Vacuum Coating Unit Central Anode Homogeneous PVD
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Solution Overview
Problem
Existing PVD coating systems for three-dimensional substrates often result in inhomogeneous layer structures due to anisotropic plasma distribution, leading to undesirable microstructure, hardness, wear resistance, and corrosion properties.
Innovation Solution
A vacuum coating system with a central anode connected to a pulse voltage source and multiple magnetron sputtering or arc evaporator sources connected to both pulse and DC voltage sources, using balanced magnetron cathodes operated as unbalanced by electromagnetic coils, to create a more isotropic plasma distribution and increased ionization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If substrates are coated in front of a planar cathode, then the coating process is simple, but the layer structure becomes inhomogeneous due to anisotropic plasma distribution
Solution Approach 1:
The single planar cathode is divided into multiple planar cathodes arranged around a central axis, with a central cathode positioned in the middle. This segmentation creates multiple plasma sources that collectively provide isotropic plasma distribution, resolving the contradiction between process simplicity and layer uniformity.
Solution Approach 2:
The patent transitions from a two-dimensional planar cathode arrangement to a three-dimensional configuration with multiple planar cathodes positioned at different locations around a central axis, plus a central cathode. This dimensional expansion enables uniform plasma distribution in all directions, achieving homogeneous coating without complicating the basic planar cathode structure.
2Manufacturing precision
If substrates are positioned between two opposing cathodes, then coating uniformity improves, but the device complexity increases
Solution Approach 1:
The multiple planar cathodes serve dual functions: individually, they provide localized plasma generation, and collectively, they create isotropic plasma distribution when viewed from the substrate. This multi-functionality achieves coating uniformity without requiring the substrate to be positioned between specifically opposing cathodes, reducing arrangement complexity.
Solution Approach 2:
The patent adds a central cathode positioned on the rotational axis, creating a three-dimensional cathode configuration. This dimensional addition provides plasma from the center in addition to the peripheral cathodes, achieving complete isotropic coverage without requiring complex opposing cathode pairs at multiple locations.
3Reliability
If balanced magnetron cathodes are used, then plasma is confined to a spatial zone in front of the cathode, but ion bombardment intensity varies with distance
Solution Approach 1:
The single magnetron cathode is segmented into multiple planar magnetron cathodes positioned around a central axis, with a central magnetron cathode in the middle. This segmentation ensures that every substrate surface point is at approximately the same distance from at least one cathode, maintaining plasma confinement while achieving uniform ion bombardment intensity across the entire substrate surface.
Solution Approach 2:
Different regions of the substrate receive plasma from different cathodes, but the local plasma properties (confinement and ion bombardment intensity) are optimized for each region by positioning the appropriate cathode at the optimal distance. This local optimization ensures uniform coating quality across the entire substrate surface.
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 achieves a cost-effective, high-throughput, and uniform coating of three-dimensional substrates with improved ionization and electron emission, enhancing substrate properties like adhesion and internal stress.
Implementation Method 1
Between the anode (5) and the magnetron sputtering sources (3) there are electrical discharges
Implementation Method 2
The anode (5) and the magnetron sputtering sources (3) are surrounded by plasma during the coating
Implementation Method 3
The magnetic field of the permanent magnet sets (11) and of the electromagnetic coils (12) intensifies and encloses the plasma (14) in a spatial zone in front of the magnetron cathodes (3)
Implementation Method 4
magnetron sputtering sources or arc evaporator sources
Implementation Method 5
vacuum coating system for homogeneous PVD coating
Implementation Method 6
magnetron sputtering sources or arc evaporator sources
Data Source
Figure 1
Figure 2
Figure 3a
AI summary
The apparatus (1) comprises a coating chamber (2), two or more cathodes (3), which are arranged peripherally within the coating chamber, substrate carriers (6) for holding the substrate (4), vacuum pumps (8) and voltage sources (15, 16, 17, 18, 19) wherein an individual anode (5) is arranged centrally between the cathodes (3) in the coating chamber (2) and the substrate (4) is positioned between the anode (5) and the cathode (3). In each case a gas discharge with a plasma (14) is ignited between the individual anode (5) and the cathodes (3). The substrates (4) are held fixed in position or are rotated about one or more axes and in the process subjected to the plasma (14).