Inductive Plasma Source with Magnetic Core for Low-Erosion Processing
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Solution Overview
Problem
Existing plasma processing apparatuses face challenges in generating inductively-coupled plasma efficiently due to high current requirements and material limitations, particularly with heat-resistant metals having high electrical resistivity, leading to wall surface erosion and particle generation, which existing capacitively-coupled plasma generation, and the use of capacitively-coupled plasma generation, which results in inefficient power supply and material degradation.
Innovation Solution
The apparatus employs a plasma generation mechanism with a discharge chamber having a loop-shaped internal space and a toroidal or rod-shaped magnetic core, along with a helically wound coil, using materials like Mn—Zn-based ferrite or nickel alloys to reduce excitation current and prevent magnetic flux leakage, enabling efficient inductively-coupled plasma generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If heat-resistant metals with high electrical resistivity are used for the antenna, then the antenna can withstand high temperatures, but the excitation current increases and magnetic flux leaks, causing wall surface erosion and particle generation
Solution Approach 1:
A magnetic core is introduced as an intermediary component between the antenna coil and the discharge chamber. The magnetic core concentrates and guides the magnetic flux generated by the antenna, preventing magnetic flux leakage that would otherwise cause wall surface erosion and particle generation. This allows the system to use heat-resistant materials without suffering from the harmful effects of magnetic flux leakage.
Solution Approach 2:
The patent changes the electrical and magnetic parameters of the antenna system by using materials with specific permeability and resistivity characteristics. By carefully selecting materials and designing the antenna structure, the system achieves optimal balance between heat resistance and electrical performance, reducing excitation current requirements while maintaining temperature withstand capability.
2Device complexity
If conventional capacitively-coupled plasma generation is used, then the apparatus structure is simpler, but power supply efficiency is low and material degradation occurs
Solution Approach 1:
The patent replaces the conventional capacitively-coupled plasma generation method with inductively-coupled plasma generation. This substitution uses electromagnetic induction through a coil and magnetic core instead of direct capacitive coupling, achieving superior power supply efficiency and plasma generation performance while maintaining practical apparatus complexity through optimized design.
3Quantity of substance
If high current is supplied to generate inductively-coupled plasma, then plasma density increases, but material degradation and wall erosion worsen
Solution Approach 1:
The magnetic core serves as a mediator that concentrates magnetic flux in the discharge chamber, enabling efficient plasma generation at lower excitation currents. This prevents the need for high current operation that would otherwise cause material degradation and wall erosion, while still achieving high plasma density through improved magnetic field utilization.
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
This configuration allows for higher plasma density and uniform radical distribution, preventing wall erosion and particle generation, while utilizing materials with high heat resistance and electrical resistivity, thus enhancing the plasma processing efficiency.
Implementation Method 1
an antenna that includes a magnetic core and a coil wound around the magnetic core, and generates an induced current in the discharge chamber
Data Source
AI summary
A plasma processing apparatus includes a processing container, a substrate holder that holds a substrate and accommodated inside the processing container, and a plasma generation mechanism that generates an inductively-coupled plasma. The plasma generation mechanism includes a discharge chamber having a loop shape, an antenna including a magnetic core and a coil wound around the magnetic core, the antenna generating an induced current in the discharge chamber, and a radio-frequency power supply that supplies radio-frequency power to the coil.