Preparation method of bulk acoustic wave resonator and bulk acoustic wave resonator

Abstract

The invention discloses a preparation method of a bulk acoustic wave resonator and the bulk acoustic wave resonator. The preparation method of the bulk acoustic wave resonator comprises the following steps: providing a substrate, wherein the substrate comprises an active region and a transition region surrounding the active region; forming a first sacrificial layer on the surface of the substrate, wherein the first sacrificial layer covers the active region and the transition region; the first sacrificial layer in the transition region comprises a first step and a second step which are connected; the height of the first step is larger than that of the first sacrificial layer in the active region; and the height of the second step is smaller than that of the first sacrificial layer in the transition region; and the height of the second step is smaller than that of the first sacrificial layer in the active region; forming a lower electrode on the surface, away from the substrate, of the first sacrificial layer; forming a piezoelectric layer on the surface, away from the first sacrificial layer, of the lower electrode; forming an upper electrode on the surface, away from the lower electrode, of the piezoelectric layer; and removing the first sacrificial layer. According to the technical scheme provided by the embodiment of the invention, the process steps for preparing the bulk acoustic wave resonator are simplified, and the yield of the bulk acoustic wave resonator is improved.

Description

technical field [0001] Embodiments of the present invention relate to the technical field of semiconductors, and in particular to a method for preparing a bulk acoustic wave resonator and the bulk acoustic wave resonator. Background technique [0002] Bulk Acoustic Wave (BAW) resonators have excellent characteristics such as small size, high resonance frequency, high quality factor, and large power capacity, and play an important role in the field of communication. [0003] In the process of forming a bulk acoustic wave resonator in the prior art, in order to reduce the energy loss of the bulk acoustic wave, a structure is provided inside the bulk acoustic wave resonator to avoid the energy loss of the acoustic wave. In the prior art, in the process of preparing the bulk acoustic wave resonator, it is necessary to On the first surface side of the piezoelectric layer and on the second surface of the piezoelectric layer opposite to the first surface, an etching process is used...

AI Technical Summary

Problems solved by technology

[0003] In the process of forming a bulk acoustic wave resonator in the prior art, in order to reduce the energy loss of the bulk acoustic wave, a structure is provided inside the bulk acoustic wave resonator to avoid the energy loss of the acoustic wave. In the prior art, in the process of preparing the bulk acoustic wave resonator, it is necessary to On the first surface side of the piezoelectric layer and on the second surface of the piezoelectric layer opposite to the first surface, an etching process is used to form a structure to avoid the loss of acoustic wave energy. The above-mentioned preparation method uses a mask plate and an etching process. Too many times lead to cumbersome process steps for preparing bulk acoustic wave resonators, and the yield rate of bulk acoustic wave resonators is not high

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