Calibration Substrate for Thermal Process Chamber Temperature Measurement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current temperature measurement methods for semiconductor wafers during thermal treatment are inaccurate due to interference from environmental radiation and require time-consuming calibration with thermocouples, especially for rotating substrates and low-temperature measurements.
Innovation Solution
A calibration substrate with temperature-dependent transmissivity is used, featuring passage openings for optical radiation, allowing for the comparison of transmitted and incident radiation to determine transmissivity values, which can be associated with specific temperatures, enabling calibration of temperature measuring devices without thermocouples or pyrometers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pyrometric temperature measuring systems are used for non-contact measurement, then the thermal treatment process is not impaired, but measurement accuracy deteriorates due to interference from environmental radiation and substrate transmission effects
Solution Approach 1:
A calibration substrate with known temperature-dependent transmissivity characteristics is introduced as an intermediary between the pyrometer and the actual substrate. This calibration substrate serves as a mediator that allows the pyrometer to be calibrated against known transmissivity values at different temperatures, thereby improving measurement accuracy without compromising the non-contact nature of the measurement process
Solution Approach 2:
The invention utilizes the temperature-dependent transmissivity parameter of the calibration substrate to establish a correlation between transmissivity measurements and temperature. By measuring how the transmissivity changes with temperature and using this relationship to calibrate the pyrometer, the system achieves accurate temperature measurements while maintaining non-contact operation
2Measurement precision
If thermocouples are used for calibration, then temperature measurement accuracy can be verified, but calibration time increases and the process becomes complex
Solution Approach 1:
The invention extracts the calibration function from the actual substrate processing and implements it using a dedicated calibration substrate with known transmissivity characteristics. This separate calibration substrate can be quickly exchanged and measured, eliminating the need for time-consuming thermocouple placement and measurement procedures while maintaining calibration accuracy
Solution Approach 2:
The invention replaces the mechanical contact-based thermocouple calibration method with an optical measurement-based calibration system. Instead of physically attaching thermocouples to substrates and measuring electrical signals, the system uses optical transmissivity measurements through the calibration substrate, which is faster and eliminates mechanical contact complications
3Measurement precision
If thermocouples are placed on substrates for calibration, then temperature verification is possible, but the substrate must be contacted and installed, increasing process complexity
Solution Approach 1:
The calibration substrate acts as an intermediary that embodies known transmissivity-temperature relationships. Instead of placing thermocouples on actual substrates, the system uses this dedicated calibration substrate with predetermined optical properties to verify and calibrate temperature measurements, simplifying the overall calibration process
Solution Approach 2:
The calibration substrate creates an optical copy or representation of the temperature measurement process without requiring physical contact with actual processing substrates. By measuring the transmissivity of light through the calibration substrate at known temperatures, the system can verify pyrometer accuracy without the complexity of thermocouple installation and substrate handling
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 method provides a simple and reliable way to determine transmittance-temperature values and calibrate temperature measuring devices, improving accuracy and reducing calibration time, while allowing for use in various thermal process chambers and temperature ranges.
Implementation Method 1
the substrate consists at least partly of a first material which changes its transmission characteristic in dependence on its temperature
Implementation Method 2
At least one passage opening is provided in the first material and this forms a free passage for optical radiation through the substrate at least in a partial region
Data Source
AI summary
A system and method is disclosed that reliably determines the transmissivity of a substrate. By determining the transmissivity of a calibration substrate, for instance, a temperature measuring device can be calibrated. The method and system are particularly well suited for use in thermal processing chambers that process semiconductor wafers used for forming integrated circuit chips.