A binocular machine vision system for ball grid array package inspection

摘要

Purpose - In this paper, an optical inspection method of the ball grid array package(BGA) is proposed using a binocular machine vision system. Design/methodology/approach - The height of each solder ball is calculated based on spatial geometrical size and location obtained from the two CCD cameras capturing range images of a LED illuminated BGA chip at certain orientation. Findings - The structure of this system is simple and the accuracy is 0.02 mm, The experimental results have proved the validity of this system for BGA failure detection. Practical implications - The developed machine vision system can provide some of the critical factors for BGA quality evaluation, such as the height of solder ball, diameter, pitch and coplanarity. Originality/value - Compared with other systems, the structure of this system is simple and accurate, which meets the demand of off-line and on-line inspection. The limitation of this system is that the margin of field of view (FOV) is fuzzy. Further study could be focused on this problem.