Characterization of adhesive wafer bonded CMUTs realized from BCB based sealed cavity

Abstract

This paper presents the characterization results of a CMUT array fabricated using a Bisbenzocyclobutene (BCB) based adhesive wafer bonding technology. A resonant frequency of 17.3 MHz has been measured using an Agilent ENA5061B Vector Network Analyzer that is in good agreement with the results from 3-D FEA using IntelliSuite™. The extracted coupling coefficient from the electrical impedance measurement shows 40% higher transduction efficiency as compared to another research work published elsewhere. Optical measurements of the membrane deflection using a Polytec™ laser Doppler vibrometer and pitch catch mode experimental results validate the CMUT operation in both transmit and receive mode.