Beam membrane structure piezoelectric transducer and manufacturing method

Abstract

The invention discloses a beam membrane structure piezoelectric transducer and a manufacturing method. The beam membrane structure piezoelectric transducer consists of a rood screen and four sensitive stress film; the rood screen is provided with four piezoelectric sheets; the voltage of the piezoelectric sheet is led out by an upper electrode and a lower electrode; the upper electrode and the lower electrode are connected to a welding plate; the manufacturing method comprises steps of obtaining a cavity in a silicon base and a flat membrane sheet structure through etching of a silicon anisotropic wet process, performing right side photoetching and forming the rood screen and the four rectangle membrane sheets, performing the right side photoetching, image development, sputtering and positive photoresist stripping, forming a Ti-Pt lower electrode metal layer, adopting a modified sol-gel method technology and a wet processing technology to prepare a PZT-5H film layer on the Ti-Pt electrode, forming a Ti-Pt lower electrode metal layer through the right side photoetching, the image development, the sputtering and the positive photoresist stripping, adhering borosilicate glass on the back side of the silicon substrate to obtain the sensor. The invention has better sensitivity, lower flexibility, wide frequency band width, higher signal to noise ratio, and simple structure, and is reliable in working and light in weight.

Description

technical field [0001] The invention relates to the technical field of pressure sensors, in particular to a beam-membrane structure piezoelectric sensor and a manufacturing method thereof. Background technique [0002] At this stage, micro-electro-mechanical system MEMS micro-sensors have been widely used and achieved great success, and people have higher and higher expectations for it. It is hoped that through micro-electro-mechanical system MEMS technology, humans can perceive information provided by various physical worlds. As far as the piezoresistive pressure sensor is concerned, its small size, good linear relationship between input and output, and mature technology have been widely used in the fields of automobiles, mobile phones, and medical equipment. Compared with capacitive complex integrated circuits, piezoresistive pressure sensors only integrate a simple Wheatstone bridge to obtain signals, and the processing cost of silicon as a sensitive element is much lower...

AI Technical Summary

Problems solved by technology

From the flat membrane structure to the island membrane structure to the beam membrane structure, the improvement of these structures is aimed at improving the performance of the sensor, but each structure has different degrees of advantages and disadvantages.

[0003] The flat membrane structure is widely used, but when the flat membrane structure is used, the diaphragm is thin, and the tensile deformation of the pressure bearing surface produces a large deflection, so that the nonlinearity of the mechanical properties becomes significantly larger; the thickness of the island membrane structure has a lower limit, and the stress concentration The area is determined by factors such as the position of the island on the back, the thickness of the silicon wafer, and the etching depth. It is difficult to control accurately. The quality of the hard core is easily disturbed by the acceleration signal and affects the signal output.

[0004] The piezoresistive sensor is greatly affected by temperature, temperature compensation should be performed, and the signal-to-noise ratio is not high

The piezoresistive sensor needs to be diffused on the substrate of the semiconductor material when it is manufactured, and at the same time, it is connected in the form of a bridge in the substrate, and the process is more complicated.

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