Automated Inspection of Printed Circuit Board Patterns Referenced to CAD Data

Abstract

This paper describes a system which automatically inspects defects in printed circuit patterns. The system is aimed to achieve the maximum defect detection capability, and has the function of automated recognition of fatality of detected defects. The system detects defects by comparing detected patterns with the patterns which are electrically-generated from CAD-data of the printed circuit patterns. Methods to accomplish the targets mentioned above are described : fluorescence detection method for exact pattern acquisition, modulation compensation method of detected signals, precise registration method of the two patterns, defects' fatality recognition method, etc.