Vacuum Plasma Anode Shielding for Stable DC Impedance
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Solution Overview
Problem
The deposition of solids with higher DC impedance on the anode surface during DC plasma discharge processes leads to unstable plasma discharge characteristics, reducing the reproducibility and homogeneity of surface treatments, especially in low voltage plasma discharges, and requires substantial anode heating which is inefficient and leads to rapid anode consumption.
Innovation Solution
A method involving a vacuum plasma source with a metal anode having cavities to generate a shielding plasma on selected areas, maintaining low and invariant DC impedance by shielding these areas from solid deposition, allowing for stable plasma discharge characteristics and flexible operation with different processing parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the anode surface is heated to prevent solid deposition, then the DC impedance stability is improved, but the anode consumption rate increases and processing efficiency decreases
Solution Approach 1:
A magnetic field is introduced as an intermediary to prevent solid deposition on the anode surface. The magnetic field confines plasma electrons through the Lorentz force, creating a protective barrier that prevents solid particles from reaching and depositing on the anode, thereby maintaining DC impedance stability without requiring thermal heating that would cause anode consumption.
Solution Approach 2:
The thermal heating mechanism is replaced with a magnetic field-based confinement mechanism. Instead of using thermal energy to prevent deposition (which causes anode consumption), the invention uses magnetic field forces to confine plasma and prevent solid deposition, achieving the same protective effect without the harmful thermal side effects.
2Reliability
If the anode surface is heated to maintain low DC impedance, then the plasma discharge stability is improved, but the processing time increases and energy efficiency decreases
Solution Approach 1:
A magnetic field is introduced as an intermediary to prevent solid deposition on the anode surface. The magnetic field confines plasma electrons through the Lorentz force, creating a protective barrier that prevents solid particles from reaching and depositing on the anode, thereby maintaining DC impedance stability without requiring thermal heating that would cause anode consumption.
Solution Approach 2:
The thermal heating mechanism is replaced with a magnetic field-based confinement mechanism. Instead of using thermal energy to prevent deposition (which causes anode consumption), the invention uses magnetic field forces to confine plasma and prevent solid deposition, achieving the same protective effect without the harmful thermal side effects.
3Reliability
If the anode surface is heated to prevent solid deposition, then the DC impedance is maintained, but the treatment homogeneity deteriorates due to inhomogeneous heating
Solution Approach 1:
The thermal heating mechanism is replaced with a magnetic field-based confinement mechanism. Instead of using thermal energy to prevent deposition (which causes anode consumption), the invention uses magnetic field forces to confine plasma and prevent solid deposition, achieving the same protective effect without the harmful thermal side effects.
Solution Approach 2:
The magnetic field is applied locally to the anode surface regions where solid deposition is most problematic. By configuring magnets or electromagnetic coils to generate concentrated magnetic fields at specific anode locations, the invention provides targeted protection against deposition while maintaining uniform plasma treatment across the entire surface, avoiding the inhomogeneous heating problems of thermal methods.
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 method ensures stable plasma discharge characteristics and extended anode surface life by preventing solid deposition on critical areas, maintaining low DC impedance and allowing for efficient and homogeneous surface treatment across varying processing conditions.
Implementation Method 1
establishing a shielding plasma on selected areas of the anode surface by means of a magnetic field
Implementation Method 2
an electric DC field and thus an electric DC voltage results in direction from the anode to the cathode
Implementation Method 3
The addressed problems in context with solid deposition are primarily encountered when operating respective physical vapour deposition PVD
Data Source
AI summary
When treating workpiece or substrate surfaces with the help of a vacuum plasma discharge between an anode (9) and an cathode (7= and whereby due to such treatment a solid (19) is formed and deposited on the anode surface (21), which solid has a higher specific DC impedance than the specific DC impedance of the anode material, at least parts of the anode surface are shielded from such deposition by establishing thereat a shielding plasma (25).