Magnetron Sputtering Cathode Cooling System
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Solution Overview
Problem
Prior magnetron sputtering devices face limitations in cooling efficiency, leading to overheating, non-uniform coatings, and frequent short outs due to inefficient cooling and anode shield material buildup, restricting continuous high-power discharge and resulting in lower deposition rates.
Innovation Solution
A magnetron sputtering electrode with an improved cooling system featuring a magnet receiving chamber with high-energy magnets and a contoured anode shield with recesses for coolant passageways, allowing for efficient coolant circulation and reducing target material buildup, enabling continuous discharge at high power levels without burning out.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high power discharge is applied to increase deposition rate, then productivity improves, but overheating occurs causing stress cracks and arcing
Solution Approach 1:
The cooling system is segmented into multiple channels including a first cooling channel in the cathode body, a second cooling channel in the anode shield, and a third cooling channel in the target holder. This segmentation allows distributed heat removal from different components, enabling high power discharge without localized overheating that would cause stress cracks and arcing.
Solution Approach 2:
Coolant acts as an intermediary substance that absorbs heat from the sputtering components through the cooling channels. The coolant circulates through the cathode body, anode shield, and target holder, transferring thermal energy away from the high-power discharge zones, thereby enabling continuous high-power operation without thermal damage.
2Productivity
If high power discharge is applied to increase deposition rate, then productivity improves, but non-uniform coatings are produced
Solution Approach 1:
The magnetic field is configured with specific polarity arrangements where the first and second magnets have first polarity and the third and fourth magnets have second polarity. This creates localized magnetic field regions that control plasma distribution, ensuring uniform sputtering across the target surface even at high power densities, thereby producing uniform coatings.
Solution Approach 2:
The magnetic field configuration creates equipotential regions for plasma potential distribution. By arranging magnets with alternating polarities, the plasma potential is balanced across different areas of the target, ensuring uniform ion flux and thus uniform coating thickness and composition throughout the deposited film.
3Reliability
If standard cooling methods are used, then device complexity is low, but frequent short outs occur due to overheating
Solution Approach 1:
The cooling function is merged with the structural components of the sputtering device. The cooling channels are integrated directly into the cathode body, anode shield, and target holder structures, combining structural support and thermal management functions. This integration provides reliable overheating prevention while minimizing additional complexity compared to separate cooling systems.
4Reliability
If anode shield is positioned above target surface level, then device structure is simple, but target material buildup flakes off causing short outs
Solution Approach 1:
Instead of positioning the anode shield above the target surface as in conventional designs, the anode shield is positioned below the target surface level. This inverted configuration prevents target material from accumulating on the anode shield surface, eliminating the flaking and short out problem while maintaining structural simplicity through the recessed channel design.
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
The enhanced cooling system allows for continuous high-power operation up to 1000 watts/in2, achieving uniform coatings and higher deposition rates by preventing overheating and short outs, while maintaining structural integrity.
Implementation Method 1
a magnet assembly comprising a magnetic field shaping ring, a plurality of magnets, a base ring and a central magnet centered within the magnetic field shaping ring
Implementation Method 2
The water chamber is defined between the cathode body and the sealing plate and includes a magnetic assembly... A water inlet supply and a water outlet for allowing cooling water to flow through the water chamber
Implementation Method 3
Electrical power supplied to the electrode produces an electronic discharge which ionizes the process gas and produces charged gaseous ions from the atoms of the process gas
Implementation Method 4
The ions are accelerated and retained within a magnetic field formed over the target, and are propelled toward the surface of the target
Data Source
AI summary
A magnetron sputtering electrode for use within a magnetron sputtering device that includes a cathode body, a target receiving area defined adjacent the cathode body, a plurality of magnets received within a magnet receiving chamber and an anode shield surrounding the cathode body. At least a portion of a coolant passageway is defined by the anode shield, whereby the coolant passageway is adapted to receive coolant to circulate therethrough thereby cooling the anode shield.