Wafer surface pollution defect detection method and device

The SNR estimation and dual threshold segmentation method enhances the detection of subtle defects on wafers by accurately distinguishing background and defect signals, addressing the challenges of varying cleanliness standards and complex background signals in dark field inspection.

CN120318181AActive Publication Date: 2025-07-15SKYVERSE TECH CO LTD
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Patent Information

Application Number
CN202510395081.8
Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Filing Date
2025-03-31
Publication Date
2025-07-15
Estimated Expiration
2045-03-31

AI Technical Summary

Technical Problem

The existing dark field detection methods face problems such as complex background signals and weak defect signals in wafer surface pollution defect detection, which leads to increased detection difficulty and is difficult to meet the requirements of semiconductor manufacturing for high precision and high efficiency.

Method used

The neighborhood SNR estimation principle is adopted, and the wafer dark field image is segmented by setting high and low thresholds. Combined with the neighborhood SNR estimation calculation, the background signal and defect signal are accurately distinguished, which improves the detection ability of subtle defects and dirty.

Benefits of technology

In a complex context, it can stably and accurately identify extremely weak defect signals, which improves the stability and efficiency of detection and meets the comprehensive requirements of industrial production.

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Abstract

The invention relates to the technical field of wafer detection, in particular to a wafer surface pollution defect detection method and device, and the method comprises the steps: carrying out the dark field shooting of a target wafer, obtaining a surface dark field scattering image of the wafer, traversing each pixel in the dark field image, forming an SNR estimation graph through the neighborhood setting and SNR estimation calculation, and carrying out the detection of the surface pollution defect of the wafer. Global threshold segmentation is carried out on the SNR estimation image through a double-threshold principle to obtain a low-threshold binary image and a high-threshold binary image, a connected region in the low-threshold binary image is traversed, if at least one pixel in the connected region is marked as a defect in the high-threshold binary image, all pixels in the connected region are marked as real defects, and if at least one pixel in the connected region is marked as a defect in the high-threshold binary image, all pixels in the connected region are marked as real defects. Otherwise, marking the defect as a pseudo defect. According to the invention, under the conditions of large dynamic range of background noise, small number of defect pixels, weak defect signals and the like, defects and defect contours can still be detected stably.
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