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WO2018117060A1 - 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
WO2018117060A1
WO2018117060A1 PCT/JP2017/045402 JP2017045402W WO2018117060A1 WO 2018117060 A1 WO2018117060 A1 WO 2018117060A1 JP 2017045402 W JP2017045402 W JP 2017045402W WO 2018117060 A1 WO2018117060 A1 WO 2018117060A1
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Prior art keywords
reflector
bus bar
comb
electrode
idt electrode
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PCT/JP2017/045402
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English (en)
Japanese (ja)
Inventor
明雄 金田
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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 having a plurality of acoustic wave resonators has been put into practical use, such as a band-pass filter 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.
  • each of the plurality of acoustic wave resonators constituting the filter device is required to have a steep resonance characteristic.
  • the elastic wave resonator disclosed in Patent Document 1 may have insufficient resonance characteristics.
  • the present invention has been made to solve the above-described problems, and an object thereof is to improve the steepness of resonance characteristics of an acoustic wave resonator or the like.
  • 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; a shared reflector provided on the piezoelectric substrate and disposed between the first IDT electrode and the second IDT electrode in the predetermined direction;
  • a second reflector provided on the opposite side of the shared reflector as viewed from the 2IDT electrode, each of the first IDT electrode and the second IDT electrode extending in the predetermined direction and One comb-tooth bus bar and the other comb-tooth bus bar facing each other in the orthogonal direction of the fixed direction, and each of the first reflector and the second reflector extends in the predetermined direction and mutually in the orthogonal direction
  • the other comb bus bar of the second IDT electrode and the other reflector bus bar of the second reflector are arranged along the predetermined direction and connected to each other. At least one of the states that are being used.
  • one reflector bus bar of the first reflector and one comb bus bar of the first IDT electrode face each other with different potentials, and a capacitance is added to the acoustic wave resonator.
  • one comb-tooth bus bar of the second IDT electrode and one reflector bus bar of the second reflector face each other with different potentials, and a capacitance is added to the acoustic wave resonator.
  • the other reflector bus bar of the first reflector and the other comb bus bar of the first IDT electrode are located between the other reflector bus bar and the other comb bus bar.
  • the other comb-tooth busbar of the second IDT electrode and the other reflector busbar of the second reflector are connected via one connection electrode, the other comb-tooth busbar and the other reflector busbar. And may be connected via a second connection electrode located between the two.
  • the adjacent bus bars can be connected at a short distance. Can do. Therefore, it is possible to reduce the electrical resistance for connecting the other reflector bus bar and the other comb-tooth bus bar, and to increase the capacity formed by one reflector bus bar and one comb-tooth bus bar. it can. Thereby, the steepness of the resonance characteristics in the acoustic wave resonator can be improved.
  • a first input / output wiring is connected to the one comb-tooth bus bar of each of the first IDT electrode and the second IDT electrode, and a second comb-tooth bus bar of each of the first IDT electrode and the second IDT electrode is connected to the first comb-tooth bus bar.
  • Two input / output wirings are connected, and the first IDT electrode and the second IDT electrode may be connected in parallel in a path connecting the first input / output wiring and the second input / output wiring.
  • the elastic wave resonator further faces the one reflector bus bar on the side opposite to the other reflector bus bar when viewed from the one reflector bus bar of the first reflector in the orthogonal direction.
  • a first counter electrode is provided, and the first counter electrode is connected to the ground, and in the orthogonal direction, the other reflector bus bar as viewed from the one reflector bus bar of the second reflector.
  • a second counter electrode facing the one reflector bus bar is provided on the opposite side of the first counter bus bar, and the second counter electrode may have at least one state of being connected to the ground. .
  • the elastic wave resonator further includes a first insulating layer provided on the one reflector bus bar of the first reflector, and a third opposing to the one reflector bus bar on the first insulating layer.
  • a counter electrode is provided, and the third counter electrode is connected to the one comb-shaped bus bar of the first IDT electrode, and a second insulation is provided on the one reflector bus bar of the second reflector.
