Preset hollow cavity protection wall type film bulk acoustic wave resonator, and preparation method

Abstract

The invention discloses a preset hollow cavity protection wall type film bulk acoustic wave resonator, and a preparation method. The film bulk acoustic wave resonator comprises an SOI substrate with apreset hollow cavity and a transducer stacking structure; the preset hollow cavity is formed by enclosing protection walls of side walls and a protection bottom at the bottom, and the protection walls and the protection bottom are used for ensuring that the SOI substrate is not excessively corroded; the transducer stacking structure is located on the SOI substrate and is opposite to the preset hollow cavity; and at least one release channel penetrating through the transducer stacking structure and communicating with the preset hollow cavity is arranged on the transducer stacking structure. According to the preset hollow cavity protection wall type film bulk acoustic wave resonator disclosed by the invention, the situation of insufficient corrosion and excessive corrosion of the preset hollow cavity in a corrosion process can be avoided, and the size and the shape of the preset hollow cavity can be accurately controlled, so that the effective preparation of the film bulk acoustic waveresonator is realized.

Description

technical field [0001] The invention relates to the technical field of resonators, in particular to a pre-cavity protective wall type film bulk acoustic wave resonator and a preparation method thereof. Background technique [0002] With the rapid development of wireless communication technology (such as mobile communication, wireless sensor, radar, satellite communication, etc.) and faster transfer speeds. With the continuous development and maturity of Micro-Electro-Mechanical Systems (MEMS) technology, the Film Bulk Acoustic Resonator (FBAR), which realizes electrical frequency selection based on acoustic resonance, is widely used in the field due to its excellent performance and operability. Wireless communication technology plays an extremely important role. [0003] The core structure of the film bulk acoustic resonator is a sandwich structure composed of a top electrode, a piezoelectric film layer, and a bottom electrode. When an electrical signal is applied to the ...

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Problems solved by technology

The patent (CN104202010A) of the Institute of Electronic Engineering, China Academy of Engineering Physics also releases the etching solution through the window to form a cavity. This type of process has the problem that the size of the cavity is difficult to accurately control.

Etching solution corrodes the sacrificial layer to form a cavity. The size of the cavity is often controlled according to the calculation of the etching time. If the etching time is too short, it will easily cause incomplete etching and irregular shape of the cavity. If the etching time is too long, it will easily cause excessive etching and damage the substrate. , it is difficult to precisely control the resonant frequency

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