Reflective Film Temperature Sensing for Low-Temperature Substrates
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Solution Overview
Problem
Current temperature measurement techniques for semiconductor substrates during plasma processing lack accuracy and efficiency, particularly in low-temperature environments, as they often require direct light application and alignment, which can lead to instability and inaccuracies in reflectance-based temperature calculations.
Innovation Solution
A non-contact temperature measurement method using a reflective film on the substrate surface, where measurement light is applied and reflected light is received by an optical member to calculate the substrate temperature based on the ratio of intensities, allowing for precise temperature determination without direct alignment and enhancing measurement stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If direct light application and alignment are used for temperature measurement, then measurement can be performed, but measurement accuracy and stability deteriorate due to alignment difficulties and light scattering
Solution Approach 1:
A reflective film is formed on the substrate surface before temperature measurement to pre-establish a stable reflection interface. This preliminary preparation eliminates the need for complex real-time alignment during measurement, as the reflective film provides a consistent reflection surface that simplifies the optical path setup and improves measurement stability.
2Reliability
If non-contact temperature measurement is used, then substrate damage is avoided, but measurement accuracy deteriorates in low-temperature environments
Solution Approach 1:
The reflective film changes the optical parameters of the substrate surface by providing a high-reflectivity interface that enhances the intensity of reflected light. This parameter change improves the signal-to-noise ratio in reflectance-based temperature measurements, thereby improving measurement accuracy in low-temperature environments while maintaining non-contact measurement advantages.
3Measurement precision
If reflectance-based temperature calculation is used, then non-contact measurement is achieved, but measurement stability deteriorates due to light intensity variations
Solution Approach 1:
The system uses the reflective film to provide a stable reference reflection that serves as a baseline for temperature calculation. By comparing the reflected light intensity from the reflective film against known reflectance-temperature relationships, the system achieves stable and accurate temperature measurements that are insensitive to light source intensity variations, thereby improving measurement stability.
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 improves the accuracy and reliability of temperature measurements in semiconductor manufacturing, enabling better control of processing conditions, such as in cryoetching, by providing a stable and efficient means to calculate substrate temperatures, even in low-temperature environments.
Implementation Method 1
a temperature measurement method includes a step of applying measurement light having a predetermined wavelength to a reflective film formed on a first surface of a substrate, a step of receiving, with an optical member, reflected light generated by the measurement light being reflected by the reflective film
Data Source
AI summary
A temperature measurement method according to one embodiment includes a step of applying measurement light having a predetermined wavelength to a reflective film formed on a first surface of a substrate. Furthermore, the temperature measurement method includes a step of receiving, with an optical member, reflected light generated by the measurement light being reflected by the reflective film. Furthermore, the temperature measurement method includes a step of calculating the temperature of the substrate based on a reflectance based on the ratio between the intensity of the measurement light and the intensity of the reflected light.