  • a fourth counter electrode facing the one reflector bus bar is provided on the second insulating layer, and the fourth counter electrode is connected to the one comb-tooth bus bar of the second IDT electrode. It may have at least one of the states.
  • 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.
  • the steepness in the pass band of the filter device can be improved.
  • a multiplexer may include the above filter device.
  • the steepness in the pass band of the multiplexer can be improved.
  • the steepness of the resonance characteristics of the acoustic wave resonator can be improved.
  • steepness in the pass band of the filter device and the multiplexer can be improved.
  • 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 acoustic wave resonator in the first embodiment and the comparative example.
  • FIG. 6 is a diagram showing the insertion loss of the filter device in the first embodiment and the comparative example.
  • 7A and 7B are diagrams illustrating the frequency characteristics of the multiplexer according to the first embodiment and the comparative example, where FIG. 7A is a diagram illustrating insertion loss and FIG. 7B is a diagram illustrating isolation characteristics.
  • FIG. 8 is a plan view illustrating an acoustic wave resonator according to the second embodiment.
  • FIG. 9 is an equivalent circuit of the acoustic wave resonator according to the second embodiment.
  • 10A and 10B are diagrams illustrating an acoustic wave resonator according to the third embodiment.
  • FIG. 10A is a plan view
  • FIG. 10B is a cross-sectional view taken along line XB-XB shown in FIG.
  • FIG. 11 is an equivalent circuit of the acoustic wave resonator according to the third 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 finger 17 is shorter than the cross electrode fingers 16 and 26 and is disposed to face the cross electrode finger 16 in the orthogonal direction D2.
  • the offset electrode finger 27 is shorter than the cross electrode fingers 16 and 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.
  • the first input / output wiring 41 is connected to one comb-tooth bus bar 15 a of the IDT electrode 11 and one comb-tooth bus bar 25 a of the IDT electrode 22, and the other comb-tooth bus bar 15 b of the IDT electrode 11 and the other of the IDT electrode 22 are connected.
  • a second input / output wiring 42 is connected to the comb-tooth bus bar 25b. That is, the IDT electrode 11 and the IDT electrode 22 are connected in parallel in a path connecting the first input / output wiring 41 and the second input / output wiring 42.
  • the common reflector 30 is disposed between the IDT electrode 11 and the IDT electrode 22 in the predetermined direction 1.
  • 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 extends in the predetermined direction D1 and is disposed so as 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 extends in the predetermined direction D1, and is disposed so as 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 other reflector bus bar 31b and the other comb bus bar 15b are arranged and connected along a predetermined direction D1.
  • the other comb-tooth bus bar 25b and the other reflector bus bar 32b are arranged and connected along a predetermined direction D1.
  • a first connection electrode 51 is provided between the other reflector bus bar 31b and the other comb bus bar 15b, and the first connection electrode 51 is connected to the other reflector bus bar 31b and the other comb bus bar. 15b.
  • a second connection electrode 52 is provided between the other comb-tooth bus bar 25b and the other reflector bus bar 32b, and the second connection electrode 52 connects the other comb-tooth bus bar 25b and the other reflector bus bar 32b. Connected.
  • the width of the connection electrode 51 is the same as the width of the reflector bus bar 31b and the comb-shaped bus bar 15b, and the thickness of the connection electrode 51 is the same as the thickness of the reflector bus bar 31b and the comb-shaped bus bar 15b. That is, the reflector bus bar 31b, the connection electrode 51, and the comb-shaped bus bar 15b are integrally formed linearly along the predetermined direction D1.
  • the width of the connection electrode 52 is the same as the width of the comb-tooth bus bar 25b and the reflector bus bar 32b, and the thickness of the connection electrode 52 is the same as the thickness of the comb-tooth bus bar 25b and the reflector bus bar 32b.
  • 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 bars 31b and 32b, and have the same laminated structure.
  • the acoustic wave resonator 10 has capacitors C1 and C2 corresponding to the respective acoustic wave elements F1 and F2 configured by the IDT electrodes 11 and 22 (see FIG. 3).
  • the capacitor C1 is configured such that one reflector bus bar 31a and one comb tooth bus bar 15a located on the opposite sides of the reflector bus bar 31b and the comb tooth bus bar 15b connected by the connection electrode 51 have different potentials. Formed by facing each other.
