RF Power Source Symmetric Frequency Segmentation
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Solution Overview
Problem
Current plasma processing apparatuses using radio frequency power sources face challenges in efficiently generating plasma with narrow bandwidth pulsed radio frequency power, leading to increased reflected waves due to narrow impedance matching frequency ranges.
Innovation Solution
A radio frequency power source is designed to generate power with multiple frequency components symmetrically spaced around a fundamental frequency, featuring pulses with zero power levels between peaks, narrowing the bandwidth and optimizing energy delivery to substrates through synchronized pulsed radio frequency and bias power cycles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If rectangular pulse radio frequency power is supplied periodically, then plasma generation is achieved, but reflected waves increase due to narrow bandwidth
Solution Approach 1:
The radio frequency power is segmented into multiple frequency components (fundamental frequency and harmonic frequencies) rather than using a single rectangular pulse. This segmentation into frequency components broadens the bandwidth, reducing reflected waves while maintaining effective plasma generation.
Solution Approach 2:
The waveform is transformed from a static rectangular pulse to a dynamic composite waveform with multiple frequency components. The power waveform is constructed to have zero power levels between peaks, creating a more dynamic signal that adapts to the plasma load impedance variations, thereby reducing reflections.
2Use of energy by moving object
If narrow bandwidth pulsed radio frequency power is used, then energy delivery is concentrated, but impedance matching frequency range becomes too narrow
Solution Approach 1:
The power signal is divided into multiple frequency segments (fundamental and harmonic components) that collectively provide both concentrated energy delivery and broad impedance matching capability. Each frequency component contributes to the overall energy transfer while the combination ensures wide bandwidth adaptability.
Solution Approach 2:
The radio frequency power is constructed as a composite signal combining multiple frequency components with specific amplitude and phase relationships. This composite waveform achieves both narrow pulse duration for concentrated energy delivery and broad spectral content for wide impedance matching range.
3Loss of energy
If pulsed radio frequency power with multiple frequency components is supplied, then bandwidth is narrowed and reflected waves are suppressed, but device complexity increases
Solution Approach 1:
The power generator supplies pulsed radio frequency power with periodic timing, where pulses are delivered at specific intervals with zero power levels between peaks. This periodic action pattern, combined with multiple frequency components, suppresses reflected waves while maintaining manageable device complexity through rhythmic power delivery.
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 configuration reduces the bandwidth of pulsed radio frequency power, suppressing reflected waves and allowing for precise energy adjustment of ions supplied to substrates, even with narrow impedance matching frequency ranges.
Implementation Method 1
a power generator configured to generate radio frequency power HF
Implementation Method 2
In order to generate a plasma from the gas, radio frequency power is supplied by the radio frequency power source
Data Source
AI summary
A radio frequency power source according to an exemplary embodiment includes a power generator configured to generate radio frequency power. The radio frequency power includes a plurality of power components. The plurality of power components respectively have a plurality of frequencies set symmetrically with respect to a fundamental frequency at an interval of a predetermined frequency. The envelope of the radio frequency power has peaks that periodically appear at a time interval defined by the predetermined frequency or a frequency that is a multiple of twice or more the predetermined frequency. The power level of the radio frequency power is set to be zero in a period excluding a period between a zero-cross region of the envelope immediately before a point in time of appearance of each of the peaks and a zero-cross region of the envelope immediately after the point in time of the appearance.