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WO2018117059A1 - Résonateur à ondes acoustiques, dispositif de filtre et multiplexeur - Google Patents

Résonateur à ondes acoustiques, dispositif de filtre et multiplexeur Download PDF

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Publication number
WO2018117059A1
WO2018117059A1 PCT/JP2017/045401 JP2017045401W WO2018117059A1 WO 2018117059 A1 WO2018117059 A1 WO 2018117059A1 JP 2017045401 W JP2017045401 W JP 2017045401W WO 2018117059 A1 WO2018117059 A1 WO 2018117059A1
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Prior art keywords
reflector
bus bar
comb
electrode
idt electrode
Prior art date
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Ceased
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PCT/JP2017/045401
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English (en)
Japanese (ja)
Inventor
明雄 金田
普一 中村
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Murata Manufacturing Co Ltd
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Murata Manufacturing Co Ltd
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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00—Networks comprising electromechanical or electro-acoustic elements; Electromechanical resonators
    • H03H9/02—Details
    • H03H9/125—Driving means, e.g. electrodes, coils
    • H03H9/145—Driving means, e.g. electrodes, coils for networks using surface acoustic waves
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00—Networks comprising electromechanical or electro-acoustic elements; Electromechanical resonators
    • H03H9/46—Filters
    • H03H9/64—Filters using surface acoustic waves
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00—Networks comprising electromechanical or electro-acoustic elements; Electromechanical resonators
    • H03H9/70—Multiple-port networks for connecting several sources or loads, working on different frequencies or frequency bands, to a common load or source
    • H03H9/72—Networks using surface acoustic waves

Definitions

  • the present invention relates to an elastic wave resonator having an IDT (InterDigital Transducer) electrode and a reflector, and a filter device and a multiplexer including the elastic wave resonator.
  • IDT InterDigital Transducer
  • a filter device composed of a plurality of acoustic wave resonators has been put into practical use for a band-pass filter or the like disposed in a front end portion of a mobile communication device.
  • FIG. 4 of Patent Document 1 includes two IDT electrodes arranged in parallel so as to have the same acoustic wave propagation direction, and an acoustic wave propagation direction.
  • An acoustic wave resonator is disclosed that includes one reflector disposed between two IDT electrodes and a plurality of reflectors disposed outside the two IDT electrodes.
  • one reflector disposed between two IDT electrodes is shared by the two IDT electrodes, thereby downsizing the acoustic wave resonator.
  • the present invention has been made to solve the above-described problems, and an object thereof is to provide an elastic wave resonator or the like having a small insertion loss and excellent steepness.
  • an acoustic wave resonator is an IDT electrode having a piezoelectric substrate and a pair of comb-like electrodes facing each other, and is provided on the piezoelectric substrate.
  • a first IDT electrode and a second IDT electrode disposed along a predetermined direction; and a shared reflector provided on the piezoelectric substrate and disposed between the first IDT electrode and the second IDT electrode in the predetermined direction.
  • the shared reflector has one reflector bus bar and the other reflector bus bar extending in the predetermined direction and facing each other in a direction orthogonal to the predetermined direction, and each of the first IDT electrode and the second IDT electrode Has one comb tooth bus bar and the other comb tooth bus bar extending in the predetermined direction and facing each other in the orthogonal direction, and the other comb tooth bar of the first IDT electrode. And a bar, and the other reflector busbar of the common reflector, and the other comb busbar of the first 2IDT electrode is disposed along the predetermined direction, are connected.
  • the first IDT electrode and the second IDT electrode are connected by using the other comb-tooth busbar of the first IDT electrode, the other reflector busbar, and the other comb-tooth busbar of the second IDT electrode.
  • the voltage applied to each of the 1 IDT electrode and the second IDT electrode can be reduced.
  • the first IDT electrode and the second IDT electrode are connected using the other comb-shaped bus bar, the other reflector bus bar, and the other comb-shaped bus bar described above, the first IDT electrode and the second IDT electrode are connected to each other.
  • the electrical resistance for connection can be reduced. Thereby, the insertion loss of the acoustic wave resonator can be reduced.
  • the other comb-tooth bus bar of the first IDT electrode and the other reflector bus bar of the shared reflector are a first connection located between the other comb-tooth bus bar and the other reflector bus bar.
  • the second reflector bus bar and the other comb bus bar of the second IDT electrode, which are connected via an electrode, are located between the other reflector bus bar and the other comb bus bar. It may be connected via an electrode.
  • a first input / output wiring is connected to the one comb tooth bus bar of the first IDT electrode
  • a second input / output wiring is connected to the one comb tooth bus bar of the second IDT electrode
  • the first input / output wiring is connected.
  • the first IDT electrode and the second IDT electrode may be connected in series in a path connecting the first input / output wiring and the second input / output wiring.
  • the electrical resistance can be reduced while connecting the first IDT electrode and the second IDT electrode in series in the path connecting the first input / output wiring and the second input / output wiring.
  • the insertion loss of the acoustic wave resonator can be reduced.
