Low-Pressure Halide Gas Analysis for SiF4 and CF4 Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional gas analysis devices using non-dispersive infrared absorption (NDIR) face challenges in accurately measuring SiF4 and CF4 in semiconductor manufacturing processes due to interference from other components with similar absorption wavelengths, leading to reduced light detection accuracy.
Innovation Solution
A gas analysis device that decompresses the gas cell to a pressure lower than atmospheric pressure and uses laser light with modulated wavelengths within specific ranges to enhance the light absorption signal of halides, allowing for interference removal and accurate concentration or partial pressure measurement of SiF4 and CF4.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the wavelength range of the band pass filter is narrowed to reduce interference influence, then measurement accuracy of halide is improved, but the amount of light detected decreases making measurement difficult
Solution Approach 1:
The patent changes the pressure parameter of the gas cell from atmospheric pressure to a predetermined pressure lower than atmospheric pressure. This parameter change causes the light absorption spectrum of the halide to become sharper with higher peak values, thereby improving measurement accuracy without requiring narrow bandwidth filtering that would reduce light intensity.
2Reliability
If the wavelength range of the band pass filter is narrowed to reduce interference influence, then specificity of halide detection is improved, but light intensity for detection decreases
Solution Approach 1:
The patent changes the pressure parameter of the gas cell from atmospheric pressure to a predetermined pressure lower than atmospheric pressure. This parameter change causes the light absorption spectrum of the halide to become sharper with higher peak values, thereby improving measurement accuracy without requiring narrow bandwidth filtering that would reduce light intensity.
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 achieves high-accuracy measurement of halides by enhancing the light absorption spectrum contrast and reducing interference, enabling precise concentration or partial pressure determination of SiF4 and CF4 with simplified spectral analysis.
Implementation Method 1
absorption of light by a component to be measured is measured using an infrared light source that generates light of a wide wavelength
Implementation Method 2
a laser light source that irradiates the gas cell with laser light whose wavelength is modulated
Implementation Method 3
the gas cell is decompressed to a predetermined pressure lower than atmospheric pressure, and the laser light source modulates the wavelength of the laser light in a wavelength modulation range including a feature part of the light absorption signal of the halide
Data Source
AI summary
The present invention is a gas analysis device that measures a concentration or partial pressure of a halide contained in a material gas used in semiconductor manufacturing process or a by-product gas generated in semiconductor manufacturing process with good accuracy, the device being for analyzing a concentration or partial pressure of a halide contained in a material gas used in a semiconductor manufacturing process or a by-product gas generated in a semiconductor manufacturing process, the device including a gas cell into which the material gas or the by-product gas is introduced, a laser light source that irradiates the gas cell with laser light whose wavelength is modulated, a light detector that detects the laser light transmitted through the gas cell, and a signal processing unit that calculates the concentration or partial pressure of the halide by using a light absorption signal obtained from an output signal of the light detector.