Thermal Imaging of Heat Sources in Rapid Thermal Processing
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Solution Overview
Problem
Current thermal processing systems face challenges in accurately measuring workpiece temperatures due to heat source irradiation reflections and variations, especially in rapid thermal processing, where precise temperature control is crucial for semiconductor fabrication.
Innovation Solution
Incorporating a camera to capture thermal images of heat sources within the thermal processing chamber, which allows for direct thermal imaging and real-time mapping of heat source irradiation, combined with a thermal model that estimates irradiation flux and workpiece temperature, using high-speed imaging and wavelength filtering to handle dynamic heat source variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If thermal imaging is used to measure workpiece temperature, then temperature measurement capability is improved, but measurement precision deteriorates due to heat source irradiation reflections and variations
Solution Approach 1:
The patent extracts and separately measures the heat source irradiation by capturing images of the heat sources themselves with a camera. This separated measurement of heat source characteristics is then used to compensate for the harmful reflections in the workpiece temperature measurement, effectively removing the interference factor.
Solution Approach 2:
The system implements feedback by using the captured heat source images to dynamically adjust and compensate for irradiation variations. The measured heat source characteristics feed back into the temperature calculation algorithm to correct for reflections and improve measurement accuracy in real-time.
2Productivity
If rapid thermal processing is used to improve productivity, then processing speed is improved, but temperature control precision deteriorates due to dynamic heat source variations
Solution Approach 1:
The system performs preliminary measurement of heat source characteristics by capturing images of the heat sources before they affect the workpiece temperature measurement. This advance characterization of heat source state allows the system to pre-compensate for upcoming irradiation variations during rapid thermal processing.
Solution Approach 2:
The patent employs dynamic adaptation by continuously capturing heat source images and updating the compensation parameters in real-time during rapid thermal processing. The system adapts to changing heat source conditions dynamically, maintaining temperature control precision despite the high-speed processing variations.
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 enables more precise temperature measurement and control of workpieces by accounting for heat source irradiation and emissivity changes, improving the accuracy and efficiency of thermal processing, particularly in rapid thermal processing systems.
Implementation Method 1
capturing one or more images of thermal radiation of the plurality of heat sources with at least one camera
Data Source
AI summary
Thermal imaging of heat sources in thermal processing systems for determination of workpiece temperature are provided. In one example, a thermal processing apparatus can include a processing chamber, a workpiece support, a plurality of heat sources configured to heat a workpiece, and at least one camera. The at least one camera can capture one or more images of thermal radiation of the plurality of heat sources during thermal treatment of the workpiece. In one example, a method for calibrating the camera can include obtaining the one or more images of thermal radiation of at least one heat source, obtaining one or more reference signals indicative of irradiation of the at least one heat source, and calibrating the camera based at least in part on a comparison between the one or more images of thermal radiation and the one or more reference signals indicative of irradiation of the heat source.