# US 11,444,596 B2 · Acoustic wave device

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 11,444,596 B2
- Document ID: US11444596B2
- Status: Granted
- Kind: B2
- Application number: 15/963,123
- Filed: 2018-04-26
- Published: 2018-08-23
- Granted: 2022-09-13
- Earliest claimed: 2015-12-11
- Assignees: Murata Manufacturing Co., Ltd.
- Applicants: Murata Manufacturing Co., Ltd.
- Inventors: Daisuke Sekiya; Yasuhiko Hirano
- Web page: https://patentgrep.com/patent/US11444596B2

## CPC

- H03H 9/02897: {of strain or mechanical damage, e.g. strain due to bending influence}
- H03H 9/02559: {of lithium niobate or lithium-tantalate substrates}
- H03H 9/0576: {including surface acoustic wave [SAW] devices}
- H03H 9/059: {consisting of mounting pads or bumps}
- 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}
- 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}
- H03H 9/145: for networks using surface acoustic waves
- H03H 9/25: Constructional features of resonators using surface acoustic waves {(devices for manipulating acoustic surface waves in general G10K11/36)}
- H03H 9/64: using surface acoustic waves
- H10N 30/877: {Conductive materials}
- H10W 72/012: {of bump connectors, dummy bumps or thermal bumps}
- H10W 72/241: {Dispositions, e.g. layouts}
- H10W 72/252: {comprising solid metals or solid metalloids, e.g. PbSn, Ag or Cu}
- H10W 72/29: Bond pads specially adapted therefor
- H10W 72/923: {Bond pads having multiple stacked layers}
- H10W 72/952: {comprising metals or metalloids, e.g. PbSn, Ag or Cu}
- H03H: IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS (waveguides, resonators, lines or other devices of the waveguide type H01P)
- H10N: ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10

## Abstract

An acoustic wave device includes a piezoelectric substrate, an IDT electrode and an electrode pad provided on a front surface of the piezoelectric substrate, a support layer provided on the front surface so as to surround the IDT electrode, a first cover layer and a second cover layer provided on the support layer such that the first cover layer, the second cover layer, the support layer, and the piezoelectric substrate seal the IDT electrode in a hollow space, a UBM portion joined to the electrode pad, and a bump joined to the UBM portion. A joint surface of the UBM portion at which the UBM portion is joined to the bump has a spherical shape or substantially spherical shape that is convex towards the bump side.

## Claims

### Claim 1

An acoustic wave device comprising:
a piezoelectric substrate;
a functional electrode provided on a front surface of the piezoelectric substrate;
an electrode pad provided on the front surface of the piezoelectric substrate;
a support provided on the front surface of the piezoelectric substrate and surrounding the functional electrode;
a cover provided on the support such that the cover, the support, and the piezoelectric substrate seal the functional electrode in a hollow space;
a via conductor joined to the electrode pad; and
a bump joined to the via conductor; wherein
a joint surface of the via conductor at which the via conductor is joined to the bump has a curved shape that is convex towards a bump side;
the via conductor penetrates through the piezoelectric substrate; and
the bump projects from a rear surface of the piezoelectric substrate.

### Claim 2 (depends on 1)

The acoustic wave device according to claim 1, wherein the via conductor and the bump are made of different materials from each other.

### Claim 3 (depends on 1)

The acoustic wave device according to claim 1, wherein a convex portion of the joint surface of the via conductor at which the via conductor is joined to the bump projects to a level below a level of the piezoelectric substrate.

### Claim 4 (depends on 1)

The acoustic wave device according to claim 1, wherein a sectional area of the via conductor in a plane direction of the piezoelectric substrate increases from a joint surface at which the via conductor is joined to the electrode pad towards the joint surface at which the via conductor is joined to the bump except for a convex portion of the joint surface at which the via conductor is joined to the bump.

### Claim 5 (depends on 1)

The acoustic wave device according to claim 1, wherein the functional electrode is an IDT electrode that converts elastic waves propagating through the piezoelectric substrate into electric signals or converts the electric signals into the elastic waves.

### Claim 6 (depends on 1)

The acoustic wave device according to claim 1, wherein the piezoelectric substrate is made of a LiNbO3 single crystal or a LiTaO3 single crystal.

### Claim 7 (depends on 1)

The acoustic wave device according to claim 1, wherein the functional electrode is made of Cu, Al, Pt, a multilayer body of Cu, Al, or Pt, or an alloy of Cu, Al, or Pt.

### Claim 8 (depends on 1)

The acoustic wave device according to claim 1, wherein the cover includes a first cover layer provided on the support, and a second cover layer provided on the first cover layer.

### Claim 9 (depends on 8)

The acoustic wave device according to claim 8, wherein the first cover layer is made of a material that includes at least one of epoxy, urethane, phenol, polyester, BCB, and PBO.

### Claim 10 (depends on 8)

The acoustic wave device according to claim 8, wherein the second cover layer is made of a material that includes at least one of polyimide, epoxy, BCB, PBO, silicon, silicon oxide, LiTaO3 and LiNbO3.

### Claim 11 (depends on 1)

The acoustic wave device according to claim 1, wherein the support is made of a material that includes at least one of polyimide, epoxy, benzocyclobutene (BCB), polybenzoxazole (PBO), metal, and silicon oxide.

### Claim 12 (depends on 2)

The acoustic wave device according to claim 2, wherein
the material of the via conductor is Cu/Ni alloy or Ni/Au alloy; and
the material of the bump is Sn/Ag/Cu or a material primarily including Au.

### Claim 13 (depends on 1)

The acoustic wave device according to claim 1, wherein the joint surface of the via conductor at which the via conductor is joined to the bump has a spherical shape or substantially spherical shape that is convex towards the bump side.

### Claim 14

An acoustic wave device comprising:
a piezoelectric substrate;
a functional electrode provided on a front surface of the piezoelectric substrate and that converts an elastic wave propagating through the piezoelectric substrate into an electric signal or converts an electric signal into the elastic wave;
a mounting substrate on which the piezoelectric substrate is mounted;
an electrode provided on the front surface of the piezoelectric substrate or a main surface of the mounting substrate and that extracts the electric signal from the functional electrode or supplies an electric signal to the functional electrode;
a bump joined to the electrode; and
a sealing member that seals the piezoelectric substrate to the mounting substrate; wherein
a joint surface of the electrode at which the electrode is joined to the bump has a curved shape that is convex towards a bump side.

### Claim 15 (depends on 14)

The acoustic wave device according to claim 14, wherein the piezoelectric substrate is made of a LiNbO3 single crystal or a LiTaO3 single crystal.

### Claim 16 (depends on 14)

The acoustic wave device according to claim 14, wherein the functional electrode is made of Cu, Al, Pt, a multilayer body of Cu, Al, or Pt, or an alloy of Cu, Al, or Pt.

### Claim 17 (depends on 14)

The acoustic wave device according to claim 14, wherein the joint surface of the electrode at which the electrode is joined to the bump has a spherical shape or substantially spherical shape that is convex towards the bump side.