Dielectric Barrier Plasma Source for High-Conductance Vacuum Cleaning
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Solution Overview
Problem
Existing plasma generators are inefficient in cleaning vacuum systems due to non-uniform discharge current density, limited conductance, manufacturing complexity, and difficulty in scaling to larger sizes, leading to issues like valve wear and clogging in semiconductor manufacturing processes.
Innovation Solution
A capacitively-coupled plasma source with a dielectric barrier discharge structure, featuring a supply electrode, return electrode, and barrier dielectric material, capable of generating localized plasmas within vacuum components, such as cylindrical or rectangular geometries, to maintain high conductance and unrestricted gas flow, and is scalable for various sizes and geometries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cylindrical plasma sources are used for valve cleaning, then plasma generation capability is achieved, but device complexity and manufacturing difficulty increase due to ceramic fabrication limitations
Solution Approach 1:
The plasma source is divided into modular components: a body portion with discharge regions, a coupling portion for connection, and removable electrode assemblies. This segmentation allows independent fabrication and assembly of complex parts, reducing overall manufacturing difficulty while maintaining cleaning effectiveness.
Solution Approach 2:
The electrode structures are nested within the dielectric material, with conductive elements embedded in cavities or channels of the dielectric body. This nested configuration achieves complex plasma generation geometry without requiring complex external structures, simplifying fabrication.
2Reliability
If plasma sources with labyrinth structures are used, then plasma generation is achieved, but conductance is reduced due to limited line of sight between input and output ports
Solution Approach 1:
The plasma source separates plasma generation functions (in discharge regions) from gas flow pathways (through body channels). This segmentation allows the gas flow path to remain open and direct while plasma is generated in localized regions, maintaining high conductance without compromising plasma generation.
Solution Approach 2:
Plasma generation is localized to specific discharge regions with dielectric barriers, while the majority of the internal volume provides unobstructed gas flow paths. This local concentration of plasma generation maintains conductance by avoiding labyrinthine structures throughout the entire device.
3Reliability
If inductive coupling is used for plasma generation, then plasma is produced, but ignition difficulty increases
Solution Approach 1:
The patent replaces inductive coupling (electromagnetic field-based) with capacitive coupling using dielectric barriers and electrode structures. This substitution changes the plasma ignition mechanism from requiring strong time-varying magnetic fields to using direct electric field breakdown across dielectric barriers, which is easier to initiate and control.
Solution Approach 2:
Dielectric barrier materials serve as intermediaries between electrodes and the plasma discharge region. These dielectric layers enable controlled electric field distribution that facilitates reliable plasma ignition and sustenance without the complexity of inductive coupling systems.
4Reliability
If remote plasma sources are used for foreline cleaning, then plasma treatment is achieved, but cleaning effectiveness is reduced due to insufficient proximity to valves
Solution Approach 1:
The plasma source concentrates discharge regions directly at or near the valve interface locations that require cleaning. This localized plasma generation ensures high-density plasma exposure exactly where deposition occurs, maximizing cleaning precision and effectiveness rather than using remote diffuse plasma treatment.
Solution Approach 2:
The plasma source is positioned and configured to treat valve surfaces before they become heavily contaminated. By placing discharge regions in direct contact with or adjacent to valve surfaces, the system performs preventive cleaning during regular operation, maintaining valve performance before significant deposition accumulates.
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 plasma source effectively extends the life of vacuum components by uniformly distributing discharge current, reducing erosion, maintaining full pumping speed, and preventing clogging, while being easily integratable into different vacuum systems.
Implementation Method 1
A capacitively-coupled plasma source with a dielectric barrier discharge structure
Implementation Method 2
capacitively-coupled plasma source with a dielectric barrier discharge structure, featuring a supply electrode, return electrode, and barrier dielectric material
Implementation Method 3
uniformly distributing discharge current, reducing erosion
Data Source
AI summary
A plasma source is provided that is configured to form a section of a wall of a vacuum component. The plasma source comprises a body including a dielectric member, a first surface exposed to an exterior region of the vacuum component, and a second surface exposed to an interior region of the vacuum component. The plasma source also comprises at least one electrode disposed in a receiving channel of the body with at least a portion of the dielectric member located adjacent to the at least one electrode in the receiving channel. The plasma source further comprise at least one discharge region adjacent to the receiving channel within the body. The at least one discharge region is exposed to the interior region of the vacuum component via an opening on the second surface of the body.