Near-Infrared Foreign Substance Detection in Substrate Processing
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Solution Overview
Problem
Conventional methods for detecting foreign substances in processing liquids used in semiconductor manufacturing, such as visible light-based systems, face challenges in accuracy when dealing with colored liquids due to high absorbance, leading to decreased intensity of scattered light and reduced detection precision.
Innovation Solution
The use of near-infrared light with a peak wavelength of 940 nm is implemented to detect foreign substances in the processing liquids, reducing absorption and increasing the intensity of scattered light, thereby enhancing detection accuracy and reliability across various liquid types, including colored and colorless coatings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If visible light is used for foreign substance detection in processing liquids, then the detection system can be implemented with conventional technology, but the detection accuracy decreases due to high absorbance in colored liquids
Solution Approach 1:
The patent changes the wavelength parameter of the light source from visible light to near-infrared light (peak wavelength 940 nm). This parameter change reduces the absorbance of colored processing liquids, allowing light to pass through and enabling accurate foreign substance detection that would be impossible with visible light.
Solution Approach 2:
Instead of trying to improve visible light detection through conventional means, the patent inverts the approach by using near-infrared light, which has fundamentally different interaction properties with colored liquids. This inversion transforms the detection capability from failing in colored liquids to excelling in them.
2Measurement precision
If high-intensity light is used to improve detection signal, then detection sensitivity increases, but heat generation increases causing damage to flow path components
Solution Approach 1:
The patent changes the wavelength parameter to near-infrared (940 nm), which has lower absorption coefficients in processing liquids compared to visible light. This allows sufficient detection signal to be obtained with lower light intensity, thereby reducing heat generation and preventing damage to flow path components while maintaining detection sensitivity.
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
This approach allows for precise detection of foreign substances in both colored and colorless liquids, minimizing heat generation and reducing the risk of damage to the flow path components, while maintaining high signal-to-noise ratios and ensuring reliable foreign substance detection.
Implementation Method 1
a foreign substance detecting unit configured to detect a foreign substance in the liquid based on a signal obtained when light, which is near-infrared light, is radiated toward a flow path forming unit
Implementation Method 2
increasing the intensity of scattered light, thereby enhancing detection accuracy
Data Source
AI summary
A substrate processing apparatus includes a supply channel through which a liquid to be supplied to a substrate flows; and a foreign substance detecting unit configured to detect a foreign substance in the liquid based on a signal obtained when light, which is near-infrared light, is radiated toward a flow path forming unit constituting a part of the supply channel by a light projector so that light is emitted from the flow path forming unit and a light receiver receives the light emitted from the flow path forming unit.