Resonant RF Structures for Plasma Uniformity Control
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Solution Overview
Problem
Plasma uniformity, particularly in high frequency plasma processes, is challenging due to standing waves that cause non-uniform plasma profiles, with higher frequencies exacerbating the issue and leading to desirable ion energy and flux qualities but poor spatial uniformity.
Innovation Solution
Incorporation of source-less resonant structures within the RF field of plasma processing chambers to induce localized electromagnetic effects, adjusting plasma properties through resonant frequency interaction and capacitance, without additional power sources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If higher frequency source power is used to generate plasma, then desirable ion energy and high ion and radical fluxes are achieved, but plasma uniformity deteriorates due to standing waves causing center-peaked profiles
Solution Approach 1:
The patent applies local quality by introducing resonant structures at specific locations within the plasma processing chamber to create localized electromagnetic fields. These structures modify plasma properties in specific regions (edge regions) without affecting the entire plasma volume, thereby addressing the uniformity problem locally while preserving the beneficial high-frequency plasma characteristics in the bulk.
Solution Approach 2:
The patent utilizes parameter changes by adjusting the resonant frequency of the introduced structures to match the source power frequency. By tuning the resonant structures' electrical characteristics (inductance, capacitance), the system creates controlled local field enhancements that modify plasma density distribution, transforming the center-peaked profile into a more uniform or edge-enhanced profile while maintaining high-frequency operation.
2Reliability
If source power frequency is increased to improve ion quality, then ion energy and flux increase, but standing wave effects worsen causing non-uniform plasma distribution
Solution Approach 1:
The patent introduces resonant structures as intermediary elements between the source power and the plasma. These structures act as mediators that couple the high-frequency source power to the plasma in a controlled manner, creating localized electromagnetic fields that enhance ion quality while simultaneously suppressing standing wave effects that cause non-uniform distribution.
Solution Approach 2:
The patent exploits resonant vibration principles by designing structures with specific resonant frequencies that match the source power frequency. When excited by the RF source, these structures undergo electromagnetic resonance, creating oscillating local fields that enhance plasma generation efficiency and improve ion quality while the resonant coupling suppresses unwanted standing waves in the main plasma volume.
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
Enhances plasma uniformity by increasing edge plasma density, providing real-time spatial control over plasma properties, and maintaining desirable ion energy and flux qualities.
Implementation Method 1
a resonant structure disposed in the RF field and configured to induce localized effects in the plasma using current induced in the resonant structure by the RF field
Implementation Method 2
adjusting plasma properties through resonant frequency interaction
Data Source
AI summary
A plasma processing apparatus includes a plasma processing chamber, a radio frequency waveguide, and a resonant structure. The plasma processing apparatus is configured to generate a plasma within the plasma processing chamber using a radio frequency field propagating through the radio frequency waveguide. The plasma includes a plasma sheath extending laterally along a surface of the radio frequency waveguide. The resonant structure is disposed in the radio frequency field and configured to induce localized effects in the plasma using current induced in the resonant structure by the radio frequency field.