Semiconductor Layer Characterization With Reduced Spectral Sampling
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Solution Overview
Problem
Existing methods for determining the properties of semiconductor layer structures, particularly in semiconductor wafers used for solar cells, are time-consuming and inefficient, especially when spatially resolved data is required, which hampers inline production monitoring and quality assurance.
Innovation Solution
A method that utilizes optical properties of semiconductor layer structures to determine properties such as porosity and thickness by measuring reflected and emitted radiation, using a combination of reference data and models to infer layer properties with high accuracy and spatial resolution, even with reduced spectral resolution and number of measurement intensities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high-precision spectrophotometers are used to measure semiconductor layer structure properties, then measurement accuracy is improved, but measurement time increases significantly
Solution Approach 1:
The patent segments the spectral measurement range into multiple discrete wavelength regions. Instead of measuring the entire spectrum with high resolution, the method divides it into segments and selects representative wavelengths for measurement, reducing the number of measurement points while maintaining adequate accuracy for determining layer properties.
Solution Approach 2:
The patent changes the measurement parameters by reducing the spectral resolution and selecting specific discrete wavelengths rather than measuring continuously across the spectrum. This parameter change allows faster measurements using fewer data points while still enabling accurate determination of layer thickness and porosity through the established measurement-evaluation method.
2Measurement precision
If spatially resolved data across the entire layer is required, then quality assurance accuracy is improved, but measurement time increases
Solution Approach 1:
The patent applies segmentation by dividing the measurement area into discrete locations and using a reduced number of wavelength points per location. This allows spatially resolved measurements across multiple positions to be completed faster, as each position requires fewer spectral measurements while still providing comprehensive quality assurance coverage.
Solution Approach 2:
The patent implements partial action by measuring at selected discrete wavelengths rather than the full spectral range at each spatial position. This partial measurement approach provides sufficient information for quality assurance without the time cost of complete spectral analysis at every location.
3Productivity
If the number of wavelength-dependent measurement intensities is reduced, then measurement speed is improved, but spectral resolution decreases
Solution Approach 1:
The patent segments the spectrum into discrete wavelength regions and selects representative measurement wavelengths from each segment. This segmentation approach reduces the total number of measurement points needed while preserving the essential spectral information required for accurate determination of layer properties.
Solution Approach 2:
The patent uses a simplified measurement approach that copies only the essential spectral information at selected wavelengths rather than measuring the complete spectrum. This copying strategy captures sufficient data for property determination while significantly reducing measurement time and data processing requirements.
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
Enables rapid and accurate determination of semiconductor layer properties, facilitating inline quality control and reducing measurement times, thereby improving production efficiency and ensuring high-quality semiconductor wafers.
Implementation Method 1
measuring the semiconductor layer structure at at least one measurement point and generating measurement data which, for the measurement point on the semiconductor layer structure, contain a plurality of wavelength-dependent measurement intensities of radiation reflected and/or emitted by the semiconductor layer structure
Data Source
Figure 1
Figure 2a~2b
Figure 3a~3b
AI summary
Method for determining at least one property of a semiconductor layer structure, comprising the following steps: A - providing the semiconductor substrate with the semiconductor layer structure; B - providing reference data which, for at least one reference location of a reference layer structure, contains a plurality of wavelength-dependent reference intensities of radiation reflected and/or emitted by the reference layer structure; C - providing at least one reference property of the reference layer structure at the reference location, wherein the reference property comprises at least a layer thickness and/or a porosity;D - Measuring the semiconductor layer structure at at least one measurement point and generating measurement data which, for the measurement point on the semiconductor layer structure, contain a plurality of wavelength-dependent measurement intensities of radiation reflected and/or emitted by the semiconductor layer structure, wherein the number of wavelength-dependent measurement intensities is lower than the number of wavelength-dependent reference intensities and/or wherein the measurement data have a lower spectral resolution than the reference data; E - Determining the property of the semiconductor layer structure at the measurement point as a function of the reference intensities and the reference property and the measurement intensities, wherein the determined property of the semiconductor layer structure includes a layer thickness and/or a porosity.