Understanding Water Ingress in Scanning Acoustic Microscopy and a Method to Observe Defects that are Open to the Surface

Scanning Acoustic Microscopy (SAM) is a very important tool in the evaluation of molded plastic electronic components. SAM is used to non-destructively determine the configuration and quality of components using ultrasonic sound waves and consequently is an important test step in the screening, Destructive Physical Analysis (DPA) or Failure Analysis (FA) of plastic components. SAM is performed in a water bath so if internal defects are open to the surface of the device they can fill with water and become invisible to SAM.