Résumé
The high frequency micro acoustic imaging (10MHz - 1GHz) reaches its limits when it is necessary to observe through absorbing or thick layers, not perfectly flat, at high frequency for a good resolution. The objective of this paper is to present a new method of acquisition and signal processing to image with high resolution buried defects through layers not perfectly flat and to reconstruct the topography and see possible delaminations. Typically a displacement of the focused transducer is achieved to maintain a constant temporal position of the echo of the interface to be examined. This allows the creation of an image of the interface, but the acquisition time and complexity of the device is often prohibitive. This method, in the continuity of a paper presented at the 2010 CFA, does not use a hardware control of the transducer, but a software control. Applications of this method allow the imaging of multilayers power electronics devices composed of stacks of conductive substrates or not conductive, with microelectronic circuits. Two types of representations are used: images and 3D reconstruction movies.