Acoustic micro-imaging tools perform the non-destructive imaging and analysis of internal features (including anomalies and defects) in advanced ceramics and other materials by pulsing ultrasound into the sample and receiving the return echoes. The resulting acoustic image displays the material interfaces within the sample within the vertical limits defined by the operator.
Because a pulse of ultrasound may send back echoes from multiple depths within the sample, control of those echoes is generally important. “Control” in this case means defining the vertical limits that are imaged by collecting only those echoes that were returned from the depth of interest. In the imaging of multilayer ceramic capacitors (MLCCs), the standard approach is to use the echoes from all or nearly all depths, because the exact depth of a delamination or other defect in such a layered device is relatively unimportant; a capacitor having an anomaly at any depth that meets the user’s definition of a defect will be rejected.