Plasma Electrode Frequency Tuning for Selective Ion Energy Control
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Solution Overview
Problem
Existing plasma processing apparatuses struggle to selectively adjust the energy of specific types of ions, as they typically change the acceleration of all ions based on plasma sheath thickness, making it difficult to control the energy of only specific types of ions.
Innovation Solution
A plasma processing apparatus that measures the state of plasma and obtains the ion plasma frequency for specific types of ions using a network analyzer and Langmuir probe, applying a high-frequency voltage of the corresponding frequency to selectively increase the energy of these ions through an intermediate electrode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If plasma sheath thickness is changed to adjust ion energy, then the energy of ions can be adjusted, but only specific types of ions cannot be selectively adjusted
Solution Approach 1:
The patent applies electromagnetic vibration at the ion plasma frequency to selectively resonate and accelerate specific ion types. By tuning the frequency of the applied electric field to match the natural plasma frequency of target ions, these ions experience resonant acceleration while other ion types remain unaffected, achieving selective energy adjustment based on ion mass and charge characteristics.
Solution Approach 2:
The patent changes the frequency parameter of the applied electric field to match the ion plasma frequency of specific ion types. By adjusting the frequency rather than just the amplitude or sheath thickness, the system can selectively target different ion species based on their unique plasma frequencies, which depend on ion mass, charge, and density.
2Power
If all ions are accelerated by changing plasma sheath thickness, then ion energy is increased, but selective control over specific ion types is lost
Solution Approach 1:
The patent uses resonant electromagnetic vibration at the ion plasma frequency to selectively accelerate specific ion types. This resonance approach provides precise control over which ions gain energy, as only ions matching the applied frequency experience significant acceleration, enabling manufacturing precision in ion energy control.
Solution Approach 2:
The system measures the ion plasma frequency and uses this information to adjust the applied frequency, creating a feedback loop that ensures precise targeting of specific ion types. This feedback mechanism maintains accurate frequency matching despite changes in plasma conditions, preserving manufacturing precision.
3Adaptability or versatility
If a broadband power supply is used to apply high-frequency voltage at ion plasma frequency, then selective ion energy enhancement is achieved, but device complexity increases
Solution Approach 1:
The broadband power supply serves multiple functions: it generates the high-frequency voltage, allows frequency tuning to match different ion plasma frequencies, and can be adjusted for different power levels. This multi-functionality consolidates what would otherwise require separate components into a single versatile device, reducing overall system complexity.
Solution Approach 2:
The broadband power supply enables frequency parameter changes to match different ion plasma frequencies, allowing a single device to handle multiple ion types and processing conditions. This parameter adjustability replaces the need for multiple fixed-frequency power supplies, simplifying the device architecture while maintaining selectivity.
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 allows for the selective enhancement of specific ion energy, enabling precise plasma processing such as anisotropic or isotropic film formation and etching by actively using specific types of ions on a substrate.
Implementation Method 1
the first electrode applies a high-frequency voltage into the processing chamber to generate the plasma from the processing gas
Implementation Method 2
the controller applies a high-frequency voltage of the ion plasma frequency from the second electrode to the plasma by setting the frequency of the high-frequency power supplied from the second high-frequency power supply to the second electrode as the ion plasma frequency
Data Source
AI summary
A plasma processing apparatus, comprising: a processing chamber; a gas supply part; a first electrode and a second electrode facing each other; first and second high-frequency power supply for supplying high-frequency powers to the first and second electrodes; a sensor part for measuring a state of plasma in the processing chamber; and a controller, wherein the first electrode applies a high-frequency voltage to generate the plasma from the processing gas, the second high-frequency power supply is a broadband power supply that is capable of setting a frequency of the high-frequency power supplied to the second electrode, the controller obtains an ion plasma frequency for a specific type of ion based on the measurement result, and the controller applies a high-frequency voltage of the ion plasma frequency to the plasma by setting the frequency of the high-frequency power supplied from the second high-frequency power supply as the ion plasma frequency.