Domed Window Thermal Processing for Accurate Workpiece Temperature Sensing
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Solution Overview
Problem
Existing thermal processing systems face challenges in accurately measuring workpiece temperatures during rapid thermal processing due to interference from stray radiation, which affects process control and uniformity.
Innovation Solution
The system incorporates domed windows with opaque and transparent regions to block stray radiation, combined with phase-locked emitters and sensors to measure workpiece temperature accurately, allowing for both rapid heating and cooling, and includes a gas delivery system for process control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If heat sources are used to rapidly heat the workpiece, then heating speed is improved, but temperature measurement accuracy deteriorates due to stray radiation interference
Solution Approach 1:
A domed window is introduced as an intermediary component between the heat sources and the workpiece. This window selectively transmits heating radiation while blocking stray radiation from reaching the temperature measurement system, thereby resolving the contradiction between rapid heating and accurate temperature measurement
Solution Approach 2:
The domed window is designed with different optical properties in different regions - it is transparent to heating radiation wavelengths while being opaque to stray radiation wavelengths. This local differentiation of optical properties allows simultaneous achievement of rapid heating and accurate temperature measurement
2Measurement precision
If domed windows with opaque regions are used to block stray radiation, then temperature measurement accuracy is improved, but device complexity increases
Solution Approach 1:
The domed window serves multiple functions simultaneously: it acts as a protective cover for the heat sources, a selective radiation filter (transparent to heating radiation, opaque to stray radiation), and a structural component of the processing chamber. This multi-functionality reduces overall device complexity while achieving improved temperature measurement accuracy
3Measurement precision
If phase-locked emitters and sensors are used for accurate temperature measurement, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The emitter operates in a periodic pulsed manner, and the sensor is synchronized to detect radiation during specific phases of this periodic cycle. This phase-locked periodic operation allows accurate temperature measurement during rapid thermal processing while using relatively simple hardware components
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
Enhances temperature measurement accuracy and process control, improving workpiece throughput and uniformity by reducing interference from stray radiation and enabling precise temperature monitoring.
Implementation Method 1
one or more domed windows disposed between the workpiece support plate and the one or more heat sources
Implementation Method 2
workpieces can be heated by an array of lamps through the support plate to temperatures from about 300° C. to about 1,200° C. over time durations that are typically less than a few minutes
Implementation Method 3
A temperature measurement system configured to generate data indicative of a temperature of the workpiece
Data Source
AI summary
A thermal processing system for performing thermal processing can include a workpiece support plate configured to support a workpiece and heat source(s) configured to heat the workpiece. The thermal processing system can include one or more domed window(s) disposed between the workpiece support plate and the one or more heat sources. The system includes a temperature measurement configured to generate data indicative of a temperature of the workpiece. The system includes a gas delivery system configured to flow a process gas over the workpiece.