Ion Implanter Electrode Cooling and Plasma Gap Design
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Solution Overview
Problem
Existing ion implanters face challenges in improving the life performance and reducing downtime due to material deposition and short circuiting during ion beam operation, with high temperature components requiring refractory materials and complex designs.
Innovation Solution
The ion implanter incorporates a support and electrode assembly with coolant circulation for cooling, a tortuous gap to prevent plasma leaks, and shielding to protect insulators from metallic deposition, reducing the number of parts and preventing short circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high current ion beam operation is performed, then ion beam current is improved, but material deposition and short circuiting occur reducing reliability
Solution Approach 1:
The harmful plasma is extracted from the arc chamber through a dedicated exhaust port and removed by a vacuum pump, preventing material deposition on insulators and electrodes. This extraction mechanism allows high current operation while maintaining reliability by continuously removing the harmful byproducts of ion generation.
Solution Approach 2:
A tortuous gap filled with inert gas or vacuum acts as an intermediary barrier between the plasma source and the insulator surfaces. This gap prevents direct contact between reactive plasma species and insulator materials, eliminating the short circuiting problem while allowing electrical field penetration for ion extraction.
2Temperature
If refractory materials are used for high temperature components, then temperature resistance is improved, but device complexity increases
Solution Approach 1:
The mechanical/thermal solution of using refractory materials is replaced with a plasma control solution. By actively managing plasma exhaust and using a tortuous gap configuration, the system achieves temperature resistance through plasma dynamics control rather than relying on high-melting-point materials, thereby reducing material complexity.
Solution Approach 2:
The system changes the operational parameters of the plasma environment by introducing a tortuous gap and controlled exhaust flow. This transforms the thermal problem into a plasma flow control problem, allowing standard materials to operate in high-temperature environments by controlling plasma behavior rather than relying on refractory material properties.
3Ease of operation
If complex electrode assemblies are used, then ion beam control is improved, but susceptibility to short circuiting increases
Solution Approach 1:
Harmful plasma and deposited materials are continuously extracted from the arc chamber through a dedicated exhaust port, preventing accumulation on electrode surfaces. This extraction mechanism maintains electrode cleanliness and electrical insulation, allowing complex electrode assemblies to operate reliably without short circuiting.
Solution Approach 2:
The tortuous gap and exhaust system provide preliminary protection against plasma contamination before it can reach the electrode assemblies. By creating a controlled plasma flow path and removal system, the design prevents the harmful effects of plasma exposure on complex electrodes, maintaining their control functionality without susceptibility to short circuits.
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 design enhances the life performance of the ion source assembly, improves cooling efficiency, and reduces downtime by preventing short circuits and material deposition, thus maintaining stable ion beam operation.
Implementation Method 1
A voltage is supplied to filament which produces enough current through the filament to heat the filament and to cause thermionic emission of electrons
Implementation Method 2
The cathode is indirectly heated via the filament by biasing the cathode more positively than the filament which causes these thermo-electrons to accelerate from the filament toward the cathode, thereby heating the cathode
Implementation Method 3
The emitted electrons are confined between the cathode and repeller which collide with the dopant feed gas introduced into the chamber via a conduit to generate a plasma having the desired properties
Implementation Method 4
The ions formed from the dopant gas are extracted from the source chamber via an aperture by way of, for example, a standard three (3) electrode configuration comprising a plasma electrode, a suppression electrode and a ground electrode used to create an electric field
Implementation Method 5
The mass analyzer itself is configured with a particular magnetic field such that only the ions with a desired mass-to-charge ratio are able to travel through the analyzer for maximum transmission through a mass resolving slit
Implementation Method 6
the support and electrode assemblies of the ion implanter are cooled by circulating a coolant through these parts during operation
Data Source
AI summary
The support and electrode assemblies of the ion implanter are cooled by circulating a coolant through these parts during operation. The support for the arc chamber includes a one piece block of aluminum through which coolant passes and a hollow rectangular post on which the arc chamber sits with a space therebetween.