Elastic wave device

Patent metadata

Field	Value
Publication number	US-10622964-B2
Application number	US-201715413561-A
Country	US
Kind code	B2
Filing date	Jan 24, 2017
Priority date	Jul 28, 2014
Publication date	Apr 14, 2020
Grant date	Apr 14, 2020

Abstract

An elastic wave device includes a piezoelectric substrate, an IDT electrode on the piezoelectric substrate and including first and second busbars and first and second electrode fingers connected to the first and second busbars, a bump electrode electrically connected to the IDT electrode, a protective film covering the IDT electrode, and a heat-conductive material layer that has an insulating property and that is provided only in a region excluding an excitation region of any IDT electrode and a region located above the bump electrode.

First claim

What is claimed is:

1. An elastic wave device comprising:
a piezoelectric substrate;
an interdigital transducer (IDT) electrode on the piezoelectric substrate and including first and second busbars and first and second electrode fingers connected to the first and second busbars;
a mount electrode electrically connected to the IDT electrode;
a protective film covering the IDT electrode;
a heat-conductive material layer that has an insulating property and that is provided only in a region excluding an excitation region of any IDT electrode and a region located above the mount electrode; and
a wiring electrode that connects at least one of the first and second busbars of the IDT electrode to the mount electrode; wherein
a ladder-type filter circuit is provided;
a serial arm resonator of the ladder-type filter circuit is connected to the mount electrode via the heat-conductive material layer;
the heat-conductive material layer is in contact with at least a portion of the wiring electrode; and
the heat-conductive material layer is stacked on the wiring electrode.

2. The elastic wave device according to claim 1 , wherein the wiring electrode has a multilayer structure in which two metal layers are stacked one on top of another.

3. The elastic wave device according to claim 1 , wherein the heat-conductive material layer is adjacent to the wiring electrode.

4. The elastic wave device according to claim 1 , wherein the heat-conductive material layer is connected to the mount electrode.

5. The elastic wave device according to claim 1 , wherein the heat-conductive material layer has a thickness larger than a thickness of the protective film.

6. The elastic wave device according to claim 1 , wherein the protective film includes at least one of SiO 2 and SiN.

7. The elastic wave device according to claim 1 , wherein the heat-conductive material layer includes at least one type of dielectric material selected from a group consisting of alumina, sapphire, aluminum nitride, diamond, aluminum nitride doped with scandium, SiO 2 , and SiN.

8. The elastic wave device according to claim 1 , wherein
serial arm resonators including the serial arm resonator of the ladder-type filter circuit that is connected to the mount electrode via the heat-conductive material layer and parallel arm resonators of the ladder-type filter circuit are disposed on the piezoelectric substrate.

9. The elastic wave device according to claim 8 , wherein each of the serial arm resonators and the parallel arm resonators is defined by a one-port resonator.

10. The elastic wave device according to claim 1 , wherein wiring electrodes and the protective film are stacked on the piezoelectric substrate in this order, and the heat-conductive material layer is provided on the protective film.

11. The elastic wave device according to claim 10 , wherein in a region in which the wiring electrodes are not disposed, the protective film and the heat-conductive material layer are stacked on the piezoelectric substrate in this order.

12. The elastic wave device according to claim 1 , wherein the heat-conductive material layer is provided on none of the first and second electrode fingers and conductors defining the mount electrode.

13. A transmission filter of a duplexer comprising the elastic wave device according to claim 1 .

14. An elastic wave device comprising:
a piezoelectric substrate;
an interdigital transducer (IDT) electrode on the piezoelectric substrate and including first and second busbars and first and second electrode fingers connected to the first and second busbars;
a mount electrode electrically connected to the IDT electrode;
a protective film covering the IDT electrode; and
a heat-conductive material layer that has an insulating property and that is provided only in a region excluding an excitation region of any IDT electrode and a region located above the mount electrode; wherein
a ladder-type filter circuit is provided;
a serial arm resonator of the ladder-type filter circuit is connected to the mount electrode via the heat-conductive material layer; and
the heat-conductive material layer, wiring electrodes, and the protective film are stacked on the piezoelectric substrate in this order.

Assignees

• Murata Manufacturing Co

Inventors

• Kawasaki Koichiro

Classifications

• H03H9/6483

  Ladder SAW filters · CPC title

• H03H9/14541

  Multilayer finger or busbar electrode · CPC title

• H03H9/725

  Duplexers · CPC title

• H03H9/02992

  Details of bus bars, contact pads or other electrical connections for finger electrodes · CPC title

• H03H9/02944 Primary

  of ohmic loss · CPC title