Capacitive ultrasonic sensor chip and manufacturing method thereof

Abstract

The invention relates to a capacitive ultrasonic sensor chip. The capacitive ultrasonic sensor chip comprises a doped silicon substrate, wherein a first area and a second area are arranged on the surface of the doped silicon substrate, and the first area is provided with an integrated circuit with a metal conducting layer extending to the second area; an additional film covers the metal conducting layer on the second area, a vibrating film capable of conducting electricity covers the additional film, a contact through hole connected with the vibrating film is formed in the additional film, and a cavity is formed between the additional film and the vibrating film. According to the capacitive ultrasonic sensor chip, the additional film, a sacrificial layer and the vibrating film capable of conducting electricity cover the metal conducting layer of the integrated circuit of the standard CMOS manufacturing technology, finally, a micro sensor unit is manufactured, the existing CMOS technology is not changed, and good compatibility is achieved. Besides, the invention relates to a manufacturing method of the capacitive ultrasonic sensor chip.

Description

technical field [0001] The invention relates to the field of sensors, in particular to a capacitive ultrasonic sensor chip and a manufacturing method thereof. Background technique [0002] Ultrasonic wave is a mechanical wave whose vibration frequency is higher than that of sound wave. It has the characteristics of high frequency, short wavelength, small diffraction phenomenon, good directionality, and can become ray and directional propagation. Ultrasound has a great penetrating ability to liquids and solids, especially in solids that are opaque to sunlight, it can penetrate to a depth of tens of meters. Therefore, ultrasonic detection is widely used in industry, national defense, biomedicine and so on. [0003] The main materials of ultrasonic sensors are piezoelectric crystal (electrostrictive) and nickel-iron-aluminum alloy (magnetostrictive). Electrostrictive materials include lead zirconate titanate (PZT) and the like. Due to the serious uncoupling phenomenon betwee...

AI Technical Summary

Problems solved by technology

However, the process of releasing the sacrificial layer and sealing the corrosion hole is relatively complicated. The low-temperature deposited nitride film conventionally used to seal the corrosion hole is porous in nature, and the effect of sealing the corrosion hole is not very good.

In addition, the traditional CMUTs manufacturing process is poorly compatible with the standard CMOS process, and the high cost of monolithic integration of sensor array chips has become a major obstacle to large-scale promotion.

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