Scanning acoustic microscopy stress measurements in electronic packaging

Scanning acoustic microscopy has been successfully implemented for the nondestructive detection of cracks and delaminations in integrated circuit packages. The incorporation of scanning acoustic microscope inspections in reliability tests of molded surface mount components has identified delamination at the mold compound/die interface as the primary cause of electrical failure during temperature cycling. The ability of the acoustic microscope to nondestructively image stress distributions prior to failure would greatly extend the impact of scanning acoustic microscopy on new package development and process control. This may be particularly important for the packaging of devices with fragile low-K (dielectric constant) layers in the device structure.