Planar Plasma Antenna Layout for Accurate Density Measurement
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Solution Overview
Problem
Existing plasma diagnosis methods face challenges in accurately measuring plasma density due to structural interference, low signal intensity, and resonance signals caused by the insertion of frequency probes, leading to unreliable measurements.
Innovation Solution
A planar-type plasma diagnosis apparatus with insulated transmission and reception antennas, buried in a wafer-shaped circular member or electrostatic chuck, enhances capacitive coupling and minimizes structural interference, allowing for real-time plasma density measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a frequency probe is inserted into the plasma to measure plasma density, then plasma density can be measured, but structural interference with the plasma is caused and measurement accuracy is reduced due to perturbation of surrounding plasma density
Solution Approach 1:
The invention extracts the harmful probe structure from the plasma environment by using a planar antenna configuration that operates through capacitive coupling with the plasma rather than physical insertion. The transmission and reception antennas are positioned to measure plasma density through electromagnetic field interaction without mechanical contact, thereby eliminating structural interference while maintaining measurement capability
Solution Approach 2:
The invention introduces an intermediary capacitive coupling mechanism between the antenna system and the plasma. Instead of direct probe insertion, the planar antennas create an electric field that couples capacitively with the plasma, allowing measurement of plasma density through the intermediary electromagnetic field without direct structural contact that would cause perturbation
2Measurement precision
If transmission and reception antennas are disposed in a concentric structure with ring-shaped reception antenna, then cut-off frequency can be detected, but resonance signals occur due to structural characteristics making reliable plasma density measurement difficult
Solution Approach 1:
The invention applies asymmetry by positioning the transmission and reception antennas in a non-concentric, non-symmetric arrangement. The planar antennas are disposed at specific orientations and positions that break the symmetry of conventional ring-shaped structures, thereby eliminating the resonance signals that arise from symmetric geometric configurations while maintaining the ability to detect cut-off frequency for plasma density measurement
3Measurement precision
If an ultra-high frequency transmission/reception antenna is formed in a planar-type, then plasma density can be obtained from cut-off frequency, but signal intensity is too low making it difficult to measure plasma density
Solution Approach 1:
The invention transitions from conventional three-dimensional probe structures to a two-dimensional planar antenna configuration. This dimensional change allows for larger effective antenna area and improved capacitive coupling with the plasma, thereby increasing signal intensity while maintaining the planar geometry needed for high-frequency operation and cut-off frequency detection capability
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 reliable plasma density measurement by increasing signal intensity and preventing resonance signals, while minimizing structural changes in the plasma chamber, facilitating real-time monitoring during the plasma process at low cost.
Implementation Method 1
increases capacitive coupling between transmission/reception antennas
Implementation Method 2
apply a frequency-variable microwave to plasma; receive the microwave from the plasma
Implementation Method 3
forming an ultra-high frequency transmission/reception antenna for measuring the plasma cut-off frequency
Data Source
Figure 1(a)~1(c)
Figure 2~3
Figure 4A~4B
AI summary
The present invention relates to a planar-type plasma diagnosis apparatus comprising: a transmission antenna for applying a frequency-variable microwave to plasma; a reception antenna for receiving the microwave from the plasma; and a body part encompassing the transmission antenna and the reception antenna so that same are insulated from each other, wherein the upper surface of the transmission antenna for applying the microwave and the upper surface of the reception antenna for receiving the microwave are planar, and side surfaces of the upper surfaces of the transmission antenna and the reception antenna face each other.