Planar Plasma Density Probe Layout Without Chamber Interference
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Solution Overview
Problem
Existing methods for observing plasma density in a chamber suffer from reduced accuracy and interference issues, particularly when using optical spectroscopy or probe insertion.
Innovation Solution
An apparatus and method utilizing a measuring cable that penetrates an upper plate with a planar-type probe to measure plasma density by deriving transmission coefficients, allowing for precise plasma density information in each position of the processing space without protruding into the space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a probe is directly inserted into the plasma processing space for direct measurement, then measurement precision is improved, but interference with plasma occurs and reliability deteriorates
Solution Approach 1:
The patent uses an upper plate with through-holes as an intermediary structure. The measuring cable passes through the upper plate to reach the plasma processing space, allowing measurement without direct probe insertion. This intermediary structure enables the measurement function while maintaining plasma integrity and avoiding interference.
2Reliability
If Optical Emission Spectroscopy is used for indirect plasma observation, then reliability is improved by avoiding interference, but measurement precision deteriorates
Solution Approach 1:
The patent replaces optical measurement methods with an electrical measurement approach. Instead of using Optical Emission Spectroscopy that measures light emission, the invention uses a measuring cable to directly measure electrical parameters (voltage, current, impedance) in the plasma space, providing more accurate measurements without optical interference issues.
3Measurement precision
If a probe protrudes into the processing space to measure plasma density, then measurement precision is improved, but device complexity increases and space is occupied
Solution Approach 1:
The upper plate serves multiple functions: it acts as a structural component of the chamber, provides support for the processing space, and simultaneously serves as a mounting structure for multiple measuring cables. This multi-functionality reduces overall device complexity while enabling precise measurements at multiple positions.
Solution Approach 2:
The measurement system is segmented into multiple through-holes in the upper plate, each accommodating a measuring cable for specific position measurements. This segmentation allows independent measurement at different locations without requiring a complex single probe structure, simplifying the overall device design.
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
Minimizes environmental impact and optimizes space usage while providing accurate plasma density measurements through a non-intrusive, planar-type probe configuration.
Implementation Method 1
measuring plasma density information in each position of the processing space based on a transmission coefficient measured using the measuring cable
Data Source
AI summary
The present disclosure relates to an apparatus for measuring plasma density and a method for measuring plasma density, the apparatus including: a chamber having a processing space therein; a plasma generating unit for generating plasma in the processing space; an upper plate disposed in an upper portion of the chamber and having a plurality of through-holes; and a measuring unit including a measuring cable penetrating the upper plate, and measuring plasma density in each position of the processing space based on the measured transmission coefficient using the measuring cable.