Assembly of Piezoelectric MEMS Vibration Sensor for Cochlear Implant

The use of implantable devices for biomedical applications has been made possible by the ubiquity of vibration sensors and accelerometers, coupled with advances in microfabrication technologies. Among these devices, implantable auditory prostheses, such as hearing aids and cochlear implants, have emerged as a viable alternative to traditional external devices, which can cause discomfort to users. To meet the requirements for implantable auditory devices, a piezoelectric microelectromechanical systems (MEMS) accelerometer has been developed, which includes an AlN (Aluminun Nitrate) piezoelectric signal generator attached to a silicon proof mass. This paper presents the fabrication route developed at the Assembly, Packaging and System Integration Division from Renato Archer Center for Information Technology (DIMES/CTI), including anisotropic etching of silicon cavities, flip chip assembly and signal extraction routes, to seal a silicon proof mass sample (accelerometer) fabricated by a third party.