Manufacturing method of multi-frequency CMUT device and multi-frequency CMUT device

Abstract

The invention provides a manufacturing method of a multi-frequency CMUT device and the multi-frequency CMUT device. The method comprises the steps: selecting a high-concentration doped silicon wafer as a substrate to manufacture a silicon-based layer; arranging an insulating layer on the upper surface of the silicon-based layer; depositing amorphous silicon on the upper surface of the insulating layer to prepare a sacrificial layer and define a CMUT unit, wherein the sacrificial layer comprises a circular main body and a plurality of release channels connected with the circular main body; depositing a vibration film on the CMUT unit; forming a corrosion hole in the opening position of each release channel, and releasing the sacrificial layer to form a cavity; sealing the corrosion hole after the sacrificial layer is released; etching a supporting wall with a preset width around a cavity formed by the circular main body by using a photoetching process; performing a deep etching operation to the silicon-based layer so as to deposit a bottom electrode; and depositing a connecting wire between the electrode and a device, and depositing a top electrode on the upper surface of the vibration film.

Description

Technical field [0001] This application relates to the technical field of ultrasonic sensor manufacturing, in particular to a method for manufacturing a multi-frequency CMUT device and a multi-frequency CMUT device. Background technique [0002] Ultrasound probes play a key role in ultrasonic imaging; ultrasonic sensors are the key components of ultrasonic probes. Early ultrasonic sensors generally used lead zirconate titanate ceramics (PZT). With the development of technology, capacitive micromachined ultrasonic The sensor (CMUT) has the advantage of replacing it because of its wide frequency bandwidth, easy integration of integrated circuits, and easy processing. The intrinsic frequency of the CMUT can determine the accuracy of imaging. Generally, methods to increase the intrinsic frequency of the CMUT include reducing the film radius, increasing the film thickness, and changing the film material. However, methods such as adjusting the film radius, increasing the film thicknes...

AI Technical Summary

Problems solved by technology

However, methods such as adjusting the radius of the film, increasing the thickness of the film, and changing the material of the film need to adjust the layout of at least two layers of design layout, and the production process is more complicated.

Images