JP2022165310A - Acoustic wave device and module equipped with the acoustic wave device - Google Patents

Abstract

To provide an acoustic wave device capable of improving heat dissipation.SOLUTION: An acoustic wave device 1 is equipped with a wiring board 3, a device chip 5 that includes a plurality of series resonators, a plurality of bumps 15, a heat sink 6, a veer 7, a heat conductive member 16, and a sealing portion 17. The plurality of series resonators is formed on a first main surface of the device chip. The bumps electrically connect the plurality of series resonators formed on the first main surface of the device chip. The heat sink is formed on a second main surface of the device chip. The veer is joined with the heat sink through the device chip. The heat conductive member is formed on the first main surface of the deice chip, and is joined with the bump and the veer.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to acoustic wave devices and modules comprising the acoustic wave devices.

Patent Literature 1 discloses an acoustic wave device. The acoustic wave device radiates heat through heat radiation paths such as through vias.

JP 2017-157922 A

However, the heat dissipation path of the acoustic wave device described in Patent Document 1 does not have a sufficient heat capacity. Therefore, heat dissipation is not sufficient.

The present disclosure has been made to solve the above problems. An object of the present disclosure is to provide an acoustic wave device capable of improving heat dissipation and a module including the acoustic wave device.

The acoustic wave device according to the present disclosure is
a substrate;
a plurality of series resonators formed on the first main surface of the substrate;
wiring that electrically connects the plurality of series resonators formed on the first main surface of the substrate;
a heat sink formed on the second main surface of the substrate;
a via penetrating the substrate and bonded to the heat sink;
a thermally conductive layer formed on the first main surface of the substrate and bonded to the wiring and the via;
and an elastic wave device.

An aspect of the present disclosure is that the heat conductive layer is made of metal.

An aspect of the present disclosure is that the thermally conductive layer is a multilayer metal film.

An aspect of the present disclosure is that the heat conductive layer is covered with an insulating film.

One aspect of the present invention is that the heat sink has an uneven shape.

According to one aspect of the present invention, a plurality of bumps are provided on the first main surface of the substrate, and the thermally conductive layer is formed including one of the plurality of bumps. be done.

It is an aspect of this disclosure that the heat sink, the vias and the thermally conductive layer are not grounded.

It is an aspect of the present disclosure to include a metal layer formed on the second major surface of the substrate, wherein the metal layer is not bonded to the heat sink.

An aspect of the present disclosure is that the substrate is a substrate made of lithium tantalate, lithium niobate, quartz, or piezoelectric ceramics.

It is an aspect of the present disclosure that a substrate made of sapphire, silicon, alumina, spinel, crystal, or glass is bonded to the second main surface of the substrate.

It is an aspect of the present disclosure to include a ladder filter that further comprises a plurality of parallel resonators.

A module including the acoustic wave device is one aspect of the present disclosure.

According to the present disclosure, it is possible to provide an acoustic wave device capable of improving heat dissipation and a module including the acoustic wave device.

1 is a longitudinal sectional view of an acoustic wave device according to Embodiment 1; FIG. 1 is a perspective view of an acoustic wave device according to Embodiment 1; FIG. 1 is a plan view of an acoustic wave device according to Embodiment 1; FIG. 1 is a plan view of an acoustic wave device according to Embodiment 1; FIG. 4A and 4B are diagrams illustrating an example of an acoustic wave element of the acoustic wave device according to Embodiment 1; FIG. FIG. 4 is a diagram showing an example in which the acoustic wave element of the acoustic wave device in Embodiment 1 is an acoustic thin film resonator; FIG. 10 is a vertical cross-sectional view of an acoustic wave device according to Embodiment 2; FIG. 10 is a perspective view of an acoustic wave device according to Embodiment 2; FIG. 10 is a plan view of an acoustic wave device according to Embodiment 2; FIG. 10 is a plan view of an acoustic wave device according to Embodiment 2; FIG. 10 is a vertical cross-sectional view of a module to which an acoustic wave device according to Embodiment 3 is applied;

Embodiments will be described with reference to the accompanying drawings. In addition, the same code|symbol is attached|subjected to the part which is the same or corresponds in each figure. Redundant description of the relevant part will be simplified or omitted as appropriate.

Embodiment 1.
FIG. 1 is a longitudinal sectional view of an acoustic wave device according to Embodiment 1. FIG. FIG. 2 is a perspective view of the acoustic wave device according to Embodiment 1. FIG.

1 and 2 show an example of an acoustic wave device that is a duplexer as the acoustic wave device 1. FIG.

As shown in FIG. 1, the acoustic wave device 1 includes a wiring board 3, a device chip 5, a plurality of bumps 15, a heat sink 6, vias 7, a heat conducting member 16, and a sealing portion 17. As shown in FIG.

