RF Power Supply Frequency Control to Reduce Plasma Reflected Waves
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Solution Overview
Problem
Existing plasma processing apparatuses face challenges in reducing the power level of reflected radio-frequency power waves, which can lead to inefficiencies and potential damage during plasma processing.
Innovation Solution
A plasma processing apparatus with a radio-frequency power supply that selects an initial frequency group corresponding to a specified process and adjusts the source frequencies in subsequent periods to decrease the power level of reflected waves by using a transformation matrix to minimize errors and optimize frequency settings based on process conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the radio-frequency power supply uses a fixed frequency for source radio-frequency power, then the system operation is simple, but the power level of reflected waves cannot be effectively reduced
Solution Approach 1:
The patent applies dynamics by transitioning from a fixed frequency system to a dynamic frequency adjustment system. The radio-frequency power supply continuously or periodically adjusts the source frequency based on real-time impedance matching requirements, allowing the system to adapt to changing plasma conditions and minimize reflected wave power levels through active frequency control
Solution Approach 2:
The patent implements feedback by using a sensor to detect the impedance state of the plasma load and feeding this information back to the radio-frequency power supply. This closed-loop control enables the system to automatically adjust the source frequency to maintain optimal impedance matching, thereby reducing reflected wave power levels through continuous monitoring and adjustment
2Productivity
If the radio-frequency power supply dynamically adjusts frequency to reduce reflected waves, then energy efficiency improves, but the control system complexity increases
Solution Approach 1:
The patent applies self-service by enabling the radio-frequency power supply to automatically adjust its own operating frequency based on feedback from the plasma impedance sensor. The system performs self-diagnosis and self-adjustment without requiring external intervention, maintaining optimal plasma processing efficiency through autonomous frequency control while minimizing reflected wave power
Solution Approach 2:
The patent implements parameter changes by dynamically varying the source frequency parameter in response to changing plasma conditions. The system monitors impedance parameters and adjusts the frequency parameter accordingly, allowing the plasma processing efficiency to be maintained or improved while reducing reflected wave power through continuous parameter optimization
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 reduces the power level of reflected radio-frequency power waves, enhancing the efficiency and safety of plasma processing by dynamically adjusting frequencies in response to process conditions.
Implementation Method 1
The radio-frequency power supply is electrically coupled to a radio-frequency electrode to generate source radio-frequency power to generate plasma from a gas in the chamber
Implementation Method 2
The bias power supply is electrically coupled to the substrate support to generate electrical bias energy. The electrical bias energy has a bias frequency
Implementation Method 3
The radio-frequency power supply adjusts, in a second period subsequent to the first period, the plurality of source frequencies of the source radio-frequency power for the respective plurality of phase periods in a waveform cycle of the electrical bias energy to decrease a power level of a reflected wave of the source radio-frequency power from a load
Data Source
AI summary
In a plasma processing apparatus, electrical bias energy is provided from a bias power supply to a substrate support. Source radio-frequency power is provided from a radio-frequency power supply to a radio-frequency electrode. The radio-frequency power supply selects, from a plurality of frequency groups, an initial frequency group corresponding to a specified process. The radio-frequency power supply uses, in a first period, a plurality of frequencies included in the initial frequency group as a plurality of source frequencies of the source radio-frequency power for a respective plurality of phase periods in a waveform cycle of the electrical bias energy. The radio-frequency power supply adjusts, in a second period, the plurality of source frequencies of the source radio-frequency power for the respective plurality of phase periods in a waveform cycle of the electrical bias energy.