Fabrication of Linear Array and Top-Orthogonal-to-Bottom Electrode CMUT Arrays With a Sacrificial Release Process

The microfabrication processes for sacrificial-release-based capacitive micromachined ultrasound transducer arrays are provided with an emphasis on top-orthogonal-to-bottom electrode 2-D arrays. These arrays have significant promise for high-quality 3-D imaging with reduced wiring complexity compared with fully wired arrays. The protocols and best practices are outlined in significant detail along with design considerations and notes of caution for pitfalls and factors impacting yield.