Image processing of die attach's X-ray images for automatic voids detection and evaluation

The goal of this paper is to present the method for automatic detection and location of power chip, which is soldered on DBC substrate, and voids in die attach solder joint. The method of chip location is provided by two dimension correlation applied on X-Ray images. When chip location is detected, voids in solder joints can be detected. It is very important to make such analysis, because during soldering process lot of voids and defects in die attach can occur. Basic indicator of joints' quality is quantity and size of voids in die attach. Quality of solder joints depends on homogeneity of solder, which have the crucial effect on it. Automatic detection of chip and voids in die attach is achieved by techniques of image processing like filtering, energetic normalization, thresholding and image enhancement. In the paper, results of analyses of more solder alloy (99.9Sn, SnCu3In0.5, 96Sn4Ag, 99Sn1Ag) are presented. This paper offers the effective and precise method for automatic detection and evaluation of the voids from X-Ray images of solder joint.