Dielectric Fluid Cooling for High Voltage Plasma Ion Source
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Solution Overview
Problem
Conventional plasma ion sources face challenges with heat dissipation and electrical insulation due to high power density and voltage bias, limiting their effectiveness in applications like FIB tools, SIMS, and high-energy particle accelerators.
Innovation Solution
The use of a dielectric fluid to actively bias the reactor chamber to high voltages and circulate through the induction coils and chamber walls, providing efficient heat transfer and electrical insulation, allowing the plasma chamber to be biased up to 30 kV while maintaining the antenna and Faraday shield at ground potential.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If high power density is deposited into the plasma from the antenna to create high density plasma, then plasma density is improved, but heat dissipation becomes problematic
Solution Approach 1:
A dielectric fluid is introduced as an intermediary substance between the plasma chamber and the surrounding environment. This fluid serves dual functions: it acts as a thermal conductor to efficiently remove heat from the plasma chamber walls and induction coils, while simultaneously providing electrical insulation to maintain the high voltage potential difference between the plasma chamber (biased to several thousand volts) and the grounded antenna and Faraday shield.
2Power
If the plasma chamber is biased to high voltage to enable ion extraction, then ion beam current is improved, but electrical insulation requirements increase
Solution Approach 1:
The dielectric fluid acts as a mediator that enables the plasma chamber to be maintained at high voltage potentials (several thousand volts) relative to ground, while providing the necessary electrical insulation. This allows high ion beam currents to be extracted through the chamber wall without electrical breakdown, as the dielectric fluid prevents charge leakage and maintains the potential difference required for ion acceleration.
3Use of energy by moving object
If the antenna and plasma chamber are in close proximity for efficient power coupling, then power transfer efficiency is improved, but electrical breakdown risk increases
Solution Approach 1:
The dielectric fluid fills the space between the grounded antenna and the high-voltage plasma chamber, enabling close proximity positioning for efficient inductive power coupling while preventing electrical breakdown. The fluid's dielectric properties allow the antenna to be positioned very close to the chamber wall without arcing, as the dielectric fluid suppresses electric field breakdown and allows sustained high voltage operation at small gaps.
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 solution effectively manages thermal issues and maintains electrical isolation, enabling stable operation and efficient power coupling, with the dielectric fluid efficiently transferring heat away from the plasma chamber and maintaining high voltage stability with minimal gap requirements.
Implementation Method 1
Use of the dielectric fluid both electrically insulates the plasma chamber, so that it can be biased to 30 kV and up
Implementation Method 2
efficiently transfers heat away from the plasma chamber
Implementation Method 3
Coolant circulated through the fluid circuit carries heat away from adjacent elements of the plasma ion source
Implementation Method 4
Energy is transferred by inductively coupling power from the antenna into the plasma
Implementation Method 5
a high power density is deposited into the plasma from the antenna in order to create a high density plasma
Data Source
AI summary
A plasma source for processing or imaging a substrate, for ion source for proton therapy, for ion thrusters, or for high energy particle accelerators includes a coolant circuit passing adjacent to a plasma ion reactor chamber and RF antenna coils. In a method for operating the plasma ion source having an induction coil adjacent to a reaction chamber for inductively coupling power into the plasma from a radio frequency power source, the method comprises pumping a dielectric fluid into contact with induction coils of the plasma ion source along the coolant circuit. Use of the dielectric fluid both electrically insulates the plasma chamber, so that it can be biased to 30 kV and up, and efficiently transfers heat away from the plasma chamber.