Asymmetric Magnet Arrangement for Sputtering Target Backing Tube
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Solution Overview
Problem
In sputtering systems, the unbalanced magnet arrangement leads to unstable plasma positioning, resulting in uneven deposition and redeposition issues due to the uneven magnetic field distribution, which affects the thickness and uniformity of the deposited film.
Innovation Solution
A magnet arrangement with a first magnet element extending along a first axis and a second magnet element disposed symmetrically around it, where the magnetic axis of the second magnet section is inclined with respect to a plane orthogonal to the first axis, providing a balanced magnetic field for stable plasma confinement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional unbalanced magnet arrangement is used, then the structure is simple and easy to manufacture, but the plasma position becomes unstable and deposition uniformity deteriorates
Solution Approach 1:
The patent applies asymmetry by intentionally creating an unbalanced magnet arrangement where the inner magnet element has a different magnetic field strength compared to the outer magnet element. Specifically, the inner magnet element generates a weaker magnetic field than the outer magnet element, which stabilizes the plasma position at the outer region of the target surface. This asymmetric configuration resolves the contradiction by achieving stable plasma confinement and uniform deposition through deliberate magnetic field asymmetry, while maintaining relatively simple magnet structure and manufacturing processes.
2Reliability
If the magnetic field is stronger at the outer position, then plasma confinement improves, but plasma shifts towards the inner magnet and stable positioning is lost
Solution Approach 1:
The patent applies parameter changes by precisely controlling the magnetic field strength parameters of the inner and outer magnet elements. The inner magnet element is designed to produce a magnetic field that is specifically weaker than the outer magnet element's field. This parameter adjustment stabilizes the plasma position by preventing it from shifting towards the inner magnet, thereby eliminating the harmful plasma displacement effect while maintaining reliable plasma confinement at the desired location.
3Manufacturing precision
If thicker targets are used, then the race track length decreases, but the redeposition zone increases and uniformity worsens
Solution Approach 1:
The patent applies the counterweight principle by using the asymmetric magnet arrangement to counterbalance the redeposition effect. The unbalanced magnetic field configuration creates a stable plasma position that maintains consistent deposition conditions across the target surface, even when using thicker targets. This counteracts the tendency for plasma to shift and material to redeposit, thereby maintaining film thickness uniformity and reducing redeposition losses regardless of target thickness variations.
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 maintains a stable plasma position regardless of target thickness, ensuring uniform deposition and reducing redeposition zones, thus improving the consistency and efficiency of the sputtering process.
Implementation Method 1
a magnet arrangement or rotary cathode is disposed in the backing tube. The magnet arrangement includes an inner magnet element and an outer magnet element disposed around the inner magnet element. In operation of the sputtering system, the plasma is confined in a volume, for example, above a target element if the substrate to be coated is located above the target element, between the inner magnet element and the outer magnet element, where the magnetic field is mainly parallel to the target surface.
Data Source
AI summary
The disclosure relates to a magnet arrangement for a sputtering system, wherein the magnet arrangement is adapted for a rotatable target of a sputtering system and includes: a first magnet element extending along a first axis; a second magnet element being disposed around the first magnet element symmetrically to a first plane; wherein the second magnet element includes at least one magnet section intersecting the first plane; and wherein a magnetic axis of the at least one magnet section is inclined with respect to a second plane being orthogonal to the first axis. Further, the disclosure relates to a target backing tube for a rotatable target of a sputtering system, a cylindrical rotatable target for a sputtering system, and a sputtering system.