Plasma Electrode Balun Ground Inductor for In-Phase Current Suppression
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Solution Overview
Problem
Existing plasma processing apparatuses face challenges in reducing in-phase current without increasing the size of the balun, particularly when plasma density is low due to low pressure, large electrode distances, small electrode areas, or low frequency, leading to increased impedance and the need for larger windings or cores.
Innovation Solution
Incorporating a connection unit with an inductor to electrically connect the vacuum container and ground, which suppresses AC current and reduces in-phase current without enlarging the balun, while maintaining high isolation performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the reactance X of the balun winding is increased to reduce in-phase current, then the isolation performance is improved, but the size of the balun increases
Solution Approach 1:
The patent introduces a ground connection unit as an intermediary element between the vacuum container and ground. This unit includes a capacitor connected between the vacuum container and ground, and an inductor connected between the capacitor and ground. The ground connection unit acts as a mediator to suppress in-phase current without requiring the balun to be enlarged, thus resolving the contradiction between isolation performance and balun size.
Solution Approach 2:
The patent extracts the in-phase current suppression function from the balun structure itself and relocates it to a separate ground connection unit. By taking out the current suppression function and implementing it through the capacitor-inductor network connected to ground, the balun can maintain its original size while achieving the desired isolation performance.
2Object-generated harmful factors
If the number of turns of the balun winding is increased to increase reactance, then the in-phase current is reduced, but the manufacturing complexity increases
Solution Approach 1:
The ground connection unit with capacitor and inductor serves as an intermediary system that suppresses in-phase current without requiring modifications to the balun winding. This approach avoids the manufacturing complexity associated with increasing the number of turns while effectively reducing harmful in-phase current.
Solution Approach 2:
Instead of changing the physical parameters of the balun (number of turns, wire gauge), the patent changes the electrical parameters of the overall system by introducing the capacitor-inductor network. This parameter change approach suppresses in-phase current through reactive impedance matching rather than through increased winding complexity.
3Object-generated harmful factors
If the size of the toroidal core is increased to increase reactance, then the in-phase current is reduced, but the volume of the balun increases
Solution Approach 1:
The ground connection unit acts as a mediator that handles the in-phase current suppression function externally, eliminating the need to increase the toroidal core size. The capacitor and inductor in the ground connection unit provide the necessary reactive impedance to suppress in-phase current while keeping the balun volume compact.
Solution Approach 2:
The patent moves the current suppression function from the horizontal dimension (balun core size) to the vertical dimension (ground connection path). By introducing the capacitor-inductor network connected to ground, the system suppresses in-phase current through a different dimensional approach, avoiding volume increase in the balun.
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
Stabilizes plasma potential over time by reducing sensitivity to vacuum container surface conditions and facilitates plasma ignition, ensuring consistent operation without enlarging the balun.
Implementation Method 1
a connection unit configured to electrically connect the vacuum container and ground, the connection unit including an inductor
Implementation Method 2
generates plasma by applying a high frequency between two electrodes
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3B
AI summary
A plasma processing apparatus includes a balun having a first input terminal, a second input terminal, a first output terminal, and a second output terminal, a vacuum container, a first electrode electrically connected to the first output terminal, a second electrode electrically connected to the second output terminal, and a connection unit configured to electrically connect the vacuum container and the second input terminal, the connection unit including an inductor.