Acoustic wave device, radio-frequency front end circuit, and communication device

Patent metadata

Field	Value
Publication number	US-2019288665-A1
Application number	US-201915929139-A
Country	US
Kind code	A1
Filing date	Jun 6, 2019
Priority date	Dec 16, 2016
Publication date	Sep 19, 2019
Grant date	—

Abstract

An acoustic wave device includes a piezoelectric substrate, an IDT electrode provided on the piezoelectric substrate, a support provided on the piezoelectric substrate so as to surround the IDT electrode, and a cover provided on the support. The support has a larger thermal expansion coefficient than the piezoelectric substrate. The IDT electrode is provided in a hollow space that is surrounded by the piezoelectric substrate, the support, and the cover. The support includes an inner surface on a side of the hollow space, and an outer surface on a side opposite to the inner surface, and the support includes a recess provided in at least one of the inner and outer surfaces.

First claim

What is claimed is:

1 . An acoustic wave device comprising:
a piezoelectric body; a functional electrode provided on the piezoelectric body; a support provided on the piezoelectric body so as to surround the functional electrode; and a cover provided on the support; wherein the support has a larger thermal expansion coefficient than the piezoelectric body; the functional electrode is provided inside a hollow space surrounded by the piezoelectric body, the support, and the cover; and the support includes an inner surface on a side of the hollow space, and an outer surface on a side opposite to the inner surface, and the support includes a recess provided in at least one of the inner surface and the outer surface.

2 . The acoustic wave device according to claim 1 , wherein, when a depth of the recess is a dimension of the recess in a direction that connects the inner surface and the outer surface of the support, a portion of the recess at which the depth is largest is closer to the piezoelectric body than to the cover.

3 . The acoustic wave device according to claim 1 , wherein
the support includes a plurality of corners in a plan view; and the recess is provided at at least one of the plurality of corners.

4 . The acoustic wave device according to claim 1 , wherein the recess is provided in the outer surface of the support.

5 . The acoustic wave device according to claim 4 , wherein the recess is provided in the inner surface and the outer surface of the support.

6 . The acoustic wave device according to claim 1 , wherein
the support has a frame shape in a plan view; and the recess is provided along an entire or substantially an entire periphery of the support.

7 . The acoustic wave device according to claim 1 , wherein the functional electrode is an IDT electrode.

8 . A radio-frequency front end circuit comprising:
the acoustic wave device according to claim 1 ; and a power amplifier.

9 . The radio-frequency front end circuit according to claim 8 , wherein, when a depth of the recess is a dimension of the recess in a direction that connects the inner surface and the outer surface of the support, a portion of the recess at which the depth is largest is closer to the piezoelectric body than to the cover.

10 . The radio-frequency front end circuit according to claim 8 , wherein
the support includes a plurality of corners in a plan view; and the recess is provided at at least one of the plurality of corners.

11 . The radio-frequency front end circuit according to claim 8 , wherein the recess is provided in the outer surface of the support.

12 . The radio-frequency front end circuit according to claim 11 , wherein the recess is provided in the inner surface and the outer surface of the support.

13 . The radio-frequency front end circuit according to claim 8 , wherein
the support has a frame shape in a plan view; and the recess is provided along an entire or substantially an entire periphery of the support.

14 . The radio-frequency front end circuit according to claim 8 , wherein the functional electrode is an IDT electrode.

15 . A communication device comprising:
the frequency front end circuit according to claim 8 ; and an RF signal processing circuit.

16 . The communication device according to claim 15 , wherein, when a depth of the recess is a dimension of the recess in a direction that connects the inner surface and the outer surface of the support, a portion of the recess at which the depth is largest is closer to the piezoelectric body than to the cover.

17 . The communication device according to claim 15 , wherein
the support includes a plurality of corners in a plan view; and the recess is provided at at least one of the plurality of corners.

18 . The communication device according to claim 15 , wherein the recess is provided in the outer surface of the support.

19 . The communication device according to claim 18 , wherein the recess is provided in the inner surface and the outer surface of the support.

20 . The communication device according to claim 15 , wherein the support has a frame shape in a plan view; and
the recess is provided along an entire or substantially an entire periphery of the support.

Assignees

• Murata Manufacturing Co

Inventors

• Hatsuda Ippei

Classifications

• H10W76/60

  Seals · CPC title

• H10W76/10

  Containers or parts thereof · CPC title

• H03F2200/294

  the amplifier being a low noise amplifier [LNA] · CPC title

• H03F3/245

  with semiconductor devices only · CPC title

• H03F2200/165

  A filter circuit coupled to the input of an amplifier · CPC title