  • a second reflector provided on the opposite side of the shared reflector as viewed from the second IDT electrode in a direction, each of the first reflector and the second reflector extending in the predetermined direction and One reflector bus bar and the other reflector bus bar facing each other in the orthogonal direction, and the other reflector bus bar of the first reflector and the other comb-tooth bus bar of the first IDT electrode are the predetermined Arranged along the direction and connected to each other, and / or the other comb bus bar of the second IDT electrode and the other reflector bus bar of the second reflector Are arranged along the direction, they may be connected to each other.
  • one reflector bus bar of the first reflector and one comb tooth bus bar of the first IDT electrode face each other with different potentials, so that capacitance is added to the acoustic wave resonator.
  • one comb-shaped bus bar of the second IDT electrode and one reflector bus bar of the second reflector face each other with different potentials, capacitance is added to the acoustic wave resonator.
  • the steepness in the passband of the acoustic wave resonator can be improved.
  • a counter electrode may be provided, and the first counter electrode may be connected to a ground.
  • an insulating layer is provided on the one reflector bus bar of the shared reflector and on the one comb-shaped bus bar of each of the first IDT electrode and the second IDT electrode, and on the insulating layer
  • a second counter electrode facing the one reflector bus bar and the one comb-tooth bus bar may be provided, and the second counter electrode may be connected to the ground.
  • a filter device is a ladder-type filter device including one or more series arm resonators and one or more parallel arm resonators, and the series arm resonators At least one of the parallel arm resonators may include the elastic wave resonator described above.
  • the filter device by configuring the filter device with an acoustic wave resonator having a small insertion loss, the insertion loss in the pass band of the filter device can be reduced.
  • the steepness in the pass band of the filter device can be improved.
  • a filter device is a ladder-type filter device including one or more series arm resonators and one or more parallel arm resonators, and the series arm resonators May include the elastic wave resonator.
  • the insertion loss in the pass band of the filter device can be reduced by configuring the series arm resonator of the filter device with an acoustic wave resonator having a small insertion loss.
  • the IDT electrodes of the acoustic wave resonator are divided into two and connected in series, even if a large voltage is applied to the series arm resonator, the applied voltage is applied to the two IDT electrodes ( Since the first IDT electrode and the second IDT electrode can be dispersed, deterioration of electrical characteristics can be suppressed.
  • the steepness in the pass band of the filter device can be improved.
  • a multiplexer may include the above filter device.
  • the insertion loss in the pass band of the multiplexer can be reduced.
  • the insertion loss of the acoustic wave resonator can be reduced. Further, the insertion loss in the pass band of the filter device and the multiplexer can be reduced.
  • FIG. 1 is a circuit configuration diagram of a multiplexer and a filter device using the acoustic wave resonator according to the first embodiment.
  • 2A and 2B are diagrams illustrating the acoustic wave resonator according to the first embodiment, in which FIG. 2A is a plan view and FIG. 2B is a cross-sectional view taken along the line IIB-IIB shown in FIG.
  • FIG. 3 is an equivalent circuit of the acoustic wave resonator according to the first embodiment.
  • FIG. 4 is a plan view showing an acoustic wave resonator in a comparative example.
  • FIG. 5 is a diagram showing insertion loss of the filter device in the first embodiment and the comparative example.
  • FIG. 6 is a diagram illustrating the insertion loss of the multiplexer in the first embodiment and the comparative example.
  • FIG. 7 is a plan view illustrating an acoustic wave resonator according to the second embodiment.
  • FIG. 8 is an equivalent circuit of the acoustic wave resonator according to the second embodiment.
  • FIG. 9 is a diagram showing insertion loss of the acoustic wave resonator in the second embodiment and the comparative example.
  • FIG. 10 is a diagram illustrating the insertion loss of the filter device in the second embodiment and the comparative example.
  • FIG. 11 is a diagram illustrating the frequency characteristics of the multiplexer according to the second embodiment and the comparative example, where (a) is an insertion loss and (b) is a diagram illustrating an isolation characteristic.
  • FIG. 12 is a plan view illustrating an acoustic wave resonator according to the third embodiment.
  • FIG. 13 is an equivalent circuit of the acoustic wave resonator according to the third embodiment.
  • 14A and 14B are diagrams illustrating an acoustic wave resonator according to the fourth embodiment, in which FIG. 14A is a plan view and FIG. 14B is a cross-sectional view taken along line XIVB-XIVB shown in FIG.
  • FIG. 15 is an equivalent circuit of the acoustic wave resonator according to the fourth embodiment.
  • the multiplexer and filter device according to the present embodiment are used for communication devices such as mobile phones.
  • a duplexer of Band 5 transmission pass band: 824 to 849 MHz, reception pass band: 869 to 894 MHz
  • transmission pass band: 824 to 849 MHz reception pass band: 869 to 894 MHz
  • FIG. 1 is a circuit configuration diagram of the multiplexer 1 according to the first embodiment.
  • the multiplexer 1 includes a transmission filter 7 that is one filter device, a reception filter 8 that is the other filter device, an input / output terminal 6a on the antenna side, and an input / output terminal on the transmitter side. 6b and an input / output terminal 6c on the receiver side.
