Semiconductor BSE Image Crosstalk Correction Using SE Feature Masks
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Solution Overview
Problem
Current semiconductor examination tools face challenges in accurately measuring critical dimensions due to image artifacts caused by crosstalk between surface and underlayer features, affecting the reliability and precision of metrology operations.
Innovation Solution
A computerized system processes secondary electron (SE) and backscattered electron (BSE) images to generate a corrected BSE image by creating a feature mask from the SE image, applying a correction factor to suppress image artifacts, and iteratively optimizing the correction factor to minimize the impact of surface features on the BSE image.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If BSE images are used to examine underlayer features, then depth information and compositional contrast are improved, but image artifacts caused by surface layer structural features increase
Solution Approach 1:
The patent introduces an intermediary correction process that uses SE image data as a mediator to remove surface feature artifacts from BSE images. The SE image serves as an intermediary source containing surface feature information, which is then processed to generate correction data that eliminates harmful artifacts from the BSE image without sacrificing underlayer feature visibility.
Solution Approach 2:
The patent extracts surface feature information from the SE image and separates it from the BSE image data. By taking out the surface feature component through image segmentation and mask generation, the system removes the harmful artifacts while preserving the underlayer feature information in the BSE image.
2Reliability
If multiple examination steps and repeated measurements are performed, then measurement reliability is improved, but examination time and process complexity increase
Solution Approach 1:
The patent performs preliminary action by acquiring both SE and BSE images in a single examination step, and by pre-processing the SE image to create feature masks and correction data before the actual measurement. This preliminary preparation enables artifact removal without requiring repeated measurement steps, thus improving reliability without increasing time.
Solution Approach 2:
The patent maintains continuity of useful action by integrating the artifact removal process into the existing examination workflow. The correction process uses the SE image data already acquired during the examination, continuously processing information without interrupting or extending the examination timeline, thereby maintaining measurement reliability while avoiding additional time loss.
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 corrected BSE image reduces image artifacts, enhancing the accuracy of metrology operations such as CD measurements and overlay, thereby improving the reliability and precision of semiconductor fabrication processes.
Implementation Method 1
obtain a secondary electron (SE) image and a backscattered electron (BSE) image of the specimen acquired by an electron beam tool
Implementation Method 2
obtain a secondary electron (SE) image and a backscattered electron (BSE) image of the specimen acquired by an electron beam tool
Data Source
AI summary
There is provided a system and method of examination of a semiconductor specimen. The semiconductor specimen comprises at least a surface layer and a under layer. The method includes obtaining a secondary electron (SE) image and a backscattered electron (BSE) image of the specimen acquired by an electron beam tool, wherein the BSE image possesses one or more image artifacts caused by one or more structural features on the surface layer; processing the SE image to generate a feature mask comprising a set of segments representative of the one or more structural features; and generating a corrected BSE image based on the BSE image and the feature mask, wherein the corrected BSE image possesses suppressed image artifacts with respect to the one or more image artifacts in the BSE image.