Bulk acoustic wave resonator and manufacturing method thereof and filter

Patent metadata

Field	Value
Publication number	US-12537502-B2
Application number	US-202519025829-A
Country	US
Kind code	B2
Filing date	Jan 16, 2025
Priority date	May 13, 2024
Publication date	Jan 27, 2026
Grant date	Jan 27, 2026

Abstract

A bulk acoustic wave resonator and manufacturing method thereof and filter, the bulk acoustic wave resonator includes: a resonant body structure, and a carrier structure and a cover structure on two opposite sides of the resonant body structure; a first cavity is between the carrier structure and the resonant body structure; the cover structure includes a cover substrate, and a cover bonding layer, a second cavity is between the cover structure and the resonant body structure; first and second conductive connectors, and a pad layer are on opposite sides of the resonant body structure, and the pad layer includes one or more bonding pads bonded with the cover bonding layer, each bonding pad has a recess recessed toward the resonant body structure, and the cover bonding layer includes a protrusion part filling the recess and surrounded by the bonding pad.

First claim

The invention claimed is:

1 . A bulk acoustic wave resonator, comprising:
a resonant body structure, comprising a piezoelectric layer, a first electrode structure layer and a second electrode layer, wherein the piezoelectric layer has a first side and a second side opposite to each other in a first direction; the first electrode structure layer is disposed on the first side of the piezoelectric layer and comprises a first electrode structure; the second electrode layer is disposed on the second side of the piezoelectric layer and comprises a second electrode; a carrier structure, disposed on a side of the resonant body structure away from the second electrode layer, wherein a first cavity is arranged between the carrier structure and the resonant body structure, and a portion of the first electrode structure is located in the first cavity; a cover structure, disposed on a side of the resonant body structure opposite to the carrier structure, and comprising a cover bonding layer and a cover substrate, wherein the cover bonding layer is disposed between the cover substrate and the resonant body structure in the first direction, a second cavity is provided between the cover structure and the resonant body structure, and a portion of the second electrode layer is located in the second cavity; a first conductive connector and a second conductive connector, disposed on a side of the resonant body structure away from the cover structure, wherein the first conductive connector extends through the carrier structure to be electrically connected with the first electrode structure, and the second conductive connector extends through the carrier structure and is electrically connected with the second electrode through an intermediate connecting component, the intermediate connecting component is spaced apart from the first cavity; and a pad layer, located on a side of the resonant body structure away from the carrier structure, and comprising one or more bonding pads, wherein at least a portion of each of the one or more bonding pads is bonded with the cover bonding layer, and the each of the one or more bonding pads has a recess recessed toward the first electrode structure layer, and the cover bonding layer comprises a protrusion part filling the recess and surrounded by the each of the one or more bonding pads, wherein the intermediate connecting component comprises: an additional electrode structure, located in the first electrode structure layer, and spaced apart and electrically isolated from the first electrode structure; and an interconnection pad, disposed in the pad layer, located on a side of the additional electrode structure away from the carrier structure, and electrically connected with the additional electrode structure and the second electrode, and serving as a second bonding pad among the one or more bonding pads, wherein the cover bonding layer comprises a second protrusion part, located in the recess of the interconnection pad, and surrounded by the interconnection pad.

2 . The bulk acoustic wave resonator according to claim 1 , wherein an orthographic projection of the recess of the each of the one or more bonding pads on a main surface of the piezoelectric layer is located within an orthographic projection of the cover bonding layer on the main surface of the piezoelectric layer.

3 . The bulk acoustic wave resonator according to claim 1 , wherein the piezoelectric layer comprises a piezoelectric via hole, and a bonding pad of the one or more bonding pads comprises a horizontally extending part and a recessed part, the horizontally extending part is located at a side of the piezoelectric layer away from the first electrode structure layer, the recessed part is filled into the piezoelectric via hole, and defines the recess.

4 . The bulk acoustic wave resonator according to claim 3 , wherein an orthographic projection of the recessed part of the bonding pad on the piezoelectric layer is offset from an orthographic projection of the second cavity on the piezoelectric layer.

5 . The bulk acoustic wave resonator according to claim 1 , wherein the protrusion part of the cover bonding layer overlaps the piezoelectric layer in a direction parallel to a main surface of the piezoelectric layer.

6 . The bulk acoustic wave resonator according to claim 1 , wherein the pad layer comprises: a first conductive pad, disposed on a surface of the piezoelectric layer at the second side, and extending through the piezoelectric layer to be electrically connected with the first electrode structure;
the first conductive pad serves as a first bonding pad among the one or more bonding pads, and the cover bonding layer comprises a first protrusion part, located in the recess of the first conductive pad and surrounded by the first conductive pad.

7 . The bulk acoustic wave resonator according to claim 1 , wherein the first electrode structure layer at least comprises a first electrode layer, the first electrode layer comprises a first electrode and an additional electrode which are spaced apart and electrically isolated from each other, the first electrode forms at least a portion of the first electrode structure, and the additional electrode forms at least a portion of the additional electrode structure.

8 . The bulk acoustic wave resonator according to claim 7 , wherein the first electrode structure layer further comprises: an edge protruding layer, located on a side of the first electrode layer away from the piezoelectric layer and/or a side of the first electrode layer close to the piezoelectric layer; wherein the edge protruding layer comprises a first electrode edge protruding part and an additional electrode protruding part which are electrically isolated from each other, the first electrode edge protruding part and the first electrode are stacked in the first direction and electrically connected to each other; the additional electrode protruding part and the additional electrode are stacked in the first direction and electrically connected to each other.

9 . The bulk acoustic wave resonator according to claim 1 , further comprising:
a passivation layer, located between the resonant body structure and the carrier structure, and located between the resonant body structure and the first cavity, and separating the first electrode structure from the first cavity.

10 . The bulk acoustic wave resonator according to claim 1 , wherein the carrier structure comprises:
a supporting dielectric layer, disposed on a side of the first electrode structure layer away from the piezoelectric layer; a cavity boundary layer, located on a side of the supporting dielectric layer and the resonant body structure away from the cover structure, and defining a portion of a boundary of the first cavity, a carrier bonding layer, located on a side of the cavity boundary layer away from the resonant body structure, and a carrier substrate, located on a side of the carrier bonding layer away from the resonant body structure.

11 . The bulk acoustic wave resonator according to claim 10 , wherein the first conductive connector and the second conductive connector are in contact with the carrier substrate and the carrier bonding layer, and are spaced apart from the supporting dielectric layer.

12 . The bulk acoustic wave resonator according to claim 10 , wherein the first electrode structure layer comprises a gap between the first electrode structure and an additional electrode structure of the intermediate connecting component, and an orthographic projection of the gap on a main surface of the piezoelectric layer is offset from an orthographic projection of the supporting dielectric layer on the mai

Assignees

• Shenzhen Newsonic Tech Co Ltd

Inventors

• Hu Weiwei
• Zou Jie
• Feng Duan

Classifications

• H03H2003/021

  the resonators or networks being of the air-gap type · CPC title

• H03H9/173

  Air-gaps · CPC title

• H03H9/105

  the enclosure being defined by a cover cap mounted on an element forming part of the BAW device · CPC title

• H03H9/0523

  for flip-chip mounting · CPC title

• H03H9/02102 Primary

  of temperature influence (cutting angles H03H9/02015) · CPC title