Substrate Temperature Measurement Synchronized With Heating Radiation
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Solution Overview
Problem
Existing methods for monitoring temperature and reflectivity/emissivity of semiconductor wafers during thermal processing are hindered by interference from high-intensity radiation sources used for heating, which can obscure thermal radiation measurements.
Innovation Solution
A system where radiation sources are switched between active and inactive states, allowing temperature measuring devices to synchronize measurements only during inactive states, thereby avoiding interference from heating radiation and enabling accurate temperature and reflectivity/emissivity calculations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If radiation sources continuously irradiate the substrate to heat it, then heating efficiency is improved, but temperature measurement accuracy deteriorates due to radiation interference
Solution Approach 1:
The radiation sources are switched between active and inactive states periodically. During active states, the radiation sources heat the substrate. During inactive states, the radiation sources are turned off to allow accurate temperature measurement without radiation interference. This periodic switching resolves the contradiction by separating the heating function from the measurement function in time.
2Measurement precision
If radiation sources are turned off to enable accurate temperature measurement, then measurement accuracy is improved, but heating productivity deteriorates
Solution Approach 1:
The system uses periodic switching with optimized duty cycles where the radiation sources are active for most of the time to maintain heating productivity, and inactive only for brief measurement intervals. This minimizes the impact on overall heating efficiency while enabling accurate temperature monitoring.
Solution Approach 2:
The heating process maintains continuity by quickly switching between active and inactive states, ensuring that the substrate remains close to the target temperature throughout the cycle. The brief measurement intervals do not significantly interrupt the overall heating process, maintaining productivity while enabling continuous temperature monitoring capability.
3Measurement precision
If radiation sources are switched between active and inactive states, then temperature measurement accuracy is improved, but device complexity increases due to synchronization requirements
Solution Approach 1:
The system uses feedback from the radiation source control signals to trigger temperature measurements at the appropriate times. The control system that manages the radiation source switching also provides synchronization signals to the temperature measurement device, ensuring measurements are taken during inactive states without requiring a separate complex synchronization mechanism.
Solution Approach 2:
The synchronization function is merged with the existing radiation source control system. The same controller that manages the active/inactive switching of radiation sources also coordinates the temperature measurement timing, eliminating the need for a separate synchronization device and reducing overall system complexity.
4Productivity
If temperature measurements are taken during active states, then measurement frequency is improved, but measurement reliability deteriorates due to radiation interference
Solution Approach 1:
The system performs temperature measurements periodically during inactive states when no radiation interference is present. While measurements can only be taken during inactive periods, the periodic nature of the switching allows for regular monitoring at reliable intervals, maintaining both frequency and reliability.
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 precise temperature monitoring and determination of reflectivity/emissivity without interference from heating radiation, improving the accuracy and reliability of thermal processing control.
Implementation Method 1
measure temperature via measurement of thermal radiation emitted by a substrate or workpiece that is heated by a plurality of radiation sources
Implementation Method 2
high-intensity radiation sources such as LEDs, lasers or lamps... irradiate the substrate so as to heat the substrate
Data Source
AI summary
Methods, systems, devices, and apparatus measure temperature of a substrate by switching one or more sources between an active state and an inactive state. When in the active state, the one or more sources heat at least one portion of the substrate. When in the inactive state, the one or more sources cause substantially no radiation or a negligible amount of radiation to be generated. A temeprature measuring device is synchronized to the switching between the active and inactive states, such that the temperature measuring device measures the temperature of the at least one portion of the substrate substantially only when the one or more sources are in the inactive state.