Plasma Processing Member Impedance Control for High Frequency Uniformity
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Solution Overview
Problem
Conventional plasma processing members with a plasma generating electrode embedded in a ceramic base fail to generate plasma uniformly when high-frequency power exceeding 13.56 MHz is used, due to impedance mismatch between the plasma processing member and the reaction vessel, leading to nonuniform plasma generation in unintended areas.
Innovation Solution
A plasma processing member with an electrode power supply member connected to the plasma generating electrode, reducing the impedance to 25Ω or less by adjusting the inductance and dimensions of the electrode power supply member, ensuring uniform plasma generation between the upper electrode and the plasma processing member even at higher frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the frequency of high frequency power is increased to exceed 13.56 MHz, then plasma generation efficiency is improved, but plasma is nonuniformly generated in unintended areas due to impedance mismatch
Solution Approach 1:
The patent changes the electrical parameter (impedance) of the plasma processing member by modifying its structural parameters (conductive layer thickness, pattern, or material properties). This parameter adjustment ensures that the impedance remains lower than the reaction vessel impedance even at high frequencies exceeding 13.56 MHz, thereby maintaining both plasma generation efficiency and positional accuracy.
2Manufacturing precision
If the distance between the wall of the reaction vessel and the upper electrode or plasma processing member is increased to increase impedance, then plasma generation uniformity is improved, but the reaction vessel size increases and manufacturing efficiency decreases
Solution Approach 1:
Instead of changing the spatial parameter (distance), the patent changes the electrical parameter (impedance) by modifying the conductive layer properties in the plasma processing member. This allows achieving the desired impedance mismatch for uniform plasma generation without increasing the reaction vessel size, thereby maintaining high manufacturing efficiency.
3Manufacturing precision
If the impedance of the plasma processing member is reduced to ensure proper plasma generation at high frequency, then plasma generation uniformity is improved, but the inductance of the electrode power supply member must be precisely controlled
Solution Approach 1:
The patent provides specific parameter ranges for the conductive layer (thickness, pattern, material) that directly control the impedance. By optimizing these parameters, the inductance of the electrode power supply member is controlled to ensure proper plasma generation at high frequencies, balancing performance with design feasibility.
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 solution allows for consistent and uniform plasma generation between the upper electrode and the plasma processing member at frequencies higher than 13.56 MHz, preventing plasma generation in unintended areas and maintaining apparatus miniaturization without increasing the reaction vessel size.
Implementation Method 1
The plasma processing member generates plasma between the plasma processing member and an upper electrode placed in a reaction vessel. The upper electrode is supplied with high frequency power at 13.56 MHz.
Implementation Method 2
A plasma processing member with an electrode power supply member connected to the plasma generating electrode, reducing the impedance to 25Ω or less by adjusting the inductance and dimensions of the electrode power supply member
Data Source
AI summary
A plasma processing member includes a ceramic base, a plasma generating electrode embedded in the ceramic base, and an electrode power supply member connected to the plasma generating electrode. The impedance of the plasma processing member when plasma is generated using high frequency power at a frequency higher than 13.56 MHz is adjusted to 25Ω or less.