Improving Structural Strength and Stability of Parylene-Based Capacitive Micro Pressure Sensor Using Corrugated Sidewall

This paper reports a new method to improve the structural strength and stability of parylene-based microfabricated implantable capacitive blood pressure sensor. The key idea or contribution is to introduce corrugations to the side wall of the sensor supporting the top membrane in order to effectively increase the thickness and thus stiffness of the sidewall. This design significantly reduces the possibility of membrane collapses during fabrication or operation that otherwise would commonly occur in the conventional parylene-based capacitive sensors with large diaphragm and small gap between electrodes. The fabricated sensor with corrugations shows a stable linear output behavior within the desired range of up to 200 mmHg, which is optimal for the application of the implantable real-time blood pressure monitoring system.