Multi-Electrode RF Sputtering With Reactance-Tuned Plasma Coupling
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Solution Overview
Problem
Current RF magnetron sputtering systems face issues with non-uniformity of deposited thin film thickness, particularly in rotary cathode applications.
Innovation Solution
An apparatus utilizing multiple electrodes with capacitive and inductive reactance management to optimize RF power coupling, incorporating an RF matching network and electrical components like capacitors and inductors, to enhance plasma coupling and uniformity during sputtering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If RF power is applied to a rotary cathode to enable sputtering operation, then the sputtering process can be performed, but the deposited thin film thickness becomes non-uniform
Solution Approach 1:
The system divides the single RF power source into multiple independent RF power sources, each connected to separate electrodes. This segmentation allows independent control of power distribution to different regions, enabling uniform deposition across the substrate while maintaining productive sputtering operation.
Solution Approach 2:
The patent implements different electrical components (capacitive vs. inductive) for different electrodes to optimize local plasma coupling conditions. By tailoring the reactance management to each electrode's specific requirements, the system achieves uniform thin film deposition while maintaining high sputtering efficiency.
2Device complexity
If single RF power source is used for simplicity, then device complexity is reduced, but plasma coupling optimization is limited
Solution Approach 1:
The system segments the power supply into multiple RF sources with dedicated matching networks and electrical components for each electrode. This segmentation, while increasing component count, enables precise plasma coupling optimization that improves overall system reliability and deposition uniformity.
Solution Approach 2:
The patent introduces intermediary electrical components (capacitors and inductors) between the RF power sources and electrodes to manage reactance. These intermediaries optimize plasma coupling by compensating for capacitive and inductive effects, thereby improving power transfer efficiency and deposition control.
3Reliability
If RF matching network is implemented to optimize power delivery, then plasma coupling improves, but device complexity increases
Solution Approach 1:
The patent employs matching networks with capacitive and inductive components as intermediaries between RF power sources and electrodes. These components manage reactance effects and optimize power coupling to the plasma, improving deposition uniformity despite the added complexity of the electrical configuration.
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 solution achieves improved impedance, uniformity, and deposition rate by managing inductive and capacitive reactance, resulting in more desirable thin film properties and deposition profiles.
Implementation Method 1
RF power signals are simultaneously delivered to the plurality of electrodes during a sputtering operation
Implementation Method 2
The plurality of electrodes and a set of electrical components are operative to manage the inductive and capacitive reactance for coupling the RF power signals to provide optimized plasma coupling
Implementation Method 3
The plurality of electrodes and a set of electrical components are operative to manage the inductive and capacitive reactance for coupling the RF power signals
Implementation Method 4
a vacuum chamber configured to produce a substantially atmospheric vacuum environment for plasma processing
Implementation Method 5
A magnetron assembly is disposed adjacent to or within the target structure and supplies a magnetic field such that there is adequate magnetic flux at the outer surface of the target structure for the sputtering process
Implementation Method 6
Magnetron sputtering of target materials is well known and used extensively for producing a wide variety of thin films on various substrates
Data Source
AI summary
An apparatus comprises a vacuum chamber configured to produce a substantially atmospheric vacuum environment for plasma processing; a radio frequency (RF) power supply located outside of the vacuum chamber; an RF matching network operatively coupled to the RF power supply; and a plurality of electrodes mounted within the vacuum chamber, the plurality of electrodes configured to receive RF power signals from the RF power supply through the RF matching network. The RF power signals are simultaneously delivered to the plurality of electrodes during a sputtering operation. The plurality of electrodes and a set of electrical components are operative to manage the inductive and capacitive reactance for coupling the RF power signals to provide more desirable plasma coupling during the sputtering operation.