Sonoscan’s AW322 200 automated system for ultrasonic inspection of MEMS wafers images and identifies internal gap-type defects down to 5 µm in size. It is especially useful for finding non-bonds, voids, and other defects in the seals surrounding the MEMS wafer cavities. System features include two loadports, two stages, and multiple transducers, enabling it to image two 8-in MEMS wafers simultaneously. Other models in the series accommodate wafer sizes of 100-300 mm. In operation, the robotic handling station counts and unloads wafers from the carriers, aligns wafers for scanning, and positions wafers on the stage. After scanning, both the acoustic wafer image and the wafer data can be used for accept/reject determination.