CN115940871A

CN115940871A - Elastic wave device chip, elastic wave device, and module including elastic wave device chip or elastic wave device

Info

Publication number: CN115940871A
Application number: CN202211197198.8A
Authority: CN
Inventors: 桑原英司
Original assignee: Sanyan Japan Technology Co ltd
Current assignee: Sanyan Japan Technology Co ltd
Priority date: 2021-10-01
Filing date: 2022-09-29
Publication date: 2023-04-07
Also published as: JP2023053471A

Abstract

An elastic wave device chip includes a chip substrate; a plurality of series resonators formed on the first main surface of the chip substrate; a plurality of parallel resonators formed on the first main surface of the chip substrate; an input pad formed on a first main surface of the chip substrate; an output pad formed on the first main surface of the chip substrate; a ground pad formed on the first main surface of the chip substrate; a wiring pattern formed on the first main surface of the chip substrate and electrically connected to the series resonator, the parallel resonator, the input pad, the output pad, and the ground pad; and a broadband damping circuit formed on a second main surface of the chip substrate opposite to the first main surface, and electrically connected to the wiring pattern via a first via wiring penetrating the chip substrate at a position where two adjacent series resonators on a first half side counted from one side of the input pad are electrically connected. Thus, an elastic wave device chip and the like which can improve filter characteristics and achieve miniaturization can be provided.

Description

Elastic wave device chip, elastic wave device, and module including elastic wave device chip or elastic wave device

Technical Field

The present disclosure relates to an elastic wave device chip, an elastic wave device, and a module including the elastic wave device chip or the elastic wave device.

Background

Patent document 1 (international publication No. 2017/170071) discloses an elastic wave filter according to which the characteristics of the filter are improved.

Disclosure of Invention

[ problems to be solved by the invention ]

However, the elastic wave filter described in patent document 1 requires an attenuation circuit. Therefore, it is difficult to miniaturize the device in which the elastic wave filter is mounted.

The present disclosure is made to solve the above problems, and an object of the present disclosure is to provide an elastic wave device chip, an elastic wave device, and a module including the elastic wave device chip or the elastic wave device, which can improve filter characteristics and achieve miniaturization.

[ means for solving the problems ]

The elastic wave device chip of the present disclosure includes:

a chip substrate;

a plurality of series resonators formed on the first main surface of the chip substrate;

a plurality of parallel resonators formed on a first main surface of the chip substrate;

an input pad formed on a first main surface of the chip substrate;

an output pad formed on the first main surface of the chip substrate;

a ground pad formed on the first main surface of the chip substrate;

a wiring pattern formed on the first main surface of the chip substrate and electrically connected to the series resonator, the parallel resonator, the input pad, the output pad, and the ground pad;

a first via wiring penetrating the chip substrate; and

and a broadband damping circuit formed on a second main surface of the chip substrate opposite to the first main surface, one end of the broadband damping circuit being electrically connected to the wiring pattern via the first via wiring at a position where two adjacent series resonators are electrically connected in a front half of the chip substrate counted from one side of the input pad.

In one aspect of the present disclosure, the broadband damping circuit is electrically connected to the wiring pattern via the first via wiring at a position where a first series resonator and a second series resonator counted from one side of the input pad are electrically connected.

In one aspect of the present disclosure, the series resonator and the parallel resonator function as a transmission filter.

In one aspect of the present disclosure, the chip further includes a second via wiring penetrating through the chip substrate, and the other end of the broadband damping circuit is electrically connected to the ground pad through the second via wiring.

In one aspect of the present disclosure, when the series resonator and the parallel resonator are used as an elastic wave filter, the wide band attenuation circuit resonates in a frequency band between a second harmonic and a third harmonic of a fundamental wave corresponding to a frequency of the elastic wave filter.

In one aspect of the present disclosure, the broadband damping circuit resonates in a frequency band between 3GHz and 7 GHz.

In one aspect of the present disclosure, the broadband damping circuit includes an inductance element and a capacitance element.

In one aspect of the present disclosure, the inductance element has an inductance value of 0.5nH to 4.0nHz, and the capacitance element has a capacitance value of 0.2pF to 2.0 pF.

In one aspect of the present disclosure, the chip substrate includes a piezoelectric substrate, and a support substrate made of sapphire, silicon, alumina, spinel, crystal, or glass and bonded to the piezoelectric substrate.

In one aspect of the present disclosure, the series resonator and the parallel resonator are each a surface acoustic wave resonator, and the series resonator and the parallel resonator as a whole function as a band pass filter or a duplexer.

In one aspect of the present disclosure, the series resonator and the parallel resonator are each divided into an acoustic thin film resonator, and the series resonator and the parallel resonator as a whole function as a band pass filter or a duplexer.

An elastic wave device according to the present disclosure includes the elastic wave device chip, and a wiring substrate electrically connected to the elastic wave device chip.

A module of the present disclosure includes the elastic wave device chip or the elastic wave device.

In one aspect of the present disclosure, the module further includes an integrated circuit electrically connected to the input pad.

In one aspect of the present disclosure, the integrated circuit includes a series inductor element having an inductance value of 0.5nH to 10nH and a parallel inductor element having an inductance value of 5nH to 50 nH.

[ Effect of the invention ]

The invention has the beneficial effects that: according to the present disclosure, it is possible to provide an elastic wave device chip, an elastic wave device, and a module including the elastic wave device chip or the elastic wave device, which improve filter characteristics and achieve miniaturization.

Drawings

Fig. 1 is a cross-sectional view of an acoustic wave device in which the acoustic wave device chip is mounted in the first embodiment.