  • the capacitor C2 is configured such that one comb-tooth bus bar 25a and one reflector bus bar 32a, which are located on the opposite sides of the comb-tooth bus bar 25b and the reflector bus bar 32b connected by the connection electrode 51, face each other with different potentials. It is formed.
  • the acoustic wave resonator 10 includes the capacitors C1 and C2, the steepness of the resonance characteristics in the acoustic wave resonator 10 can be improved.
  • FIG. 4 is a plan view showing an acoustic wave resonator 510 in a comparative example.
  • the acoustic wave resonator 510 of the comparative example is different from the first embodiment in that the first connection electrode 51 and the second connection electrode 52 are not provided.
  • the acoustic wave resonator 510 since the other reflector bus bar 30b and the other comb-tooth bus bar 15b are not connected, a structure in which capacitance is hardly generated between the one reflector bus bar 31a and the one comb-tooth bus bar 15a. It has become.
  • the other comb-tooth bus bar 25b and the other reflector bus bar 32b are not connected to each other, it is difficult to generate a capacity between the one comb-tooth bus bar 25a and the one reflector bus bar 32a. .
  • FIG. 5 is a diagram showing the insertion loss of the acoustic wave resonator in the first embodiment and the comparative example.
  • the increase value of the insertion loss of the acoustic wave resonator 510 of the comparative example is 5.57 dB
  • the elasticity of the first embodiment is The increase value of the insertion loss of the wave resonator 10 is 5.84 dB, which is higher than the comparative example.
  • FIG. 6 is a diagram showing the 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 (see FIG. 4) of the comparative example.
  • the increase value of the insertion loss in the pass band of the filter device of the comparative example is 27.37 dB with respect to the change from the frequency 856 MHz to 865 MHz, whereas the filter of the first embodiment
  • the increase value of the insertion loss in the pass band of the device is 29.18 dB, which is higher than the comparative example.
  • FIG. 7 is a diagram showing the frequency characteristics of the multiplexers in the first embodiment and the comparative example, where (a) is an insertion loss and (b) is a diagram showing isolation characteristics.
  • 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 27.64 dB.
  • the increase value of the insertion loss in the transmission passband of the multiplexer 1 of the first embodiment is 29.48 dB, which is higher than the comparative example.
  • the first embodiment has a frequency difference ⁇ f of 0.3 MHz between the frequency where the Tx loss is 2 dB and the frequency where the Rx band Iso is 50 dB as compared with the comparative example. Improved (becomes smaller) and improved isolation.
  • 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.
  • 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 first reflector 31 has one reflector bus bar 31a and the other reflector bus bar 31b extending in the predetermined direction D1 and facing each other in the orthogonal direction D2.
  • the second reflector 32 has one reflector bus bar 32a and the other reflector bus bar 32b extending in the predetermined direction D1 and facing each other in the orthogonal direction D2.
  • the other reflector bus bar 31b of the first reflector 31 and the other comb bus bar 15b of the IDT electrode 11 are arranged 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.
  • one reflector bus bar 31a and one comb bus bar 15a which are located on opposite sides of the reflector bus bar 31b and the comb bus bar 15b connected to each other, face each other with different potentials. Therefore, a capacitance is added to the acoustic wave resonator 10.
  • the acoustic wave resonator 10 Capacity is added to In this way, by adding the capacitance to the acoustic wave resonator 10, the steepness of the resonance characteristics in the acoustic wave resonator 10 can be improved.
  • At least one of the state where the reflector bus bar 31b and the comb bus bar 15b are connected and the 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. 8 is a plan view showing an acoustic wave resonator 10A according to the second embodiment.
  • FIG. 9 is an equivalent circuit of the acoustic wave resonator 10A.
  • This elastic wave resonator 10A is further provided with a first counter electrode 61 and a second counter electrode 62 in addition to the elastic wave resonator 10 of the first embodiment.
  • the first counter electrode 61 is provided on the opposite side to the other reflector bus bar 31b when viewed from one reflector bus bar 31a of the first reflector 31 in the orthogonal direction D2, and is connected to the ground. Yes.
  • the first counter electrode 61 faces the reflector bus bar 31a by being arranged in parallel with a predetermined distance from the reflector bus bar 31a.