  • the transmission filter 7 and the reception filter 8 are connected to the input / output terminal 6a on the antenna side by bundling respective lead wires.
  • the transmission filter 7 is a band pass filter that filters the transmission wave input from the input / output terminal 6b on the transmitter side in each transmission pass band and outputs it to the input / output terminal 6a on the antenna side.
  • the reception filter 8 is a band pass filter that filters the received wave input from the input / output terminal 6a on the antenna side in each reception pass band and outputs it to the input / output terminal 6c on the receiver side.
  • the transmission filter 7 is a ladder-type filter, and series arm resonators 2a, 2b, 2c, 2d provided on a path connecting the input / output terminal 6a on the antenna side and the input / output terminal 6b on the transmitter side, and Parallel arm resonators 3a, 3b, and 3c are connected between a connection path from the series arm resonator 2a to the series arm resonator 2d and a reference terminal (ground).
  • the reception filter 8 includes a series resonator 4 and a longitudinally coupled acoustic wave filter unit 5 provided on a path connecting the input / output terminal 6a on the antenna side and the input / output terminal 6c on the receiver side.
  • the elastic wave resonator 10 is included in the series arm resonator 2b of the transmission filter 7, for example.
  • the acoustic wave resonator 10 may be included in at least one of the series arm resonators 2 a to 2 d in the transmission filter 7 or in the series resonator 4 in the reception filter 8.
  • the elastic wave resonator 10 may be included in the parallel arm resonators 3 a to 3 d of the transmission filter 7 or may be included in the resonators 5 a and 5 b of the longitudinally coupled elastic wave filter unit 5. .
  • the configuration of the acoustic wave resonator 10 will be described.
  • FIG. 2A and 2B are diagrams illustrating the acoustic wave resonator 10 according to the first embodiment, in which FIG. 2A is a plan view and FIG. 2B is a cross-sectional view taken along the line IIB-IIB shown in FIG. FIG. 3 is an equivalent circuit of the acoustic wave resonator 10.
  • the acoustic wave resonator 10 is sometimes referred to as a piezoelectric substrate 90, and a first IDT electrode 11 and a second IDT electrode 22 (hereinafter referred to as IDT electrode 11 and IDT electrode 22) provided on the piezoelectric substrate 90.
  • the piezoelectric substrate 90 is made of, for example, LiTaO 3 piezoelectric single crystal, LiNbO 3 piezoelectric single crystal, or piezoelectric ceramic having a predetermined cut angle.
  • the cross-sectional structures of the IDT electrodes 11 and 22, the shared reflector 30, the first reflector 31, and the second reflector 32 will be described.
  • the IDT electrodes 11 and 22 have a laminated structure of an adhesion layer 91 and a main electrode layer 92 provided on the adhesion layer 91.
  • the first reflector 31, the shared reflector 30, and the second reflector 32 have a laminated structure of the adhesion layer 91 and the main electrode layer 92, similarly to the IDT electrodes 11 and 22.
  • the adhesion layer 91 is a layer for improving the adhesion between the piezoelectric substrate 90 and the main electrode layer 92, and, for example, Ti is used as a material.
  • the film thickness of the adhesion layer 91 is, for example, 12 nm.
  • the main electrode layer 92 is made of, for example, Al containing 1% Cu.
  • the film thickness of the main electrode layer 92 is, for example, 162 nm.
  • the protective layer 93 is formed so as to cover the IDT electrodes 11 and 22.
  • the protective layer 93 is a layer for the purpose of protecting the main electrode layer 92 from the external environment, adjusting frequency temperature characteristics, and improving moisture resistance, for example, a film containing silicon dioxide as a main component. .
  • a first input / output wiring 41, a second input / output wiring 42, a first connection electrode 51, and a second connection electrode 52 are provided on the piezoelectric substrate 90.
  • the IDT electrodes 11 and 22 are arranged along a predetermined direction D1.
  • the IDT electrode 11 is composed of a pair of comb-like electrodes 11a and 11b facing each other.
  • the IDT electrode 22 is composed of a pair of comb-like electrodes 22a and 22b facing each other.
  • the predetermined direction D1 in the present embodiment is the same direction as the elastic wave propagation direction.
  • the predetermined direction D1 is not limited to the same direction as the elastic wave propagation direction, and may be a direction slightly inclined with respect to the elastic wave propagation direction.
  • the plus side of the orthogonal direction D2 orthogonal to the predetermined direction D1 is referred to as one and the minus side of the orthogonal direction D2 is referred to as the other.
  • One comb-shaped electrode 11a of the IDT electrode 11 includes one comb-shaped bus bar 15a extending in a predetermined direction D1, a cross electrode finger 16 and an offset electrode connected to the comb-shaped bus bar 15a and extending in the orthogonal direction D2 (minus side). And a finger 17.
  • the other comb-shaped electrode 11b of the IDT electrode 11 includes the other comb-shaped bus bar 15b extending in the predetermined direction D1, the cross electrode finger 16 connected to the comb-shaped bus bar 15b and extending in the orthogonal direction D2 (plus side) and the offset electrode. And a finger 17.