Fig. 2 is a circuit diagram of an acoustic wave device in which the acoustic wave device chip is mounted in the first embodiment.

Fig. 3 is a plan view of the first main surface of the elastic wave device chip in the first embodiment.

Fig. 4 is a perspective view of the second main surface of the acoustic wave device chip as viewed from the first main surface side in the first embodiment.

Fig. 5 is a first example of an acoustic wave device having the acoustic wave device chip mounted thereon according to the first embodiment.

Fig. 6 is a second example of an acoustic wave device in which the acoustic wave device chip is mounted in the first example.

Fig. 7 is a Smith chart (Smith chart) showing impedance characteristics of the acoustic wave device in which the acoustic wave device chip is mounted in the first embodiment and a comparative example.

Fig. 8 is a smith chart showing impedance characteristics of the acoustic wave device in which the acoustic wave device chip is mounted in the first embodiment and a comparative example.

Fig. 9 is a smith chart showing impedance characteristics of the acoustic wave device in which the acoustic wave device chip is mounted in the first embodiment and a comparative example.

Fig. 10 is a diagram showing simulation results of frequency characteristics of an acoustic wave device in which the acoustic wave device chip is mounted in the first embodiment and a comparative example.

Fig. 11 is a diagram showing a simulation result of frequency characteristics of an acoustic wave device in which the acoustic wave device chip is mounted in the first embodiment and a comparative example.

Fig. 12 is a diagram showing simulation results of frequency characteristics of an acoustic wave device in which the acoustic wave device chip is mounted in the first embodiment and a comparative example.

Fig. 13 is a diagram showing simulation results of frequency characteristics of an acoustic wave device in which the acoustic wave device chip is mounted in the first embodiment and a comparative example.

Fig. 14 is a diagram showing a simulation result of frequency characteristics of an acoustic wave device in which the acoustic wave device chip is mounted in the first embodiment and a comparative example.

Fig. 15 is a diagram showing simulation results of frequency characteristics of an acoustic wave device in which the acoustic wave device chip is mounted in the first embodiment and a comparative example.

Fig. 16 is a diagram showing the simulation results of the isolation characteristics of the acoustic wave device in which the acoustic wave device chip is mounted in the first embodiment and a comparative example.

Fig. 17 is a cross-sectional view of a modified example of the acoustic wave device in which the acoustic wave device chip is mounted in the first embodiment.

Fig. 18 is a sectional view of a module including an acoustic wave device having the acoustic wave device chip mounted thereon according to a second embodiment.

Fig. 19 is a circuit diagram of a module including an acoustic wave device having the acoustic wave device chip mounted thereon according to the second embodiment.

Detailed Description

Embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the same or corresponding parts in the various figures are denoted by the same reference numerals. The same or equivalent portions will be appropriately simplified or omitted from repetitive description.

(first embodiment)

Fig. 1 is a cross-sectional view of an acoustic wave device 1 with an acoustic wave device chip mounted thereon in a first embodiment.

As shown in fig. 1, acoustic wave device 1 includes wiring substrate 3, a plurality of bumps 15, at least one acoustic wave device chip 5, and sealing portion 17.

The wiring substrate 3 is, for example, a multilayer substrate made of a plurality of layers of resins. The wiring substrate 3 is, for example, a Low Temperature Co-fired ceramic (LTCC) multilayer substrate formed of a plurality of dielectric layers.

The bump 15 is electrically connected to the wiring substrate 3. The bumps 15 are, for example, gold bumps. For example, the height of the bump 15 is 10 μm to 50 μm.

For example, acoustic wave device chip 5 is electrically connected to wiring substrate 3, and includes chip substrate 20, wiring pattern 21, a plurality of acoustic wave elements 22, and broadband attenuation circuit 23.

The chip substrate 20 is made of, for example, lithium tantalate or lithium niobate.

The wiring pattern 21 is formed on a first main surface (lower surface in fig. 1) of the chip substrate 20. For example, the wiring pattern 21 may be formed of an appropriate metal or alloy of silver, aluminum, copper, titanium, palladium, or the like. For example, the wiring pattern 21 has a multilayer metal structure in which a plurality of metal layers are stacked. For example, the wiring pattern 21 has a thickness of 1500nm to 4500nm. The wiring pattern 21 is electrically connected to the bump 15.

The acoustic wave device 22 is formed on the first main surface of the chip substrate 20. The acoustic wave device 22 is electrically connected to the wiring pattern 21. For example, the elastic wave element 22 can pass an electric signal of a desired frequency band. For example, the elastic wave element 22 functions as a ladder-type elastic wave filter including a plurality of series resonators and a plurality of parallel resonators.

The broadband attenuation circuit 23 is formed on a second main surface (upper surface in fig. 1) of the chip substrate 20 opposite to the first main surface. For example, the broadband damping circuit 23 is electrically connected to the wiring pattern 21 via a first via wiring 31a and a second via wiring 31b penetrating the chip substrate 20.

The sealing portion 17 covers the acoustic wave device chip 5. The sealing portion 17 seals the acoustic wave device chip 5 together with the wiring substrate 3. The sealing portion 17 is formed of an insulator such as a synthetic resin, for example. The seal portion 17 is formed of metal, for example. For example, the sealing portion 17 is formed of a resin layer and a metal layer.

In the case where the sealing portion 17 is formed of a synthetic resin, the synthetic resin may be an epoxy resin, a polyimide, or the like. Preferably, the sealing portion 17 is formed of an epoxy resin through a low-temperature hardening process.

Next, the elastic wave device 1 will be described by way of example with reference to fig. 2.

