RF Supply Impedance Converter for Plasma Chamber
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Solution Overview
Problem
Conventional RF supply systems for plasma processing suffer from high transmission loss and heat generation, limited flexibility in the size and location of the matching unit, and inability to adapt to larger process chamber diameters due to impedance mismatch and inefficient power distribution.
Innovation Solution
Incorporating an impedance converter on the transmission path between the matching unit and the RF electrode to transform the load impedance to a higher value, reducing transmission loss and heat generation, and allowing for a more compact and flexible design of the matching unit and RF generation mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a conventional matching unit is used to supply RF power to the electrode, then the RF power can be delivered to the plasma processing chamber, but transmission loss and heat generation are high
Solution Approach 1:
The patent divides the matching unit into two separate functional sections: a first matching section that matches the impedance of the RF power supply with the transmission path, and a second matching section that matches the impedance of the transmission path with the electrode. This segmentation allows each section to operate at optimized impedance levels, reducing overall transmission loss and heat generation in the RF power supply system.
2Adaptability or versatility
If a conventional matching unit is used, then RF power supply is achieved, but the size and location flexibility of the matching unit is limited
Solution Approach 1:
By dividing the matching unit into two separate matching sections, each section can be designed more compactly and positioned at different locations along the transmission path. The first matching section can be placed near the RF power supply while the second matching section can be positioned closer to the electrode, providing greater location flexibility and reducing the overall volume requirement for each individual component.
3Adaptability or versatility
If the process chamber diameter is increased to handle larger substrates, then processing capability is improved, but impedance mismatch and power distribution efficiency deteriorate
Solution Approach 1:
The segmented matching unit structure enables independent optimization for different process chamber sizes. When the process chamber diameter is increased, the second matching section can be adjusted to compensate for the changed impedance characteristics of the larger electrode structure, while the first matching section maintains optimal coupling with the RF power supply. This allows the system to maintain high power distribution efficiency across different chamber sizes.
Solution Approach 2:
The patent employs adjustable impedance parameters in both matching sections that can be modified to adapt to different process chamber diameters. By changing the impedance values in the matching circuits, the system can optimize power transfer efficiency for various chamber sizes, from small research chambers to large production-scale chambers handling bigger substrates.
Data Source
AI summary
An RF supply system is to be connected to an RF electrode disposed outside or inside a process chamber to assist a plasma process performed in the process chamber. This system includes an RF power supply, a matching unit, and an impedance converter. The RF power supply is configured to supply an RF power for plasma generation to the electrode through a transmission path. The matching unit is disposed on the transmission path between the RF power supply and the electrode, and configured to match a load impedance viewing from the RF power supply with an impedance of the RF power supply side. The impedance converter is disposed on the transmission path between the matching unit and the electrode, and configured to convert a load impedance viewing from the matching unit to an impedance higher than an actual impedance on the electrode side.