An automated IC chip marking inspection system for surface mounted devices on taping machines

Abstract

This study presents a new automated system for inspecting markings on surface mounted devices (SMDs) prior to packaging. In proposed design, marking region is identified using a normalized cross-correlation template-matching scheme. A multi-resolution pyramid image processing approach is used to enhance speed of search process. Target image is filtered using a hybrid digital logic filter (DLC) / mean and standard deviation gray scale (MSDGS) algorithm for noise filtering. Individual characters in marking are segmented and fed to a neural network for automatic recognition. DLC / MSDGS filtering scheme is found more straightforward and far more robust toward a noise filtering than conventional image processing schemes. System achieves a recognition rate of 99.14% with identifying each IC chip marking within 0.05 sec. System provides an ideal solution for real-time inspection of IC markings in high-throughput SMD packaging applications.