Single-Beam Plasma Source With Tunable Ion Energy and Angle
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Solution Overview
Problem
Conventional ion sources, such as racetrack designs, face limitations in producing a focused ion beam with a wide range of emission angles, high ion energies that can damage films, and require frequent maintenance due to contamination and alignment issues, making them unsuitable for thin film processing and semiconductor manufacturing.
Innovation Solution
A single beam plasma or ion source apparatus utilizing multiple power sources, including DC and AC or RF power supplies, with magnets and magnetic shunts creating a magnetic flux in an open space, and a removable cathode design for easy maintenance, allowing operation at various pressures and with inert and reactive gases, producing a tunable ion beam with adjustable diameter and length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If racetrack ion source design is used, then plasma discharge can be sustained, but ion beam emission angles become wide and cannot be tuned
Solution Approach 1:
The ion source is segmented into separate functional components: an electron emission source positioned at a focus point, magnetic lenses for beam focusing, and extraction electrodes. This segmentation allows independent optimization of each component and enables precise control of ion beam parameters without the constraints of a fixed racetrack geometry.
Solution Approach 2:
The invention transitions from the two-dimensional racetrack electron drift path to a three-dimensional focused ion beam configuration. Electrons are emitted from a point source and focused by magnetic lenses into a narrow beam, enabling precise angular control and eliminating the wide emission angles inherent in racetrack designs.
2Reliability
If high voltage greater than 250 V is applied to sustain plasma discharge, then plasma can be maintained, but ion energies become too high and damage deposited films
Solution Approach 1:
The invention changes the operational parameters by using lower voltage (less than 250 V) combined with optimized magnetic field configurations and electron emission control. This allows plasma discharge to be sustained at lower energies, producing ion beams with adjustable energies that are sufficient for thin film processing without causing damage to deposited films.
Solution Approach 2:
The invention replaces the high-voltage electrical field-based plasma sustainment with a magnetic field-based electron confinement and ionization system. Magnetic lenses and field configurations enable plasma maintenance at lower voltages by confining electrons and enhancing ionization efficiency through magnetic field interactions rather than relying solely on high electrical fields.
3Productivity
If narrow emission slit is used in traditional racetrack ion sources, then ion beam can be extracted, but frequent maintenance is required due to contamination and contamination of anode and cathode
Solution Approach 1:
The invention extracts the electron emission function from the racetrack anode-cathode structure and places it in a separate focus-point emission source. This separation removes the emission slit from the high-voltage plasma region, eliminating the contamination problem that requires frequent maintenance while maintaining efficient ion beam extraction through the magnetic focusing system.
Solution Approach 2:
Magnetic lenses serve as intermediaries between the electron emission source and the ion extraction region. These magnetic fields guide and focus electrons and ions without requiring physical slits or apertures in the high-voltage region, reducing material exposure to contamination and minimizing maintenance requirements.
4Reliability
If racetrack ion source produces two beams in straight section and ring-shaped beam in circular source, then plasma discharge is sustained, but ion incident angle distribution is wide and limits optimization of ion-assisted processing
Solution Approach 1:
Instead of using a racetrack configuration that naturally produces wide-angle beams, the invention inverts the approach by using a point-source electron emission with magnetic focusing to create a narrow, well-collimated ion beam. This inverted geometry provides precise control over ion incident angles, enabling optimization of ion-assisted processing for specific manufacturing applications.
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 apparatus achieves stable, tunable ion beams with adjustable energies and diameters, reducing contamination and maintenance needs, enabling high-quality thin film deposition and surface treatment across a wide range of pressures and gases, improving film quality and stability.
Implementation Method 1
simultaneous excitation of an ion source by DC and AC, or DC and RF power supplies
Implementation Method 2
magnets and magnetic shunts which create a magnetic flux with a central dip or outward undulation located in an open space where a plasma is created
Implementation Method 3
the electromagnetic fields in between the anode and cathode. Therefore, the ion energies could be so high that they can damage the deposited films
Data Source
AI summary
A single beam plasma or ion source apparatus, including multiple and different power sources, is provided. An aspect of the present apparatus and method employs simultaneous excitation of an ion source by DC and AC, or DC and RF power supplies. Another aspect employs an ion source including multiple magnets and magnetic shunts arranged in a generally E cross-sectional shape.