For example, the wiring board 3 is a multilayer board made of resin. For example, the wiring board 3 is a Low Temperature Co-fired Ceramics (LTCC) multilayer board consisting of a plurality of dielectric layers.

For example, the device chip 5 is a substrate made of piezoelectric single crystal such as lithium tantalate, lithium niobate, or quartz. For example, the device chip 5 is a substrate made of piezoelectric ceramics. For example, the device chip 5 is a substrate in which a piezoelectric substrate and a support substrate are bonded together. For example, the support substrate is a substrate made of sapphire, silicon, alumina, spinel, quartz or glass.

The device chip 5 is a substrate on which functional elements are formed. For example, a reception filter and a transmission filter are formed on the first main surface (lower surface in FIG. 1) of the device chip 5 .

The receive filter is formed so that an electrical signal in a desired frequency band can pass. For example, the receive filter is a ladder-type filter consisting of a plurality of series resonators and a plurality of parallel resonators.

The transmission filter is formed so that an electrical signal in a desired frequency band can pass. For example, the transmission filter is a ladder-type filter consisting of multiple series resonators and multiple parallel resonators.

A plurality of bumps 15 are formed on the first main surface of the device chip 5 . For example, bump 15 is a gold bump. For example, the bump 15 has a height of 20 μm to 50 μm. A plurality of bumps 15 are electrically connected to wiring on the first main surface of device chip 5 . A plurality of bumps 15 are electrically connected to wiring substrate 3 .

The heat sink 6 is formed on the second main surface (upper surface in FIG. 1) of the vice chip 5 . As shown in FIG. 2, the heat sink 6 has an uneven shape.

A via 7 penetrates the device chip 5 . Vias 7 are bonded to heat sink 6 .

For example, the heat conducting member 16 is made of metal. For example, the heat conducting member 16 is a multilayer metal film. For example, the heat conducting member 16 is covered with an insulating film. The heat conducting member 16 penetrates the device chip 5 . The heat-conducting member 16 is joined to the wiring and vias 6 on the first main surface of the device chip 5 as part of the heat-conducting layer. The thermally conductive member 16 is bonded to one bump 15 out of the plurality of bumps 15 .

The sealing portion 17 is formed so as to cover the device chip 5 . For example, the sealing portion 17 is made of an insulator such as synthetic resin. For example, the sealing portion 17 is made of metal. For example, the sealing portion 17 is formed of a resin layer and a metal layer.

When the sealing portion 17 is made of synthetic resin, the synthetic resin is epoxy resin, polyimide, or the like. Preferably, the encapsulant 17 is made of epoxy using a low temperature curing process.

Next, the configuration of the device chip 5 will be described with reference to FIGS. 3 and 4. FIG.
3 and 4 are plan views of the acoustic wave device according to Embodiment 1. FIG.

As shown in FIGS. 3 and 4, a plurality of acoustic wave elements 52 and wiring patterns 54 are formed on the first main surface of device chip 5 .

The multiple acoustic wave devices 52 include multiple series resonators S1, S2, S3, S4, and S5 and multiple parallel resonators P1, P2, P3, and P4.

The plurality of series resonators S1, S2, S3, S4, S5 and the plurality of parallel resonators P1, P2, P3, P4 are configured to function as transmission filters. Other series resonators and other parallel resonators are formed to function as receive filters.

For example, the wiring pattern 54 is made of an appropriate metal or alloy such as silver, aluminum, copper, titanium, palladium. For example, the wiring pattern 54 is formed of a laminated metal film formed by laminating a plurality of metal layers. For example, the wiring pattern 54 has a thickness of 1500 nm to 4500 nm.

The wiring pattern 54 includes an antenna pad ANT, a transmission pad Tx, a reception pad Rx, four ground pads GND, and a heat radiation pad HR. The wiring pattern 54 is electrically connected to the acoustic wave element 52 .

In the present disclosure, the heat dissipation pad HR is not grounded. A heat radiation pad HR is provided at a position corresponding to the heat sink 6 . Although not shown, the heat dissipation pad HR is joined to the heat sink 6 via one bump 15 of the plurality of bumps 15 and the heat conduction member 16 .

Next, an example of the elastic wave element 52 will be described with reference to FIG.
FIG. 5 is a diagram showing an example of an acoustic wave element of the acoustic wave device according to Embodiment 1. FIG.

As shown in FIG. 5 , an IDT (Interdigital Transducer) 52 a and a pair of reflectors 52 b are formed on the first main surface of the device chip 5 . The IDT 52a and the pair of reflectors 52b are provided so as to excite surface acoustic waves.

