Inverted high frequency Scanning Acoustic Microscopy inspection of power semiconductor devices

A high frequency Scanning Acoustic Microscopy (SAM) method with inverted inspection direction and its application to power semiconductor devices are described. The method comprises a preparation technique, which in turn allows the inversion of the inspection direction, which means inspection through the die backside and the use of high frequency SAM up to 230 MHz, for packaged power semiconductor devices. The improved resolution limit allows the detection of defects, such as metal degradation, bad wirebond adhesion and cracks. Case studies demonstrate the power of this method and advantages over other analysis methods.