Technique for rapid inspection of hermetic seals of microelectronic packages using shearography

One possible failure of microelectronic devices is due to leakage resulting from an imperfect hermetical seal in microelectronic packages such as microchips. This malfunction is often experienced in automobiles in which the electronic devices are exposed to hostile environments. Traditional leak-testing methods are very time consuming. A shearographic technique for rapid evaluation of hermetic seals is presented. The package under test is stressed by an external pressure change. With the pressure change maintained, the lid of a perfectly sealed package will remain deformed while a leaky package will not hold the deformation, which can be monitored by shearography. This leak testing is fast and practical and can be extended to testing pharmaceutical packages, food packages, etc. © 1998 Society of Photo-Optical Instrumentation Engineers.