Fig. 2 is a circuit diagram of acoustic wave device 1 in which the acoustic wave device chip is mounted in the first embodiment.

In fig. 2, the elastic wave device 1 has a quadruplex (quadrplexer) function. Specifically, the acoustic wave device 1 includes four acoustic wave device chips 5, and the four acoustic wave device chips 5 are a first receiving chip 5a, a first transmitting chip 5b, a second receiving chip 5c, and a second transmitting chip 5d, respectively.

For example, the first receiving chip 5a is a receiving chip corresponding to the frequency band 1. For example, the first transmission chip 5b is a transmission chip corresponding to the frequency band 1. For example, the second receiving chip 5c is a receiving chip corresponding to band 3. For example, the second transmission chip 5d is a transmission chip corresponding to the frequency band 3.

The first receiving chip 5a includes the wiring pattern 21, a first receiving antenna pad Ant-R1, a first receiving output pad Rx-R1, and a plurality of first receiving ground pads GND-R1.

In the first receiving chip 5a, the elastic wave element 22 includes a plurality of series resonators S1 to R1, S2 to R1, S3 to R1, and S4 to R1 and a plurality of parallel resonators P1 to R1, P2 to R1, P3 to R1, and P4 to R1. The series resonators S1-R1, S2-R1, S3-R1, S4-R1 and the parallel resonators P1-R1, P2-R1, P3-R1, P4-R1 are electrically connected to the wiring pattern 21. In the wiring of the wiring pattern 21 between the first reception output pad Rx-R1 and the first reception antenna pad Ant-R1, the series resonators S1-R1, S2-R1, S3-R1, and S4-R1 are arranged in the aforementioned order from near to far from the first reception output pad Rx-R1. In the wiring of the wiring pattern 21 between the first reception antenna pad Ant-R1 and the first reception output pad Rx-R1, the parallel resonators P1-R1, P2-R1, P3-R1, and P4-R1 are arranged in the aforementioned order from the near side to the far side with respect to the first reception output pad Rx-R1. The series resonators S1-R1, S2-R1, S3-R1, S4-R1 and the parallel resonators P1-R1, P2-R1, P3-R1, P4-R1 function as a first receiving filter.

The first receiving antenna pad Ant-R1 serves as an input pad of the first receiving filter. The first reception output pad Rx-R1 is used as an output pad of the first reception filter. The first receiving ground pad GND-R1 serves as a ground pad of the first receiving filter.

When an electric signal is inputted to the first receiving antenna pad Ant-R1, only the electric signal of the receiving band corresponding to the band 1 passes through the series resonators S1-R1, S2-R1, S3-R1, S4-R1 and the parallel resonators P1-R1, P2-R1, P3-R1, P4-R1 completely. Accordingly, an electric signal corresponding to the reception band of the band 1 is output from the first reception output pad Rx-R1.

The first transmitting chip 5b includes the wiring pattern 21, a first transmitting input pad Tx-T1, a first transmitting antenna pad Ant-T1, and a plurality of first transmitting ground pads GND-T1.

In the first transmitting chip 5b, the elastic wave element 22 includes a plurality of series resonators S1-T1, S2-T1, S3-T1, S4-T1, S5-T1 and a plurality of parallel resonators P1-T1, P2-T1, P3-T1, P4-T1. The series resonators S1-T1, S2-T1, S3-T1, S4-T1, S5-T1 and the parallel resonators P1-T1, P2-T1, P3-T1, P4-T1 are electrically connected to the wiring pattern 21. In the wiring of the wiring pattern 21 between the first transmission input pad Tx-T1 and the first transmission antenna pad Ant-T1, the series resonators S1-T1, S2-T1, S3-T1, S4-T1, S5-T1 are arranged in the aforementioned order from the near side to the far side with respect to the first transmission input pad Tx-T1. In the wiring of the wiring pattern 21 between the first transmission input pad Tx-T1 and the first transmission antenna pad Ant-T1, the parallel resonators P1-T1, P2-T1, P3-T1, and P4-T1 are arranged in the aforementioned order from near to far from the first transmission input pad Tx-T1. The series resonators S1-T1, S2-T1, S3-T1, S4-T1, S5-T1 and the parallel resonators P1-T1, P2-T1, P3-T1, P4-T1 function as a first transmission filter.

The first transmission input pad Tx-T1 serves as an input pad of the first transmission filter. The first transmitting antenna pad Ant-T1 is used as an output pad of the first transmitting filter. The first transmission ground pad GND-T1 serves as a ground pad of the first transmission filter.

When an electrical signal is input to the first transmission input pad Tx-T1, only the electrical signal of the transmission band corresponding to the band 1 passes through the series resonators S1-T1, S2-T1, S3-T1, S4-T1, S5-T1 and the parallel resonators P1-T1, P2-T1, P3-T1, P4-T1. Therefore, an electric signal of the transmission band corresponding to the band 1 is output from the first transmission antenna pad Ant-T1.

The second receiving chip 5c includes the wiring pattern 21, a second receiving antenna pad Ant-R2, a second receiving output pad Rx-R2, and a plurality of second receiving ground pads GND-R2.

