PIEZOELECTRIC DEVICES AND METHODS FOR MANUFACTURING SAME

• US 20100192342A1
• Filed: 04/15/2010
• Published: 08/05/2010
• Est. Priority Date: 10/15/2007
• Status: Active Grant

• Current Assignee: Nihon Dempa Kogyo Company Limited
• Original Assignee: Nihon Dempa Kogyo Company Limited
• Inventors: Inoue, Takahiro, Ono, Kozo
• Granted Patent: US 8,689,415 B2
• Time in Patent Office: Days
• US Class Current: 29/25.35
• CPC Class Codes: H03H 2003/026 the resonators or networks being of the tuning fork type
• CPC Class Codes: H03H 3/02 for the manufacture of piezoelectric or electrostrictive resonators or networks H03H3/08 takes precedence
• CPC Class Codes: H03H 9/0595 the holder support and resonator being formed in one body
• CPC Class Codes: H03H 9/1035 the enclosure being defined by two sealing substrates sandwiching the piezoelectric layer of the BAW device
• CPC Class Codes: H03H 9/178 of a laminated structure of multiple piezoelectric layers with inner electrodes
• CPC Class Codes: H03H 9/21 Crystal tuning forks
• CPC Class Codes: H10N 30/02 Forming enclosures or casings
• CPC Class Codes: H10N 30/03 Assembling devices that include piezoelectric or electrostrictive parts
• CPC Class Codes: H10N 30/057 by stacking bulk piezoelectric or electrostrictive bodies and electrodes
• CPC Class Codes: H10N 30/063 Forming interconnections, e.g. connection electrodes of multilayered piezoelectric or electrostrictive parts
• CPC Class Codes: H10N 30/067 Forming single-layered electrodes of multilayered piezoelectric or electrostrictive parts
• CPC Class Codes: H10N 30/50 having a stacked or multilayer structure
• CPC Class Codes: H10N 30/802 Circuitry or processes for operating piezoelectric or electrostrictive devices not otherwise provided for, e.g. drive circuits
• CPC Class Codes: H10N 30/874 embedded within piezoelectric or electrostrictive material, e.g. via connections
• CPC Class Codes: H10N 30/875 Further connection or lead arrangements, e.g. flexible wiring boards, terminal pins
• CPC Class Codes: H10N 30/88 Mounts; Supports; Enclosures; Casings
• CPC Class Codes: Y10T 29/42 Piezoelectric device making
• CPC Class Codes: Y10T 29/49005 Acoustic transducer
• CPC Class Codes: Y10T 29/4908 Acoustic transducer
• CPC Class Codes: Y10T 29/49798 Dividing sequentially from leading end, e.g., by cutting or breaking

Abstract

Piezoelectric devices and associated fabrication methods are disclosed. An exemplary piezoelectric device includes a piezoelectric vibrating piece having first and second electrodes and first and second surfaces, a glass base having first and second surfaces, and a lid. These three parts also form the device package. The first surface of the piezoelectric vibrating piece is mounted to the base, and the lid is mounted to the second surface of the piezoelectric vibrating piece to seal the package. The glass base includes first and second metal wires having ends that protrude from the surfaces of the base. The side surfaces of the protruding wire ends are connected to the first and the second electrodes, respectively. Manufacture is performed using whole wafers that are processed, sandwiched, bonded, and then cut to produce individual devices.

Claims

1. A method for manufacturing a piezoelectric device, comprising:

preparing a lid wafer defining multiple lids;

preparing a piezoelectric wafer in which are formed multiple piezoelectric vibrating pieces each comprising first and second electrodes;

preparing a base wafer made of glass and having a first surface, the base wafer defining multiple bases each comprising first and second metal wires extending through the glass, each wire having a respective end and a respective side surface at the end that protrude at least partially from the first surface;

forming a wafer sandwich comprising the base wafer, the piezoelectric wafer superposed on and aligned with the base wafer, and the lid wafer superposed on and aligned with the piezoelectric wafer, such that respective lids, bases, and piezoelectric vibrating pieces are registered with each other, and the protruding ends of the first and second wires contact respective first and second electrodes;

anodic bonding the layers of the wafer sandwich together, the anodic bonding also bonding the protruding ends of the first and second wires to the respective first and second electrodes; and

cutting the bonded three-wafer sandwich to separate individual piezoelectric devices thus formed in the sandwich from each other.

2. The method of claim 1, wherein preparing the base wafer further comprises:

roughening surfaces of the metal wires; and

applying a layer of gold to roughened surfaces.

3. The method of claim 2, wherein, in preparing the base wafer, the respective end and respective entire side surface at the end of each wire protrude from the first surface.

4. The method of claim 2, wherein:

preparing the piezoelectric wafer further comprises forming the first and second electrodes of an under-layer to which a layer of gold (Au) is applied; and

anodic bonding of the layers of the wafer sandwich further comprises electrical connection of the gold layer of each of the first and second metal wires with the gold layer of the respective first and second electrodes.

5. The method of claim 4, wherein, in preparing the base wafer, the respective end and respective entire side surface at the end of each wire protrude from the first surface.

6. The method of claim 1, wherein:

preparing the base wafer comprises applying a gold layer to at least protruding portions of the first and second wires;

preparing the piezoelectric wafer further comprises forming the first and second electrodes to include at least a surficial layer of gold (Au); and

anodic bonding of the layers of the wafer sandwich further comprises electrical connection of the gold layer of each of the first and second metal wires with the gold layer of the respective first and second electrodes.

7. The method of claim 6, wherein, in preparing the base wafer, the respective end and respective entire side surface at the end of each wire protrude from the first surface.

8. The method of claim 1, wherein, in preparing the base wafer, the respective end and respective entire side surface at the end of each wire protrude from the first surface.