Scanning Acoustic Microscope to Probe Voids and Interfaces in Functionalized Materials and Hybrid Devices

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The recently deployed wafer bonding capabilities at Ecole Polytechnique create a wealth of opportunities to develop a new class of hybrid devices by allowing large scale integration of materials with different properties in the same platform thereby achieving single multifunctional entities. Assessing the quality of bonded interface and its behavior during processing is of the utmost importance in order to exploit the full potential of this heterogeneous integration. The interface between dissimilar materials plays a central role in shaping the physical, chemical, optical, and electrical properties of engineered heterostructures and hence defines the reliability and performance of a variety of current and emerging hybrid technologies. Therefore, a precise inspection of interfaces is crucial to verify the quality of the fabricated hybrid devices and to track their long-term stability, which is of compelling importance to optimize various fabrication, functionalization, and integration processes. With this perspective and to establish the characterization infrastructure that complements our wafer bonding facilities, we seek to set up a scanning acoustic microscope, which enables a non-destructive, high resolution, and sensitive imaging of buried interfaces. This microscope works like a sonar, sending a high frequency acoustic signal and measuring the time it takes to reflect back to the detector. It is particularly sensitive to voids, cavities, porosity, delaminations, cracks, and particles trapped between two joint surfaces thus providing valuable insights into microstructural characteristics of materials. The microscope will be managed by the Microfabrication Laboratory which hosts state-of-the-art facilities accessible to all researchers from public and private sectors. The microscope will be central to advance research activities in microelectronics, optoelectronics, photonics, photovoltaics, microfluidics, electromechanics, and surface coating technologies. The acquisition of the SAM will also offer an excellent opportunity to enhance the training of highly qualified personnel