Acoustic Imaging Techniques Effectively Map Buried Layer Contours

Abstract

Acoustic microscopes pulse ultrasound into a sample and use the return echoes to find and image cracks, delaminations, and other gap-type flaws in manufactured parts and products. New developments in microscope technology enable mapping of the point-by-point contour of tilted or warped interfaces, as well as individual material layer thicknesses. This article includes an example of mapping of buried layers in power insulated gate bipolar transistor modules used in railroad engines, heavy mining equipment, and electric automobiles.