Coaxial Coil Filter Layout for Plasma HF Wave Blocking
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Solution Overview
Problem
In plasma processing apparatuses, the limited space under the chamber main body poses a challenge for disposing filters that block or attenuate high-frequency waves, leading to decreased impedance due to stray capacitance.
Innovation Solution
A filter device comprising multiple coils and capacitors, where the coils are arranged in coil groups with spirally extending windings and sequentially arranged turns, are provided coaxially to share a central axis, minimizing space occupation and maintaining impedance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If filters are disposed in the limited space under the chamber main body, then high-frequency wave blocking function is achieved, but impedance decreases due to stray capacitance
Solution Approach 1:
The patent applies nesting by placing multiple coils coaxially one inside another, with inner coils nested within outer coils. This nested arrangement allows multiple filter elements to occupy minimal space under the chamber main body while maintaining proper electrical isolation through insulating structures, thereby achieving high-frequency wave blocking without significant impedance degradation from stray capacitance.
Solution Approach 2:
The patent transitions from a planar arrangement to a three-dimensional coaxial configuration. By arranging coils in the radial and axial dimensions rather than simply side-by-side in a plane, the design achieves compact space utilization while controlling stray capacitance through vertical stacking and radial positioning, resolving the contradiction between space constraints and impedance maintenance.
2Object-affected harmful factors
If multiple filters are provided to block high-frequency waves, then filtering effectiveness is improved, but device complexity increases
Solution Approach 1:
The patent merges multiple filter functions into a single integrated structure. Instead of providing separate filter assemblies that would increase complexity, multiple coils are combined in a coaxial arrangement within a unified structure, sharing common support elements and insulating structures. This merging achieves effective high-frequency wave blocking across multiple frequencies while reducing overall structural complexity.
Solution Approach 2:
The coaxial coil structure serves multiple functions simultaneously: it provides high-frequency wave blocking, maintains impedance control, occupies minimal space, and provides structural support for the filter assembly. This multi-functionality reduces the need for separate components, thereby decreasing device complexity while achieving effective filtering.
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 filter device effectively inhibits the introduction of high-frequency waves into the heater controller, maintains impedance, and allows for the compact disposition of coils, addressing the space constraints and impedance issues in plasma processing apparatuses.
Implementation Method 1
Each of the plurality of filters has a plurality of resonant frequencies. The coils of the plurality of filters are provided directly under the chamber main body of the plasma processing apparatus.
Implementation Method 2
filters for blocking or attenuating the high-frequency wave are provided in the plurality of power supply lines, respectively
Implementation Method 3
The plurality of capacitors are connected between the plurality of coils and the ground
Data Source
AI summary
Provided is a filter device includes: a first coil group including a plurality of coils arranged along a central axis and spirally wound with a first inner diameter; and a second coil group including a plurality of coils arranged along the central axis and spirally wound with a second inner diameter larger than the first inner diameter. A pitch between respective turns of the plurality of coils of the second coil group is larger than a pitch between respective turns of the plurality of coils of the first coil group.