IMAGE ANALYIS METHODS FOR SOLDER BALL INSPECTION IN INTEGRATED CIRCUIT MANUFACTURING.

The authors address the problem of segmenting and analyzing images of solder balls in integrated circuits. Two methods are explored, one based on projections computed along curved contours derived from the geometry of the problem, and the other using a supervised, feature-based polynomial classification method. High accuracy is required for the machine vision solution to be successful, and the authors have included some considerations concerning subpixel accuracy for the computation of the values of parameters determining the two-dimensional solder ball shapes. The classification technique has performed with satisfactory results on available data.