In the second receiving chip 5c, the elastic wave element 22 includes a plurality of series resonators S1 to R2, S2 to R2, S3 to R2, and S4 to R2 and a plurality of parallel resonators P1 to R2, P2 to R2, P3 to R2, and P4 to R2. The series resonators S1-R2, S2-R2, S3-R2, S4-R2 and the parallel resonators P1-R2, P2-R2, P3-R2, P4-R2 are electrically connected to the wiring pattern 21. In the wiring of the wiring pattern 21 between the second reception output pad Rx-R2 and the second reception antenna pad Ant-R2, the series resonators S1-R2, S2-R2, S3-R2, and S4-R2 are arranged in the aforementioned order from the near side to the far side with respect to the second reception output pad Rx-R2. In the wiring of the wiring pattern 21 between the second reception output pad Rx-R2 and the second reception antenna pad Ant-R2, the parallel resonators P1-R2, P2-R2, P3-R2, and P4-R2 are arranged in the aforementioned order from near to far from the second reception output pad Rx-R2. The series resonators S1-R2, S2-R2, S3-R2, S4-R2 and the parallel resonators P1-R2, P2-R2, P3-R2, P4-R2 have the function of a second receiving filter.

The second reception antenna pad Ant-R2 serves as an input pad of the second reception filter. The second reception output pad Rx-R2 is used as an output pad of the second reception filter. The second reception ground pad GND-R2 serves as a ground pad of the second reception filter.

When an electric signal is inputted to the second receiving antenna pad Ant-R2, only the electric signal of the receiving band corresponding to the band 3 passes through the series resonators S1-R2, S2-R2, S3-R2, S4-R2 and the parallel resonators P1-R2, P2-R2, P3-R2, P4-R2 completely. Accordingly, an electric signal corresponding to the reception band of the band 3 is output from the second reception output pad Rx-R2.

The second transmitting chip 5d includes the wiring pattern 21, a second transmitting input pad Tx-T2, a second transmitting antenna pad Ant-T2, and a plurality of second transmitting ground pads GND-T2.

In the second transmitting chip 5d, the elastic wave element 22 includes a plurality of series resonators S1 to T2, S2 to T2, S3 to T2, S4 to T2, and S5 to T2 and a plurality of parallel resonators P1 to T2, P2 to T2, P3 to T2, and P4 to T2. The series resonators S1-T2, S2-T2, S3-T2, S4-T2, S5-T2 and the parallel resonators P1-T2, P2-T2, P3-T2, P4-T2 are electrically connected to the wiring pattern 21. In the wiring of the wiring pattern 21 between the second transmission input pad Tx-T2 and the second transmission antenna pad Ant-T2, the series resonators S1-T2, S2-T2, S3-T2, S4-T2, and S5-T2 are arranged in the aforementioned order from near to far from the second transmission input pad Tx-T2. In the wiring of the wiring pattern 21 between the second transmission input pad Tx-T2 and the second transmission antenna pad Ant-T2, the parallel resonators P1-T2, P2-T2, P3-T2, and P4-T2 are arranged in the aforementioned order from near to far from the second transmission input pad Tx-T2. The series resonators S1-T2, S2-T2, S3-T2, S4-T2, S5-T2 and the parallel resonators P1-T2, P2-T2, P3-T2, P4-T2 function as a second transmit filter.

The second transmission input pad Tx-T2 serves as an input pad of the second transmission filter. The second transmitting antenna pad Ant-T2 serves as an output pad of the second transmitting filter. The second transmission ground pad GND-T2 serves as a ground pad of the second transmission filter.

Upon input of an electrical signal to the second transmission input pad Tx-T2, only the electrical signal of the transmission band corresponding to the band 3 passes through the series resonators S1-T2, S2-T2, S3-T2, S4-T2, S5-T2 and the parallel resonators P1-T2, P2-T2, P3-T2, P4-T2 entirely. Therefore, an electric signal of the transmission band corresponding to the band 3 is output from the second transmission antenna pad Ant-T2.

For example, the broadband attenuation circuit 23 is provided in a circuit of the second transmitting chip 5d. The wide band attenuation circuit 23 resonates in a frequency band between the second harmonic and the third harmonic of the fundamental wave of the frequency passed through the second transmission filter. For example, the broadband attenuation circuit 23 resonates between frequency bands between 3GHz and 7 GHz. For example, the broadband attenuation circuit 23 includes an inductance element 23a and a capacitance element 23b.

For example, the inductance element 23a has an inductance value of 0.5nH to 4.0 nH. Preferably, the inductance element 23a has an inductance value of 1.9 nH. For example, the capacitive element 23b has a capacitance value of 0.2pF to 2.0 pF. Preferably, the capacitive element 23b has a capacitance value of 0.52 pF.

One end of the inductance element 23a is electrically connected to the wiring pattern 21 at a position where two adjacent series resonators on the first half side counted from one side of the second transmission input pad Tx-T2 are electrically connected. Specifically, one end of the inductance element 23a is electrically connected to the wiring pattern 21 at a position where the first series resonator S1-T2 and the second series resonator S2-T2 are electrically connected from one side of the second transmission input pad Tx-T2.

One end of the capacitor element 23b is electrically connected to the other end of the inductor element 23 a. The other end of the capacitor element 23b is electrically connected to the second transmission ground pad GND-T2.

Next, the configuration of the broadband attenuation circuit 23 is described with reference to fig. 3 and 4.

Fig. 3 is a plan view of the first main surface of the second transmitting chip 5d in the first embodiment. Fig. 4 is a perspective view of the second main surface of the second transmitting chip 5d as viewed from the first main surface side in the first embodiment.

In the left outer edge of the chip board 20 in fig. 3, three second transmission ground pads GND-T2 are formed in the upper portion, the central portion, and the lower portion of the chip board 20, respectively.

The second transmitting antenna pad Ant-T2 is formed on the upper portion of the chip substrate 20 at the right outer edge of the chip substrate 20 in fig. 3. The second transmission ground pad GND-T2 is formed in the center portion of the chip board 20. The second transmission input pad Tx-T2 is formed at a lower portion of the chip substrate 20.

