Research On Detection Technology Of Circuit Geometric Defects In High-density Flexible Integrated Circuit Substrate

The high-density Flexible Integrated Circuit Packaging Substrates(FICS)is a highly dense flexible circuit board that provides circuit carriers for electronic components.With the vigorous development of the electronics industry,FICS has also developed in the direction of small size and high integration,and its line width,line spacing and other line geometric dimensions have reached the micron level.However,the defect detection method of manual visual inspection cannot measure the geometrical dimensions of high-density FICS lines with dense lines.Therefore,it is an urgent need to use high-precision automatic optical inspection(AOI)system to measure the geometric dimensions of the lines and then detect the geometric defects of the lines.In this paper,based on the detection of geometric defects of high-density flexible substrates,the contour extraction and straight line and curve detection technology in the detection algorithm are studied.The main work of the article is as follows:(1)An iterative threshold segmentation method based on gray histogram is proposed.According to the shape characteristics of the grayscale histogram of the FICS image,this method divides the histogram into three categories and performs multiple Oust threshold segmentation iterations to obtain a suitable threshold that meets the accuracy.Finally,the threshold can be used to quickly and accurately segment the FICS line and background.(2)A contour detection algorithm based on multi-feature fusion and intelligent path exploration is proposed.The anchor points are selected through the brightness features of the image,and then the anchor points are connected by combining the local multi-scale features with intelligent heuristic contour exploration when the contours are on different lines,and finally a complete high-quality contour is obtained.(3)A fast straight line and curve detection algorithm based on contour extraction and validity determination and corresponding line geometric defect detection are designed.First,the contour detection algorithm based on multi-feature fusion and intelligent path exploration proposed in this paper is used to extract the contour of the line,then the straight line is positioned and the standard line width and distance measurement,and then the straight line and curve is detected based on the contour and the positioned straight line.The remaining contours are calculated and analyzed to detect the corresponding geometric defects of the line.