  • One comb-shaped electrode 22a of the IDT electrode 22 includes one comb-shaped bus bar 25a extending in a predetermined direction D1, a cross electrode finger 26 connected to the comb-shaped bus bar 25a and extending in the orthogonal direction D2 (minus side), and an offset electrode.
  • the other comb-shaped electrode 22b of the IDT electrode 22 includes the other comb-shaped bus bar 25b extending in a predetermined direction D1, a cross electrode finger 26 connected to the comb-shaped bus bar 25b and extending in the orthogonal direction D2 (plus side), and an offset electrode. Finger 27.
  • the cross electrode fingers 16 and 26 cross each other as seen from the predetermined direction D1.
  • the offset electrode fingers 17 are shorter than the cross electrode fingers 16 and are disposed so as to face the cross electrode fingers 16 in the orthogonal direction D2.
  • the offset electrode finger 27 is shorter than the cross electrode finger 26 and is disposed to face the cross electrode finger 26 in the orthogonal direction D2.
  • the wavelength of the acoustic wave resonator 10 is defined by the repetition pitch ⁇ of the cross electrode fingers 16 and 26 in the predetermined direction D1.
  • One comb-shaped bus bar 15a, 25a and the other comb-shaped bus bar 15b, 25b are wider than the cross electrode fingers 16, 26 and the offset electrode fingers 17, 27 in order to reduce the electric resistance, and the thickness is also large. It is formed to be thick.
  • the first input / output wiring 41 is connected to one comb-tooth bus bar 15 a of the IDT electrode 11, and the second input / output wiring 42 is connected to one comb-tooth bus bar 25 a of the IDT electrode 22.
  • the common reflector 30 is disposed between the IDT electrode 11 and the IDT electrode 22 in the predetermined direction D1.
  • the shared reflector 30 is one reflector that is commonly used by the IDT electrodes 11 and 22.
  • the shared reflector 30 has one reflector bus bar 30a, the other reflector bus bar 30b, and a plurality of reflective electrode fingers 30c.
  • Each of the reflector bus bars 30a and 30b is disposed so as to extend in a predetermined direction D1 and to face each other in the orthogonal direction D2.
  • Each of the plurality of reflective electrode fingers 30c is connected to each of the reflector bus bars 30a and 30b and arranged to extend in the orthogonal direction D2.
  • the plurality of reflective electrode fingers 30c are arranged to be parallel to each other at a predetermined interval in the predetermined direction D1.
  • the first reflector 31 is provided on the side opposite to the shared reflector 30 when viewed from the IDT electrode 11 in the predetermined direction D1.
  • the first reflector 31 has one reflector bus bar 31a, the other reflector bus bar 31b, and a plurality of reflective electrode fingers 31c.
  • Each of the reflector bus bars 31a and 31b is disposed so as to extend in the predetermined direction D1 and to face each other in the orthogonal direction D2.
  • Each of the plurality of reflective electrode fingers 31c is connected to the reflector bus bars 31a and 31b and arranged to extend in the orthogonal direction D2.
  • the plurality of reflective electrode fingers 31c are arranged in parallel to each other at a predetermined interval in the predetermined direction D1.
  • the second reflector 32 is provided on the side opposite to the shared reflector 30 when viewed from the IDT electrode 22 in the predetermined direction D1.
  • the second reflector 32 has one reflector bus bar 32a, the other reflector bus bar 32b, and a plurality of reflective electrode fingers 32c.
  • Each of the reflector bus bars 32a and 32b is disposed so as to extend in the predetermined direction D1 and to face each other in the orthogonal direction D2.
  • Each of the plurality of reflective electrode fingers 32c is connected to the reflector bus bars 32a and 32b and arranged to extend in the orthogonal direction D2.
  • the plurality of reflective electrode fingers 32c are arranged to be parallel to each other with a predetermined interval in the predetermined direction D1.
  • the reflector bus bars 30a, 30b, 31a, 31b, 32a, and 32b are formed to be wider and thicker than the reflective electrode fingers 30c, 31c, and 32c in order to reduce electrical resistance. .
  • the other comb-shaped bus bar 15b, the other reflector bus bar 30b, and the other comb-shaped bus bar 25b are arranged and connected along the predetermined direction D1.
  • a first connection electrode 51 is provided between the other comb bus bar 15b and the other reflector bus bar 30b, and between the other reflector bus bar 30b and the other comb bus bar 25b.
  • the second connection electrode 52 is provided.
  • the first connection electrode 51 connects the comb bus bar 15b and the reflector bus bar 30b
  • the second connection electrode 52 connects the reflector bus bar 30b and the comb bus bar 25b.
  • connection electrodes 51 and 52 are the same as the widths of the comb-tooth bus bars 15b and 25b and the reflector bus bar 30b.
  • the thicknesses of the connection electrodes 51 and 52 are comb-tooth bus bars 15b and 25b and the reflector bus bar, respectively. It is the same as the thickness of 30b. That is, the comb-tooth bus bar 15b, the connection electrode 51, the reflector bus bar 30b, the connection electrode 52, and the comb-tooth bus bar 25b are integrally formed linearly along the predetermined direction D1.
