A 3D packaging technology for acoustically optimized integration of 2D CMUT arrays and front end circuits

As compared to piezoelectric technology, MEMS technology employed for Capacitive Micromachined Ultrasonic Transducer (CMUT) fabrication provides increased compatibility with 3D packaging methods, enabling the possible development of advanced transducer-electronics multi-chip modules (MCM) for medical imaging applications. Interconnection of 2D CMUT arrays and analog front end integrated circuits (IC) using die-level packaging methods was demonstrated earlier. However, no effort was devoted to the study and optimization of the acoustic behavior of the resulting MCM. In this paper, we propose an acoustically optimized 3D packaging method for the interconnection of Reverse-Fabricated CMUT [doi: 10.1088/0960-1317/25/1/015012] 2D arrays and front end ICs using a wafer-level compatible process.