of branching at a plurality of branch parts, a plurality of rods having a conductor and a dielectric enclosing the conductor with a second gap provided between the dielectric and the conductor, the plurality of rods connecting two end parts of the coaxial waveguide branched at the branch parts, so as to connect the first gap and the second gap, and a conductive stub provided at a branched portion, obtained by branching at the branch parts, of the coaxial waveguide, the conductive stub being insertable to and removable from the first gap.