Rotary Cathode Coolant Routing for Magnetron Sputtering
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Solution Overview
Problem
Conventional coolant routing methods in magnetron sputtering devices result in incomplete cooling, target damage, and inefficient water removal, leading to reduced productivity and increased maintenance costs due to air pockets, trapped water, and spills, especially in horizontal and vertical orientations.
Innovation Solution
A rotary cathode design with a unique coolant routing scheme that allows water to flow in the opposite direction of conventional methods, ensuring complete filling and removal by using a rotating aperture and fluid pathway between the inner and outer passageways, allowing for efficient coolant circulation and removal regardless of cathode orientation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If water is pumped into the inlet of a rotary feedthru passage and returned to an outlet at the same end through a central tube, then the cooling system is simple to implement, but air pockets are trapped at the top of the target tube resulting in incomplete cooling
Solution Approach 1:
The patent reverses the conventional water flow direction by routing water through the outer passageway first (between target tube and central tube) and then through the inner passageway (central tube), rather than the typical inner-then-outer sequence. This inversion allows water to enter at the bottom and fill the target tube completely from below, eliminating air pockets that would otherwise trap at the top, thereby ensuring complete cooling while maintaining system simplicity
Solution Approach 2:
The cooling system is divided into two separate passageways: an outer passageway between the target tube and central tube, and an inner passageway through the central tube itself. This segmentation allows independent flow control and ensures that water can completely fill the outer passageway before entering the inner passageway, preventing air entrapment and ensuring reliable cooling throughout the entire target tube volume
2Productivity
If the magnet array is directed upward in horizontal application, then the process plasma can be applied to the target, but the magnet array is partially in air pocket resulting in reduced power and slower processing
Solution Approach 1:
By inverting the water flow direction to enter through the outer passageway first and then the inner passageway, the system ensures complete filling of the target tube with cooling water from the bottom up. This eliminates air pockets that would otherwise form at the top when the magnet array is directed upward, allowing full plasma power to be applied without concern for inadequate cooling, thereby maintaining high processing speed and productivity
3Loss of substance
If compressed air is used to blow down the target tube to remove water, then water can be removed from the system, but the process is time-consuming and may not completely remove all water
Solution Approach 1:
The patent inverts the conventional blow-down approach by introducing compressed air through the inner passageway (central tube) while water exits through the outer passageway. This reverse flow pattern efficiently pushes water out through the outer annular space, ensuring complete water removal from both passageways more quickly and thoroughly than conventional methods, thereby reducing both time and incompleteness issues
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 design provides comprehensive cooling to all portions of the target, reduces the risk of target damage, and minimizes downtime and cleanup costs by ensuring complete water removal and filling, enhancing productivity and safety.
Implementation Method 1
A rotating aperture is adjacent to the inner surface of the target cylinder at the distal end thereof, with the rotating aperture configured to direct a fluid toward the inner surface at the distal end
Implementation Method 2
A coolant such as water typically flows inside the target tube for cooling during the sputtering process
Implementation Method 3
Some target materials need more cooling than others in order to keep them from being damaged
Implementation Method 4
The magnet array is directed at a substrate in a vacuum chamber and holds processing plasma in a desired location for coating the target material on the substrate
Implementation Method 5
A magnetron sputtering device is used for depositing thin film layers on a substrate and utilizes a rotary cathode
Data Source
AI summary
A rotary cathode for a magnetron sputtering apparatus is disclosed. The rotary cathode comprises a rotatable target cylinder, and a non-rotatable interior structure in the target cylinder. The interior structure has an outer surface and an inner passageway. An outer passageway is defined between an inner surface of the target cylinder and the outer surface of the interior structure. An end cap is affixed at a distal end of the target cylinder. A rotating aperture is adjacent to an inner surface of the target cylinder at the distal end thereof, with the rotating aperture configured to direct a fluid toward the inner surface at the distal end. A fluid pathway is at least partially defined by the end cap, with the pathway providing fluid communication between the outer passageway and the inner passageway through the rotating aperture.