Circular Waveguide Reflection Cancellation for Stable Plasma Processing
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Solution Overview
Problem
Existing plasma processing apparatuses face challenges in achieving uniform plasma generation and efficient microwave power utilization due to reflection issues, which can lead to increased manufacturing costs and reduced productivity.
Innovation Solution
The apparatus incorporates a circularly polarized wave generator and a reflected wave generator within the circular waveguide, which generates a reflected wave to cancel out the reflected wave from the processing chamber, ensuring efficient microwave power delivery and maintaining circularly polarized wave integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a conventional microwave plasma processing apparatus is used, then plasma can be generated, but the reflected wave from the processing chamber reduces microwave power utilization efficiency
Solution Approach 1:
The patent applies preliminary anti-action by introducing a reflected wave generator that produces a reflected wave in advance to cancel out the harmful reflected wave from the processing chamber. The reflected wave generator creates an opposing wave that interferes destructively with the unwanted reflection, thereby preventing energy loss and improving microwave power utilization efficiency before the reflected wave can cause problems.
Solution Approach 2:
The patent converts the harmful reflected wave into a beneficial component by using the reflected wave generator to create a controlled reflected wave that cancels the unwanted one. The generator transforms the problematic reflection into a useful tool for improving plasma generation stability and microwave power utilization by manipulating wave interference patterns.
2Adaptability or versatility
If the plasma processing conditions are expanded, then more versatile processing is possible, but plasma uniformity may deteriorate
Solution Approach 1:
The patent implements feedback by using a reflected wave generator that continuously monitors and compensates for reflected waves from the processing chamber. This feedback mechanism allows the system to maintain plasma uniformity across varying processing conditions by dynamically adjusting the canceling reflected wave, thereby enabling versatile processing while preserving manufacturing precision.
3Power
If a circular waveguide is used for microwave transmission, then plasma generation is efficient, but reflected waves cause impedance mismatching
Solution Approach 1:
The patent introduces an intermediary component - the reflected wave generator - that mediates between the circular waveguide and the processing chamber. This intermediary device manages impedance mismatching by generating a reflected wave that cancels the harmful reflections, thereby maintaining efficient power transmission while simplifying the overall impedance matching requirements.
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 enhances plasma uniformity and stability, expands the conditions for plasma generation, and improves the utilization of microwave power, thereby reducing manufacturing costs and increasing productivity.
Implementation Method 1
a circularly polarized wave generator (0408) disposed inside the circular waveguide (0407) and generating a circularly polarized wave
Implementation Method 2
a reflected wave generator (0409) disposed between the circularly polarized wave generator (0408) and the processing chamber (0414) and generating a reflected wave that cancels, without inhibiting the circularly polarized wave, a reflected wave propagating from the processing chamber
Implementation Method 3
a plasma processing apparatus including: a processing chamber (0414) configured to plasma-process a sample; a radio frequency power supply configured to supply, via a circular waveguide (0407), radio frequency power of a microwave
Data Source
AI summary
In a plasma processing apparatus using a circularly polarized wave, in order to reduce an influence caused by a reflected wave and to efficiently utilize a circularly polarized wave for a plasma process, the plasma processing apparatus includes a microwave source configured to generate a microwave, a plasma processing chamber configured to process a processing target disposed therein by using plasma generated by the microwave, and a waveguide portion that includes a rectangular waveguide connected to the microwave source and a circular waveguide connected to the plasma processing chamber, and the plasma processing apparatus is further provided with, inside the circular waveguide, a reflected wave generator configured to generate a reflected wave that cancels a reflected wave propagating in the circular waveguide from a plasma processing chamber side in a state where the plasma is generated inside the plasma processing chamber by the microwave.