Wafer Inspection System Defect Sorting Automation
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Solution Overview
Problem
Conventional wafer inspection systems rely on subjective human judgment for defect determination, leading to inconsistencies and inefficiencies, and existing methods fail to provide instant determination of defective dies during the fabrication process.
Innovation Solution
A wafer inspection system comprising an electrical testing part, a defect detecting part, a defect sorting part with image processing capabilities, and a defective determining part that uses image pickup and signal processing to objectively determine defect types and degrees by analyzing defect images and calculating contact positions and transformation degrees.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If subjective human judgment is used for defect determination, then inspection flexibility is maintained, but inspection consistency and reliability deteriorate
Solution Approach 1:
The patent replaces the mechanical system of human visual inspection with an automated optical inspection system. The defect detection apparatus captures images of wafers and uses computer-based image processing to automatically determine defect presence and characteristics, eliminating subjective human judgment while maintaining inspection reliability and consistency.
Solution Approach 2:
The inspection system performs self-service by automatically analyzing defect images without human intervention. The computer processes captured images, applies analysis algorithms, and autonomously determines whether defects are present and their characteristics, making the system self-sufficient in the defect determination process.
2Measurement precision
If conventional reference image comparison is used, then defect detection is simplified, but inspection accuracy deteriorates due to position adjustment requirements and complex backgrounds
Solution Approach 1:
The system performs preliminary actions by capturing a background image before capturing defect images. This background image is then subtracted from the defect image to remove complex background patterns and positioning artifacts, leaving only the actual defect information for accurate analysis without requiring manual position adjustment.
Solution Approach 2:
The patent extracts the essential defect information by subtracting the background image from the defect image. This process removes unnecessary background elements and positioning variations, isolating only the relevant defect characteristics for accurate measurement and determination.
3Loss of time
If feedback from sample wafer analysis is used, then process improvement is enabled, but instant defect determination during fabrication is lost
Solution Approach 1:
The inspection system enables continuous useful action by performing real-time defect detection during the wafer fabrication process. Rather than waiting for sample analysis after fabrication, the system continuously monitors wafers as they are produced, providing immediate defect determination that maintains production flow and enables instant quality control.
Data Source
AI summary
A wafer inspection system includes an electrical testing part to control a probe to be in contact with a pad of a wafer to perform a predetermined electrical test, a defect detecting part to detect a defect in the wafer passing through the electrical test, a defect sorting part to sort the defect detected in the defect detecting part by an in-line method, and a defective determining part to determine whether the wafer is a defective according to a sorting result of the defect sorting part. The wafer inspection system and a method thereof can determine the kinds of the defect in the wafer during a fabricating procedure, so that it is possible to instantly and correctly determine whether the die on the wafer is a defective.