For example, the first via hole wiring 31a penetrates the chip substrate 20 near the second transmission input pad Tx-T2. One end of the first via wiring 31a is electrically connected to the wiring pattern 21 at a position where the first series resonator S1-T2 and the second series resonator S2-T2 are electrically connected from one side of the second transmission input pad Tx-T2.

For example, the second via wiring 31b penetrates the chip substrate 20 in the vicinity of the second transmission ground pad GND-T2 located in the left center portion. One end of the second via wiring 31b is electrically connected to the second transmitting ground pad GND-T2 located at the left center portion.

As shown in fig. 4, the inductance element 23a has a meandering portion 41a. The meandering portion 41a is formed on the lower side of the chip substrate 20 and extends back and forth between one side and the other side of the chip substrate 20. The inductance element 23a is formed in a metal pattern so that a desired inductance value can be obtained. One end of the inductance element 23a is electrically connected to the other end of the first via wiring 31 a.

As shown in fig. 4, the capacitor element 23b has a pair of comb-shaped portions 41b. The comb-shaped portions 41b face each other. The comb-shaped portion 41b is formed by a metal pattern, and a desired capacitance value can be obtained. The other end of the capacitor element 23b is electrically connected to the other end of the second via wiring 31 b.

Next, a first example of the elastic wave device 22 will be described with reference to fig. 5.

Fig. 5 shows a first example of acoustic wave element 22 to which acoustic wave device chip 5 is attached in the first embodiment.

Fig. 5 illustrates a case where the elastic wave element 22 is a surface acoustic wave resonator. As shown in fig. 5, an IDT (inter Transducer) 22a and a pair of reflectors 22b are formed on the first main surface of the chip substrate 20. One of the reflectors 22b abuts one of the sides of the IDT22 a. The other of the reflectors 22b is adjacent to the other side of the IDT22 a. The IDT22a and the reflectors 22b are provided so as to excite a surface acoustic wave.

For example, the IDT22a and the reflectors 22b are formed of an alloy of aluminum and copper. For example, the IDT22a and the reflectors 22b are formed of a suitable metal such as titanium, palladium, or silver, or an alloy thereof. For example, the IDT22a and the reflectors 22b may have a multilayer metal structure in which a plurality of metal layers are laminated. For example, the thickness of the IDT22a and the reflector 22b is 150nm to 400nm.

The IDT22a has a pair of comb electrodes 22c. The comb electrodes 22c are opposed to each other. The comb electrodes 22c each have a plurality of electrode fingers 22d and bus bars 22e. The electrode fingers 22d extend in the longitudinal direction. The bus bar 22e connects the electrode fingers 22d.

Next, a second example of the elastic wave device 22 will be described with reference to fig. 6.

Fig. 6 is a second example of acoustic wave device 22 in which acoustic wave device chip 5 is mounted in the first example.

Fig. 6 illustrates a case where the elastic wave element 22 is an acoustic thin film resonator. In fig. 6, the chip substrate 60 is a semiconductor substrate such as silicon, or an insulating substrate such as sapphire, alumina, spinel, or glass.

The chip substrate 60 is provided with a piezoelectric film 62. The material of the piezoelectric film 62 is, for example, aluminum nitride.

The lower electrode 64 and the upper electrode 66 sandwich the piezoelectric film 62 therebetween. The lower electrode 64 and the upper electrode 66 are made of metal such as ruthenium, for example.

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

The lower electrode 64 and the upper electrode 66 excite an elastic wave in a thickness longitudinal vibration mode in the piezoelectric film 62.

Next, the impedance characteristics of the second receiving chip 5c and the second transmitting chip 5d will be described with reference to fig. 7 to 9.

Fig. 7 to 9 are smith charts showing impedance characteristics of acoustic wave device 1 in which acoustic wave device chip 5 is mounted in the first embodiment and a comparative example.

Specifically, fig. 7 is a smith chart showing impedance characteristics observed from one side of the second receiving antenna pad Ant-R2 and the second transmitting antenna pad Ant-T2 of the elastic wave device mounted with the elastic wave device chip 5 in the first embodiment and the comparative example. Fig. 8 is a smith chart showing impedance characteristics observed from the elastic wave device mounted with the elastic wave device chip 5 in the first embodiment and one side of the second reception output pad Rx-R2 in the comparative example. Fig. 9 is a smith chart showing impedance characteristics observed from the elastic wave device mounted with the elastic wave device chip 5 in the first embodiment and one side of the second transmitting antenna pad Ant-T2 in the comparative example.

In fig. 7 to 9, a broken line a shows the impedance characteristic of a comparative example not provided with the broadband damping circuit 23. Solid line B shows the impedance characteristics of elastic wave device 1 of the first embodiment.

As shown in fig. 7 to 9, the dotted line a is not much different from the solid line B.

Next, the frequency characteristics of the second receiving chip 5c will be described with reference to fig. 10 to 12.

Fig. 10 to 12 are schematic diagrams showing simulation results of frequency characteristics of acoustic wave device 1 having acoustic wave device chip 5 mounted thereon according to the first embodiment and comparative examples.

Specifically, fig. 10 is a schematic diagram of the insertion loss of the second receiving chip 5c of the first embodiment and the insertion loss of the second receiving chip 5c of the comparative example, the insertion loss being represented by the attenuation (dB). Fig. 11 is a schematic diagram of the attenuation amount of the second receiving chip 5c of the first embodiment and the attenuation amount of the second receiving chip 5c of the comparative example. Fig. 12 is a schematic diagram showing the attenuation of the second receiving chip 5c of the first embodiment and the attenuation of the second receiving chip 5c of the comparative example, which are expanded to the third harmonic in the frequency range.

