CN-122026844-A - Preparation method of resonator, resonator and filter

CN122026844ACN 122026844 ACN122026844 ACN 122026844ACN-122026844-A

Abstract

The invention discloses a preparation method of a resonator, the resonator and a filter. The preparation method comprises the steps of providing a substrate, preparing a transducer stacking structure on one side of the substrate, etching the transducer stacking structure to form a first lead hole, a second lead hole and a release hole, filling metal materials in the first lead hole and the second lead hole to form a bottom electrode lead in the first lead hole and a top electrode lead in the second lead hole, and introducing an etching medium into the release hole to form a cavity in the substrate, wherein the cavity part penetrates through the substrate. According to the technical scheme, the first lead hole, the second lead hole and the release hole are simultaneously formed in the resonator, so that the number of masks in the preparation process of the resonator is reduced, the process risk is reduced, the wafer flowing efficiency is improved, and the cost is reduced.

Inventors

CHEN HUI
XIE YING
YU JUNYING
HU HAOYU
DAI JINHAO

Assignees

武汉敏声新技术有限公司

Dates

Publication Date: 20260512
Application Date: 20260126

Claims (10)

1. A method of manufacturing a resonator, comprising: Providing a substrate and preparing a transducer stacking structure at one side of the substrate, wherein the transducer stacking structure comprises a bottom electrode layer, a piezoelectric layer, a top electrode layer and a passivation layer which are stacked; etching the transducer stack structure to form a first lead hole, a second lead hole and a release hole, wherein the first lead hole, the second lead hole and the release hole are arranged in a non-resonance area of the transducer stack structure, the non-resonance area is a non-overlapping area of the bottom electrode layer, the piezoelectric layer and the top electrode layer, the release hole penetrates through the transducer stack structure, and the first lead hole and the second lead hole partially penetrate through the transducer stack structure; Filling metal materials in the first lead hole and the second lead hole to form a bottom electrode lead in the first lead hole and a top electrode lead in the second lead hole, wherein the bottom electrode lead is electrically connected with the bottom electrode layer, and the top electrode lead is electrically connected with the top electrode layer; and introducing an etching medium into the release hole to form a cavity in the substrate, wherein the cavity part penetrates through the substrate.
2. The method of manufacturing according to claim 1, wherein manufacturing a transducer stack structure on the substrate side comprises: growing a metal layer on one side of the substrate and etching the metal layer to form a bottom electrode layer and a first connecting layer which are mutually independent; And sequentially growing a piezoelectric layer, a top electrode layer and a passivation layer on one side of the metal layer, which is far away from the substrate, wherein the bottom electrode layer is positioned in the non-resonance area and the resonance area, and the first connecting layer is positioned in the non-resonance area, and the resonance area is an overlapping area of the bottom electrode layer, the piezoelectric layer and the top electrode layer.
3. The method of manufacturing of claim 2, wherein etching the transducer stack to form a first lead hole and a second lead hole comprises: Etching a first groove on the passivation layer to expose the top electrode layer, wherein the projection of the first connection layer on the substrate covers the projection of the first groove on the substrate along the thickness direction of the resonator; And etching the transducer stack structure to form a first lead hole exposing the bottom electrode layer to form a second lead hole exposing the first connection layer, wherein the second lead hole comprises the first groove.
4. The method of claim 2, wherein growing a piezoelectric layer, a top electrode layer, and a passivation layer in this order on a side of the metal layer remote from the substrate comprises: Sequentially growing a piezoelectric layer and a metal layer on one side of the bottom electrode layer away from the substrate; Etching the metal layer to form a top electrode layer and a second connecting layer which are mutually independent, etching the second connecting layer to form a first through hole penetrating through the second connecting layer, and etching the top electrode layer to form a second through hole penetrating through the top electrode layer, wherein the projection of the bottom electrode layer on the substrate covers the first through hole along the thickness direction of the resonator; and growing a passivation layer on one side of the top electrode layer away from the piezoelectric layer.
5. The method of manufacturing of claim 4, wherein etching the transducer stack to form a first lead hole and a second lead hole comprises: and etching the passivation layer and the piezoelectric layer to form a first lead hole and a second lead hole, wherein the first lead hole comprises the first through hole, and the second lead hole comprises the second through hole.
6. The method of manufacturing according to claim 1, wherein manufacturing a transducer stack structure on the substrate side comprises: Sequentially growing a bottom electrode layer and a piezoelectric layer on one side of the substrate; Growing a sacrificial layer on one side of the piezoelectric layer away from the bottom electrode layer and etching the sacrificial layer to form a sacrificial structure; And growing a metal layer on one side of the sacrificial layer far away from the piezoelectric layer, etching the metal layer to form a top electrode layer, and growing a passivation layer on one side of the top electrode layer, wherein the top electrode layer covers the sacrificial structure and the sacrificial structure is positioned at the edge of the top electrode layer.
7. The method of manufacturing of claim 6, wherein etching the transducer stack to form a relief hole comprises: The transducer stack structure is etched to form a release hole in communication with the sacrificial structure.
8. The method of manufacturing according to claim 1, wherein providing a substrate comprises: providing a substrate and etching the substrate to form the cavity; and filling a sacrificial layer in the cavity.
9. A resonator prepared by the method of any one of claims 1-8; the resonator comprises a substrate and a transducer stacking structure, wherein the substrate comprises a cavity which partially penetrates through the substrate, and an opening of the cavity faces one side of the transducer stacking structure; The transducer stacking structure comprises a non-resonance area, wherein the non-resonance area is a non-overlapping area of the bottom electrode layer, the piezoelectric layer and the top electrode layer; the non-resonant region includes a release hole extending through the transducer stack and first and second lead holes extending partially through the transducer stack, the release hole being in communication with the cavity, a bottom electrode lead disposed in the first lead hole and electrically connected to the bottom electrode layer, and a top electrode lead disposed in the second lead hole and electrically connected to the top electrode layer.
10. A filter is characterized in that, comprising the resonator of claim 9.

