Microwave Transceiver Antenna for Plasma Ion Density Measurement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current plasma diagnosis technologies, such as Langmuir probes and microwave probes, cannot accurately measure ion density in plasma, leading to difficulties in controlling ion density in thin film deposition and etching processes, as they primarily rely on electron density measurements.
Innovation Solution
A device using a transceiver antenna to apply and receive microwaves with varying frequencies, coupled with a frequency analyzer to measure cut-off frequencies, which are then converted into plasma ion density, allowing for accurate comparison and control of ion density in plasma processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If Langmuir probe is used to measure plasma density, then electron density can be obtained from I-V characteristic, but measurement accuracy is lowered and high voltage may change plasma
Solution Approach 1:
The patent replaces the mechanical Langmuir probe measurement system with an electromagnetic wave-based measurement system. Instead of using physical probes that require high voltage application, the invention uses microwave signals to measure plasma density through cut-off frequency detection, thereby eliminating the harmful effects of high voltage on plasma while maintaining measurement capability
Solution Approach 2:
The patent introduces microwave electromagnetic waves as an intermediary medium to measure plasma density indirectly through cut-off frequency analysis. This intermediary approach allows density measurement without direct physical contact or high voltage application to the plasma, avoiding plasma modification while achieving accurate measurements
2Measurement precision
If microwave frequency scanning is used to measure electron density, then plasma frequency can be analyzed, but ion density cannot be measured
Solution Approach 1:
The patent dynamically adjusts the microwave frequency scanning range and analysis method to detect both electron plasma frequency and ion plasma frequency characteristics. By making the measurement system adaptive to different frequency ranges and plasma conditions, the invention can extract both electron density and ion density information from the same electromagnetic wave interaction
Solution Approach 2:
The patent changes the analysis parameters of microwave frequency scanning to extract multiple types of plasma density information. By analyzing different aspects of the frequency response (cut-off frequencies at different ranges, resonance characteristics), the system can determine both electron density and ion density from the same measurement process
3Device complexity
If only electron density is measured in plasma, then plasma frequency analysis is simplified, but ion density control in thin film processes becomes impossible
Solution Approach 1:
The patent makes the microwave measurement system universal by enabling it to perform multiple measurement functions simultaneously. The same electromagnetic wave interaction and frequency analysis system can determine both electron density and ion density, eliminating the need for separate measurement systems while providing comprehensive plasma characterization for thin film process control
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
Enables precise measurement and control of ion density in plasma processes, improving the accuracy of thin film deposition and etching by distinguishing between ion and electron densities, thereby enhancing process control.
Implementation Method 1
a transceiver antenna (10) configured to apply and receive a microwave, of which a frequency is varied, to and from plasma
Implementation Method 2
a frequency analyzer (20) configured to analyze a frequency of the microwave received from the transceiver antenna (10) and measure a cut-off frequency
Data Source
AI summary
Disclosed herein is a device for measuring a plasma ion density, which includes a transceiver antenna configured to apply and receive a microwave, of which a frequency is varied, to and from plasma, and a frequency analyzer configured to analyze a frequency of the microwave received from the transceiver antenna and measure a cut-off frequency, wherein the frequency of the microwave applied to the plasma is varied in the range of 100 kHz to 500 MHz.