  • the connection electrodes 51 and 52 are formed by the same process (for example, lift-off method) as the comb-tooth bus bars 15b and 25b and the reflector bus bar 30b, and have the same laminated structure.
  • the acoustic wave resonator 10 includes the IDT electrode 11 and the IDT electrode 22 in the path connecting the first input / output wiring 41 and the second input / output wiring 42, the first connection electrode 51, the reflector bus bar 30 b,
  • the second connection electrode 52 is connected in series. Since the IDT electrodes 11 and 22 are connected in series, the voltage applied to each of the IDT electrodes 11 and 22 can be reduced. Further, the IDT electrodes 11 and 22 are wider than the electrode fingers 16, 17, 26, and 27, and the comb bus bar 15 b, the first connection electrode 51, the reflector bus bar 30 b, the second connection electrode 52, and the comb are thick. Since it connects using the tooth bus bar 25b, the electrical resistance for connecting the IDT electrodes 11 and 22 can be made small. Thereby, the insertion loss of the acoustic wave resonator 10 can be reduced.
  • the acoustic wave resonator 10 has capacitors C1 and C2 corresponding to the respective acoustic wave elements F1 and F2 formed of the IDT electrodes 11 and 22 (see FIG. 3).
  • the capacitor C1 includes one comb-shaped bus bar 15a and one reflector bus bar 30a, which are located on the opposite side of the comb-shaped bus bar 15b and the reflector bus bar 30b connected by the first connection electrode 51. They are formed by facing each other with different potentials.
  • one reflector bus bar 30a and one comb bus bar 25a which are located on opposite sides of the reflector bus bar 30b and the comb bus bar 25b connected by the second connection electrode 52, face each other with different potentials. Is formed.
  • the acoustic wave resonator 10 has the capacitors C1 and C2, the steepness in the pass band of the acoustic wave resonator 10 can be improved.
  • the acoustic wave resonator 10 includes a piezoelectric substrate 90, an IDT electrode 11 having a pair of comb-like electrodes 11a and 11b facing each other, and an IDT having a pair of comb-like electrodes 22a and 22b.
  • the electrode 22 is provided on the piezoelectric substrate 90 and disposed along the predetermined direction D1, and the IDT electrode 11 and the IDT electrode 22 are provided on the piezoelectric substrate 90, and the IDT electrode 11 and the IDT electrode in the predetermined direction D1. 22 and a common reflector 30 disposed between them.
  • the shared reflector 30 has one reflector bus bar 30a and the other reflector bus bar 30b extending in the predetermined direction D1 and facing each other in the orthogonal direction D2 of the predetermined direction D1.
  • the IDT electrode 11 has one comb-tooth bus bar 15a and the other comb-tooth bus bar 15b extending in the predetermined direction D1 and facing each other in the orthogonal direction D2.
  • the IDT electrode 22 has one comb-tooth bus bar 25a and the other comb-tooth bus bar 25b extending in the predetermined direction D1 and facing each other in the orthogonal direction D2.
  • the other comb-tooth bus bar 15b of the IDT electrode 11, the other reflector bus bar 30b, and the other comb-tooth bus bar 25b of the IDT electrode 22 are arranged and connected along a predetermined direction D1.
  • the IDT electrodes 11 and 22 are connected in series using the comb-tooth bus bar 15b, the reflector bus bar 30b, and the comb-tooth bus bar 25b, the voltage applied to the IDT electrodes 11 and 22 can be reduced. Can do. Moreover, since the IDT electrodes 11 and 22 are connected using the comb-tooth bus bar 15b, the reflector bus bar 30b, and the comb-tooth bus bar 25b, the electrical resistance for connecting the IDT electrodes 11 and 22 can be reduced. . Thereby, the insertion loss of the acoustic wave resonator 10 can be reduced.
  • the acoustic wave resonator 510 in the comparative example will be described as an example.
  • FIG. 4 is a plan view showing an acoustic wave resonator 510 in a comparative example.
  • the second connection electrode 52 connects one reflector bus bar 30a and one comb-tooth bus bar 25a, and the second input / output wiring 42 is connected to the other comb-tooth bus bar 25b. This is different from the elastic wave resonator 10 of the first embodiment.
  • the IDT electrode 11 and the IDT electrode 22 are connected in series via the reflective electrode fingers 30 c of the shared reflector 30.
  • the IDT electrodes 11 and 22 include the other comb-shaped bus bar 15b, the first connection electrode 51, the other reflector bus bar 30b, the reflection electrode finger 30c, the one reflector bus bar 30a, the second connection electrode 52, and the like. Are connected through one comb-tooth bus bar 25a.
  • the width and thickness of the reflective electrode finger 30c are smaller than the width and thickness of the comb-tooth bus bars 15b and 25b and the reflector bus bars 30a and 30b.
  • FIG. 5 is a diagram showing insertion loss of the filter device in the first embodiment and the comparative example.
  • the series arm resonator 2b shown in FIG. 1 includes the elastic wave resonator 10 of the present embodiment.
