Wafer Defect Inspection via Image Matching and Feature Variation
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Solution Overview
Problem
Manual inspection of semiconductor wafers for defects is prone to human errors due to the heavy workload of on-site technicians, which can lead to erroneous readings of optical images.
Innovation Solution
A machine-based inspection system that includes an inspection tool and a review tool, configured to generate and process inspection images of semiconductor wafers, automatically detect defects, and enhance image quality to reduce human intervention and errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If manual inspection is performed by on-site technicians, then human judgment and flexibility can be applied, but human errors and erroneous readings occur due to heavy workload
Solution Approach 1:
The patent replaces the manual mechanical inspection process with an automated machine-based inspection system that captures optical images of wafers and uses image processing algorithms to detect defects automatically, eliminating human workload and associated errors while maintaining or improving inspection accuracy
Solution Approach 2:
The inspection system performs self-inspection by automatically capturing images, processing them through algorithms, and identifying defects without requiring human technicians to manually examine each wafer, allowing the system to serve itself in the inspection task
2Productivity
If machine-based inspection is implemented, then human errors are reduced and work efficiency is enhanced, but system complexity increases
Solution Approach 1:
The inspection system is designed to perform multiple functions including image capture, image processing, defect detection, and analysis within a single integrated platform, allowing it to handle various inspection tasks efficiently without requiring multiple separate systems
Solution Approach 2:
The patent introduces an image processing module as an intermediary between the optical image capture and defect detection, using algorithms to enhance images and extract features automatically, which simplifies the overall system architecture while improving productivity
Data Source
AI summary
A defect inspection method, an inspection system, and a non-transitory computer-readable storage medium are provided. The defect inspection method includes providing a processed image and a reference image of a wafer, both the processed image and the reference image comprising a pattern of interest; determining the processed image as a qualified image in response to a matching ratio that reflects a percentage of correctly aligned features of the pattern of interest between the processed image and the reference image is above a first predetermined threshold; selecting a first feature of the qualified image; selecting a second feature of the reference image corresponding to the first feature of the processed image; comparing the qualified image with the reference image to determine a variation of the first feature with respect to the second feature; and detecting a defect of the wafer based on a comparison of the first and second features.