ELASTIC WAVE DEVICE

• US 20160149557A1
• Filed: 02/01/2016
• Published: 05/26/2016
• Est. Priority Date: 08/13/2013
• Status: Active Grant

• Current Assignee: Murata Manufacturing Co Limited
• Original Assignee: Murata Manufacturing Co Limited
• Inventors: HIRA, Mitsuyoshi, KAI, Seiji
• Granted Patent: US 9,876,484 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H03H 9/0057 the balanced terminals being on the same side of the tracks
• CPC Class Codes: H03H 9/1042 the enclosure being defined by a housing formed by a cavity in a resin
• CPC Class Codes: H03H 9/1071 the enclosure being defined by a frame built on a substrate and a cap, the frame having no mechanical contact with the SAW device
• CPC Class Codes: H03H 9/1092 the enclosure being defined by a cover cap mounted on an element forming part of the surface acoustic wave [SAW] device on the side of the IDT's
• CPC Class Codes: H03H 9/64 using surface acoustic waves
• CPC Class Codes: H03H 9/725 Duplexers

Abstract

In an elastic wave device, a plurality of elastic wave elements that include IDT electrodes are provided on a piezoelectric substrate, and a support layer that surrounds the elastic wave elements is provided on the piezoelectric substrate to define hollow portions in which the elastic wave elements are located. A cover member is stacked on the support layer, so that the hollow portions, in which the elastic wave elements are located, are provided, and the support layer includes a first support layer and a second support layer. The first support layer extends along an outer peripheral edge of the piezoelectric substrate, and the second support layer is located in a region surrounded by the first support layer and disposed around the elastic wave elements so as to have the hollow portions, in which the elastic wave elements are located. A hollow path is provided between the first support layer and the second support layer and arranged to allow communication between at least two of the hollow portions.

Claims

1. An elastic wave device comprising:

a piezoelectric substrate;

a plurality of elastic wave elements provided on the piezoelectric substrate and each of which includes at least one IDT electrode;

a support layer that is disposed outside regions in which the elastic wave elements are provided on the piezoelectric substrate to define hollow portions in portions in which the elastic wave elements are provided; and

a cover member that seals the portions in which the elastic wave elements are provided, and that is stacked on the support layer to define the hollow portions;

wherein

the support layer includes;

a first support layer that is disposed along an outer peripheral edge of the piezoelectric substrate; and

a second support layer that is disposed in a region surrounded by the first support layer to surround the portions in which the elastic wave elements are provided;

wherein

a hollow path is provided between the first support layer and the second support layer; and

the hollow path enables between at least two of the hollow portions.

2. The elastic wave device according to claim 1, wherein an opening is provided in the second support layer that reduces a planar area of the second support layer.

3. The elastic wave device according to claim 1, wherein the first support layer has a closed-loop shape.

4. The elastic wave device according to claim 1, wherein the plurality of hollow portions are liquid-tightly sealed.

5. The elastic wave device according to claim 1, wherein, when seen in plan view, an outer peripheral edge of the cover member reaches the outer peripheral edge of the piezoelectric substrate, and a wafer-level package is provided.

6. The elastic wave device according to claim 1, wherein the plurality of elastic wave elements include serial arm resonators and the parallel arm resonators on the piezoelectric substrate.

7. The elastic wave device according to claim 6, wherein a rectangular or substantially rectangular frame surrounds the plurality of elastic wave elements include serial arm resonators and the parallel arm resonators.

8. The elastic wave device according to claim 1, wherein the support layer is made of a resin.

9. The elastic wave device according to claim 1, wherein the second support layer surrounds the elastic wave elements and defines the hollow portions in which the elastic wave elements are present.

10. The elastic wave device according to claim 1, wherein the cover member is made of a resin.

11. The elastic wave device according to claim 1, wherein the plurality of hollow portions are air-tightly sealed.

12. The elastic wave device according to claim 1, wherein the first support layer and the second support layer are made of a same material.

13. The elastic wave device according to claim 1, wherein the second support layer includes a plurality of openings.

14. The elastic wave device according to claim 1, wherein a plurality of the hollow path is provided between the first support layer and the second support layer.

15. A duplexer comprising:

a substrate; and

a plurality of elastic wave devices on the substrate;

wherein

at least one of the plurality of elastic wave devices is the elastic wave device according to claim 1.

16. The duplexer according to claim 15, wherein the substrate is a piezoelectric substrate.

17. The duplexer according to claim 15, wherein each of the plurality of elastic wave devices is the elastic wave device according to claim 1.