Film covering alignment error detection method and system

Abstract

This application relates to the field of electronic manufacturing technology, specifically to a method and system for detecting alignment errors in a film coating process. The method includes: acquiring a grayscale image of a coated substrate and a local film thickness gradient along the substrate transport direction; determining the center frequency and notch bandwidth of interference fringes in the image frequency domain based on the local film thickness gradient, and filtering the spectrum of the grayscale image of the coated substrate according to the center frequency and the notch bandwidth to obtain a cleaned image; extracting the gradient amplitude of the cleaned image within the region of interest of a marked point, and determining a calculation window based on the statistical characteristics of the gradient amplitude, calculating the sub-pixel center coordinates of the marked point within the calculation window; performing error calculation based on the sub-pixel center coordinates, and verifying the result by combining a preset alignment tolerance, thereby obtaining the alignment error detection result. This application can adaptively separate interference frequency components and achieve accurate detection and correction of alignment errors.

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