For example, the IDT 52a and the pair of reflectors 52b are made of an alloy of aluminum and copper. For example, the IDT 52a and the pair of reflectors 52b are made of an appropriate metal such as titanium, palladium, silver, or an alloy thereof. For example, the IDT 52a and the pair of reflectors 52b are formed of a laminated metal film in which a plurality of metal layers are laminated. For example, the thickness of the IDT 52a and the pair of reflectors 52b is 150 nm to 400 nm.

The IDT 52a includes a pair of comb electrodes 52c. A pair of comb electrodes 52c are opposed to each other. The comb-shaped electrode 52c includes a plurality of electrode fingers 52d and busbars 52e. The plurality of electrode fingers 52d are arranged with their longitudinal directions aligned. Bus bar 52e connects a plurality of electrode fingers 52d.

One of the pair of reflectors 52b is adjacent to one side of the IDT 52a. The other of the pair of reflectors 52b is adjacent to the other side of the IDT 52a.

Next, an example in which the elastic wave element 52 is an acoustic thin film resonator will be described with reference to FIG.
FIG. 6 is a diagram showing an example in which the acoustic wave element of the acoustic wave device according to Embodiment 1 is an acoustic thin film resonator.

In FIG. 6, the chip substrate 60 functions as the device chip 5. As shown in FIG. For example, the chip substrate 60 is a semiconductor substrate such as silicon, or an insulating substrate such as sapphire, alumina, spinel or glass.

A piezoelectric film 62 is provided on the chip substrate 60 . For example, the piezoelectric film 62 is made of aluminum nitride.

The lower electrode 64 and the upper electrode 66 are provided so as to sandwich the piezoelectric film 62 . For example, the lower electrode 64 and the upper electrode 66 are made of metal such as ruthenium.

A gap 68 is formed between the lower electrode 64 and the chip substrate 60 .

In the acoustic thin film resonator, the lower electrode 64 and the upper electrode 66 excite an elastic wave in the thickness longitudinal vibration mode inside the piezoelectric film 62 .

According to the first embodiment described above, the thermally conductive member 16 is joined to the heat sink 6 via the wiring and the vias 7 on the first main surface of the device chip 5 as part of the thermally conductive layer. Therefore, the heat dissipation of the acoustic wave device 1 can be improved. As a result, the power durability of the acoustic wave device 1 can be improved.

Also, the heat conducting member 16 is made of metal. Therefore, it is possible to more reliably improve the heat dissipation of the acoustic wave device 1 .

Also, the heat conducting member 16 is a multilayer metal film. Therefore, it is possible to more reliably improve the heat dissipation of the acoustic wave device 1 .

Moreover, the heat conducting member 16 is covered with an insulating film. Therefore, it is possible to more reliably improve the heat dissipation of the acoustic wave device 1 .

Moreover, the heat sink 6 has an uneven shape. Therefore, it is possible to more reliably improve the heat dissipation of the acoustic wave device 1 .

Also, the thermally conductive layer is formed including one bump 15 out of the plurality of bumps 15 . Therefore, it is possible to more reliably improve the heat dissipation of the acoustic wave device 1 .

Also, the heat sink 6, the vias 7 and the thermally conductive layer are not grounded. Therefore, it is possible to more reliably improve the heat dissipation of the acoustic wave device 1 .

Also, the device chip 5 is a substrate made of lithium tantalate, lithium niobate, crystal, or piezoelectric ceramics. Therefore, it is possible to more reliably improve the heat dissipation of the acoustic wave device 1 .

A substrate made of sapphire, silicon, alumina, spinel, crystal, or glass may be bonded to the second main surface of the device chip 5 . In this case, the heat dissipation of the acoustic wave device 1 can be improved more reliably.

Acoustic wave device 1 also includes a ladder-type filter that further includes a plurality of parallel resonators. Therefore, it is possible to more reliably improve the heat dissipation of the acoustic wave device 1 including the ladder-type filter.

Embodiment 2.
FIG. 7 is a longitudinal sectional view of an acoustic wave device according to Embodiment 2. FIG. FIG. 8 is a perspective view of an acoustic wave device according to Embodiment 2. FIG. 9 and 10 are plan views of the acoustic wave device according to the second embodiment. The same reference numerals are given to the same or corresponding parts as those of the first embodiment. Description of this part is omitted.

As shown in FIGS. 7 to 10, the plurality of vias 7, the plurality of heat sinks 6, and the plurality of thermally conductive members 16 are positioned corresponding to the transmission pad Tx, the two ground pads GND, and the heat dissipation pad HR. are provided respectively.

A metal layer 8 is formed on the second main surface of the device chip 5 . The metal layer 8 is not bonded to any of the multiple heat sinks 6 .

According to the second embodiment described above, metal layer 8 is not bonded to heat sink 6 . Therefore, it is possible to more reliably separate signals between a plurality of terminals respectively corresponding to the antenna pad ANT, the transmission pad Tx, and the reception pad Rx.