In fig. 10 to 12, a broken line C shows the frequency characteristics of the second receiving chip 5C of the comparative example in which the broadband damping circuit 23 is not provided. Solid line D shows the frequency characteristics of second receiving chip 5c of elastic wave device 1 according to the first embodiment.

As shown in fig. 10 to 12, the dotted line C is not much different from the solid line D.

Next, the frequency characteristics of the second transmitting chip 5d will be described with reference to fig. 13 to 15. Fig. 13 to 15 are schematic diagrams showing simulation results of frequency characteristics of acoustic wave device 1 having acoustic wave device chip 5 mounted thereon according to the first embodiment and a comparative example.

Specifically, fig. 13 is a schematic diagram of the insertion loss of the second transmitting chip 5d of the first embodiment and the insertion loss of the second transmitting chip 5d of the comparative example. Fig. 14 is a schematic diagram of the attenuation amount of the second transmitting chip 5d of the first embodiment and the attenuation amount of the second transmitting chip 5d of the comparative example. Fig. 15 is a schematic diagram showing the attenuation amount of the second transmitting chip 5d of the first embodiment and the attenuation amount of the second transmitting chip 5d of the comparative example being enlarged to the third harmonic in the frequency range.

In fig. 13 to 15, a broken line E shows the frequency characteristics of the second transmitting chip 5d of the comparative example in which the broadband damping circuit 23 is not provided. Solid line F shows the frequency characteristics of second transmitting chip 5d of elastic wave device 1 according to the first embodiment.

As shown in fig. 13, the frequency at which the attenuation of the dotted line E and the solid line F reaches 5.0dB is almost the same. As shown in the region W1, the width of the solid line F is about 1.2MHz greater than the width of the broken line E in the region where the attenuation amount is 3.0 dB. Thus, the transition width of the solid line F is improved by about 1.2MHz compared to the transition width of the dashed line E.

As shown in fig. 14, in the regions W2 and W3, the attenuation of the solid line F is improved by about 5.0dB as compared with the attenuation of the broken line E.

As shown in fig. 15, in the region W4 of the second harmonic, the attenuation of the solid line F is improved by about 4.0dB as compared with the attenuation of the broken line E. In the region W5 of the third harmonic, the attenuation of the solid line F is improved by about 7.0dB as compared with the attenuation of the broken line E.

Next, isolation characteristics between the second receiving chip 5c and the second transmitting chip 5d will be described with reference to fig. 16.

Fig. 16 is a diagram showing simulation results of isolation characteristics of acoustic wave device 1 in which acoustic wave device chip 5 is mounted in the first embodiment and a comparative example.

In fig. 16, a broken line G shows the isolation characteristic of the comparative example in which the broadband damping circuit 23 is not provided. Solid line H shows the isolation characteristic of elastic wave device 1 of the first embodiment.

As shown in fig. 16, in the reception band region W6 of the second reception filter, the solid line H is improved by about 5.0dB as compared with the broken line G.

According to the first embodiment, the broadband damping circuit 23 is electrically connected to the wiring pattern 21 through the first via wiring 31a at a position where two adjacent series resonators on the first half side counted from one side of the second transmission input pad Tx-T2 are electrically connected. Specifically, in n (n is an integer of 3 or more) series resonators, any two adjacent series resonators from the 1 st to the m th (m is an integer of more than 1 and less than n/2+ 1) counted from the second transmission input pad Tx-T2 side are electrically connected to the wiring pattern 21 through the first via wiring 31 a. Therefore, the filter characteristics of the second transmission chip 5d can be improved, and the second transmission chip 5d can be miniaturized.

For example, the broadband attenuation circuit 23 is electrically connected to the wiring pattern 21 at a position where the first series resonator S1 to T2 and the second series resonator S2 to T2 are electrically connected from one side of the second transmission input pad Tx to T2. Therefore, the filter characteristics of the second transmitting chip 5d can be surely improved.

The wide band attenuation circuit 23 is provided in the second transmitting chip 5d. Therefore, the heat dissipation of the second transmitting chip 5d serving as the second transmitting filter can be improved. Therefore, the voltage resistance of the second transmitting chip 5d can be improved.

The broadband damping circuit 23 is electrically connected to the second transmission ground pad GND-T2 through the second via wiring 31 b. Therefore, the filter characteristics of the second transmitting chip 5d can be surely improved.

The wide band attenuation circuit 23 resonates in a frequency band between the second harmonic and the third harmonic of the fundamental wave of the frequency of the second transmission filter. Therefore, the filter characteristics of the second transmitting chip 5d can be improved reliably.

The wide band attenuation circuit 23 resonates between frequency bands of 3GHz to 7 GHz. Therefore, the filter characteristics of the second transmitting chip 5d can be improved reliably.

The broadband attenuation circuit 23 includes the inductance element 23a and a capacitance element 23b. With a simple structure, the filter characteristics of the second transmitting chip 5d can be improved.

And, the inductance element 23a has an inductance value of 0.5nH to 4.0 nH. The capacitive element 23b has a capacitance value of 0.2pF to 2.0 pF. Therefore, the filter characteristics of the second transmitting chip 5d can be improved reliably.

The broadband damping circuit 23 may be provided in one of the first receiving chip 5a, the first transmitting chip 5b, and the second receiving chip 5c, in the acoustic wave device chip 5. In this case, the filter characteristics of the acoustic wave device chip 5 can be improved, and the acoustic wave device chip 5 can be miniaturized.

