Multilayer piezoelectric thin film cantilever beam sensor and preparation method therefor

Abstract

The invention provides a multilayer piezoelectric thin film cantilever beam sensor and a preparation method therefor. A sacrificial layer releasing process is adopted to release the sacrificial layer from the front surface to form a piezoelectric micro-cantilever beam structure; the commonly-adopted CMOS process is fully utilized, so that the process is simple and controllable; the compatibility between the piezoelectric cantilever beam sensor manufacturing process and an silicon integrated circuit process is improved; the problem of pollution existing in a process that the bulk-silicon substrate is etched by a wet etching method and the cantilever beam is released from the back surface is avoided; in addition, the multilayer piezoelectric thin film and a flexible supporting layer are adopted, so that the sensitivity of the sensor or the deformation amplitude of an actuator is improved, and the response of the cantilever beam to external excitation and the signal output are improved; in addition, due to the flexible supporting layer, the structure and the processing technology of the sensor are simplified; and the piezoelectric micro-sensor adopting the structure can be applied to objects of any sizes and any surface shapes, so that the application range of the micro-sensor is expanded.

Description

technical field [0001] The invention relates to the technical field of semiconductors, in particular to a multilayer piezoelectric film cantilever beam sensor and a preparation method thereof. Background technique [0002] The piezoelectric principle is another new way to realize microsensors. Through the piezoelectric effect, the perceived quantities such as force and acceleration can directly output voltage on the piezoelectric film, and the inverse piezoelectric effect enables the microsensor to drive the microstructure to generate displacement by applying an external voltage, so as to have the function of an actuator at the same time. The data show that microsensors / actuators made of piezoelectric thin film materials have unparalleled advantages compared with existing silicon-based microsensors / actuators, and are a new field of research and development for microsensors. [0003] The sensor based on the piezoelectric effect is a self-generating and electromechanical conv...

AI Technical Summary

Problems solved by technology

[0004] At present, many research institutions in the world have carried out research on piezoelectric thin film microsensor technology, and have achieved certain results in the theoretical analysis of the principle, structure, and performance of piezoelectric thin film microdevices. Piezoelectric microdevices are rarely used in practice, and the key problems are: first, the microfabrication technology of piezoelectric thin films and the compatibility of piezoelectric thin films and silicon integrated circuit technology have not been well resolved; second, most of the The piezoelectric sensor adopts the bulk silicon process, and the release of the microstructure adopts the backside etching process of the silicon substrate. The process is complex and difficult to control. rate reduction

Third, most of the piezoelectric microsensors use a single piezoelectric film structure for the convenience of design, processing and production, which limits the sensitivity of the sensor or the deformation range of the actuator, and reduces the response of the cantilever beam to external excitation and the signal. Output

Fourth, most of the applied piezoelectric microdevices use rigid support structures such as polysilicon and piezoelectric ceramics, which are not sensitive to small signal excitation and have low sensitivity; at the same time, microdevices with rigid support structures cannot be mounted on any size and surface application on object

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