Optical Interference Temperature Measurement for Substrate Processing
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Solution Overview
Problem
Existing temperature measuring systems using optical interference face challenges in achieving high sampling rates and accurate thickness measurement, which are essential for precise temperature detection, particularly in substrate processing applications.
Innovation Solution
A temperature measuring system incorporating a light source, spectroscope, optical transfer mechanism, optical path length calculation unit, and temperature calculation unit, where the light source and spectroscope are optimized to satisfy specific wavelength span and sampling conditions, enabling accurate temperature measurement through Fourier transformation and data interpolation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the mirror is driven at high speed to achieve high sampling rate, then the sampling rate is improved, but the device complexity and difficulty of control increase
Solution Approach 1:
The patent extracts the mechanical moving component (mirror) from the system and replaces it with a stationary optical setup. The measurement function is achieved through optical path difference created by the stationary interferometer structure rather than by moving the mirror, thereby eliminating the need for high-speed driving units while maintaining measurement capability.
Solution Approach 2:
The patent replaces the mechanical mirror driving system with an optical field-based measurement approach. Instead of mechanically moving the mirror to change optical path length dynamically, the system uses the stationary optical interference pattern and processes the data computationally to achieve thickness and temperature measurement.
2Productivity
If the thickness is measured based on light intensity to achieve high sampling rate, then the sampling rate is improved, but the measurement precision deteriorates
Solution Approach 1:
The patent replaces direct mechanical/optical thickness measurement with a two-stage process: first measuring optical path length with high precision using stationary optical interference, then converting to thickness through computational processing. This substitution maintains measurement precision while enabling high sampling rates through rapid optical data acquisition.
Solution Approach 2:
The patent performs preliminary calibration to establish the relationship between optical path length and thickness before actual measurements. This pre-established conversion relationship allows rapid thickness calculation from optical path length measurements without requiring complex real-time computations, thereby achieving both high precision and high sampling rate.
3Adaptability or versatility
If the wavelength span of the spectroscope is increased to improve measurement range, then the maximum measurable thickness is improved, but the data interval and measurement resolution deteriorate
Solution Approach 1:
The patent optimizes the wavelength span parameter of the spectroscope to achieve a balance between measurement range and resolution. By carefully selecting the wavelength span to match the specific measurement requirements (maximum expected thickness), the system achieves adequate measurement range while maintaining sufficient optical path length resolution for accurate temperature measurement.
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 stable and accurate temperature measurement, overcoming the limitations of previous systems by defining data intervals and maximum measurable thickness, ensuring precise temperature detection in substrate processing environments.
Implementation Method 1
a temperature measuring system using an optical interference
Implementation Method 2
The spectroscope measures an interference intensity distribution that is an intensity distribution of the reflected light representing an intensity distribution depending on a wavelength or frequency
Implementation Method 3
The optical path length calculation unit calculates an optical path length by Fourier transforming the interference intensity distribution that is an intensity distribution of light reflected from the first main surface and the second main surface
Data Source
AI summary
The temperature measuring system using optical interference includes a light source which generates measuring light; a spectroscope which measures an interference intensity distribution that is an intensity distribution of reflected light; optical transfer mechanisms which emit light reflected from a surface and a rear surface of the object to be measured to the spectroscope; an optical path length calculation unit which calculates an optical path length by performing Fourier transformation; and a temperature calculation unit which calculates a temperature of the object to be measured on the basis of a relation between optical path lengths and temperatures. The light source has a half-width at half-maximum of a light source spectrum that satisfies conditions based on a wavelength span of the spectroscope. The spectroscope measures the intensity distribution by using the number of samplings that satisfies conditions based on the wavelength span and a maximum measurable thickness.