Wafer Edge Inspection via Area Segmentation
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Solution Overview
Problem
Conventional substrate inspection methods fail to accurately detect macroscopic abnormalities in the peripheral portion of wafers, particularly during semiconductor device manufacturing, due to difficulties in controlling the peripheral edge area and poor pattern matching, leading to incorrect determination of film formation and coating quality.
Innovation Solution
A substrate inspection method that divides a predetermined area in the peripheral edge image into multiple areas and acquires feature amounts, such as average pixel values or standard deviations, to perform precise determination based on comparison with a reference image, enabling accurate detection of macroscopic abnormalities like large-scale coating failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional substrate inspection methods are used to inspect the peripheral portion of substrates, then the inspection process is simple, but the measurement precision is insufficient to accurately detect macroscopic abnormalities
Solution Approach 1:
The inspection image of the peripheral portion is divided into multiple divided areas, and feature amounts are acquired for each divided area independently. This segmentation enables precise detection of macroscopic abnormalities in specific regions without being affected by other areas, resolving the contradiction between measurement precision and device complexity by applying complexity only where needed for accurate detection.
2Manufacturing precision
If the peripheral edge area is controlled loosely to maintain ease of operation, then the operation is simpler, but the manufacturing precision of film formation and coating quality deteriorates
Solution Approach 1:
The inspection method applies different analysis approaches to different regions: divided areas for macroscopic abnormality detection and specific positions for microscopic defect detection. This local quality approach enables precise control of manufacturing quality in critical areas while maintaining operational simplicity in less critical areas, resolving the contradiction between manufacturing precision and ease of operation.
3Reliability
If pattern matching is used for inspection, then the inspection process is straightforward, but the reliability of determination is poor due to incorrect detection of coating unevenness
Solution Approach 1:
The inspection method segments the determination process into two independent stages: first determining macroscopic abnormalities in divided areas, then determining microscopic defects in specific positions. This segmentation eliminates the reliability issues of conventional pattern matching by preventing false detection of coating unevenness as defects, while maintaining reasonable method complexity through systematic organization.
Solution Approach 2:
Instead of using pattern matching to directly determine coating quality, the invention inverts the approach by first identifying macroscopic abnormalities and then checking for microscopic defects only in relevant areas. This inversion of the determination logic significantly improves reliability by eliminating false positives from coating unevenness, while the structured two-stage process keeps the method complexity manageable.
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 approach allows for accurate inspection of wafer peripheral edges, preventing false detection of coating unevenness and correctly identifying the formation state of resist films, thereby improving the yield and quality of semiconductor devices.
Implementation Method 1
the camera includes an imaging element to which light from the peripheral area of the front surface of the substrate held by the holding plate is input through a lens together with the reflected light obtained when the light from the end surface of the substrate held on the holding table is reflected from the reflection surface of the mirror member
Data Source
AI summary
A substrate inspection method includes: acquiring a feature amount of each of divided areas in an inspection target peripheral edge image, the inspection target peripheral edge image being an image of a peripheral portion of a target substrate as an inspection target, the divided areas being obtained by dividing a predetermined area in the image of the peripheral portion of the target substrate into a plurality of areas; and performing a predetermined determination concerning inspection of the peripheral portion of the target substrate based on an acquisition result in the acquiring the feature amount.