Magnetron Sputtering Apparatus with Movable Magnetic Field
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Solution Overview
Problem
Existing magnetron sputtering apparatuses face challenges in achieving high plasma ionization and improved physical properties of sputtered layers while maintaining low reconstruction costs, particularly in producing fine crystal structures with small grain sizes and high density, as they tend to melt under high power densities.
Innovation Solution
A magnetron sputtering apparatus with a magnetic field generation device comprising three aligned permanent magnets, where the center magnet is oppositely poled and stronger than the side magnets, concentrating the magnetic field to achieve peak power densities above 500 W/cm² and stabilizing plasma at a single spot, allowing for controlled target temperature and uniform target consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high power densities are applied to increase plasma ionization, then plasma ionization and coating properties are improved, but the target melts
Solution Approach 1:
The magnetic field is made movable along the axial direction of the target, allowing the high power density region to be dynamically positioned and moved, preventing localized overheating and target melting while maintaining high plasma ionization
Solution Approach 2:
The magnetic field is moved periodically or reciprocally along the target axis, creating periodic exposure of different target regions to high power density, which distributes thermal load and prevents melting
2Quantity of substance
If strong magnets are used to confine electrons and increase plasma density, then plasma density and coating quality are improved, but the magnetic field strength must be uniformly controlled which limits fine crystal structure production
Solution Approach 1:
The magnetic field strength is varied locally along the axial direction with stronger fields at the center and weaker fields at the edges, creating different plasma confinement conditions in different regions, which enables fine crystal structure formation while maintaining high overall plasma density
Solution Approach 2:
The magnetic field parameters are changed along the axial direction, with the center magnet having stronger field strength than the side magnets, creating a gradient that controls electron confinement and enables precise control of crystal structure formation
3Power
If the magnetic field is concentrated to increase power density, then plasma ionization is improved, but the target temperature increases causing melting
Solution Approach 1:
The concentrated magnetic field is moved dynamically along the target axis, so that while high power density is achieved at any given moment, the heat is distributed over time and space, preventing localized melting
Solution Approach 2:
The magnetic field moves continuously or periodically along the target, ensuring that the useful action of high power density plasma generation is maintained while preventing thermal accumulation through continuous redistribution of the heat load
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 enables higher power densities up to 1 kW/cm² without target melting, resulting in improved coating properties such as increased ionization, density, and crystal structure, while reducing the need for expensive power supplies and enhancing industrial suitability.
Implementation Method 1
at least one magnet or other magnetic field generation device forming a magnetic field so as to confine electrons in the plasma at or near a surface of the target
Implementation Method 2
sputtering or sputter deposition is a well-known technique... material is vaporized from a target by a high-power electric arc, by heat or by high-energy particles. The vaporized material then condenses on the substrate, forming a thin film
Implementation Method 3
Electrons which are present in the sputtering gas are accelerated away from the cathode causing collisions with nearby atoms of sputtering gas. These collisions cause ionization. Once the plasma is ignited
Implementation Method 4
high voltage is applied between the cathode and the anode... electrons emitted from the cathode surface are accelerated by so called plasma sheet
Data Source
Figure 1~2
Figure 3~6
Figure 7A~7C
AI summary
Described is a magnetron sputtering apparatus (2) for coating a substrate, comprising: a treatment chamber (4) to be evacuated and then to be supplied with a sputtering gas (6); substrate holding means (8) for holding the substrate; a cathode (12), an anode (14) and a power supply (16) for applying high voltage, 300V to 1000V, between the cathode (12) and the anode (14) ;a target (10) forming the cathode (12) or being supported by the cathode (12), facing the substrate and being subject to sputtering by plasma formed within the treatment chamber (4); at least one magnet (18) or magnetic field generation device forming a magnetic field so as to confine electrons in the plasma at or near a surface of the target (10); and moving means (20) for moving the at least one magnet or magnetic field generation device (18) in an axial direction of the target (10). The magnetic field generation device (18) has a set of three aligned magnets (28, 30, 32), wherein a center magnet (30) is oppositely poled to and magnetically stronger than the side magnets (28, 32), thereby concentrating the magnetic field to a slim area at the center magnet (30) for allowing there at or near the target surface the generation of peak power densities above 500 W/cm2.