Pulsed-DC Power Generator for Adaptive Arc Extinction in Sputtering
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Solution Overview
Problem
Conventional pulsed-DC power generators with fixed voltage ratios and pulse frequencies struggle to effectively suppress arcs in plasma systems, leading to slow sputtering rates and poor film quality due to excessive recovery voltages causing secondary arcs.
Innovation Solution
A pulsed-DC power generator with a control unit that automatically adjusts arc extinction parameters by integrating first and second voltages with opposite polarities, using a switch unit and detection unit to manage pulse voltage, and implementing a soft-start period to prevent excessive recovery voltage surges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional fixed voltage ratio and pulse frequency output is used, then device complexity is reduced, but arc extinction effectiveness deteriorates resulting in poor film quality
Solution Approach 1:
The patent implements dynamic adjustment of pulse width modulation parameters (duty cycle, frequency, voltage level) based on real-time arc detection. The control unit automatically modifies the positive voltage power supply parameters during operation to optimize arc extinction, transitioning from fixed to dynamic control to improve film quality while maintaining manageable device complexity through automated feedback control.
Solution Approach 2:
The patent employs a feedback mechanism where the system detects arc occurrence and automatically adjusts the pulse width modulation parameters of the positive voltage power supply. The control unit receives information about arc events and modifies the duty cycle, frequency, or voltage level accordingly, creating a closed-loop control system that improves film quality by adapting to real-time plasma conditions.
2Speed
If rapid pulse voltage change is used to detect arc, then arc detection speed is improved, but recovery voltage surge increases causing secondary arcs
Solution Approach 1:
The patent applies preliminary anti-action by implementing a soft-start period after arc extinction where the pulse width modulation parameters are gradually adjusted rather than abruptly changed. The control unit progressively increases the duty cycle or frequency during this recovery period, preventing sudden voltage surges that would cause secondary arcs while maintaining the ability to rapidly detect arcs through controlled voltage transitions.
Solution Approach 2:
The patent utilizes periodic action by implementing a structured pulse width modulation cycle with distinct phases: normal operation, arc detection, arc extinction, and soft-start recovery. Each phase has specific parameter settings, and the system transitions between these periodic states based on arc conditions. This periodic structure allows rapid arc detection during normal operation while ensuring controlled recovery during the soft-start phase to prevent secondary arcs.
3Device complexity
If fixed arc extinction parameters are used, then device complexity is reduced, but arc extinction effectiveness deteriorates leading to continuous arcs
Solution Approach 1:
The patent implements self-service by enabling the power supply system to automatically adjust its own operating parameters in response to arc conditions. The control unit monitors arc events and autonomously modifies the pulse width modulation parameters of the positive voltage power supply without external intervention. This self-adjusting capability improves arc extinction reliability while keeping the device complexity manageable through automated control logic.
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 effectively extinguishes arcs and stabilizes film quality by automatically adjusting arc extinction parameters and using a soft-start period to prevent secondary arcs, ensuring consistent and high-quality sputtering processes.
Implementation Method 1
The first voltage source generates a first voltage. The second voltage source generates a second voltage with a polarity opposite to the first voltage. The switch unit is coupled between the first voltage source and the second voltage source. The control unit provides a first control signal to control the switching of the switch unit so that the first voltage and the second voltage generate a pulse voltage at an output end.
Implementation Method 2
The detection unit is coupled to the output end and the control unit, and detects the pulse voltage at the output end. The control unit switches the pulse voltage to the second voltage for a first determined time period when the pulse voltage is in a working time period of the first voltage and a voltage variation of the first voltage is higher than a range.
Data Source
AI summary
A pulsed-DC power generator is used to sputter a substrate in a chamber, and the power generator includes a first voltage source, a second voltage source, a switch unit, a control unit, and a detection unit. The control unit provides a first control signal to control the switching of the switch unit to integrate a first voltage of the first voltage source and a second voltage of the second voltage source into a pulse voltage. The control unit adjusts parameters of a first predetermined time period for arc extinction when the pulse voltage is in a working time period of the first voltage, and the number that a voltage value of the first voltage in a voltage variation to be higher than a range is higher than the number of occurrence.