Ellipsometer Stationary Modulator for Semiconductor Inspection
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Solution Overview
Problem
Current OCD measurement devices in semiconductor manufacturing face challenges in achieving high measurement accuracy and throughput due to the need for multiple measurement conditions and the limitations of existing ellipsometry techniques, such as spectral ellipsometry and Mueller matrix ellipsometry, which require extensive time and are prone to coupling issues.
Innovation Solution
An ellipsometer that calculates ellipsometry coefficients Ψ and Δ by measuring the intensity ratio and phase difference of light in two polarization states using an interference fringe, allowing for simultaneous measurement of multiple points with improved throughput and stability, utilizing a polarizing optical element and an interference member to split and overlap P-polarized and S-polarized light for interference detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If spectral ellipsometry is used to measure thin film thickness with multiple wavelengths, then measurement accuracy is improved, but measurement time increases
Solution Approach 1:
The patent replaces the mechanical rotating compensator system with a stationary modulating element that uses optical interference to achieve the same measurement function. This substitution eliminates the need for mechanical rotation while maintaining measurement accuracy, thereby reducing measurement time and improving throughput.
Solution Approach 2:
The patent employs periodic modulation of the polarization state using a stationary modulating element, which creates time-varying optical signals that can be detected and processed to extract ellipsometry parameters. This periodic action enables accurate measurements without requiring mechanical rotation, thus reducing measurement time.
2Measurement precision
If Mueller matrix ellipsometry is used to evaluate anisotropic material structures, then measurement accuracy is improved, but measurement time increases significantly
Solution Approach 1:
The patent combines multiple measurement functions into a single stationary modulating element that can modulate polarization states without requiring separate measurements for each polarization condition. This merging of functions reduces the total measurement time while maintaining the accuracy needed for evaluating anisotropic structures.
Solution Approach 2:
The patent replaces the mechanical system required for Mueller matrix measurements with a stationary optical modulating element that uses interference and polarization modulation to achieve the same measurement objectives, significantly reducing measurement time.
3Measurement precision
If a rotating compensator is used to measure ellipsometry coefficients, then measurement accuracy is improved, but device complexity and measurement time increase
Solution Approach 1:
The patent replaces the mechanical rotating compensator with a stationary modulating element that achieves polarization modulation through optical interference. This substitution eliminates mechanical complexity while maintaining measurement accuracy, thereby reducing both device complexity and measurement time.
Solution Approach 2:
The patent extracts the essential measurement function from the mechanical rotating compensator and implements it through a stationary optical element, removing the unnecessary mechanical complexity while preserving the measurement capability.
4Measurement precision
If multiple measurement conditions are used to avoid coupling issues, then measurement accuracy is improved, but productivity decreases
Solution Approach 1:
The patent enables continuous measurement by using a stationary modulating element that can modulate polarization states without interruption. This continuous action allows for accurate measurements under multiple effective conditions without the need to stop for mechanical reconfiguration, thereby maintaining high productivity.
Solution Approach 2:
The patent uses periodic modulation of polarization states through the stationary modulating element to effectively create multiple measurement conditions in a continuous process. This periodic action within a continuous measurement flow maintains both accuracy and productivity.
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 enables faster and more accurate measurement of ellipsometry coefficients, improving the throughput of OCD measurement devices and reducing the need for extensive measurement times, thereby enhancing the yield and productivity in semiconductor manufacturing.
Implementation Method 1
a polarizing optical element, comprising a prism, that is configured to split reflected light into two linearly polarized components of light having polarization directions orthogonal to each other, the reflected light generated by reflecting illuminated light, including linearly polarized light that is polarized in one direction, from a measurement surface of a sample
Implementation Method 2
an interference member, comprising at least one body, that is configured to form at least one interference fringe in which the two linearly polarized components of light interfere with each other in directions different from the polarization directions
Data Source
AI summary
An ellipsometer is provided. The ellipsometer includes: a polarizing optical element, comprising a prism, that is configured to split reflected light into two linearly polarized components of light having polarization directions orthogonal to each other, the reflected light generated by reflecting illuminated light, including linearly polarized light that is polarized in one direction, from a measurement surface of a sample; an interference member, comprising at least one body, that is configured to form at least one interference fringe in which the two linearly polarized components of light interfere with each other in directions different from the polarization directions; an image detector configured to detect the at least one interference fringe; and an analysis device including at least one processor, the analysis device configured to calculate ellipsometry coefficients Ψ and Δ based on the at least one interference fringe that is detected.