This paper highlights the possibilities of nondestructive techniques such as high frequency ultrasonics for location of internal defects and discontinuities in plastic-packaged ICs. C-scan, B-scan, through-scan and signal polarity techniques were employed. These methods can complement each other in enhancing the interpretation of the scanned images. Case studies of detection of delamination between layers, porosity, disbonds, popcorn cracking, and even die cracking when the samples are well oriented towards the ultrasonic beam are presented in this paper. In addition, electrical overstress causing localized carbonized mold compound at bond wires and/or melted metallization on the die surface can be detected.
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