Acoustic wave device

Patent metadata

Field	Value
Publication number	US-11482982-B2
Application number	US-202016901032-A
Country	US
Kind code	B2
Filing date	Jun 15, 2020
Priority date	Dec 27, 2017
Publication date	Oct 25, 2022
Grant date	Oct 25, 2022

Abstract

A through-hole that extends from an upper surface of a cover opposite a support to a lower surface of the support facing a substrate is provided in the support and the cover. The through-hole overlaps a portion of a wiring line in a plan view. An acoustic wave device further includes an electrode film that is electrically connected to the wiring line in the through-hole, and a protective layer that includes an insulating material and that covers a portion of the electrode film. The protective layer is connected to the cover and the support in the through-hole. Differences in thermal expansion coefficients between the protective layer and the cover and between the protective layer and the support are smaller than a difference in thermal expansion coefficients between the protective layer and the electrode film.

First claim

What is claimed is:

1. An acoustic wave device comprising:
a substrate;
a functional element that is provided on the substrate;
a wiring line that is provided on the substrate and that is electrically connected to the functional element;
a support that is made of an insulating material and that is provided around the functional element on the substrate; and
a cover that is made of an insulating material, that covers the functional element, and that faces the substrate with the support interposed between the substrate and the cover; wherein
a through-hole that extends from a first surface of the cover opposite the support to a second surface of the support that faces the substrate is provided in the support and the cover;
the through-hole overlaps a portion of the wiring line in a plan view;
the acoustic wave device further includes:
an electrode film that is provided on the first surface and in the through-hole and that is electrically connected to the wiring line in the through-hole; and
a protective layer that is made of an insulating material and that covers at least a portion of the first surface and a portion of the electrode film;

the protective layer is connected to at least of the cover and the support in the through-hole; and
a difference in thermal expansion coefficients between the protective layer and the at least one of the cover and the support is smaller than a difference in thermal expansion coefficients between the protective layer and the electrode film.

2. The acoustic wave device according to claim 1 , wherein the protective layer is connected to the cover and the support in the through-hole.

3. The acoustic wave device according to claim 2 , wherein an inner wall surface around the through-hole includes a third surface of the cover that faces the substrate and a fourth surface of the support that is adjacent to the third surface; and
the protective layer is connected to the third surface and the fourth surface.

4. The acoustic wave device according to claim 1 , wherein the protective layer is connected to the substrate in the through-hole.

5. The acoustic wave device according to claim 1 , wherein the functional element includes at least one interdigital transducer electrode.

6. The acoustic wave device according to claim 5 , wherein the at least one interdigital transducer electrode defines a surface acoustic wave resonator.

7. The acoustic wave device according to claim 1 , wherein a metallic layer is provided between the wiring line and the functional element.

8. The acoustic wave device according to claim 1 , wherein the insulating material of the support is a synthetic resin or a photosensitive resin.

9. The acoustic wave device according to claim 1 , wherein the insulating material of the cover is an epoxy resin or polyimide.

10. The acoustic wave device according to claim 1 , wherein a hollow space is defined by the substrate, the support, and the cover, and the functional element is located in the hollow space.

11. The acoustic wave device according to claim 1 , wherein the support and the cover are integrally provided.

12. The acoustic wave device according to claim 1 , wherein the electrode film is a multilayer film that includes a seed layer and a plating layer provided on the seed layer.

13. The acoustic wave device according to claim 1 , wherein the protective layer covers an entirety or substantially an entirety of the first surface.

14. The acoustic wave device according to claim 1 , wherein the difference in thermal expansion coefficients between the protective layer and the at least one of the cover and the support is between about 0 and about 10×10 −6 /K; and
the difference in thermal expansion coefficients between the protective layer and the electrode film is between about 30×10 −6 /K and about 50×10 −6 /K.

Assignees

• Murata Manufacturing Co

Inventors

• Inoue Kazunori

Classifications

• H10W76/12

  characterised by their shape · CPC title

• H03H9/02834

  of temperature influence (cut angles H03H9/02543) · CPC title

• H03H9/145

  for networks using surface acoustic waves · CPC title

• H03H9/25

  Constructional features of resonators using surface acoustic waves {(devices for manipulating acoustic surface waves in general G10K11/36)} · CPC title

• H03H9/02133 Primary

  of stress · CPC title