Embodiment 3.
FIG. 11 is a longitudinal sectional view of a module to which the acoustic wave device according to Embodiment 3 is applied. The same reference numerals are given to the same or corresponding parts as those of the first embodiment. Description of this part is omitted.

In FIG. 11 , module 100 includes wiring board 130 , integrated circuit component IC, acoustic wave device 1 , inductor 11 and sealing portion 117 .

The wiring board 130 is equivalent to the wiring board 3 of the first embodiment.

Although not shown, the integrated circuit component IC is mounted inside the wiring board 130 . An integrated circuit component IC includes a switching circuit and a low noise amplifier.

Acoustic wave device 1 is mounted on the main surface of wiring board 130 .

Inductor 11 is mounted on the main surface of wiring board 130 . Inductor 11 is implemented for impedance matching. For example, inductor 111 is an Integrated Passive Device (IPD).

The sealing portion 117 seals a plurality of electronic components including the acoustic wave device 1 .

According to Embodiment 3 described above, the module 100 includes the acoustic wave device 1 . Therefore, the heat resistance of the module 100 can be improved. As a result, the power resistance of the module 100 can be improved.

Having described several aspects of at least one embodiment, it is to be appreciated various alterations, modifications, and improvements will readily occur to those skilled in the art. Such alterations, modifications, and improvements are intended to be part of this disclosure, and are intended to be within the scope of this disclosure.

It is to be understood that the method and apparatus embodiments described herein are not limited in application to the details of construction and arrangement of components set forth in the foregoing description or illustrated in the accompanying drawings. The methods and apparatus can be implemented in other embodiments and practiced or carried out in various ways.

Specific implementations are provided here for illustrative purposes only and are not intended to be limiting.

The phraseology and terminology used in this disclosure is for the purpose of description and should not be regarded as limiting. The use of "including", "comprising", "having", "including" and variations thereof herein is intended to be inclusive of the items listed below and equivalents thereof as well as additional items.

References to “or (or)” shall be construed such that any term stated using “or (or)” refers to one, more than one, and all of the terms of the statement. can be

All references to front, rear, left, right, top, bottom, top, bottom, width, length, and front and back are intended for convenience of description. Such references are not limited to any one positional or spatial orientation of the components of this disclosure. Accordingly, the above description and drawings are exemplary only.

1 Acoustic Wave Device 3 Wiring Board 5 Device Chip 6 Heat Sink 7 Via 8 Metal Layer 15 Bump 16 Thermal Conductive Member 17 Sealing Portion 52 Acoustic Wave Element 52a IDT 52b Reflector 52c Comb Shape Electrode 52d Electrode finger 60 Chip substrate 62 Piezoelectric film 64 Lower electrode 66 Upper electrode 68 Air gap 70 First wafer 72 Wiring wafer 74 Second wafer 76 Metal body 100 Module 105 Device chip , 111 inductor, 117 sealing portion, 130 wiring board

Claims (12)

a substrate;
a plurality of series resonators formed on the first main surface of the substrate;
wiring that electrically connects the plurality of series resonators formed on the first main surface of the substrate;
a heat sink formed on the second main surface of the substrate;
a via penetrating the substrate and bonded to the heat sink;
a thermally conductive layer formed on the first main surface of the substrate and bonded to the wiring and the via;
An acoustic wave device comprising: The acoustic wave device according to claim 1, wherein the heat conductive layer is made of metal. 2. The acoustic wave device according to claim 1, wherein said thermally conductive layer is a multilayer metal film. The acoustic wave device according to claim 1, wherein the heat conductive layer is covered with an insulating film. The acoustic wave device according to claim 1, wherein the heat sink has an uneven shape. 2. The thermally conductive layer according to claim 1, comprising a plurality of bump pads formed on the first major surface of said substrate, wherein said thermally conductive layer is formed including one bump pad of said plurality of bump pads. Elastic wave device. 2. The acoustic wave device according to claim 1, wherein said heat sink, said vias and said thermally conductive layer are not grounded. 2. The acoustic wave device according to claim 1, further comprising a metal layer formed on the second main surface of said substrate, said metal layer not being bonded to said heat sink. 2. The acoustic wave device according to claim 1, wherein the substrate is made of lithium tantalate, lithium niobate, crystal, or piezoelectric ceramics. 2. The acoustic wave device according to claim 1, wherein a substrate made of sapphire, silicon, alumina, spinel, crystal, or glass is bonded to the second main surface of said substrate. The acoustic wave device of Claim 1, comprising a ladder-type filter, further comprising a plurality of parallel resonators. A module comprising the acoustic wave device according to any one of claims 1 to 11.

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