RF Plasma Source Frequency Modulation for Reflection Suppression
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Solution Overview
Problem
Existing plasma processing apparatuses face challenges in reducing the reflection of source radio frequency power, which affects the efficiency and stability of plasma generation.
Innovation Solution
A plasma processing apparatus with a radio frequency power supply that adjusts the source frequency in a temporal change pattern by dividing the waveform cycle into multiple periods, optimizing the source frequency at specific time points to minimize reflection, using interpolation and sequential adjustments to determine the optimal temporal change pattern.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the source frequency is kept constant, then the plasma processing apparatus is simple to operate, but the degree of reflection of source radio frequency power increases
Solution Approach 1:
The source frequency is changed dynamically over time rather than remaining constant. The radio frequency power supply varies the source frequency according to a temporal change pattern that minimizes reflection, transforming the static frequency into a dynamic parameter that adapts to plasma conditions.
Solution Approach 2:
The source frequency parameter is changed over time to optimize plasma generation efficiency. By varying the frequency parameter according to a predetermined temporal change pattern, the system reduces power reflection while maintaining ease of operation through automated control.
2Loss of energy
If the source frequency is changed frequently, then the degree of reflection of source radio frequency power is reduced, but the control complexity increases
Solution Approach 1:
The temporal change pattern of the source frequency is determined in advance before plasma processing begins. The radio frequency power supply stores a predetermined frequency variation pattern and executes it automatically, avoiding the need for complex real-time calculations and measurements during operation.
Solution Approach 2:
The source frequency varies periodically according to a predetermined temporal change pattern. This periodic variation is designed to minimize power reflection while maintaining simple control through automated execution of the pre-determined pattern.
3Productivity
If the source frequency is modulated dynamically, then the efficiency of plasma generation is improved, but the stability of plasma generation deteriorates
Solution Approach 1:
The optimal temporal change pattern is determined in advance through calculations or experiments before plasma processing. This pre-determined pattern ensures that the frequency variation improves plasma generation efficiency while maintaining stability, as the pattern is optimized for the specific processing conditions.
Solution Approach 2:
The system includes a measurement unit that measures plasma generation efficiency and provides feedback to the control unit. The control unit adjusts the temporal change pattern based on this feedback to maintain both high efficiency and stable plasma generation during the process.
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
This approach effectively reduces the degree of reflection of source radio frequency power, enhancing the efficiency and stability of plasma generation.
Implementation Method 1
The radio frequency power supply is configured to supply a source radio frequency power to generate plasma from a gas in the chamber
Implementation Method 2
The bias power supply is configured to supply an electric bias having a waveform cycle to the substrate support... uses a bias radio frequency power to attract ions from the plasma generated in the chamber onto the substrate
Data Source
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AI summary
In a disclosed plasma processing apparatus, a radio frequency power supply determines a first temporal change pattern of a source frequency of the source radio frequency power which most suppresses degree of reflection of the source radio frequency power, while changing the source frequencies of first time points in a waveform cycle of an electric bias and interpolating the source frequency in each of first division periods in the waveform cycle divided by the first time points. The radio frequency power supply determines a second temporal change pattern of the source frequency which most suppresses degree of reflection of the source radio frequency power, while changing the source frequencies of second time points in the waveform cycle from the first temporal change pattern or the derived pattern and interpolating the source frequency in each of second division periods in the waveform cycle by the second time points.