One of the acoustic wave device chips 5 may have functions of the first reception filter and the first transmission filter as a duplexer. One of the acoustic wave device chips 5 may have functions of the second reception filter and the second transmission filter as a duplexer. As a quadruplex, one of the elastic wave device chips 5 may have functions of the first receiving filter, the first transmitting filter, the second receiving filter, and the second transmitting filter.

All of the series resonators and the parallel resonators may be used as a band pass filter.

In addition, when the capacitor element 23b is formed by a metal pattern, parasitic capacitance is generated by air in a gap of the metal pattern or resin of the sealing portion 17.

Here, lithium tantalate as the chip substrate 20 had a relative dielectric constant of 40, a relative dielectric constant of 1 in air, and a relative dielectric constant of 3.6 in resin. Therefore, the capacitance generated by lithium tantalate is dominant, and the capacitance generated by air and resin is within the error range.

For example, in the case where the total capacitance generated by air is 0.52pF, the capacitance generated by lithium tantalate is 0.5pF, and the capacitance generated by air is 0.02pF. For example, in the case where the total capacitance generated by the resin is 0.52pF, the capacitance generated by lithium tantalate is 0.47pF, and the capacitance generated by the resin is 0.05pF.

Thereby, even if the resin enters the gaps of the metal patterns of the capacitance element 23b, the variation in the parasitic capacitance is very small. Therefore, by adjusting the metal pattern and considering the size of the parasitic capacitance, a desired capacitance value can be obtained in a desired frequency range.

In addition, the metal pattern of the inductance element 23a can obtain a desired inductance value in a desired frequency range with the same idea.

The broadband damping circuit 23 may be covered with resin before the wafer is diced into the acoustic wave device chips 5. This makes it possible to perform singulation processing on the elastic wave device chip 5 while protecting the broadband attenuation circuit 23. When the acoustic wave device chip 5 is bonded to the wiring substrate 3 by a flip chip bonding process, the second main surface of the acoustic wave device chip 5 on which the broadband damping circuit 23 is formed can be grasped and ultrasonically bonded. In this case, when the flip chip bonding process is performed by the ultrasonic bonding method, the resin covering the wide band attenuation circuit 23 is preferably a resin having a hardness enough to protect the wide band attenuation circuit 23.

Next, a variation of the elastic wave device 1 will be described with reference to fig. 17.

Fig. 17 is a cross-sectional view of a modified example of acoustic wave device 1 in which acoustic wave device chip 5 is mounted in the first embodiment.

As shown in fig. 17, the chip substrate 20 includes a piezoelectric substrate 20a and a support substrate 20b. For example, the piezoelectric substrate 20a is made of lithium tantalate or lithium niobate. The support substrate 20b is made of, for example, sapphire, silicon, alumina, spinel, crystal, or glass. The support substrate 20b is bonded to the upper surface of the piezoelectric substrate 20 a.

The wiring pattern 21 is formed on the lower surface of the piezoelectric substrate 20 a. The elastic wave element 22 is formed on the lower surface of the piezoelectric substrate 20 a. The broadband attenuation circuit 23 is formed on the upper surface of the support substrate 20b.

According to the modification, the chip substrate 20 has the piezoelectric substrate 20a and the supporting substrate 20b, so that the heat dissipation of the chip substrate 20 is improved. Therefore, the voltage resistance of the chip substrate 20 can be improved.

(second embodiment)

Fig. 18 is a sectional view of a module including an acoustic wave device mounted with the acoustic wave device chip in the second embodiment. It should be understood that the same or equivalent parts as those of the first embodiment are given the same reference numerals. The same or equivalent portions will be omitted from the description.

In fig. 18, module 100 includes wiring board 130, integrated circuit module IC, elastic wave device 1, integrated circuit 111, and sealing portion 117.

The wiring substrate 130 is the same as the wiring substrate 3 in the first embodiment.

The integrated circuit module IC is mounted on the wiring board 130. The integrated circuit assembly IC comprises a switching circuit and a low noise amplifier.

The acoustic wave device 1 is mounted on a main surface of the wiring board 130.

The integrated circuit 111 is mounted on a main surface of the wiring board 130. The integrated circuit 111 is mounted for impedance matching. For example, the Integrated circuit 111 is an Integrated Passive Device (IPD).

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

Next, the integrated circuit 111 is described with reference to fig. 19.

As shown in fig. 19, the module 100 includes a first receiving end P-R1, a first transmitting end P-T1, a second receiving end P-R2, a second transmitting end P-T2, and an antenna end P-Ant.

The first receiving terminal P-R1 is electrically connected to the first receiving output pad Rx-R1. The first transmitting terminal P-T1 is electrically connected to the first transmitting input pad Tx-T1. The second receiving terminal P-R2 is electrically connected to the second receiving output pad Rx-R2. The second transmitting terminal P-T2 is electrically connected to the second transmitting input pad Tx-T2. The antenna end P-Ant is electrically connected to the first receiving antenna pad Ant-R1, the first transmitting antenna pad Ant-T1, the second receiving antenna pad Ant-R2, and the second transmitting antenna pad Ant-T2.

The integrated circuit 111 includes a series inductance element 111a, a parallel inductance element 111b, and a termination impedance 111c.

One end of the series inductance element 111a is electrically connected to the second transmission input pad Tx-T2. The other end of the series inductance element 111a is electrically connected to the second transmitting terminal P-T2. For example, the series inductance element 111a has an inductance value of 0.5nH to 10 nH. Preferably, the series inductance element 111a has an inductance value of 5 nH.

