Semiconductor Defect Inspection Using Etch-Labeled Image Pairs
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Solution Overview
Problem
Current defect detection systems in semiconductor manufacturing are unable to distinguish between critical and non-critical defects without destructive testing, and they struggle to classify micropits accurately.
Innovation Solution
A machine learning model is trained using image pairs of etched and unetched specimens to classify defects on unetched specimens, employing darkfield imaging for micropit detection and supervised learning to differentiate between defect types.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If destructive etch process is used to detect defects, then defect classification accuracy is improved, but specimen loss and inspection time increase
Solution Approach 1:
The patent applies preliminary action by training a machine learning model in advance using paired images (etched and unetched specimens) to learn the correspondence between defect appearances in etched and unetched states. This pre-trained model can then rapidly classify defects in unetched specimens without requiring actual destructive etching during inspection, thus maintaining high classification accuracy while eliminating the time-consuming destructive process.
Solution Approach 2:
The patent uses copying by creating synthetic training data through image processing. It generates synthetic etched images from unetched images (and vice versa) using image processing techniques, thereby creating large datasets for training the machine learning model without requiring physical destructive etching of numerous specimens. This virtual copying approach enables the model to learn from abundant data while preserving actual specimens.
2Reliability
If destructive testing is performed to distinguish critical defects, then defect classification capability is improved, but specimen availability and inspection efficiency deteriorate
Solution Approach 1:
The patent replaces the mechanical/chemical destructive etching process with a computational machine learning system. Instead of physically etching specimens to reveal defect characteristics, the system uses a trained neural network model that analyzes optical images and predicts defect types based on learned patterns from training data, thereby substituting a non-destructive computational approach for a destructive physical process.
Solution Approach 2:
The system performs preliminary training of the machine learning model using paired etched and unetched specimen images before actual inspection. This pre-training phase enables the model to internalize the relationship between defect appearances in etched and unetched states, so that during production inspection, defects can be classified rapidly without performing actual destructive etching, thus maintaining high reliability while improving productivity.
3Measurement precision
If machine learning model is trained with labeled data from etched specimens, then defect detection accuracy is improved, but data acquisition complexity increases
Solution Approach 1:
The patent applies copying by generating synthetic paired images through image processing. It creates synthetic etched images from unetched images (or vice versa) using image processing algorithms, thereby generating large volumes of labeled training data without requiring physical etching of specimens. This virtual data generation approach reduces the complexity of data acquisition while providing sufficient training data for accurate model training.
Solution Approach 2:
The patent introduces an image processing module as an intermediary that transforms unetched specimen images into synthetic etched images (or vice versa). This intermediary process automatically generates the paired labeled data needed for training, eliminating the need for manual data collection through destructive etching and significantly reducing data acquisition complexity while maintaining data quality for accurate model training.
Data Source
AI summary
A computer-implemented method for detecting defects on specimens in an inspection system is disclosed herein. A first set of images of a plurality of specimens having defects formed thereon is received. A second set of images of the plurality of specimens is received, the second set of images includes the plurality of specimens after undergoing a destructive etch process and labels corresponding to each defect. Labels from the second set of images are transferred to the first set of images. A machine learning model is trained to classify defects on unetched specimens based on the first set of images and the labeled first set of images. Once the machine learning model has achieved a threshold of accuracy, the machine learning model may be deployed in the inspection system.


