Bulk acoustic wave resonator, manufacturing method thereof and filter

Patent metadata

Field	Value
Publication number	US-12597908-B2
Application number	US-202218580940-A
Country	US
Kind code	B2
Filing date	Aug 30, 2022
Priority date	Aug 30, 2022
Publication date	Apr 7, 2026
Grant date	Apr 7, 2026

Abstract

A bulk acoustic wave resonator, a manufacturing method thereof and a filter are provided and belong to the technical field of radio frequency micro-electro-mechanical system. The resonator includes a dielectric substrate, a first electrode, a piezoelectric layer, and a second electrode. The dielectric substrate has a first cavity penetrating through the dielectric substrate in a thickness direction thereof, and the first cavity includes a first opening penetrating through the first surface, and a second opening penetrating through the second surface. The first opening includes first sides sequentially arranged in a clockwise direction, and first connecting sides each connecting two adjacent first sides; the second opening includes second sides sequentially arranged in a clockwise direction, and second connecting sides each connecting two adjacent second sides. The first sides are in one-to-one correspondence with the second sides, and the first connecting sides are in one-to-one correspondence with the second connecting sides.

First claim

What is claimed is:

1 . A bulk acoustic wave resonator, comprising a dielectric substrate, a first electrode, a piezoelectric layer, and a second electrode; wherein the dielectric substrate comprises a first surface and a second surface opposite to each other in a thickness direction of the dielectric substrate, the first electrode is on a side of the first surface away from the second surface, the piezoelectric layer is on a side of the first electrode away from the dielectric substrate, and the second electrode is on a side of the piezoelectric layer away from the first electrode; wherein
the dielectric substrate has a first cavity penetrating through the dielectric substrate in the thickness direction of the dielectric substrate, and the first cavity comprises a first opening penetrating through the first surface, and a second opening penetrating through the second surface; the first opening comprises a plurality of first sides sequentially arranged in a clockwise direction, and a plurality of first connecting sides, each of which connects two adjacent first sides; the second opening comprises a plurality of second sides sequentially arranged in a clockwise direction, and a plurality of second connecting sides, each of which connects two adjacent second sides; the plurality of first sides are in one-to-one correspondence with the plurality of second sides, and the plurality of first connecting sides are in one-to-one correspondence with the plurality of second connecting sides; for any two adjacent first sides and the first connecting side connecting the two adjacent first sides, a tangent line at any point on one first side intersects with a tangent line at any point on the other first side at a first intersection point, and the first intersection point is on a side of the first connecting side close to the second connecting side corresponding to the first connecting side; and for any two adjacent second sides and the second connecting side connecting the two adjacent second sides, a tangent line at any point on one second side intersects with a tangent line at any point on the other second side at a second intersection point, and the second intersection point is on a side of the second connecting side away from the first connecting side corresponding to the second connecting side.

2 . The bulk acoustic wave resonator according to claim 1 , wherein the first cavity comprises a plurality of first side surfaces sequentially arranged in a clockwise direction and a plurality of first connecting surfaces, each of which connects two adjacent first side surfaces; and an angle between a tangent plane at any point on each first side surface and a plane of the second surface is in a range from 80° to 88°.

3 . The bulk acoustic wave resonator according to claim 2 , wherein each first connecting surface is an arc surface.

4 . The bulk acoustic wave resonator according to claim 1 , wherein each first connecting side is an arc segment.

5 . The bulk acoustic wave resonator according to claim 4 , wherein a curvature radius of each first connecting side is in a range from 5 μm to 50 μm.

6 . The bulk acoustic wave resonator according to claim 1 , wherein each second connecting side is an arc segment.

7 . The bulk acoustic wave resonator according to claim 6 , wherein a curvature radius of each first connecting side is in a range from 5 μm to 50 μm.

8 . The bulk acoustic wave resonator according to claim 1 , wherein each first connecting side is a straight line segment or an arc segment.

