Multi-Wavelength Spectroscopic Ellipsometer for Film Thickness
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Solution Overview
Problem
Conventional spectroscopic ellipsometers used for real-time film thickness measurement are limited by slow measuring speeds, resulting in low efficiency.
Innovation Solution
A film thickness measurement device incorporating a spectroscopic ellipsometer with a projection module that projects multi-wavelength polarized light onto a thin film and a light receiving module that includes a polarization analyzer and an optical detector with multiple optical splitting, filtering, and detection units, allowing for simultaneous measurement of multiple wavelengths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a conventional spectroscopic ellipsometer is used for real-time film thickness measurement, then the measurement can be performed non-destructively, but the measuring speed is slow resulting in low efficiency
Solution Approach 1:
The optical detector is divided into multiple optical detection units (first, second, third, and fourth detection units), each responsible for detecting specific wavelength components of the reflected light. This segmentation allows parallel processing of different wavelength ranges, thereby increasing the overall measurement speed and efficiency without sacrificing measurement accuracy.
Solution Approach 2:
The patent introduces wavelength division as an additional dimension for parallel measurement. By using multiple optical detection units that simultaneously detect different wavelength components, the system transforms a sequential single-wavelength measurement process into a parallel multi-wavelength measurement process, effectively increasing measuring speed.
2Measurement precision
If multiple wavelength measurements are performed sequentially, then each measurement can be accurate, but the total measurement time increases reducing efficiency
Solution Approach 1:
The patent implements continuous multi-wavelength measurement by simultaneously projecting multi-wavelength polarized light and detecting reflected light across different wavelength ranges using multiple optical detection units. This eliminates the need to stop and restart measurements for different wavelengths, maintaining continuous useful action and significantly reducing total measurement time while preserving accuracy.
Solution Approach 2:
The system preliminarily separates the reflected light into different wavelength components using optical filters before detection. This preliminary wavelength separation allows each detection unit to immediately process its assigned wavelength range without waiting for sequential measurement cycles, thereby reducing overall measurement time while maintaining precise ellipsometric parameter extraction.
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 configuration enhances measurement efficiency by enabling a single measuring step to obtain multiple sets of ellipsometric parameters, thereby improving the speed and accuracy of film thickness determination.
Implementation Method 1
a polarization state generator configured to generate a multi-wavelength polarized light
Implementation Method 2
The polarization analyzer is configured to screen out a multi-wavelength polarized reflection light according to reflection of the multi-wavelength polarized light by the thin film
Implementation Method 3
The at least one optical splitting unit is configured to split the multi-wavelength polarized reflection light into a first detection light and a second detection light with different wavelengths
Implementation Method 4
The at least two optical filtering units respectively allow transmission of at least part of the first detection light and transmission of at least part of the second detection light
Implementation Method 5
The at least two optical detection units is configured to respectively receive the first detection light and the second detection light
Data Source
AI summary
A film thickness measurement device includes a spectroscopic ellipsometer, and the spectroscopic ellipsometer includes a projection module and a light receiving module. The projection module is configured to project a multi-wavelength polarized light onto a thin film. The projection module includes a light source and a polarization state generator. The light receiving module includes a polarization analyzer and an optical detector. The polarization analyzer is configured to screen out a multi-wavelength polarized reflection light according to reflection of the multi-wavelength polarized light by the thin film. The optical detector is configured to receive the multi-wavelength polarized reflection light. The optical detector includes at least one optical splitting unit, at least two optical filtering units and at least two optical detection units.