Automated Spatial Filter Setting for Semiconductor Defect Inspection
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Solution Overview
Problem
The complexity of semiconductor device patterns makes it difficult to set conditions for spatial filters efficiently, requiring long times and human intervention, which hampers automation and inspection efficiency.
Innovation Solution
A defect inspection method that involves irradiating the object with light, collecting and processing reflected and scattered light through a spatial filter, displaying images to set light shielding conditions, and comparing captured images to detect foreign matters or pattern defects, enabling automated and efficient spatial filter settings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If manual setting of spatial filter conditions is performed, then inspection reliability is maintained, but inspection efficiency deteriorates due to long setting time and human intervention requirement
Solution Approach 1:
The system automatically sets spatial filter conditions by capturing images of the spatial filter itself and processing them to determine optimal filter parameters, eliminating the need for manual intervention and significantly reducing setting time while maintaining inspection reliability
Solution Approach 2:
The system captures images of the spatial filter through the detection lens, processes these images to analyze filter characteristics, and uses this feedback to automatically adjust and optimize spatial filter conditions, creating a closed-loop automation system
2Measurement precision
If complex patterns with multiple repeated cycles are inspected, then inspection coverage is improved, but spatial filter condition setting becomes difficult and time-consuming
Solution Approach 1:
The system creates an optical copy (image) of the spatial filter itself through the detection lens, allowing automated analysis of filter characteristics without physically manipulating the complex pattern structures, thereby simplifying the condition setting process while maintaining detection accuracy
Solution Approach 2:
The system transitions from analyzing spatial filter conditions in the physical domain to analyzing images of the spatial filter in the optical image domain, enabling automated processing and simplifying the complexity of handling multiple repeated pattern cycles
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 method improves the efficiency and automates the spatial filter settings, facilitating faster and more reliable defect inspection in semiconductor devices.
Implementation Method 1
collecting reflected and scattered light from the object to be inspected by use of a detection lens
Implementation Method 2
collecting reflected and scattered light from the object to be inspected by use of a detection lens
Implementation Method 3
light radiated from a repetitive pattern on the wafer is removed by a spatial filter, and a foreign matter and a defect which do not have repeatability are emphasized
Data Source
AI summary
The present invention provides a defect inspection system which enables an improvement in the efficiency of spatial filter settings, and at the same time enables automation of the spatial filter settings. An adjustable field-of-view diaphragm is narrowed to obtain an image of a spatial filter surface by use of an observation camera, and pixels of the image are classified into a plurality of groups according to the brightness level of bright spots of diffracted light. A spatial filter is set in such a manner that a group, the brightness level of which is highest, is light-shielded, and an observation image is then captured. Whether or not a repetitive pattern remains in the captured image is determined, and when it is determined that a repetitive pattern remains, the settings of the spatial filter are changed. The spatial filter is set in such a manner that in addition to the group which has been light-shielded earlier, a group, the brightness level of which is the highest next to the light-shielded group, can also be light-shielded. The same step is repeated until it is determined that no repetitive pattern remains. The settings of the spatial filter then end.