Near-Infrared Liquid Edge Detection in Substrate Processing
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Solution Overview
Problem
General CCD cameras cannot accurately detect processing liquids on substrates due to the transparency of these liquids, making it difficult to specify the processing liquid in a chamber with high accuracy.
Innovation Solution
A substrate processing apparatus that includes a chamber, a substrate holding section, a processing liquid supply section, a near-infrared light source, a near-infrared imaging section, and a controller. The near-infrared light source illuminates the chamber, and the near-infrared imaging section captures images of the processing liquid, allowing the controller to specify the outer edge and type of the processing liquid based on the captured images.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a general CCD camera is used to detect processing liquid, then the device complexity is low, but the measurement precision deteriorates because the processing liquid is transparent and cannot be detected accurately
Solution Approach 1:
The patent changes the wavelength parameter of the light used for detection from visible light to near-infrared light. This parameter change enables the detection system to capture the processing liquid effectively, as the liquid exhibits different optical properties in the near-infrared region compared to visible light, thereby resolving the transparency detection issue without requiring complex additional equipment
Solution Approach 2:
The patent introduces an intermediary near-infrared imaging section that acts as a mediator between the processing liquid and the detection system. This intermediary component converts the invisible transparent liquid into a detectable form by capturing near-infrared light interactions, enabling accurate specification of the processing liquid's outer edge and distribution
2Reliability
If a CCD camera measures interference fringes to detect processing liquid, then the measurement method is simple, but the reliability deteriorates because it cannot specify the processing liquid with high accuracy
Solution Approach 1:
The patent changes the operational parameter of the imaging system from visible light detection to near-infrared light detection. This parameter change fundamentally improves the reliability of processing liquid specification by exploiting the liquid's optical absorption characteristics in the near-infrared region, which provide superior contrast and detection accuracy compared to visible light interference fringe methods
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 high-precision specification of the processing liquid in the chamber, ensuring accurate detection and control of the liquid's distribution on the substrate.
Implementation Method 1
The near-infrared light source illuminates an inside of the chamber with near-infrared light
Implementation Method 2
The near-infrared imaging section generates a captured image by capturing an image of the processing liquid in the chamber illuminated with the near-infrared light from the near-infrared light source
Data Source
AI summary
A substrate processing apparatus includes a chamber, a substrate holding section that rotates a substrate while holding the substrate in the chamber, a processing liquid supply section that supplies a processing liquid onto an upper surface of the substrate, a near-infrared light source that illuminates an inside of the chamber with near-infrared light, a near-infrared imaging section that generates a captured image by capturing an image of the processing liquid in the chamber illuminated with the near-infrared light from the near-infrared light source, and a controller. The controller specifies an outer edge of the processing liquid in the chamber based on the captured image.