HiPIMS Coating Thickness Uniformity via Partial Cathode Segmentation
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Solution Overview
Problem
The HiPIMS method faces challenges in achieving homogeneous layer thickness over the height of a coating chamber due to the influence of plasma density and environment, leading to inefficiencies in layer thickness distribution and reduced economic efficiency.
Innovation Solution
A method involving a PVD sputtering cathode with multiple partial cathodes, where power impulse intervals are independently adjusted to maintain sustained power output, allowing for customized coating thickness profiles by varying the duration of power pulses without interrupting the power supply.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the HiPIMS method is used to coat workpieces distributed over the entire useful coating height, then the coating chamber can accommodate more workpieces, but the layer thickness becomes non-uniform due to plasma density variations
Solution Approach 1:
The cathode is divided into multiple partial cathodes (first partial cathode, second partial cathode, etc.) arranged at different heights within the coating chamber. Each partial cathode can be independently controlled with separate power impulse intervals, allowing localized adjustment of coating rates to achieve uniform layer thickness across the entire chamber height while maintaining high productivity
Solution Approach 2:
The system dynamically adjusts the duration of power impulse intervals for each partial cathode based on its position within the chamber. By varying the impulse duration dynamically, the coating rate is optimized for each location, compensating for plasma density variations and achieving uniform coating thickness across all workpieces regardless of their vertical position
2Manufacturing precision
If magnetic fields are adjusted over the height to compensate for plasma density variations, then layer thickness uniformity improves, but the plasma conditions are locally modified which affects layer properties
Solution Approach 1:
Instead of using a continuous magnetic field that affects the entire plasma volume, the system segments the cathode into multiple independently controllable partial cathodes. This allows localized control of coating parameters without globally modifying plasma conditions, thereby maintaining layer properties while achieving thickness uniformity
Solution Approach 2:
The system changes the parameter being controlled from magnetic field strength to power impulse interval duration. By adjusting the temporal parameters (impulse duration) rather than spatial parameters (magnetic field distribution), the invention achieves thickness uniformity without altering plasma density and its beneficial effects on layer properties
3Manufacturing precision
If masks are used to correct layer distribution, then coating uniformity improves, but the method becomes impractical when load or workpiece geometry changes
Solution Approach 1:
The system provides dynamic adaptability by allowing independent adjustment of power impulse intervals for each partial cathode. This enables the system to adapt to different workpiece configurations, loads, and geometries without requiring physical mask changes, offering both coating uniformity and versatility
Solution Approach 2:
The invention replaces the mechanical mask system with an electronically controlled power delivery system. Instead of using physical masks that must be manually adjusted or changed, the system uses electronic control of power impulse intervals to achieve uniform coating, providing adaptability to different geometries without mechanical intervention
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 approach enables precise control over coating thickness distribution, achieving homogenous layers across the coating chamber height without altering magnetic fields, thereby improving layer homogeneity and economic efficiency.
Implementation Method 1
The HiPIMS technique is a physical vapor coating method. More precisely, it is a magnetron-assisted sputtering process in which the target supplying the sputter material is subjected to a very high discharge current density
Implementation Method 2
a high electron density is generated in the plasma and the majority of the sputtered particles are ionized
Data Source
AI summary
The invention relates to a HiPIMS method by means of which homogeneous layers can be deposited over the height of a coating chamber. Two partial cathodes are used for said purpose. According to the invention, the length of the individual power pulse intervals applied to the partial cathodes is chosen individually and thus a required coating thickness profile over the height of the coating chamber is achieved.