Resonance structure of bulk acoustic wave resonator

Patent metadata

Field	Value
Publication number	US-10097156-B2
Application number	US-201615228298-A
Country	US
Kind code	B2
Filing date	Aug 4, 2016
Priority date	Apr 11, 2016
Publication date	Oct 9, 2018
Grant date	Oct 9, 2018

Abstract

A resonance structure of bulk acoustic wave resonator comprises a bottom electrode, a dielectric layer and a top electrode, wherein the dielectric layer is formed on the bottom electrode; the top electrode is formed on the dielectric layer. A resonance area is defined by the overlapping area of the projection of the bottom electrode, the dielectric layer and the top electrode. The resonance area has a contour. The contour includes at least three curved edges and is formed by connecting the at least three curved edges. Each curved edge is concave to a geometric center of the contour.

First claim

What is claimed is:

1. A resonance structure of bulk acoustic wave resonator comprising:
a bottom electrode;
a dielectric layer formed on said bottom electrode; and
a top electrode formed on said dielectric layer;
wherein a resonance area is defined by the overlapping area of the projection of said bottom electrode, said dielectric layer and said top electrode, said resonance area has a contour, said contour includes at least three curved edges and is formed by connecting said at least three curved edges, wherein each curved edge is concave to a geometric center of said contour,
wherein said at least three curved edges include even number of curved edges, a chord having a chord length a is formed by connecting two endpoints of each curved edge, a sagitta d is defined as the maximum distance between each curved edge and its corresponding chord, wherein:

(

2

-
1

2

)

⁢
a

<
d
≤

a
2

.

2. The resonance structure of bulk acoustic wave resonator according to claim 1 , wherein said at least three curved edges include at least one selected from the group consisting of an elliptical arc, a circular arc, a parabolic arc, a hyperbolic arc and a cycloidal arc.

3. The resonance structure of bulk acoustic wave resonator according to claim 1 , wherein said at least three curved edges include at least one circular arc, a chord is formed by connecting two endpoints of each curved edge, a center of each circular arc is located on a perpendicular bisector of the corresponding chord.

4. The resonance structure of bulk acoustic wave resonator according to claim 3 , wherein each circular arc is a minor arc or a semi-circle.

5. The resonance structure of bulk acoustic wave resonator according to claim 3 , wherein each circular arc has the same arc length.

6. The resonance structure of bulk acoustic wave resonator according to claim 3 , wherein each curved edge is a circular arc.

7. The resonance structure of bulk acoustic wave resonator according to claim 1 , wherein a chord is formed by connecting two endpoints of each curved edge, a convex polygon is formed by connecting all chords.

8. The resonance structure of bulk acoustic wave resonator according to claim 7 , wherein said at least three curved edges include four curved edges, said convex polygon is a convex quadrilateral, each interior angle of said convex polygon is greater than or equal to 60° and less than or equal to 135°.

9. The resonance structure of bulk acoustic wave resonator according to claim 1 , wherein a chord is formed by connecting two endpoints of each curved edge, at least one of the curved edges is symmetric with respect to a perpendicular bisector of the corresponding chord.

10. The resonance structure of bulk acoustic wave resonator according to claim 1 , wherein a chord is formed by connecting two endpoints of each curved edge, each curved edge is symmetric with respect to a perpendicular bisector of the corresponding chord.

11. The resonance structure of bulk acoustic wave resonator according to claim 1 , wherein a chord is formed by connecting two endpoints of each curved edge, each curved edge is located within the range between two perpendicular lines perpendicular to the corresponding chord and passing through two endpoints of the corresponding chord respectively.

12. The resonance structure of bulk acoustic wave resonator according to claim 1 , wherein each curved edge has the same curved edge length.

13. A resonance structure of bulk acoustic wave resonator comprising:
a bottom electrode;
a dielectric layer formed on said bottom electrode; and
a top electrode formed on said dielectric layer;
wherein a resonance area is defined by the overlapping area of the projection of said bottom electrode, said dielectric layer and said top electrode, said resonance area has a contour, said contour includes at least three curved edges and at least one linking curved edge and is formed by connecting said at least three curved edges and said at least one linking curved edge, wherein each curved edge is concave to a geometric center of said contour, each linking curved edge is convex to said geometric center, wherein a number of said at least three curved edges is greater than or equal to a number of said at least one linking curved edge, two endpoints of each linking curved edge are connected with two curved edges respectively, wherein a ratio of a length of each linking curved edge and a length of any one of the two curved edges adjacent to the linking curved edge is between 1:5 and 1:50.

14. The resonance structure of bulk acoustic wave resonator according to claim 13 , wherein said contour formed by connecting said at least three curved edges and said at least one linking curved edge is a smooth curve without the presence of a singular point.

15. The resonance structure of bulk acoustic wave resonator according to claim 13 , wherein said number of said at least three curved edges is equal to said number of said at least one linking curved edge, two endpoints of each curved edge are connected with two linking curved edges respectively.

16. The resonance structure of bulk acoustic wave resonator according to claim 13 , wherein said at least three curved edges include at least one selected from the group consisting of an elliptical arc, a circular arc, a parabolic arc, a hyperbolic arc and a cycloidal arc.

17. The resonance structure of bulk acoustic wave resonator according to claim 13 , wherein said at least three curved edges include even number of curved edges, a chord having a chord length a is formed by connecting two endpoints of each curved edge, a sagitta d is defined as the maximum distance between each curved edge and its corresponding chord, wherein:

(

2

-
1

2

)

⁢
a

<
d
≤

a
2

.

18. The resonance structure of bulk acoustic wave resonator according to claim 13 , wherein said at least three curved edges include odd number of curved edges, a chord having a chord length a is formed by connecting two endpoints of each curved edge, a sagitta d is defined as the maximum distance between each curved edge and its corresponding chord, wherein:

a
13

<
d
≤

a

Assignees

• Win Semiconductors Corp

Inventors

• Chang Chia-Ta
• Lin Re Ching
• Chin Yung-Chung
• Chiang Chih-Feng

Classifications

• H03H9/02118

  of lateral leakage between adjacent resonators · CPC title

• H03H9/132

  characterized by a particular shape · CPC title

• H03H9/02157 Primary

  Dimensional parameters, e.g. ratio between two dimension parameters, length, width or thickness · CPC title

• H03H9/17

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

• H03H9/0211

  of reflections · CPC title