Ionic Liquid Variable Capacitor for Fast Plasma Impedance Matching
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Solution Overview
Problem
Existing impedance matching systems in plasma processing apparatuses struggle with slow and inefficient control of electrostatic capacitance, which affects the matching speed and efficiency of radio-frequency power supply to the plasma processing chamber.
Innovation Solution
A variable capacitor using an ionic liquid held in a holder with DC and RF electrodes, allowing continuous and quick control of electrostatic capacitance by varying the direct-current voltage applied, enabling rapid adjustment to changing impedances in the plasma processing environment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional impedance matching systems are used, then the system structure is simple, but the electrostatic capacitance control speed is slow
Solution Approach 1:
The patent replaces conventional mechanical or electronic switching mechanisms with an ionic liquid-based electrochemical system. The ionic liquid undergoes electrochemical reactions when voltage is applied, causing rapid changes in electrostatic capacitance without mechanical moving parts, thereby achieving fast control speed while maintaining structural simplicity.
Solution Approach 2:
The patent changes the physical-chemical parameters of the ionic liquid by applying different voltages, which alters the electrostatic capacitance dynamically. This parameter-based control method enables continuous and rapid adjustment of capacitance values, resolving the contradiction between control speed and structural complexity.
2Productivity
If conventional capacitors are used, then the device structure is simple, but the impedance matching efficiency is low
Solution Approach 1:
The patent employs composite structure combining ionic liquid, electrodes, and holder components to create a variable capacitor with superior performance. The ionic liquid serves as the dielectric medium with unique electrochemical properties, while the electrode-ionic liquid interface enables dynamic capacitance adjustment, achieving high impedance matching efficiency through material composition rather than complex structure.
3Ease of operation
If discrete capacitor switching is used, then the control method is simple, but the capacitance adjustment is not continuous
Solution Approach 1:
The patent replaces discrete mechanical switching with continuous electrochemical control. By varying the applied voltage continuously, the ionic liquid's electrostatic capacitance changes smoothly without stepwise transitions, achieving continuous capacitance adjustment through electrochemical rather than mechanical means.
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 variable capacitor enables rapid and continuous adjustment of electrostatic capacitance, improving the matching speed of impedance matching circuits to accommodate varying impedances in the plasma processing apparatus, enhancing the efficiency of radio-frequency power supply.
Implementation Method 1
At least two second electrodes are provided on portions of the holder where electric double layers in the ionic liquid are formed when the direct-current voltage is applied to the first electrode
Data Source
AI summary
A variable capacitor includes a holder, at least one first electrode, and at least two second electrodes. The holder holds an ionic liquid, the at least one first electrode is provided in the holder, and receives either a positive or negative direct-current voltage and the at least two second electrodes are provided on portions of the holder where electric double layers in the ionic liquid are formed when the direct-current voltage is applied to the first electrode, and the at least two second electrodes supply a radio-frequency power via the holder.