  • the series arm resonator 2b shown in FIG. 1 includes the elastic wave resonator 510 of the comparative example.
  • the insertion loss in the passband of the filter device of the comparative example is 0.92 dB, whereas the insertion loss in the passband of the filter device of Embodiment 1 is 0.
  • the insertion loss is smaller than that of the comparative example.
  • FIG. 6 is a diagram showing the insertion loss of the multiplexer in the first embodiment and the comparative example.
  • the insertion loss in the transmission passband of the multiplexer of the comparative example is 0.94 dB
  • the insertion loss in the transmission passband of the multiplexer 1 of the first embodiment is The insertion loss is 0.92 dB, which is smaller than that of the comparative example.
  • the IDT electrodes 11 and 22 are connected using the comb-tooth bus bar 15b, the reflector bus bar 30b, and the comb-tooth bus bar 25b, and therefore the IDT electrodes 11 and 22 are connected. Therefore, the electrical resistance can be reduced. Thereby, the insertion loss of the acoustic wave resonator 10 can be reduced.
  • Embodiment 2 Next, an acoustic wave resonator 10A according to Embodiment 2 will be described. Note that the multiplexer and filter device of the second embodiment have the same circuit configuration as that of the first embodiment, and therefore the description thereof is omitted.
  • FIG. 7 is a plan view showing an acoustic wave resonator 10A according to the second embodiment.
  • FIG. 8 is an equivalent circuit of the acoustic wave resonator 10A.
  • This elastic wave resonator 10A is further provided with a third connection electrode 53 and a fourth connection electrode 54 in addition to the elastic wave resonator 10 of the first embodiment.
  • a third connection electrode 53 is provided between the other reflector bus bar 31b and the other comb bus bar 15b, and between the other comb bus bar 25b and the other reflector bus bar 32b, A fourth connection electrode 54 is provided.
  • the third connection electrode 53 connects the reflector bus bar 31b and the comb bus bar 15b
  • the fourth connection electrode 54 connects the comb bus bar 25b and the reflector bus bar 32b.
  • the reflector bus bar 31b, the connection electrode 53, the comb-tooth bus bar 15b, the connection electrode 51, the reflector bus bar 30b, the connection electrode 52, the comb-tooth bus bar 25b, the connection electrode 54, and the reflector bus bar 32b have the same width and thickness, It is integrally formed linearly along the predetermined direction D1.
  • the acoustic wave resonator 10A has capacitors C3 and C4 corresponding to the respective acoustic wave elements F1 and F2 constituted by the IDT electrodes 11 and 22 (see FIG. 8).
  • the capacitor C3 has one comb-shaped bus bar 15a and one reflector bus bar 30a facing each other at different potentials, and one reflector bus bar located on the opposite side of the connected bus bar. 31a and one comb-shaped bus bar 15a are formed by facing each other with different potentials.
  • the capacitor C4 is located on the opposite side of the connected bus bar so that one reflector bus bar 30a and the one comb bus bar 25a face each other with different potentials, and one comb bus bar 25a and one comb bus bar 25a It is formed by facing the reflector bus bar 32a with a different potential.
  • the acoustic wave resonator 10 since the acoustic wave resonator 10 includes the capacitors C3 and C4, the steepness in the passband of the acoustic wave resonator 10A can be improved.
  • FIG. 9 is a diagram showing the insertion loss of the acoustic wave resonator in the second embodiment and the comparative example.
  • the increase value of the insertion loss of the elastic wave resonator 510 of the comparative example is 5.62 dB
  • the elasticity of the second embodiment is The increase value of the insertion loss of the wave resonator 10A is 5.92 dB, which is higher than the comparative example.
  • FIG. 10 is a diagram showing the insertion loss of the filter device in the second embodiment and the comparative example.
  • the series arm resonator 2b shown in FIG. 1 includes the acoustic wave resonator 10A of the present embodiment.
  • the series arm resonator 2b shown in FIG. 1 includes the elastic wave resonator 510 (see FIG. 4) of the comparative example.
  • the increase value of the insertion loss in the passband of the filter device of the comparative example is 27 ⁇ 05 dB, whereas the filter of the second embodiment The increase value of the insertion loss in the pass band of the device is 29.24 dB, which is higher than the comparative example.
  • FIG. 11 is a diagram illustrating the frequency characteristics of the multiplexer according to the second embodiment and the comparative example, where (a) is an insertion loss, and (b) is a diagram illustrating an isolation characteristic.
  • the isolation characteristic was obtained by measuring the insertion loss between Tx and Rx in the multiplexer shown in FIG.
  • the increase value of the insertion loss in the transmission passband of the multiplexer of the comparative example is 27.18 dB.
  • the increase value of the insertion loss in the transmission pass band of the multiplexer 1 of the form 2 is 29.13 dB, which is higher than the comparative example.
  • the second embodiment has a frequency difference ⁇ f between the frequency f ⁇ 1 having a Tx loss of 2 dB and the frequency f ⁇ 2 having an Rx band Iso of 50 dB as compared with the comparative example. .Improved (smaller) by 3 MHz and improved isolation.