  • the second counter electrode 62 is provided on the opposite side of the second reflector 32 from the other reflector bus bar 32b when viewed from the one reflector bus bar 32a in the orthogonal direction D2, and is connected to the ground.
  • the second counter electrode 62 is opposed to the reflector bus bar 32a by being arranged parallel to the reflector bus bar 32a at a predetermined distance.
  • the same material as that of the protective layer 93 (for example, silicon dioxide) is filled between the reflector bus bar 31a and the first counter electrode 61 and between the reflector bus bar 32a and the second counter electrode 62. ing.
  • the acoustic wave resonator 10A has capacitors C3 and C4 as shown in FIG.
  • the capacitor C3 is formed by one reflector bus bar 31a and the one comb-tooth bus bar 15a facing each other with different potentials, and one reflector bus bar 31a and the first counter electrode 61 facing each other with different potentials.
  • one comb-tooth bus bar 25a and one reflector bus bar 32a face each other with different potentials
  • one reflector bus bar 32a and the second counter electrode 62 face each other with different potentials. It is formed with.
  • the acoustic wave resonator 10A has the capacitors C3 and C4, the steepness of the resonance characteristics of the acoustic wave resonator 10A can be improved.
  • At least one of the state where the reflector bus bar 31a and the first counter electrode 61 face each other and the state where the reflector bus bar 32a and the second counter electrode 62 face each other is set. If it has, it has the said effect.
  • FIG. 10A and 10B are diagrams illustrating an acoustic wave resonator 10B according to the third embodiment, in which FIG. 10A is a plan view and FIG. 10B is a plan view that is a cross-sectional view taken along line XB-XB shown in FIG. is there.
  • FIG. 11 is an equivalent circuit of the acoustic wave resonator 10B.
  • illustration of the adhesion layer 91, the main electrode layer 92, and the protective layer 93 is omitted.
  • This elastic wave resonator 10B further includes a third counter electrode 63 and a fourth counter electrode 64 in addition to the elastic wave resonator 10 of the first embodiment.
  • a first insulating layer 66 is provided on one reflector bus bar 31a of the first reflector 31, and a first opposing bus bar 31a in the thickness direction is provided on the first insulating layer 66.
  • Three counter electrodes 63 are provided.
  • the third counter electrode 63 is formed along the predetermined direction D1, and the positive end of the third counter electrode 63 in the predetermined direction D1 is connected to one comb-tooth bus bar 15a.
  • a second insulating layer 67 is provided on one reflector bus bar 32a of the second reflector 32, and a fourth counter electrode facing the one reflector bus bar 32a in the thickness direction is provided on the second insulating layer 67. 64 is provided.
  • the fourth counter electrode 64 is formed along the predetermined direction D1, and the negative end of the fourth counter electrode 64 in the predetermined direction D1 is connected to one comb-shaped bus bar 25a.
  • the material of the first insulating layer 66 and the second insulating layer 67 is appropriately selected from, for example, silicon dioxide and polyimide.
  • the acoustic wave resonator 10B has capacitors C5 and C6 as shown in FIG.
  • the capacitor C5 is formed by facing one reflector bus bar 31a and one comb-tooth bus bar 15a with different potentials, and facing one reflector bus bar 31a and the third counter electrode 63 with different potentials.
  • one comb bus bar 25a and one reflector bus bar 32a face each other with different potentials
  • one reflector bus bar 32a and the fourth counter electrode 64 face each other with different potentials. It is formed with.
  • the acoustic wave resonator 10B includes the capacitors C5 and C6, the steepness of the resonance characteristics of the acoustic wave resonator 10B can be improved.
  • At least one of the state where the reflector bus bar 31a and the third counter electrode 63 face each other and the state where the reflector bus bar 32a and the fourth counter electrode 64 face each other is set. If it has, it has the said effect.
  • the acoustic wave resonators 10 to 10B are not limited to surface acoustic wave resonators, and may be boundary acoustic wave resonators.
  • the offset electrode fingers 17 and 27 are provided on the comb-shaped electrodes 11a, 11b, 22a, and 22b, thereby suppressing spurious and the like that are unnecessary frequency components caused by harmonics and the like. is doing.
  • 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 reflector bus bars 31a and 32a may be formed to be wider and thicker than the reflective electrode fingers 31c and 32c.
  • One comb-tooth bus bar 15a, 25a may be formed to be wider and thicker than the cross electrode fingers 16, 26 and the offset electrode fingers 17, 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 improved resonance characteristics.

