MEMS (Micro-Electromechanical System) capacitive ultrasonic sensor and manufacturing method thereof

Abstract

The invention discloses an MEMS (Micro-Electromechanical System) capacitive ultrasonic sensor and a manufacturing method thereof. The MEMS capacitive ultrasonic sensor comprises a glass substrate, a lower electrode, top silicon, an upper electrode and a protective layer, wherein a concave cavity is formed in the middle of the glass substrate; both sides of the cavity are provided with grooves respectively; the lower electrode is manufactured at the bottom of the concave cavity of the glass substrate; the top silicon is manufactured on the glass substrate, and covers the cavity; the top silicon 13 is a vibrating film; the upper electrode is manufactured on a lower surface of the top silicon and positioned above the cavity, and corresponds to the lower electrode; the protective layer is manufactured in the grooves in both sides of the glass substrate, and covers the top silicon and the glass substrate; a window is formed in the protective layer of the groove; and an upper extraction electrode and a lower extraction electrode are connected with the upper electrode and the lower electrode respectively. Through adoption of the MEMS capacitive ultrasonic sensor, the parasitic capacitance can be reduced, and the sensitivity of the sensor can be increased.

Description

technical field [0001] The invention relates to a capacitive ultrasonic sensor in the field of sensors, in particular to a MEMS capacitive ultrasonic sensor and a preparation method thereof. Background technique [0002] Ultrasonic sensors have a wide range of applications in medical imaging, industry, and defense. In recent years, a capacitive ultrasonic sensor has gradually become one of the main research directions of ultrasonic transducers. Compared with piezoelectric ultrasonic transducers, capacitive ultrasonic transducers have the advantages of high sensitivity, wide bandwidth, and low mechanical impedance, and adopt large-scale integrated circuit manufacturing methods, which are easy to integrate with electronic circuits and have low manufacturing costs. Wider range of applications. In the common CMUT structure, the substrate or diaphragm is used as an integrated electrode during operation. There are many factors such as parasitic capacitance, high impedance of the...

AI Technical Summary

Problems solved by technology

In the common CMUT structure, the substrate or diaphragm is used as an integrated electrode during operation. There are many factors such as parasitic capacitance, high impedance of the substrate, and charging of the insulating layer, and many advantages of the CMUT cannot be fully utilized.

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