# US 7,745,979 B2 · Piezoelectric device

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- Number: US 7,745,979 B2
- Document ID: US7745979B2
- Status: Granted
- Kind: B2
- Application number: 12/063,213
- Filed: 2006-08-10
- Published: 2009-04-30
- Granted: 2010-06-29
- Earliest claimed: 2005-08-22
- Assignees: Seiko Epson Corporation
- Inventors: Kenji Tsuchido
- Web page: https://patentgrep.com/patent/US7745979B2

## CPC

- H03H 9/0595: {the holder support and resonator being formed in one body}
- H03H 9/1035: {the enclosure being defined by two sealing substrates sandwiching the piezoelectric layer of the BAW device}
- H03H 9/13: for networks consisting of piezoelectric or electrostrictive materials (for networks using surface acoustic waves H03H9/145)
- H03H 9/132: {characterized by a particular shape}
- H03H 9/177: {of the energy-trap type}
- H03H: IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS (waveguides, resonators, lines or other devices of the waveguide type H01P)

## Abstract

A piezoelectric device including: a piezoelectric element having, on a surface of a piezoelectric body, an exciting electrode and a drawing electrode that is electrically coupled to the exciting electrode and draws an electrode to an external section, and a substrate bonded to the drawing electrode with a metallic brazing material, in that: the piezoelectric element contains a connecting electrode connecting the exciting electrode with the drawing electrode; and the connecting electrode and/or the exciting electrode contains an underlying layer provided on the surface of the piezoelectric body and a surface layer section provided on a surface of this underlying layer, wherein: the underlying layer is provided using the metallic brazing material and a metallic material of adverse wettability; and a portion of the surface layer section is removed in a manner that the exciting electrode and the drawing electrode are separated.

## Claims

### Claim 1

A piezoelectric device, comprising: a piezoelectric element having, on a surface of a piezoelectric body, an exciting electrode and a drawing electrode that is electrically coupled to the exciting electrode and draws an electrode to an external section, and a substrate bonded to the drawing electrode with a metallic brazing material, wherein:
the piezoelectric element contains a connecting electrode connecting the exciting electrode with the drawing electrode; and
the connecting electrode and/or the exciting electrode contains an underlying layer provided on the surface of the piezoelectric body and a surface layer section provided on a surface of this underlying layer, wherein:
the underlying layer having a connected portion of the exciting electrode and the drawing electrode, is provided using the metallic brazing material and a metallic material of adverse wettability; and
a portion of the surface layer section is removed in a manner that the connected portion of the exciting electrode and the drawing electrode provided by the surface layer, are separated.

### Claim 2 (depends on 1)

The piezoelectric device according to claim 1, wherein the drawing electrode, the exciting electrode, and the connecting electrode are composed of a same layer structure and a same material except the portion of the surface layer section.

### Claim 3 (depends on 1)

The piezoelectric device according to claim 1, wherein:
the piezoelectric body contains a frame surrounding the exciting electrode, a principal plane of the frame having the drawing electrode; and
the substrate includes a lid substrate and a base substrate interposing the principal plane of the frame therebetween.

### Claim 4 (depends on 1)

The piezoelectric device according to claim 1, wherein the connecting electrode is sloped downward from a side adjacent to the drawing electrode to a side adjacent to the exciting electrode.

### Claim 5 (depends on 1)

The piezoelectric device according to claim 1, wherein the connecting electrode contains a recess whose inner bottom surface is the exposed metallic material of adverse wettability.

### Claim 6 (depends on 1)

The piezoelectric device according to claim 1, wherein the underlying layer has a thickness dimension larger than a thickness of at least the surface layer section.

### Claim 7 (depends on 1)

The piezoelectric device according to claim 1, wherein the underlying layer is composed of at least three layers, a mid layer thereof being made by disposing a metal having an electric resistance value lower than that of the metallic material of adverse wettability.