  • the other reflector bus bar 31b of the first reflector 31 and the other comb of the IDT electrode 11 are combined.
  • the tooth bus bar 15b is disposed along the predetermined direction D1 and connected to each other.
  • the other comb-tooth bus bar 25b of the IDT electrode 22 and the other reflector bus bar 32b of the second reflector 32 are arranged along the predetermined direction D1 and connected to each other.
  • the acoustic wave resonator 10A further has a capacity, steepness in the pass band of the acoustic wave resonator 10A can be improved.
  • the acoustic wave resonator 10A at least one of a state where the reflector bus bar 31b and the comb bus bar 15b are connected and a state where the comb bus bar 25b and the reflector bus bar 32b are connected is used. If it has, it has the said effect.
  • FIG. 12 is a plan view showing an acoustic wave resonator 10B according to the third embodiment.
  • FIG. 13 is an equivalent circuit of the acoustic wave resonator 10B.
  • This elastic wave resonator 10B is further provided with a first counter electrode 61 in addition to the elastic wave resonator 10 of the first embodiment.
  • the first counter electrode 61 facing the one reflector bus bar 30a is provided on the side opposite to the other reflector bus bar 30b when viewed from the one reflector bus bar 30a of the shared reflector 30.
  • the provided first counter electrode 61 is provided in parallel with a predetermined distance from the reflector bus bar 30a.
  • the first counter electrode 61 is connected to the ground.
  • the same material as the protective layer 93 (for example, silicon dioxide) mentioned above is filled between the reflector bus bar 30a and the first counter electrode 61.
  • the acoustic wave resonator 10B has a capacitor C5 in addition to the capacitors C1 and C2, as shown in FIG.
  • the capacitor C5 is formed by facing one reflector bus bar 30a and the first counter electrode 61 with different potentials.
  • the acoustic wave resonator 10B further includes the capacitor C5, the steepness in the pass band of the acoustic wave resonator 10B can be improved.
  • FIG. 14A and 14B are diagrams illustrating an acoustic wave resonator 10C according to the fourth embodiment, where FIG. 14A is a plan view and FIG. 14B is a cross-sectional view taken along line XIVB-XIVB shown in FIG. 14A.
  • FIG. 15 is an equivalent circuit of the acoustic wave resonator 10C.
  • illustration of the adhesion layer 91, the main electrode layer 92, and the protective layer 93 is omitted.
  • This elastic wave resonator 10C is further provided with a second counter electrode 62 in addition to the elastic wave resonator 10 of the first embodiment.
  • an insulating layer 63 is provided on one reflector bus bar 30a of the shared reflector 30 and one comb-tooth bus bars 15a and 25a of the IDT electrodes 11 and 22, respectively.
  • a second counter electrode 62 is provided to face one reflector bus bar 30a and one comb-tooth bus bar 15a, 25a in the thickness direction.
  • the second counter electrode 62 extends along the predetermined direction D1, the negative end of the predetermined direction D1 is connected to one reflector bus bar 31a, and the positive end is connected to one reflector bus bar 32a. Has been.
  • the second counter electrode 62 is connected to the ground.
  • the material of the insulating layer 63 is appropriately selected from, for example, silicon dioxide and polyimide.
  • the acoustic wave resonator 10C has a capacitor C6 in addition to the capacitors C3 and C4 as shown in FIG.
  • the capacitor C6 is formed by the reflector bus bar 30a, the comb-tooth bus bars 15a and 25a, and the second counter electrode 62 facing each other across the insulating layer 63 and having different potentials.
  • the acoustic wave resonator 10C further includes the capacitor C6, the steepness in the pass band of the acoustic wave resonator 10C can be improved.
  • the acoustic wave resonators 10 to 10C are not limited to surface acoustic wave resonators, and may be boundary acoustic wave resonators.
  • the electrode fingers of the comb-shaped electrodes 11a, 11b, 22a, and 22b are not limited thereto, and may include the cross electrode fingers 16 and 26 without the offset electrode fingers 17 and 27.
  • the materials constituting the adhesion layer 91, the main electrode layer 92, and the protective layer 93 of the acoustic wave resonator 10 are not limited to the materials described above.
  • the IDT electrodes 11 and 22 do not have to have the above laminated structure.
  • the IDT electrodes 11 and 22 may be made of, for example, a metal or an alloy such as Ti, Al, Cu, Pt, Au, Ag, or Pd. It may be configured.
  • the protective layer 93 may not be formed.
  • the piezoelectric substrate 90 of the acoustic wave resonator 10 may have a laminated structure in which a high sound velocity supporting substrate, a low sound velocity film, and a piezoelectric film are laminated in this order.
  • the piezoelectric film may be, for example, a 50 ° Y-cut X-propagating LiTaO 3 piezoelectric single crystal or a piezoelectric ceramic (a lithium tantalate single crystal cut along a plane whose axis is rotated by 50 ° from the Y axis with the X axis as the central axis, Alternatively, it is made of ceramic and is made of a single crystal or ceramic in which surface acoustic waves propagate in the X-axis direction.
  • the piezoelectric film has a thickness of 600 nm, for example.
