Self-Sustained Non-Ambipolar DC Plasma for Low Power Etching
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Solution Overview
Problem
Conventional reactive ion etching (RIE) techniques face challenges in controlling high-energy ions, leading to broad ion energy distribution, charge damage, and non-uniform etching due to the continuous power supply required to maintain electron beam excited plasma, which affects power efficiency and processing costs.
Innovation Solution
A self-sustained non-ambipolar plasma processing system is introduced, featuring an electron beam source chamber and an ion beam source chamber with a dielectric injector, where high-energy electrons and ions are exchanged to maintain plasma without continuous RF power, using a voltage potential gradient to sustain electron beam source plasma and electron beam excited plasma, thereby reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional RIE techniques are used with continuous power supply to maintain electron beam excited plasma, then plasma density is maintained, but power consumption increases significantly
Solution Approach 1:
The system uses pulsed electron beam excitation instead of continuous power supply. The electron beam is applied in periodic pulses to maintain plasma density, allowing the plasma to sustain itself between pulses through ion feedback mechanisms, thereby significantly reducing overall power consumption while maintaining adequate plasma density for etching processes
Solution Approach 2:
The plasma becomes self-sustaining through a feedback mechanism where ions generated in the plasma return to the electron beam source chamber and sustain the electron beam excitation process. This self-service mechanism allows the plasma to maintain itself without continuous external power input, reducing power consumption while maintaining plasma density
2Power
If high-energy ions are generated in conventional etch processes, then etching capability is improved, but control precision decreases due to broad ion energy distribution
Solution Approach 1:
The system segments the plasma generation and etching processes into separate chambers. The electron beam source chamber generates plasma with controlled ion energy, while the process chamber performs etching. This spatial segmentation allows independent optimization of ion energy control in the source chamber and etching capability in the process chamber, resolving the contradiction between control precision and etching power
Solution Approach 2:
The dielectric injector acts as an intermediary component that transports ions from the electron beam source chamber to the process chamber. This intermediary allows the system to maintain precise ion energy control during transport while preserving high etching capability at the substrate, separating the control function from the etching function
3Strength
If continuous power is supplied to electron beam source chamber, then electron beam strength is maintained, but power efficiency decreases
Solution Approach 1:
The electron beam is applied in periodic pulses rather than continuously. The pulsed operation maintains adequate electron beam strength during active etching phases while allowing power consumption to drop during idle phases, significantly improving power efficiency while maintaining necessary beam strength for effective etching
Solution Approach 2:
The plasma ions return to the electron beam source chamber and sustain the electron beam excitation process. This self-service mechanism reduces the external power needed to maintain electron beam strength, improving power efficiency while maintaining adequate beam strength through the self-sustaining ion feedback
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 enhances power efficiency by minimizing the RF power needed to maintain the electron beam, improving the precision and uniformity of substrate treatment while reducing processing costs.
Implementation Method 1
The electron beam source chamber is configured to excite electron beam source plasma and supply electrons for the ion beam source chamber to excite plasma (electron beam excited plasma)
Implementation Method 2
An energy field is generated from a voltage potential gradient applied between the electron beam source chamber and ion beam source chamber
Implementation Method 3
The dielectric injector is also configured to inject high-energy ions from the ion beam source chamber into the electron beam source chamber
Implementation Method 4
The ion beam source chamber is configured to excite electron beam excited plasma and supply ions to the electron beam source chamber
Data Source
AI summary
A processing system is disclosed, having an electron beam source chamber that excites plasma to generate an electron beam, and an ion beam source chamber that houses a substrate and also excites plasma to generate an ion beam. The processing system also includes a dielectric injector coupling the electron beam source chamber to the ion beam source chamber that simultaneously injects the electron beam and the ion beam and propels the electron beam and the ion beam in opposite directions. The voltage potential gradient between the electron beam source chamber and the ion beam source chamber generates an energy field that is sufficient to maintain the electron beam and ion beam as a plasma treats the substrate so that radio frequency (RF) power initially applied to the processing system to generate the electron beam can be terminated thus improving the power efficiency of the processing system.