Chamber Plasma Detection Using Ambient Light Sensing
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Solution Overview
Problem
In semiconductor manufacturing facilities, particularly in descum facilities, the existing end point detectors (EPDs) using optical emission spectroscopy have low efficiency and are often not used due to high costs, making it difficult to immediately identify when plasma is not discharged within the chamber, leading to inefficiencies and potential process issues.
Innovation Solution
A detection device comprising a measurement unit with an illumination sensor and a detection unit that analyzes light within the chamber to determine plasma generation, using an ambient light sensor, amplifiers, and comparators to convert light measurements into voltage values, allowing for the identification of plasma presence through a preset detection point, and optionally including a selector, amplifier, and converter for different plasma process conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an end point detector (EPD) using optical emission spectroscopy is used to detect plasma generation, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent replaces the expensive EPD with a simple ambient light sensor that detects plasma-generated light. This cheap sensor provides sufficient detection capability for plasma presence/absence without the complexity and cost of spectral analysis equipment.
Solution Approach 2:
The patent extracts only the essential function of plasma detection from the complex EPD system. Instead of analyzing full spectral information, it simply detects the presence of light emitted during plasma generation, achieving the core detection function with minimal complexity.
2Measurement precision
If an end point detector (EPD) is installed in descum facility, then measurement precision is improved, but productivity decreases due to high cost and low utility
Solution Approach 1:
The patent employs a low-cost ambient light sensor instead of the expensive EPD, making the detection system economically viable for descum facilities where plasma detection is needed but budget is constrained.
Solution Approach 2:
Instead of using complex spectral analysis to detect plasma, the patent inverts the approach by simply detecting the presence or absence of light emission, which is sufficient for plasma detection in descum applications.
3Device complexity
If no plasma detection device is installed, then device complexity is reduced, but loss of information increases as plasma status cannot be immediately identified
Solution Approach 1:
The patent uses the plasma process itself to generate the detection signal. The plasma generates light during operation, and the simple light sensor detects this self-generated signal, eliminating the need for external complex detection equipment.
Solution Approach 2:
The patent detects plasma presence through light emission (color/brightness changes) during plasma generation. The ambient light sensor monitors the visual emission characteristics that naturally occur during plasma discharge.
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
The device efficiently detects plasma presence or absence, improving productivity by replacing costly EPDs and enabling real-time monitoring of plasma processes, thus enhancing process control and maintenance capabilities.
Implementation Method 1
analyze wavelengths of light emitted from plasma by applying an end point detector (EPD) using an optical emission spectroscopy (OES) technology
Implementation Method 2
the illumination sensor may include an ambient light sensor of a current output type
Data Source
AI summary
Disclosed is a detection device which includes a measurement unit including an illumination sensor that measures an amount of light in an interior of a chamber, and a detection unit that detects whether plasma is generated in the interior of the chamber, through analysis of the amount of the light.