Plasma Processing Electromagnet With Ferrofluid Magnetic Field Control
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Solution Overview
Problem
Conventional substrate processing apparatuses using plasma face challenges in achieving uniform plasma density distribution and precise magnetic field control due to heat generation and magnetization issues in electromagnets, leading to inefficient processing.
Innovation Solution
Incorporation of a ferrofluid reservoir between electromagnet coils to manage magnetic field generation and heat, allowing for precise control of plasma density and reducing the need for demagnetization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If current is increased to generate desired magnetic field, then magnetic field strength is improved, but heat generation in coil increases
Solution Approach 1:
The patent introduces ferrofluid as an intermediary substance between the coil and the magnetic field generation process. The ferrofluid is supplied to the coil to enhance magnetic field strength without requiring increased current, thereby preventing heat generation in the coil while achieving the desired magnetic field intensity for plasma density control.
2Force
If magnetic substance is placed adjacent to electromagnet to reduce magnetic resistance, then magnetic field efficiency is improved, but magnetization occurs affecting plasma distribution
Solution Approach 1:
The patent changes the physical state and properties of the magnetic substance by using ferrofluid instead of solid magnetic materials. The ferrofluid can be supplied and removed dynamically, allowing the system to achieve high magnetic field efficiency during processing while avoiding permanent magnetization that would disrupt plasma distribution uniformity across the substrate.
3Measurement precision
If conventional electromagnet control is used, then magnetic field generation is achieved, but precise control of plasma density and independent heat management is difficult
Solution Approach 1:
The patent segments the magnetic field control function by separating the coil (for generating magnetic field) from the magnetic substance (ferrofluid supplied adjacent to the coil). This segmentation allows independent control of magnetic field strength and plasma density, enabling precise control of plasma distribution while managing heat generation separately through the ferrofluid supply system.
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 enables the formation of a desired magnetic field with minimal heat generation, improving processing efficiency and uniformity across the substrate.
Implementation Method 1
an electromagnet unit configured to generate a magnetic field in the processing space
Implementation Method 2
a ferrofluid reservoir disposed adjacent to the coil module
Data Source
AI summary
Disclosed is a substrate processing apparatus including chamber having defined therein a processing space for a processing of a substrate, a substrate support unit disposed in the chamber, a gas supply unit configured to supply gas to the interior of the chamber, a plasma generation unit including a high-frequency power supply configured to generate plasma in the processing space, an electromagnet unit configured to generate a magnetic field in the processing space, and a controller. The electromagnet unit includes a coil module and a ferrofluid reservoir disposed adjacent to the coil module. The substrate processing apparatus suppresses heat generation in the coil module and precisely controls a magnetic field.