One end of the parallel inductance element 111b is electrically connected to a wiring between the series inductance element 111a and the second transmission input pad Tx-T2. The other end of the parallel inductance element 111b is grounded. For example, the parallel inductance element 111b has an inductance value of 5nH to 50 nH. Preferably, the parallel inductance element 111b has an inductance of 25 nH.

One end of the termination impedance 111c is electrically connected to a wiring between the other end of the series inductance element 111a and the second transmitting terminal P-T2. The other end of the termination impedance 111c is grounded. The termination impedance 111c has an impedance value designed to suppress reflection of the output signal at the second transmitting end P-T2. For example, the termination impedance 111c is 50 Ω.

According to the second embodiment, the module 100 includes the elastic wave device 1 of the first embodiment. Therefore, the filter characteristics of the module 100 can be improved, and miniaturization of the module 100 can be achieved.

Also, the module 100 includes the integrated circuit 111. Therefore, impedance matching of the module 100 can be achieved surely.

And, the series inductance element 111a has an inductance value of 0.5nH to 10 nH. The parallel inductance element 111b has an inductance value of 5nH to 50 nH. Therefore, impedance matching of the module 100 can be achieved surely.

While at least one embodiment has been described above, it is to be understood that various changes, modifications or 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 the disclosure.

It is to be understood that the aspects of the method or apparatus described herein are not limited in their application to the details of construction and the arrangements of the components set forth in the above description or illustrated in the drawings. The methods and apparatus may be practiced in other embodiments or with other embodiments.

The examples are given by way of illustration only and not by way of limitation.

The description or words used in this disclosure are words of description rather than limitation. The use of "including," "comprising," "having," "containing," and variations thereof herein, is meant to encompass the items listed thereafter and equivalents thereof as well as additional items.

The use of the term "or any other term in the description using the term" or "may be interpreted to mean one, more than one, or all of the recited term.

Front, back, left, right, top, bottom, up, down, and horizontal and vertical references are for convenience of description and do not limit the position and spatial configuration of any of the components of the present invention. Accordingly, the foregoing description and drawings are by way of example only.

Claims

1. An elastic wave device chip characterized in that: the elastic wave device chip includes:

a chip substrate;

a plurality of parallel resonators formed on the first main surface of the chip substrate;

an input pad formed on a first main surface of the chip substrate;

an output pad formed on the first main surface of the chip substrate;

a ground pad formed on the first main surface of the chip substrate;

a first via wiring penetrating the chip substrate; and

and a broadband damping circuit formed on a second main surface of the chip substrate opposite to the first main surface, one end of the broadband damping circuit being electrically connected to the wiring pattern through the first via wiring at a position where two adjacent series resonators in a front half of the chip substrate counted from one side of the input pad are electrically connected.

2. The elastic wave device chip according to claim 1, wherein: the broadband attenuation circuit is electrically connected to the wiring pattern through the first via wiring at a position where a first series resonator and a second series resonator counted from one side of the input pad are electrically connected.

3. The elastic wave device chip according to claim 2, wherein: the series resonator and the parallel resonator function as a transmission filter.

4. The elastic wave device chip according to any one of claims 1 to 3, wherein: the elastic wave device chip further comprises a second through hole wiring penetrating through the chip substrate, and the other end of the broadband attenuation circuit is electrically connected with the grounding welding pad through the second through hole wiring.

5. The elastic wave device chip according to any one of claims 1 to 3, wherein: the wide band attenuation circuit resonates in a frequency band between a second harmonic and a third harmonic of a fundamental wave corresponding to a frequency of the elastic wave filter when the series resonator and the parallel resonator are used as the elastic wave filter.

6. The acoustic wave device chip according to any one of claims 1 to 3, wherein: the broadband attenuator circuit resonates in a frequency band between 3GHz and 7 GHz.

7. The elastic wave device chip according to any one of claims 1 to 3, wherein: the broadband attenuation circuit comprises an inductance element and a capacitance element.

8. The elastic wave device chip according to claim 7, wherein: the inductance element has an inductance value of 0.5nH to 4.0nH, and the capacitance element has a capacitance value of 0.2pF to 2.0 pF.

9. The acoustic wave device chip according to any one of claims 1 to 3, wherein: the chip substrate includes a piezoelectric substrate, and a support substrate made of sapphire, silicon, alumina, spinel, crystal, or glass and bonded to the piezoelectric substrate.

10. The elastic wave device chip according to any one of claims 1 to 3, wherein: the series resonator and the parallel resonator are each a surface acoustic wave resonator, respectively, and the series resonator and the parallel resonator collectively function as a band pass filter or a duplexer.

11. The acoustic wave device chip according to any one of claims 1 to 3, wherein: the series resonator and the parallel resonator are each an acoustic thin film resonator, respectively, and the series resonator and the parallel resonator collectively function as a band pass filter or a duplexer.

12. An elastic wave device characterized by: the elastic wave device includes: the acoustic wave device chip according to any one of claims 1 to 11, and a wiring substrate electrically connected to the acoustic wave device chip.

13. A module, characterized by: the module comprises: the elastic wave device chip according to any one of claims 1 to 11, or the elastic wave device according to claim 12.

14. The module of claim 13, wherein: the module also includes an integrated circuit electrically connected to the input pad.

15. The module of claim 14, wherein: the integrated circuit includes a series inductance element having an inductance value of 0.5nH to 10nH, and a parallel inductance element having an inductance value of 5nH to 50 nH.