Power Supply Arc Discharge Control Circuit
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Solution Overview
Problem
Existing power supply apparatuses for sputtering processes face issues with excessive discharge voltage and frequent arc discharge due to rapid current increases during and after arc processing, especially in large-area targets, leading to overvoltage and particle splashes.
Innovation Solution
A power supply apparatus with an output characteristics switching circuit that switches from constant-current to constant-voltage characteristics during and after arc discharge suppression, using an inductor and switching elements to control current rise and prevent overvoltage, and optionally employing a diode for simplified overvoltage management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the output characteristics of the power supply apparatus are changed to constant current during arc discharge suppression processing, then the increase in arc current can be prevented, but overvoltage occurs after arc processing due to inductance components
Solution Approach 1:
The power supply apparatus dynamically switches between constant current mode and constant voltage mode based on the arc discharge state. During arc discharge suppression processing, it operates in constant current mode to limit current increase, then switches to constant voltage mode after processing to prevent overvoltage, making the system adaptable to different operational phases
Solution Approach 2:
The invention changes the output characteristics parameter of the power supply from constant current to constant voltage at different stages. By switching the operating mode parameter based on whether arc discharge is occurring or has been suppressed, it optimizes performance for each stage while avoiding the drawbacks of maintaining a single mode
2Reliability
If switching elements are actuated to shut off arc energy supply, then overcurrent can be prevented, but rapid current increase cannot be avoided during the actuation time interval
Solution Approach 1:
The power supply apparatus is configured to switch to constant current mode before the switching elements are actuated to shut off arc energy. This preliminary action of changing output characteristics limits the rate of current rise during the actuation interval, preventing rapid current increase before the switching elements take effect
3Stability of the object's composition
If capacitors are disposed in parallel with the output to provide constant voltage characteristics, then voltage stability is improved, but overcurrent rapidly occurs during arc discharge
Solution Approach 1:
The invention makes the power supply characteristics dynamic by switching between constant voltage mode (with parallel capacitors) and constant current mode. During normal operation, constant voltage mode provides voltage stability, but during arc discharge detection, it switches to constant current mode to prevent overcurrent, adapting to the operational conditions
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
Effectively limits current rise during arc discharge and prevents excessive voltage, reducing the frequency of arc discharges and particle formation by maintaining stable plasma voltage, thereby improving film formation quality.
Implementation Method 1
an inductor and switching elements to control current rise
Implementation Method 2
a negative DC voltage is applied by a power supply apparatus to a target... thereby forming a plasma atmosphere
Implementation Method 3
arc discharge (anomalous electric discharge) occurs
Implementation Method 4
optionally employing a diode for simplified overvoltage management
Data Source
AI summary
Provided is a power supply apparatus which can effectively restrict the current rise at the time of occurrence of arc discharge that is directly related to the occurrence of splashes or particles, and which is also capable of preventing the discharge voltage from getting excessive at the time of finishing the arc processing. The power supply apparatus has: a DC power supply unit which applies a DC voltage to a target which comes into contact with a plasma; and an arc processing unit which can detect arc discharge generated in the electrode by positive and negative outputs from the DC power supply unit, and also which can perform arc discharge suppression processing. An output characteristics switching circuit switches the outputs such that the output to the electrode has constant-current characteristics and that the output to the electrode has constant-voltage characteristics by the time of completion of the arc suppressing processing.