Dual-Frequency RF Power Supply Matching Before Frequency Modulation
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Solution Overview
Problem
High-frequency power supply devices used in plasma processing face interference between impedance matching and frequency modulation control, leading to suboptimal performance due to intermodulation distortion, which affects reflected wave power.
Innovation Solution
A high-frequency power supply device with separate matching units for each power supply and sequential impedance matching and frequency modulation control, where the first matching operation is performed to reduce intermodulation distortion, followed by frequency modulation control using a modulation signal with the same frequency as the second fundamental frequency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If frequency modulation control is performed simultaneously with impedance matching operation, then reflected wave power can be reduced, but the matching operation and frequency modulation control interfere with each other and cannot be appropriately performed
Solution Approach 1:
The patent applies preliminary action by completing the impedance matching operation before initiating frequency modulation control. The controller first adjusts the matching network to achieve impedance matching between the power supply and load, then subsequently applies frequency modulation to the matched state. This sequential approach prevents the two control operations from interfering with each other while still achieving the dual benefits of reduced reflected power and proper control execution.
2Reliability
If impedance matching operation is performed, then impedance matching between power supply and load is achieved, but intermodulation distortion occurs when multiple high-frequency powers are simultaneously supplied
Solution Approach 1:
The patent applies preliminary action by first establishing proper impedance matching through the matching network before introducing frequency modulation. By completing the matching operation in advance, the system ensures reliable impedance matching is achieved, and then frequency modulation is applied to the already-matched state, reducing intermodulation distortion effects.
Solution Approach 2:
The patent applies parameter changes by modulating the frequency parameter of the high-frequency voltage output. The controller varies the frequency of the first high-frequency voltage within a predetermined range to reduce intermodulation distortion while maintaining the benefits of impedance matching. This frequency parameter adjustment allows the system to optimize performance by changing the operating frequency dynamically.
Data Source
AI summary
A high-frequency power supply device includes: a first power supply that supplies first high-frequency power to a load by outputting a first high-frequency voltage having a first fundamental frequency; a second power supply that supplies second high-frequency power to the load by outputting a second high-frequency voltage having a second fundamental frequency lower than the first fundamental frequency; a first matching unit that performs a first matching operation of matching an impedance of the first power supply with an impedance of the load in a state in which intermodulation distortion caused by the first high-frequency power and the second high-frequency power being simultaneously supplied to the load, occurs. The first power supply frequency-modulates the first high-frequency voltage with a modulation signal having a same frequency as the second fundamental frequency to output a modulated wave after the first matching operation is completed.