Magnetron Sputtering Electrode Uniform Erosion Control
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Solution Overview
Problem
In magnetron sputtering systems, electrons escaping the target due to inertial movement lead to unstable plasma and extended erosion regions, reducing film formation quality and target utilization efficiency.
Innovation Solution
A magnetron sputtering electrode with a magnet assembly featuring a central magnet and peripheral magnet, where the position of the magnetic field's vertical component zero-point is shifted to align with electron escape areas, preventing electron jump-out and ensuring uniform target erosion through controlled magnetic field adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the magnet assembly is reciprocated to uniform the erosion region, then the uniformity of target erosion is improved, but the electrons jump out of the target end side due to inertial movement, causing plasma enlargement and unstable discharge
Solution Approach 1:
The patent applies local quality by creating a non-uniform magnetic field distribution along the target surface. The magnetic field strength is specifically designed to be stronger at the end portions of the target compared to the central portion. This localized variation in magnetic field intensity prevents electron jump-out at the critical end regions while maintaining uniform plasma distribution across the entire target surface during magnet assembly reciprocation.
Solution Approach 2:
The patent changes the magnetic field parameter (intensity distribution) along the target surface to resolve the contradiction. By adjusting the magnetic field strength to be higher at the end portions and lower in the central region, the system achieves both stable plasma discharge (preventing electron jump-out) and uniform erosion when the magnet assembly reciprocates.
2Reliability
If the magnet assembly size is decreased to reduce electron jump-out, then the plasma stability is improved, but the non-eroded region of the target increases, reducing target utilization efficiency
Solution Approach 1:
Instead of uniformly decreasing the magnet assembly size, the patent applies local quality by concentrating magnetic field strength at the end portions of the target. This allows the magnet assembly to maintain a size that enables full target coverage during reciprocation while creating localized magnetic field enhancement at the ends to prevent electron jump-out and maintain plasma stability.
Solution Approach 2:
The patent employs dynamic reciprocation of the magnet assembly along the target surface. This dynamic movement, combined with the non-uniform magnetic field distribution, ensures that the entire target surface including the end portions is uniformly eroded over time, maximizing target utilization efficiency while the enhanced end-region magnetic field maintains plasma stability during the reciprocation cycle.
3Quantity of substance
If the magnetic field strength is increased to confine electrons, then the plasma density is improved, but the erosion region extends toward the target end side, causing unstable discharge
Solution Approach 1:
The patent applies local quality by creating a non-uniform magnetic field distribution where the field strength varies along the target surface. The magnetic field is specifically designed to be stronger at the end portions and weaker in the central region. This localized differentiation allows high plasma density to be maintained in the central region while preventing plasma enlargement and electron jump-out at the end portions, ensuring stable discharge.
Solution Approach 2:
The patent changes the spatial distribution parameter of the magnetic field along the target surface. By transitioning from a uniform magnetic field to a non-uniform distribution with enhanced strength at the ends, the system achieves both high plasma density in the erosion region and prevention of plasma instability at the target boundaries.
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 stabilizes plasma discharge and enhances target utilization efficiency by maintaining uniform erosion, allowing for high-quality thin film formation.
Implementation Method 1
a magnet assembly for forming a tunnel-shaped magnetic flux in front of the target
Implementation Method 2
the electrons ionized in front of the target or the secondary electrons generated by the sputtering are arrested to thereby enhance the electron density in front of the target
Implementation Method 3
By thus increasing the probability of collision of these electrons with the gas molecules of an inert gas to be introduced into a vacuum chamber, the plasma density is increased
Implementation Method 4
magnetron sputtering system... the target by charging negative DC voltage or AC voltage to the target... the film forming speed can be improved
Data Source
AI summary
In a magnetron sputtering apparatus an arrangement is made such that the peripheral portion of a target is uniformly eroded to attain a high efficiency in target utilization and, in addition, that an abnormal discharging hardly occurs to thereby enable satisfactory thin film forming. A magnet assembly is provided behind a target that is disposed opposite to the process substrate. This magnet assembly has a central magnet that is disposed linearly along the longitudinal direction, and a peripheral magnet that is disposed so as to enclose the periphery of the central magnet, while changing the polarity on the side of the target. At this time, among the respective magnetic fluxes generated between the central magnet and the peripheral magnet at the longitudinally end portions of the magnet assembly, the position at which the vertical component of the magnetic field becomes zero is locally shifted to the central magnet within a certain range.