Wet-Processing Nozzle Spout Detection via Optical Brightness Analysis
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Solution Overview
Problem
Existing wet-processing apparatuses face challenges in accurately determining whether processing liquids are being spouted from nozzles and detecting changes in the liquid's condition, such as bubbling or column narrowing, due to limited spatial and operational conditions, leading to potential defects in substrate processing.
Innovation Solution
A wet-processing apparatus with processing liquid spouting nozzles, a light source, an imaging device, and a decision unit that analyzes images of the spouted liquid column's brightness to determine if the liquid is being spouted and if changes have occurred, using a controlled illumination system to enhance image accuracy and suppress unnecessary reflections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Difficulty of detecting and measuring
If image data is captured to detect faulty nozzle conditions, then detection capability is improved, but it becomes difficult to decide whether coating liquid was spouted and whether changes occurred in spouting condition
Solution Approach 1:
The image data is segmented into multiple regions: a first region containing the nozzle tip and a second region containing the spouted coating liquid column. By analyzing these separate regions independently, the system can both detect nozzle abnormalities and accurately determine spouting conditions. The segmentation allows distinct analysis of the nozzle area versus the liquid column area, resolving the contradiction between general fault detection and specific spouting condition measurement.
Solution Approach 2:
The patent introduces an intermediary analysis process that uses image data from both regions to cross-validate spouting conditions. The first region's image data serves as an intermediary reference to confirm whether the nozzle is functioning normally, while the second region's image data provides direct information about the spouted liquid. This intermediary approach enables accurate decision-making about spouting conditions while maintaining detection of faulty nozzle states.
2Area of stationary object
If apparatus components are stacked vertically to reduce floor space, then space utilization is improved, but maintenance work and visual inspection become difficult
Solution Approach 1:
The apparatus performs self-diagnosis through automated image capture and analysis by the control unit. The system automatically detects faulty nozzle conditions and spouting abnormalities without requiring manual inspection, thereby maintaining ease of operation despite vertical stacking that limits physical access. The self-service capability compensates for reduced accessibility by eliminating the need for manual maintenance activities in cramped spaces.
Solution Approach 2:
Manual visual inspection and maintenance operations are replaced with an automated optical detection system. The imaging device and control unit substitute for human operators who would otherwise need physical access to inspect nozzles and detect spouting issues. This mechanical-to-optical substitution enables the apparatus to maintain high operational ease despite space constraints imposed by vertical stacking.
3Loss of substance
If small amount of resist solution is spouted in short time to reduce material loss, then loss of substance is reduced, but measurement of spouted amount by flowmeter becomes difficult
Solution Approach 1:
The patent replaces mechanical flowmeter measurement with optical image-based measurement. Instead of using a flowmeter that cannot accurately measure small amounts of liquid dispensed quickly, the system captures images of the spouted coating liquid column and analyzes its properties. This optical substitution enables precise measurement of minimal resist solution amounts while maintaining low material loss.
Solution Approach 2:
The measurement parameter is changed from flow rate (measured by flowmeter) to visual characteristics of the spouted liquid column (measured by image analysis). By measuring properties such as column height, width, and brightness in the captured images, the system can accurately quantify the amount of resist solution spouted even when the volume is small and the dispensing time is short, thereby resolving the measurement difficulty while maintaining low material consumption.
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 apparatus accurately decides whether processing liquids are being spouted and detects changes in their condition, reducing the risk of defective substrates and minimizing liquid loss by ensuring precise control over the processing conditions.
Implementation Method 1
a light source for illuminating an area between a plane containing tips of the processing liquid spouting nozzles and the surface of the substrate
Implementation Method 2
an image formed by the imaging device and expressing the luminous intensity of light emitted by the light source, and penetrated into and reflected by the processing liquid spouted toward the substrate
Data Source
AI summary
A wet-processing apparatus, which spouts a coating liquid onto a surface of a substrate, includes: nozzles provided with passages for the coating liquid; a light source which illuminates an area between a plane containing the tips of the nozzles and the surface of the substrate; a camera for forming an image of the area; a control unit which provides a spout signal requesting spouting the liquid from the nozzle toward the substrate, and an imaging signal requesting the camera to start an imaging operation; and a decision unit which decides whether or not the liquid was spouted from the nozzle and whether or not changes occurred in the condition of the liquid spouted from the nozzle toward the substrate on the basis of an image formed by the camera and expressing the brightness of the liquid spouted toward the substrate and illuminated by light emitted by the light source.