# US 11,451,210 B2 · Acoustic wave device, filter, and multiplexer

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- Number: US 11,451,210 B2
- Document ID: US11451210B2
- Status: Granted
- Kind: B2
- Application number: 16/214,968
- Filed: 2018-12-10
- Published: 2019-08-01
- Granted: 2022-09-20
- Earliest claimed: 2018-01-26
- Assignees: Taiyo Yuden Co., Ltd.
- Applicants: Taiyo Yuden Co., Ltd.
- Inventors: Masafumi Iwaki; Yoshio Satoh
- Web page: https://patentgrep.com/patent/US11451210B2

## CPC

- H03H 9/02818: {Means for compensation or elimination of undesirable effects}
- H03H 9/02559: {of lithium niobate or lithium-tantalate substrates}
- H03H 9/02637: {Details concerning reflective or coupling arrays}
- H03H 9/02866: {of bulk wave excitation and reflections}
- H03H 9/14541: {Multilayer finger or busbar electrode}
- H03H 9/25: Constructional features of resonators using surface acoustic waves {(devices for manipulating acoustic surface waves in general G10K11/36)}
- H03H 9/6483: {Ladder SAW filters}
- H03H 9/6489: {Compensation of undesirable effects}
- H03H 9/725: {Duplexers}
- H10N 30/877: {Conductive materials}
- 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

## Abstract

An acoustic wave device includes: a Y-cut X-propagation lithium tantalate substrate having a cut angle of 5° or greater and 18° or less; and a grating electrode that is formed of one or more metal films stacked on the lithium tantalate substrate, a number of the one or more metal films being n (n is a natural number), excites an acoustic wave, and meets a condition: 0.16 ⁢ λ ≤ ∑ i = 1 n ⁢ ⁢ ( hi × ρ ⁢ ⁢ i ρ ⁢ ⁢ 0 ) ≤ 0.24 ⁢ λ where ρi represents a density of each metal film of the one or more metal films, hi represents a film thickness of the each metal film, ρ0 represents a density of Mo, and λ represents a pitch.

## Claims

### Claim 1

An acoustic wave device comprising:
a Y-cut X-propagation lithium tantalate substrate having a cut angle of 5° or greater and 19° or less; and
a grating electrode that is formed of one or more metal films stacked on the lithium tantalate substrate, a number of the one or more metal films being n (n is a natural number), excites an acoustic wave, and meets a condition:
0.16
⁢
λ
≤
∑
i
=
1
n
⁢
⁢
(
hi
×
ρ
⁢
⁢
i
ρ
⁢
⁢
0
)
≤
0.24
⁢
λ
where ρi represents a density of each metal film of the one or more metal films, hi represents a film thickness of the each metal film, ρ0 represents a density of Mo, and λrepresents a pitch.

### Claim 2 (depends on 1)

The acoustic wave device according to claim 1, wherein
the cut angle is 5.5° or greater and 7.5° or less, and
the grating electrode meets a condition:
0.22
⁢
λ
≤
∑
i
=
1
n
⁢
⁢
(
hi
×
ρ
⁢
⁢
i
ρ
⁢
⁢
0
)
≤
0.24
⁢
λ
.

### Claim 3 (depends on 1)

The acoustic wave device according to claim 1, wherein
the cut angle is 7.5° or greater and 10.5° or less, and
the grating electrode meets a condition:
0.20
⁢
λ
≤
∑
i
=
1
n
⁢
⁢
(
hi
×
ρ
⁢
⁢
i
ρ
⁢
⁢
0
)
≤
0.24
⁢
λ
.

### Claim 4 (depends on 1)

The acoustic wave device according to claim 1, wherein
the cut angle is 10.5° or greater and 12° or less, and
the grating electrode meets a condition:
0.18
⁢
λ
≤
∑
i
=
1
n
⁢
⁢
(
hi
×
ρ
⁢
⁢
i
ρ
⁢
⁢
0
)
≤
0.24
⁢
λ
.

### Claim 5 (depends on 1)

The acoustic wave device according to claim 1, wherein
the cut angle is 12° or greater and 14° or less, and
the grating electrode meets a condition:
0.17
⁢
λ
≤
∑
i
=
1
n
⁢
⁢
(
hi
×
ρ
⁢
⁢
i
ρ
⁢
⁢
0
)
≤
0.24
⁢
λ
.

### Claim 6 (depends on 1)

The acoustic wave device according to claim 1, wherein
the cut angle is 14° or greater and 16° or less, and
the grating electrode meets a condition:
0.16
⁢
λ
≤
∑
i
=
1
n
⁢
⁢
(
hi
×
ρ
⁢
⁢
i
ρ
⁢
⁢
0
)
≤
0.20
⁢
λ
.

### Claim 7 (depends on 1)

The acoustic wave device according to claim 1, wherein
the cut angle is 16° or greater and 19° or less, and
the grating electrode meets a condition:
0.16
⁢
λ
≤
∑
i
=
1
n
⁢
⁢
(
hi
×
ρ
⁢
⁢
i
ρ
⁢
⁢
0
)
≤
0.17
⁢
λ
.

### Claim 8 (depends on 1)

The acoustic wave device according to claim 1, wherein
a primary mode of the acoustic wave is an SH-type oscillation mode, and
an acoustic velocity of the acoustic wave is lower than an acoustic velocity of Rayleigh mode spurious.

### Claim 9 (depends on 2)

The acoustic wave device according to claim 2, wherein
the one or more metal films include a metal film mainly composed of at least one of Cu, W, Ru, Mo, Ta, Pt, Pd, Ir, Rh, Re, and Te.

### Claim 10

An acoustic wave device comprising:
a Y-cut X-propagation lithium tantalate substrate having a cut angle of 5° or greater and 18° or less, and
a grating electrode that is located on the lithium tantalate substrate, and excites an acoustic wave, a primary mode of the acoustic wave being an SH-type oscillation mode, an acoustic velocity of the acoustic wave being lower than an acoustic velocity of Rayleigh mode spurious.

### Claim 11 (depends on 1)

A filter comprising
the acoustic wave device according to claim 1.

### Claim 12 (depends on 11)

A multiplexer comprising
the filter according to claim 11.

### Claim 13 (depends on 10)

A filter comprising
the acoustic wave device according to claim 10.

### Claim 14 (depends on 13)

A multiplexer comprising
the filter according to claim 13.