Bulk acoustic wave resonator and method for manufacturing the same

Patent metadata

Field	Value
Publication number	US-12184263-B2
Application number	US-202418422383-A
Country	US
Kind code	B2
Filing date	Jan 25, 2024
Priority date	Nov 29, 2023
Publication date	Dec 31, 2024
Grant date	Dec 31, 2024

Abstract

A bulk acoustic wave resonator and method for manufacturing the same, the bulk acoustic wave resonator includes: a piezoelectric layer; a first electrode layer, a carrier structure, and first and second conductive connectors disposed on a first side of the piezoelectric layer, and a second electrode layer, an interconnection pad and a cover structure disposed on a second side of the piezoelectric layer, wherein the first electrode layer includes a first electrode and an additional electrode electrically isolated from each other; the second electrode layer includes a second electrode; the interconnection pad is electrically connected to the second electrode and the additional electrode; a first cavity is disposed between the carrier structure and the piezoelectric layer; the first conductive connector is electrically connected to the first electrode, the second conductive connector is electrically connected to the second electrode through the additional electrode and the interconnection pad.

First claim

The invention claimed is:

1. A bulk acoustic wave resonator, comprising:
a piezoelectric layer, having a first side and a second side opposite to each other in a first direction;
a first electrode layer, disposed on the first side of the piezoelectric layer and comprising a first electrode and an additional electrode electrically isolated from each other;
a second electrode layer, disposed on the second side of the piezoelectric layer and comprising a second electrode;
one or more conductive pads, disposed on the second side of the piezoelectric layer and at least comprising an interconnection pad, wherein the interconnection pad is electrically connected to the second electrode and extends through the second electrode and the piezoelectric layer to be electrically connected to the additional electrode;
a carrier structure, disposed on the first side of the piezoelectric layer and a side of the first electrode layer away from the second electrode layer, wherein a first cavity is disposed between the carrier structure and the piezoelectric layer, and a portion of the first electrode is located in the first cavity;
a cover structure, disposed on the second side of the piezoelectric layer and comprising a cover bonding layer and a cover substrate, wherein the cover bonding layer is disposed between the cover substrate and the piezoelectric layer in the first direction, wherein a second cavity is disposed between the cover structure and the piezoelectric layer, and a portion of the second electrode layer is located in the second cavity; and
a first conductive connector and a second conductive connector, disposed on the first side of the piezoelectric layer away from the cover structure, wherein the first conductive connector extends through the carrier structure to be electrically connected to the first electrode, wherein the second conductive connector extends through the carrier structure to be electrically connected to the additional electrode, and further electrically connected to the second electrode through the additional electrode and the interconnection pad,
wherein the cover bonding layer is bonded to portions of surfaces of the piezoelectric layer and the one or more conductive pads, and a part of the one or more conductive pads has an embedded portion, the embedded portion is covered by the cover bonding layer.

2. The bulk acoustic wave resonator according to claim 1 , wherein the second electrode has an electrode via hole, the piezoelectric layer has an additional piezoelectric via hole, and the electrode via hole and the additional piezoelectric via hole are in spatial communication with each other to expose a portion of a surface of the additional electrode at a side close to the piezoelectric layer, and the interconnection pad is electrically connected to the additional electrode through the electrode via hole and the additional piezoelectric via hole.

3. The bulk acoustic wave resonator according to claim 2 , wherein the one or more conductive pads further comprise at least one of a first conductive pad and a second conductive pad;
the first conductive pad is disposed on a surface of the second side of the piezoelectric layer and electrically connected to the first electrode through a piezoelectric via hole in the piezoelectric layer; and
the second conductive pad is disposed on a side of the second electrode away from the piezoelectric layer and electrically connected to the second electrode.

4. The bulk acoustic wave resonator according to claim 3 , wherein the first conductive pad and the second conductive pad are used as test pads.

5. The bulk acoustic wave resonator according to claim 1 , wherein a contact area between the embedded portion and the cover bonding layer is greater than or equal to an area of a surface of the embedded portion at a side away from the piezoelectric layer.

6. The bulk acoustic wave resonator according to claim 1 , wherein there is free of a conductive component disposed in the cover bonding layer and electrically connected to the embedded portion of the part of the one or more conductive pads.

7. The bulk acoustic wave resonator according to claim 1 , wherein a portion of the carrier structure is located between the first electrode and the additional electrode in a second direction parallel to a main surface of the piezoelectric layer, and the additional electrode is located on a side of the portion of the carrier structure away from the first cavity in the second direction and is spaced apart from the first cavity.

8. 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 layer away from the piezoelectric layer, and a portion of the supporting dielectric layer is located between the first electrode and the additional electrode in a second direction parallel to a main surface of the piezoelectric layer;
a carrier bonding layer, disposed on a side of the supporting dielectric layer away from the piezoelectric layer;
a cavity boundary layer, located between the supporting dielectric layer and the carrier bonding layer, and located on a side of the carrier bonding layer close to the first cavity, wherein the cavity boundary layer delimits a portion of a boundary of the first cavity; and
a carrier substrate, located on a side of the carrier bonding layer away from the piezoelectric layer.

9. The bulk acoustic wave resonator according to claim 8 , wherein a portion of the supporting dielectric layer and a portion of the carrier bonding layer are spaced apart from each other by the cavity boundary layer; and the supporting dielectric layer and the carrier bonding layer have portions that are in contact with each other.

10. The bulk acoustic wave resonator according to claim 9 , wherein the carrier substrate and the portions that are in contact with each other of the supporting dielectric layer and the carrier bonding layer have a first connection via hole and a second connection via hole disposed therein; and
the first conductive connector is electrically connected to the first electrode through the first connection via hole, and the second conductive connector is electrically connected to the additional electrode through the second connection via hole.

11. The bulk acoustic wave resonator according to claim 8 , wherein the supporting dielectric layer comprises:
a first dielectric part, located between the first electrode and the carrier bonding layer in the first direction; and
a second dielectric part, located between the additional electrode and the carrier bonding layer in the first direction,
wherein a thickness of the second dielectric part in the first direction is greater than a thickness of the first dielectric part in the first direction.

12. The bulk acoustic wave resonator according to claim 11 , further comprising: a passivation layer, wherein a portion of the passivation layer is located between the first electrode and the first dielectric part, and the first electrode is spaced apart from the first dielectric part by the passivation layer,
wherein the additional electrode is in direct contact with the second dielectric part.

13. The bulk acoustic wave resonator according to claim 8 , wherein the carrier bonding layer comprises:
a bonding body, located on a side of the supporting dielectric layer away from the piezoelectric layer in the first direction; and
a bonding protrusion, protruded in the first direction, from a surface of the bonding body at a side away from the carrier substrate towards the piezoelectric layer, wherein the first cavity is surrounded by the bonding prot

Assignees

• Shenzhen Newsonic Tech Co Ltd

Inventors

• Hu Weiwei
• Zou Jie
• Tang Gongbin

Classifications

• H03H2003/023

  the resonators or networks being of the membrane type · CPC title

• H03H9/174

  Membranes · CPC title

• H03H9/02133

  of stress · CPC title

• H03H9/02102

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

• H03H2003/021

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