Substrate Nozzle Leakage Detection Using Reflected Light
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Solution Overview
Problem
Existing substrate processing systems face challenges in accurately detecting liquid leakage from nozzles during processing, which can lead to defects in semiconductor wafers due to inadequate monitoring methods.
Innovation Solution
A substrate processing apparatus equipped with a measurement unit that measures the intensity of reflected light from the substrate to detect liquid leakage by analyzing changes in light intensity before and after closing the supply flow path, using a controller to output signals for the flow-path opening/closing unit and detect abnormalities based on these measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an infrared camera is used to monitor liquid leakage by capturing images, then leakage detection capability is provided, but measurement precision and detection accuracy are insufficient
Solution Approach 1:
The patent replaces the infrared camera-based optical imaging system with a simple light source and photodetector arrangement. Instead of using complex image capture and processing, the invention uses direct optical measurement of light intensity changes caused by liquid leakage, substituting a mechanical/optical measurement system for an imaging system.
Solution Approach 2:
The invention extracts the essential detection function from the complex infrared camera system by isolating the key physical phenomenon (light absorption by liquid) and implementing a dedicated detection path with simple optical components. This separates the detection function from the imaging function, achieving high precision through specialization.
2Reliability
If processing liquid continues to flow during abnormality detection, then continuous processing is maintained, but substrate defects occur due to undetected leakage
Solution Approach 1:
The patent implements a real-time feedback control system where the light intensity measurement continuously monitors for leakage, and the controller immediately responds by stopping the processing liquid supply when leakage is detected. This closed-loop feedback ensures substrate quality by preventing defective processing while minimizing interruption through immediate detection and response.
Solution Approach 2:
The system performs preliminary detection of liquid leakage before it can cause substrate defects by continuously monitoring light intensity during the processing operation. The detection occurs in advance of any potential damage, allowing preventive action to be taken.
3Measurement precision
If light intensity measurement is performed continuously during processing, then leakage detection accuracy is improved, but measurement precision is affected by processing liquid interference
Solution Approach 1:
The patent employs dynamic measurement timing where the light intensity measurement is performed at specific moments during the processing cycle when the nozzle is not discharging liquid. The system dynamically adjusts when measurements occur based on the processing state, eliminating interference from discharged liquid while maintaining continuous monitoring capability.
Solution Approach 2:
The measurement system operates periodically by capturing light intensity data at regular intervals or at specific phases of the processing cycle. This periodic measurement approach allows the system to obtain accurate readings during liquid-free periods while maintaining continuous oversight of the processing operation.
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 system enables precise detection of liquid leakage with high accuracy, preventing defects by interrupting processing and alerting operators, thus ensuring higher quality in substrate processing.
Implementation Method 1
The measurement unit projects light to the substrate to measure an intensity of reflected light from the substrate
Data Source
AI summary
A substrate processing apparatus includes a chamber, a nozzle, a measurement unit, a flow-path opening/closing unit, and a controller. The chamber is capable of housing therein a substrate. The nozzle is arranged in the chamber to supply processing liquid towards the substrate. The measurement unit projects light to the substrate to measure an intensity of reflected light from the substrate. The flow-path opening/closing unit opens/closes a supply flow path of the processing liquid to the nozzle. The controller is configured to output an opening signal and a closing signal to the flow-path opening/closing unit. The controller is further configured to detect abnormality related to leakage of the processing liquid from the nozzle based on the intensity of reflected light that is measured by the measurement unit after an output of the closing signal.