Rotating-Element Spectroscopic Ellipsometer Measurement Precision Prediction
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Solution Overview
Problem
Current rotating-element spectroscopic ellipsometers lack a method to assess measurement uncertainty, particularly for state-of-the-art multi-channel systems using integral photodetectors, which hinders their application in semiconductor industries due to non-ideal substrate properties and fixed incident angles.
Innovation Solution
A theoretical model equation is developed to calculate measurement precision based on standard deviations of ellipsometric parameters, incorporating a light source, polarization state generator, analyzer, and arithmetic unit with rotatable elements, allowing for the determination of measurement limitations and physical properties like thickness and nano pattern characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a theoretical equation based on standard deviations of ellipsometric parameters is used to assess measurement uncertainty, then measurement precision can be quantified for multi-channel RE-SEs, but the method cannot be applied to systems with fixed incident angles and non-ideal substrate conditions
Solution Approach 1:
The patent transforms the measurement uncertainty assessment method by changing the parameters from requiring multiple incident angles to working with a single fixed incident angle. The theoretical equation is modified to incorporate ellipsometric parameters (psi and delta) that can be measured at a fixed angle, making the method adaptable to industrial RE-SE configurations while maintaining the ability to quantify measurement precision.
2Measurement precision
If standard samples with micro defects are used to assess measurement uncertainty, then measurement precision can be evaluated, but such standard samples cannot be produced with sufficient quality for state-of-the-art multi-channel RE-SEs
Solution Approach 1:
The patent replaces the need for physical standard samples with a theoretical model that copies the measurement process mathematically. Instead of requiring actual samples with known micro defects, the method uses theoretical equations based on ellipsometric parameters to predict and assess measurement uncertainty, eliminating the manufacturing challenges of creating perfect standard samples.
3Measurement precision
If multiple incident angles are measured to quantify measurement uncertainty, then measurement precision can be assessed, but industrial RE-SEs use fixed incident angles which complicates the assessment method
Solution Approach 1:
The patent changes the approach by using ellipsometric parameters (psi and delta) that can be obtained at a fixed incident angle. The theoretical equation is reformulated to assess measurement uncertainty through these parameters rather than requiring measurements at multiple angles, thereby reducing device complexity while maintaining measurement precision assessment capability.
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 the assessment of measurement uncertainty and precision for various multi-channel RE-SEs, improving their applicability in semiconductor manufacturing by analyzing physical properties without relying on standard samples and accounting for non-ideal substrate conditions.
Implementation Method 1
a light source 100 radiating an incident light 110 toward a sample 10
Implementation Method 2
a polarization state generator 200 disposed between the light source 100 on a traveling path of the incident light 110 and the sample 10 and controlling a polarized state of the incident light 110 radiated from the light source 100
Implementation Method 3
a polarization state analyzer 300 receiving reflected light (or transmitted light) 120 having a changed polarization state while the incident light 100 is polarized by passing through the polarization state generator 200 and then reflected (or transmitted) by the sample 10 and analyzing a change in the polarization state of the reflected light (or transmitted light) 120
Implementation Method 4
a photodetector element 400 receiving the reflected light (or the transmitted light) 120 passing through the polarization state analyzer 300 and measuring irradiance of the incident light with an electrical signal of a voltage or a current
Data Source
AI summary
Provided are a rotating-element spectroscopic ellipsometer and a method for measurement precision prediction of a rotating-element spectroscopic ellipsometer, a recording medium storing program for executing the same, and a computer program stored in a medium for executing the same, and more particularly, a rotating-element spectroscopic ellipsometer and a method for measurement precision prediction of a rotating-element spectroscopic ellipsometer capable of calculating the measurement precision of the rotating-element spectroscopic ellipsometer based on a theoretical equation on standard deviations of ellipsometric parameters for a sample, a recording medium storing program for executing the same, and a computer program stored in a medium for executing the same.