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

Abstract

La présente invention concerne un résonateur à ondes acoustiques (10) qui comprend : des électrodes IDT (11, 22) qui sont agencées le long d'une direction prescrite (D1) ; un réflecteur partagé (30) qui est disposé entre les électrodes IDT (11, 22) ; un premier réflecteur (31) qui, vu depuis l'électrode IDT (11), est disposé sur le côté opposé au réflecteur partagé (30) ; et un second réflecteur (32) qui, vu depuis l'électrode IDT (22), est disposé sur le côté opposé au réflecteur partagé (30). Une électrode IDT (11) comporte des barres omnibus en peigne (15a, 15b), et une électrode IDT (22) comporte des barres omnibus en peigne (25a, 25b). Le premier réflecteur (31) comporte des barres omnibus de réflecteur (31a, 31b), et le second réflecteur (32) comporte des barres omnibus de réflecteur (32a, 32b). Une barre omnibus de réflecteur (31b) et une barre omnibus en peigne (15b) sont agencées le long de la direction prescrite (D1) et connectées l'une à l'autre, et une barre omnibus en peigne (25b) et une barre omnibus de réflecteur (32b) sont agencées le long de la direction prescrite (D1) et connectées l'une à l'autre.
PCT/JP2017/045402 2016-12-19 2017-12-18 Résonateur à ondes acoustiques, dispositif de filtre et multiplexeur Ceased WO2018117060A1 (fr)

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JP2016245845 2016-12-19

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2020100744A1 (fr) * 2018-11-16 2020-05-22 株式会社村田製作所 Dispositif à ondes élastiques
WO2022070885A1 (fr) * 2020-09-29 2022-04-07 株式会社村田製作所 Filtre d'onde élastique type résonateur à couplage longitudinal, et filtre d'onde élastique
CN114391221A (zh) * 2019-09-27 2022-04-22 株式会社村田制作所 弹性波装置、滤波器装置以及多工器

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JPH07303023A (ja) * 1994-05-07 1995-11-14 Toko Inc 表面弾性波共振器
WO2008056697A1 (fr) * 2006-11-08 2008-05-15 Panasonic Corporation Résonateur d'onde acoustique de surface
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

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Publication number Priority date Publication date Assignee Title
JPH07303023A (ja) * 1994-05-07 1995-11-14 Toko Inc 表面弾性波共振器
WO2008056697A1 (fr) * 2006-11-08 2008-05-15 Panasonic Corporation Résonateur d'onde acoustique de surface
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

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2020100744A1 (fr) * 2018-11-16 2020-05-22 株式会社村田製作所 Dispositif à ondes élastiques
CN112997403A (zh) * 2018-11-16 2021-06-18 株式会社村田制作所 弹性波装置
JPWO2020100744A1 (ja) * 2018-11-16 2021-09-27 株式会社村田製作所 弾性波装置
US12021500B2 (en) 2018-11-16 2024-06-25 Murata Manufacturing Co., Ltd. Acoustic wave device
CN112997403B (zh) * 2018-11-16 2025-01-17 株式会社村田制作所 弹性波装置
CN114391221A (zh) * 2019-09-27 2022-04-22 株式会社村田制作所 弹性波装置、滤波器装置以及多工器
WO2022070885A1 (fr) * 2020-09-29 2022-04-07 株式会社村田製作所 Filtre d'onde élastique type résonateur à couplage longitudinal, et filtre d'onde élastique

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