Impedance Matching Network for Plasma Chamber Multi-Level Pulsing
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Solution Overview
Problem
Conventional impedance matching networks struggle to efficiently match the dynamic impedance of a plasma load during multi-level pulsing in plasma chambers, as they require significant time to adjust, which is slower than the rapid changes in plasma conditions caused by multi-level pulse signals, leading to suboptimal power delivery and plasma processing.
Innovation Solution
An impedance matching system with a controller that identifies each pulse interval of a multi-level pulse signal and adjusts an electronically switched impedance matching network to iteratively reduce impedance mismatch levels, using a combination of shunt and series capacitors and PIN diodes to quickly match the impedance, with configuration records stored for future intervals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional impedance matching networks are used to match plasma load impedance, then impedance matching is achieved, but the adjustment speed is too slow to keep up with rapid plasma condition changes during multi-level pulsing
Solution Approach 1:
The impedance matching network transitions from static mechanical adjustment to dynamic electronic switching. The system uses electronically controlled switches (such as PIN diodes or transistors) to rapidly reconfigure the matching network components, enabling the impedance to be adjusted in real-time according to plasma conditions during multi-level pulsing, thereby achieving both fast response and reliable power transfer
Solution Approach 2:
The patent replaces mechanical adjustment mechanisms (such as mechanical variable capacitors or inductors) with electronic switching systems. The electronically switched impedance matching network uses solid-state components to achieve rapid impedance transformation, eliminating the mechanical inertia and slow response inherent in conventional systems while maintaining accurate impedance matching for efficient power delivery
2Adaptability or versatility
If multi-level pulse signals are used to tailor plasma characteristics, then plasma customization is improved, but impedance mismatch increases due to rapid plasma condition changes
Solution Approach 1:
The system implements a feedback control mechanism where the actual plasma impedance is continuously monitored during multi-level pulsing, and the impedance matching network is dynamically adjusted in response to measured plasma conditions. This closed-loop control ensures that despite rapid plasma characteristic changes, the impedance remains matched, minimizing power loss while maintaining the desired plasma customization
Solution Approach 2:
The impedance matching network is synchronized with the periodic multi-level pulse signal, adjusting its configuration in sync with each pulse level transition. This periodic adaptation allows the system to maintain optimal impedance matching throughout the entire pulse cycle, ensuring efficient power transfer while achieving the desired time-dependent plasma characteristics
Data Source
Figure 1A
Figure 1B
Figure 2A~2B
AI summary
An impedance matching system includes an impedance matching network coupled between an alternating current (AC) generator and electrodes of a plasma chamber. The AC generator generates a multi-level pulse signal of cyclically recurring pulse intervals with differing amplitude levels. A controller identifies each recurring pulse interval, and for each pulse interval, determines an impedance mis-match level between the AC generator and the electrodes, adjusts a configuration of the impedance matching network according to the determined impedance mis-match level, and stores information associated with the adjusted configuration. When an ensuing pulse interval occurs, the controller obtains the stored information from memory, adjusts the configuration of the impedance matching network according to the stored information, determines another impedance mis-match level between the AC generator and the electrodes, and adjusts the configuration of the impedance matching network to iteratively reduce the impedance mismatch level.