  • the high sound velocity support substrate is a substrate that supports the low sound velocity film, the piezoelectric film, and the IDT electrode.
  • the high-sonic support substrate is a substrate in which the acoustic velocity of the bulk wave in the high-sonic support substrate is higher than that of the surface wave or boundary wave that propagates through the piezoelectric film. It functions in such a way that it is confined in the portion where the sonic film is laminated and does not leak below the high sonic support substrate.
  • the high sound speed support substrate is, for example, a silicon substrate and has a thickness of, for example, 200 ⁇ m.
  • the low acoustic velocity film is a membrane in which the acoustic velocity of the bulk wave in the low acoustic velocity film is lower than the bulk wave propagating through the piezoelectric membrane, and is disposed between the piezoelectric membrane and the high acoustic velocity support substrate. Due to this structure and the property that energy is concentrated in a medium where acoustic waves are essentially low in sound velocity, leakage of surface acoustic wave energy to the outside of the IDT electrode is suppressed.
  • the low acoustic velocity film is, for example, a film mainly composed of silicon dioxide and has a thickness of, for example, 670 nm.
  • the Q value at the resonance frequency and the anti-resonance frequency can be significantly increased as compared with a structure in which the piezoelectric substrate 90 is used as a single layer. That is, since a surface acoustic wave resonator having a high Q value can be configured, a filter with a small insertion loss can be configured using the surface acoustic wave resonator.
  • the predetermined direction D1 is the same direction as the elastic wave propagation direction.
  • the present invention is not limited thereto, and the predetermined direction D1 is a direction slightly inclined with respect to the elastic wave propagation direction.
  • each of the comb-tooth bus bars 15a, 15b, 25a, 25b and the reflector bus bars 30a, 30b, 31a, 31b, 32a, 32b in the first embodiment is 0 ° or more and 10 ° or less with respect to the elastic wave propagation direction. It may be formed extending in an inclined direction.
  • each of the crossed electrode fingers 16, 26, the offset electrode fingers 17, 27, and the reflective electrode fingers 30c, 31c, 32c may be formed so as to extend in a direction orthogonal to the elastic wave propagation direction.
  • the wavelength of the acoustic wave resonator 10 may be defined by the repetition pitch ⁇ of each of the cross electrode fingers 16 and 26 in the acoustic wave propagation direction.
  • the present invention can be widely used in mobile communication devices such as mobile phones as acoustic wave resonators, filter devices, duplexers, and multiplexers with low insertion loss.

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  • Physics & Mathematics (AREA)
  • Acoustics & Sound (AREA)
  • Surface Acoustic Wave Elements And Circuit Networks Thereof (AREA)

Abstract

Un résonateur à ondes acoustiques (10) comprend : des électrodes IDT (11, 22) qui sont agencées le long d'une direction prescrite (D1) ; et un réflecteur partagé (30) qui est disposé entre les électrodes IDT (11, 22) dans la direction prescrite (D1). Le réflecteur partagé (30) comporte des barres omnibus (30a, 30b) de réflecteur qui se font face dans une direction (D2) qui est orthogonale à la direction prescrite (D1). L'électrode IDT (11) comporte des barres omnibus en peigne (15a, 15b) qui se font face dans la direction orthogonale (D2). L'électrode IDT (22) comporte des barres omnibus en peigne (25a, 25b) qui se font face dans la direction orthogonale (D2). Une barre omnibus de peigne (15b), une barre omnibus de réflecteur (30b) et une barre omnibus de peigne (25b) sont agencées le long de la direction prescrite (D1) et connectées.
PCT/JP2017/045401 2016-12-19 2017-12-18 Résonateur à ondes acoustiques, dispositif de filtre et multiplexeur Ceased WO2018117059A1 (fr)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10862458B2 (en) * 2016-08-10 2020-12-08 Murata Manufacturing Co., Ltd. Acoustic wave device and ladder filter

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH03190411A (ja) * 1989-12-20 1991-08-20 Fujitsu Ltd 弾性表面波素子
JPH07303023A (ja) * 1994-05-07 1995-11-14 Toko Inc 表面弾性波共振器
WO2013161881A1 (fr) * 2012-04-25 2013-10-31 京セラ株式会社 Élément à onde acoustique, filtre de dérivation et module de communication
WO2014133084A1 (fr) * 2013-02-27 2014-09-04 京セラ株式会社 Élément d'onde élastique, démultiplexeur et module de communication

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH03190411A (ja) * 1989-12-20 1991-08-20 Fujitsu Ltd 弾性表面波素子
JPH07303023A (ja) * 1994-05-07 1995-11-14 Toko Inc 表面弾性波共振器
WO2013161881A1 (fr) * 2012-04-25 2013-10-31 京セラ株式会社 Élément à onde acoustique, filtre de dérivation et module de communication
WO2014133084A1 (fr) * 2013-02-27 2014-09-04 京セラ株式会社 Élément d'onde élastique, démultiplexeur et module de communication

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10862458B2 (en) * 2016-08-10 2020-12-08 Murata Manufacturing Co., Ltd. Acoustic wave device and ladder filter

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