Reactive Sputtering Voltage and Gas Flow Feedback Control
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Solution Overview
Problem
Long-term constant power sputtering in reactive sputtering devices leads to a shift in deposition mode curves, causing the transition mode to shift to metal or compound modes, resulting in inconsistent film quality and composition in compound thin films.
Innovation Solution
Implementing voltage monitoring control and gas flow rate monitoring control to adjust target voltage and gas flow rate in shorter and longer cycles, respectively, to maintain the transition mode by tracking and averaging target voltage and gas flow rate values, ensuring consistent film formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If constant power control is used for long-term sputtering, then the deposition rate is maintained, but the deposition mode shifts from transition mode to metal or compound mode causing film quality inconsistency
Solution Approach 1:
The patent implements feedback control by monitoring the target voltage and comparing it with a reference value. When the monitored voltage deviates from the reference, the system automatically adjusts the reactive gas flow rate to bring the voltage back to the reference value, thereby maintaining stable transition mode deposition and consistent film quality over long-term operation.
Solution Approach 2:
The patent dynamically changes the reactive gas flow rate parameter in response to voltage deviations. By adjusting this parameter, the system maintains the deposition mode in the transition region between metal and compound modes, ensuring consistent film properties while sustaining high deposition rates throughout the sputtering process.
2Stability of the object's composition
If the target voltage is kept constant through impedance control, then the transition mode is maintained, but the deposition mode curve shifts over time causing mode transition to metal or compound mode
Solution Approach 1:
The system continuously monitors target voltage and provides feedback control by adjusting reactive gas flow rate. This feedback mechanism compensates for the time-dependent shifting of the deposition mode curve, maintaining the operating point within the transition mode region and preventing unwanted transitions to metal or compound modes.
Solution Approach 2:
Instead of using static impedance control with fixed parameters, the patent employs dynamic control where the reactive gas flow rate is continuously adjusted based on real-time voltage monitoring. This dynamic approach adapts to the changing deposition mode curve characteristics over time, maintaining stable transition mode operation.
3Manufacturing precision
If reactive gas flow rate is increased to maintain transition mode, then compound thin film composition is improved, but deposition rate decreases
Solution Approach 1:
The feedback control system monitors target voltage and adjusts reactive gas flow rate only when necessary to maintain voltage within the transition mode range. This precise control avoids excessive gas flow that would reduce deposition rate, while still achieving accurate compound film composition by maintaining the optimal voltage window for transition mode deposition.
Solution Approach 2:
The system optimizes the reactive gas flow rate parameter to the minimum necessary value that maintains transition mode deposition. By carefully controlling this parameter through feedback, the system achieves accurate compound film composition without unnecessarily reducing the deposition rate, thus balancing film quality and productivity.
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 stabilizes the sputtering process in the transition mode, achieving high deposition rates and consistent film quality by dynamically adjusting target voltage and gas flow rate to match desired values, thereby preventing mode shifts and maintaining optimal deposition conditions.
Implementation Method 1
a reactive sputtering device including a vacuum chamber, a metal target provided inside the vacuum chamber
Implementation Method 2
forming a thin film on a substrate by using a reactive sputtering device
Data Source
AI summary
A compound thin film is obtained with a high deposition rate and consistent film quality in reactive sputtering. A thin film is formed by performing voltage monitoring control and gas flow rate monitoring control. The voltage monitoring control is control in which a gas flow rate is adjusted such that the value of a target voltage is brought closer to the value of a desired voltage by monitoring the target voltage in a first cycle time. The gas flow rate monitoring control is control in which the desired voltage for the target voltage is changed such that the value of the gas flow rate is brought closer to the value of a desired gas flow rate by monitoring the gas flow rate in a second cycle time.