Multilayer Semiconductor Inspection via Absorption Edge Calibration
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Solution Overview
Problem
The manufacturing of organic-inorganic lead halide perovskite solar cells often results in non-uniform layers, pinholes, and parasitic phases, leading to device failure and low photoconversion efficiency, which existing inspection methods fail to effectively detect and measure.
Innovation Solution
An inspection method for multilayer semiconductor devices that uses calibration functions based on absorption edges to measure stratigraphic thickness maps, detect uniformity, missing layers, and parasitic phases, and perform compositional analysis, achieving precise measurements even for extremely thin films.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional inspection methods are used for multilayer semiconductor devices, then the inspection process is simple, but the measurement precision and ability to detect defects such as pinholes, non-uniform layers, and parasitic phases is insufficient
Solution Approach 1:
The patent applies preliminary action by pre-establishing calibration functions for each layer material before actual inspection. Reference samples with known layer thicknesses are prepared in advance, and calibration curves relating optical transmittance to layer thickness are constructed beforehand. During inspection, the pre-established calibration functions are used to directly determine layer thickness from measured transmittance values, enabling precise measurement without complex real-time calculations.
Solution Approach 2:
The patent uses optical transmittance as an intermediary parameter to indirectly measure layer thickness and detect defects. Instead of directly measuring physical thickness, the method measures the transmittance of light through the multilayer structure and converts it to thickness information using calibration functions. This intermediary approach enables non-contact, high-precision measurement of extremely thin layers and detection of subsurface defects.
2Reliability
If existing inspection methods are used, then the inspection process is fast, but the ability to detect missing layers, dust particles, and parasitic phases is inadequate
Solution Approach 1:
The patent applies segmentation by dividing the inspection process into separate analysis steps for different defect types. The method segments the spectral information into different wavelength regions, each sensitive to specific defect types such as missing layers, dust particles, or parasitic phases. By segmenting the analysis, the method can efficiently detect multiple defect types simultaneously without requiring separate inspection processes for each.
Solution Approach 2:
The patent utilizes color changes (spectral transmittance variations) to detect different types of defects. Different defects cause characteristic changes in the optical transmittance spectrum - missing layers cause specific transmittance increases, dust particles cause scattering-related spectral changes, and parasitic phases cause absorption-related changes. By analyzing these spectral 'color' changes, the method can identify and classify different defect types efficiently.
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
The method enables accurate measurement of layer thickness and uniformity, detection of defects, and compositional analysis, improving the quality control of multilayer semiconductor devices by utilizing absorption edges and calibration functions.
Implementation Method 1
choosing a first region of wavelength corresponding to an absorption edge of the first material of interest
Implementation Method 2
measuring transmittances of the first covered portion and the first bare portion, to obtain first transmittances of the first covered portion and first bare transmittances of the first bare portion at the first region of wavelength
Data Source
AI summary
An inspection method for a multilayer semiconductor device is provided. The inspection method can investigate multilayered ensembles of a multilayer semiconductor device and obtain stratigraphic thickness (ST) maps of each layer in the multilayer semiconductor device by utilizing absorption edges of materials of interests and obtaining calibration quality curves.