9 . The bulk acoustic wave resonator according to claim 1 , wherein each second connecting side is an arc segment.

10 . The bulk acoustic wave resonator according to claim 1 , further comprising a supporting layer between the first surface and the first electrode.

11 . A method for manufacturing a bulk acoustic wave resonator, wherein the method comprises:
providing a dielectric substrate, wherein the dielectric substrate comprises a first surface and a second surface which are oppositely disposed in a thickness direction of the dielectric substrate; sequentially forming a first electrode, a piezoelectric layer and a second electrode on the first surface of the dielectric substrate; and etching the dielectric substrate to form a first cavity penetrating through the dielectric substrate in the thickness direction of the dielectric substrate; wherein the first cavity comprises a first opening penetrating through the first surface, and a second opening penetrating through the second surface; wherein the first opening comprises a plurality of first sides sequentially arranged in a clockwise direction, and a plurality of first connecting sides, each of which connects two adjacent first sides; the second opening comprises a plurality of second sides sequentially arranged in a clockwise direction, and a plurality of second connecting sides, each of which connects two adjacent second sides; the plurality of first sides are in one-to-one correspondence with the plurality of second sides, and the plurality of first connecting sides are in one-to-one correspondence with the plurality of second connecting sides; for any two adjacent first sides and the first connecting side connecting the two adjacent first sides, a tangent line at any point on one first side intersects with a tangent line at any point on the other first side at a first intersection point, and the first intersection point is on a side of the first connecting side close to the second connecting side corresponding to the first connecting side; and for any two adjacent second sides and the second connecting side connecting the two adjacent second sides, a tangent line at any point on one second side intersects with a tangent line at any point on the other second side at a second intersection point, and the second intersection point is on a side of the second connecting side away from the first connecting side corresponding to the second connecting side.

12 . The method according to claim 11 , wherein the etching the dielectric substrate to form the first cavity penetrating through the dielectric substrate in the thickness direction of the dielectric substrate comprises:
forming the first cavity penetrating through the dielectric substrate in the thickness direction of the dielectric substrate by performing a laser-induced etching process on the second surface of the dielectric substrate.

13 . The method according to claim 12 , wherein an etching solution used in the laser-induced etching process is hydrofluoric acid or sodium hydroxide.

14 . The method according to claim 11 , wherein the first cavity comprises a plurality of first side surfaces sequentially arranged in a clockwise direction and a plurality of first connecting surfaces, each of which connects two adjacent first side surfaces; and an angle between a tangent plane at any point on each first side surface and a plane of the second surface is in a range from 80° to 88°.

15 . The method according to claim 14 , wherein each first connecting surface is an arc surface.

16 . The method according to claim 11 , wherein each first connecting side is an arc segment.

17 . The method according to claim 16 , wherein a curvature radius of each first connecting side is in a range from 5 μm to 50 μm.

18 . The method according to claim 11 , wherein each second connecting side is an arc segment.

19 . The method according to claim 18 , wherein a curvature radius of each first connecting side is in a range from 5 μm to 50 μm.

Assignees

• Beijing Boe Optoelectronics Tech Co Ltd
• Boe Tech Group Co Ltd

Inventors

• Wei Qiuxu
• Li Yue
• Wang Lihui
• Ren Yanfei
• Zhang Taonan
• Xiao Yuelei
• Wu Yifan
• Feng Yulin
• Cao Xue
• Han Kidong
• An Qichang
• Chang Wenbo
• Li Huiying
• Qu Feng

Classifications

• H03H2003/021

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

• H03H9/568

  consisting of a ladder configuration · CPC title

• H03H9/133

  for electromechanical delay lines or filters · CPC title

• H03H3/02 Primary

  for the manufacture of piezoelectric or electrostrictive resonators or networks (H03H3/08 takes precedence) · CPC title

• H03H9/17

  having a single resonator (crystal tuning forks H03H9/21) · CPC title