Description

Preparation method of resonator, resonator and filter Technical Field The present invention relates to the field of resonator technologies, and in particular, to a method for manufacturing a resonator, and a filter. Background With the increasing development of 5G communication technology, requirements on communication frequency bands and communication quality are increasing. The film bulk acoustic resonator has the advantages of small volume, light weight, high quality factor and the like, and the constructed bulk acoustic filter has the advantages of low insertion loss, wide frequency band, high communication frequency and the like, and can well meet the requirements of high-frequency communication. Strong advantages are increasingly being presented in 5G communication technology. When the bulk acoustic wave filter is packaged and ball-planted, the bottom electrode and the top electrode are required to be led out to the surface of the device by adopting a proper method due to the structural characteristics that the bottom electrode and the top electrode are distributed on the upper surface and the lower surface of the piezoelectric material. In the traditional bottom electrode lead process, a mask plate is adopted to etch the piezoelectric layer, the bottom electrode is exposed, meanwhile, a mask plate is adopted to etch the passivation layer on the top electrode, the top electrode is exposed, and finally the piezoelectric layer is used for ball-mounting packaging. The method requires a plurality of masks to participate in the preparation process, and has low sheet flowing efficiency and high cost. Disclosure of Invention The invention provides a preparation method of a resonator, the resonator and a filter, which are used for reducing the number of masks in the preparation process of the resonator in the prior art and improving the flow sheet efficiency. According to a first aspect of the present invention, there is provided a method of manufacturing a resonator, comprising: providing a substrate and preparing a transducer stacking structure on one side of the substrate, wherein the transducer stacking structure comprises a bottom electrode layer, a piezoelectric layer, a top electrode layer and a passivation layer which are stacked; etching the transducer stack structure to form a first lead hole, a second lead hole and a release hole, wherein the first lead hole, the second lead hole and the release hole are all arranged in a non-resonance area of the transducer stack structure, the non-resonance area is a non-overlapping area of the bottom electrode layer, the piezoelectric layer and the top electrode layer; Filling metal materials in the first lead hole and the second lead hole to form a bottom electrode lead in the first lead hole and a top electrode lead in the second lead hole, wherein the bottom electrode lead is electrically connected with the bottom electrode layer, and the top electrode lead is electrically connected with the top electrode layer; And introducing an etching medium into the release hole to form a cavity in the substrate, wherein the cavity part penetrates through the substrate. Optionally, preparing a transducer stack on one side of the substrate, including: Growing a metal layer on one side of the substrate and etching the metal layer to form a bottom electrode layer and a first connecting layer which are mutually independent; The method comprises the steps of sequentially growing a piezoelectric layer, a top electrode layer and a passivation layer on one side of a metal layer, which is far away from a substrate, wherein a bottom electrode layer is located in a non-resonance area and a resonance area, a first connecting layer is located in the non-resonance area, and the resonance area is an overlapping area of the bottom electrode layer, the piezoelectric layer and the top electrode layer. Optionally, etching the transducer stack structure to form a first lead hole and a second lead hole, comprising: etching a first groove on the passivation layer to expose the top electrode layer, wherein the projection of the first connection layer on the substrate covers the projection of the first groove on the substrate along the thickness direction of the resonator; The transducer stack structure is etched to form a first lead hole exposing the bottom electrode layer to form a second lead hole exposing the first connection layer, wherein the second lead hole includes a first recess. Optionally, growing the piezoelectric layer, the top electrode layer and the passivation layer sequentially on a side of the metal layer away from the substrate, including: Sequentially growing a piezoelectric layer and a metal layer on one side of the bottom electrode layer, which is far away from the substrate; etching the metal layer to form a top electrode layer and a second connecting layer which are mutually independent, etching the second connecting layer to form a first through hole penetrating throug