Inverted Toroidal Plasma Source for Low-Recombination Radical Cleaning
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Solution Overview
Problem
Conventional toroidal plasma sources face challenges in efficiently delivering reactive radicals for cleaning due to recombination losses, requiring high power and cooling, and are large and difficult to ignite, limiting their cleaning efficiency and applicability in targeted cleaning applications.
Innovation Solution
A compact, inverted toroidal plasma source with a plasma source body comprising magnetic cores, primary windings, and a cooling structure, featuring a dielectric material and electrode for dielectric barrier discharge ignition, which forms a plasma around the outer portion of the source, minimizing recombination and power requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional toroidal plasma sources are used to generate reactive radicals, then high power densities can be achieved, but recombination losses increase significantly before radicals reach the cleaning target
Solution Approach 1:
The patent inverts the conventional plasma source configuration by placing the plasma generation region outside the vacuum chamber rather than inside. This inversion minimizes the transport distance for reactive radicals and eliminates the need for long transport tubes where recombination occurs, directly addressing the contradiction between achieving high power density and minimizing radical recombination losses
Solution Approach 2:
The plasma source is extracted from the vacuum chamber environment and positioned externally. This extraction removes the plasma source from the confined space inside the chamber, allowing radicals to be generated closer to the cleaning target and reducing the path length through which radicals must travel, thereby minimizing recombination losses while maintaining high power density
2Quantity of substance
If higher flow rates are used to increase reactive radical flux, then more radicals are generated, but pressure increases which further increases recombination losses
Solution Approach 1:
By inverting the plasma source configuration and placing it externally, the system eliminates the need for long transport tubes that cause pressure buildup. This allows higher flow rates to be used without proportionally increasing pressure and recombination losses, as the radicals are generated much closer to the cleaning target
Solution Approach 2:
The patent introduces a direct coupling mechanism between the plasma source and the cleaning target area, eliminating the need for long transport tubes that act as intermediaries causing pressure buildup and recombination. The radicals are delivered directly to the cleaning zone, breaking the relationship between flow rate and pressure increase
3Quantity of substance
If larger plasma source size is used, then more radicals can be generated, but loop voltage requirements increase and core heating increases
Solution Approach 1:
The plasma source is extracted from the vacuum chamber and reconfigured in an inverted geometry. This extraction allows for a more efficient magnetic coupling design that reduces loop voltage requirements while maintaining high radical generation rates, and improves cooling efficiency to reduce core heating
Solution Approach 2:
The patent changes the geometric configuration from a conventional internal toroidal design to an external inverted design. This dimensional reconfiguration optimizes the magnetic field coupling and allows for more efficient power transfer, reducing loop voltage requirements while maintaining high radical generation capability
4Reliability
If conventional toroidal plasma sources are used, then plasma can be generated, but ignition is difficult and substantial power is required
Solution Approach 1:
The inverted configuration places the plasma generation region outside the vacuum chamber where ignition can occur more readily. This geometric inversion improves the magnetic field coupling efficiency and reduces the power required for ignition while maintaining reliable plasma generation
Solution Approach 2:
The patent changes the geometric parameters of the plasma source configuration from conventional to inverted. This parameter change optimizes the magnetic field distribution and coupling, reducing the ignition power requirement while maintaining stable plasma generation
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 compact design reduces radical recombination and power needs, enabling efficient radical delivery for cleaning applications, such as lower chamber, foreline, and point-of-use cleaning, with high power density and robust ignition capabilities.
Implementation Method 1
when the plurality of primary windings are energized, a plasma forms around an outer portion of the plasma source body
Implementation Method 2
an electrode capable of forming a dielectric barrier discharge for ignition
Implementation Method 3
a cooling structure
Data Source
AI summary
A plasma source, comprising a plasma source body, comprising: a plurality of magnetic cores, a plurality of primary windings capable of being energized, and a cooling structure, wherein one or more sections of the plasma source body comprising a dielectric material, and wherein, when the plurality of primary windings are energized, a plasma forms around an outer portion of the plasma source body.