Substrate Temperature Determination via Radiation Segmentation
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Solution Overview
Problem
Existing methods for determining the temperature of semiconductor substrates during thermal treatment face challenges due to the need to differentiate between emitted and reflected radiation, which is complicated by emissivity changes and calibration difficulties, especially with rapid changes or unstable references.
Innovation Solution
A device with multiple radiation detectors and optical elements is used to detect and filter radiation components, allowing for simultaneous detection of substrate and reflection radiation, enabling temperature determination independent of substrate emissivity by identifying a working temperature point where the pyrometer signal is emissivity-independent.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a radiation meter is used to detect temperature, then temperature determination is possible, but the measurement becomes complicated by the need to differentiate between emitted and reflected radiation
Solution Approach 1:
The radiation detected by the pyrometer is segmented into two distinct components: emitted radiation from the substrate and reflected radiation from the heating lamps. By mathematically separating these components based on their different spectral characteristics and intensity relationships, the patent eliminates the need for complex physical differentiation methods, thus resolving the contradiction between measurement precision and device complexity
Solution Approach 2:
The patent introduces an intermediary mathematical model that relates the intensities of emitted and reflected radiation through the substrate emissivity and lamp power parameters. This intermediary relationship allows the system to calculate and subtract the reflected radiation component, enabling accurate temperature determination without adding physical complexity to the measurement device
2Measurement precision
If emissivity measurement calibration is performed, then temperature determination can be achieved, but calibration becomes difficult due to lack of stable references and emissivity changes during thermal treatment
Solution Approach 1:
The patent implements a feedback mechanism where the measured radiation intensity is continuously compared against the mathematical model predicting the relationship between emitted and reflected radiation. The system uses this feedback to iteratively determine the substrate temperature and emissivity parameters, eliminating the need for manual calibration with stable references. The feedback loop automatically adapts to emissivity changes during thermal treatment, resolving the calibration difficulty
Solution Approach 2:
The measurement system performs self-calibration by using the measured radiation data itself to determine both temperature and emissivity parameters. The mathematical model allows the system to extract emissivity information from the radiation intensity measurements without requiring external calibration standards, enabling the system to adapt to changing emissivity conditions during the thermal treatment process
3Adaptability or versatility
If rapid emissivity changes occur during thermal treatment, then process adaptability is improved, but temperature determination becomes disrupted due to slow or missing determination
Solution Approach 1:
The patent ensures continuous temperature and emissivity determination by using a mathematical model that can be applied at each measurement instant without requiring stable reference conditions. The model continuously processes the radiation intensity data to update both temperature and emissivity parameters, maintaining reliable temperature determination even during rapid emissivity changes. This continuous action eliminates gaps in temperature measurement that would otherwise occur during emissivity transitions
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 allows for accurate and reliable temperature determination of semiconductor substrates during thermal treatment, independent of emissivity changes, by identifying a specific working temperature point where the pyrometer signal is independent of emissivity, facilitating precise process control.
Implementation Method 1
determine the temperature of the substrate (W) during a thermal treatment by means of a radiation detector (20, 21) directed towards the substrate (W)
Implementation Method 2
At least one filter, which is arranged between at least one radiation source from a plurality of first radiation sources and the substrate, in order to filter out from the radiation of the at least one radiation source the radiation that lies in the range of the measuring wavelength of the radiation detector
Data Source
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Figure 3(a)~3(c)
AI summary
The invention relates to a device and to a method for determining the temperature of a substrate, in particular of a semiconductor wafer, during heating by means of at least one first radiation source. A determination of the temperature of the substrate is based on detecting first and second radiations, each composed of a temperature radiation of the substrate and different proportions of the radiation reflecting on the substrate from the first radiation source, and on a drive power of the at least one first radiation source and/or a radiation intensity thereof.