Abstract—The advantages of X-ray inspection are extensive
in scope due to the ability of X-rays to see through packages
including heat sinks, welds, encapsulation, and metallic shielding to reveal obscured connections and identify potential
quality non-destructive issues. Many assembly line
manufacturers rely on real-time X-ray technology to evaluate
solder joint integrity for BGAs and other leadless packages that
cannot be inspected by conventional vision systems. X-ray
inspection is particularly beneficial to applications that involve advanced surface-mount packaging technologies such as Ball
Grid Array (BGA) used for integrated circuits. This paper proposes a method that relies on computer vision and image processing techniques that inspects each ball image of a BGA
chip and indicates the faulty balls for further assessment. The
defective balls that are typically circular change into elongated
or elliptical shape. Therefore, it exploits the use of the basic geometric distinction between a circle (perfect soldered ball)
and an ellipse or any other shape (ball with reshaped solder joint). A contour analysis method is defined in this paper in
terms of the angle changes that occur along the outline profile of
a solder joint by moving three equal distant points located on
the border. This angle change is plotted to detect the faulty ball
joints.
Index Terms—BGA, shape analysis, solder joints, X-ray
techniques.
The authors are with the Department of Electrical Engineering, United Arab Emirates University, P. O. Box: 15551, Al Ain, United Arab Emirates
(e-mail: mslaghari@uaeu.ac.ae, qurban.memon@uaeu.ac.ae).
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Cite: Mohammad S. Laghari, Member and Qurban A. Memon, "Identification of Faulty BGA Solder Joints in X-Ray
Images," International Journal of Future Computer and Communication vol. 4, no. 2, pp. 122-125, 2015.