Elastic wave device and module

Abstract

An elastic wave device includes a piezoelectric substrate, and a bandpass filter formed on the piezoelectric substrate and including a resonator having a first IDT electrode, a second IDT electrode, a third IDT electrode, a fourth IDT electrode, and a fifth IDT electrode, the number of turns of the third IDT electrode being greater than the sum of the number of turns of the first IDT electrode, the number of turns of the second IDT electrode, the number of turns of the fourth IDT electrode, and the number of turns of the fifth IDT electrode, whereby an elastic wave device using a resonator that is closer to a rectangle, has low loss, and has a fairly excellent passband characteristic, and a module including the elastic wave device can be provided.

Description

Technical Field

[0001] The present invention relates to an elastic wave device and a module comprising the elastic wave device. Background Technology

[0002] In recent years, with technological advancements, smartphones and other mobile communication terminals have become significantly smaller and lighter. For filters used in these mobile communication terminals, miniaturized elastic wave devices are employed. Furthermore, the demand for communication systems capable of simultaneous reception and transmission, such as duplexers, in mobile communication systems has increased dramatically.

[0003] Based on the above, a resonator with unbalanced-to-balanced conversion function will be used as the filter at the receiving end of the duplexer. Furthermore, with the evolution of mobile communication systems, the specifications for duplexers are becoming increasingly stringent. In other words, a resonator that is closer to a rectangular shape, has low loss, and possesses significantly better passband characteristics than existing ones is necessary.

[0004] Patent document 1 (Japanese Patent Application Publication No. 2020-141380) exemplifies a technology related to an elastic wave device. Summary of the Invention

[0005] However, the technology exemplified in Patent Document 1 does not provide an elastic wave device using a resonator with excellent passband characteristics. The object of the present invention is to provide an elastic wave device using a resonator that is closer to a rectangle, has low loss, and possesses considerably superior passband characteristics.

[0006] The present invention relates to an elastic wave device comprising a piezoelectric substrate and a bandpass filter formed on the piezoelectric substrate and including a resonator. The resonator has a first IDT electrode, a second IDT electrode, a third IDT electrode, a fourth IDT electrode, and a fifth IDT electrode. The number of logarithms of the third IDT electrode is greater than the sum of the number of logarithms of the first IDT electrode, the second IDT electrode, the fourth IDT electrode, and the fifth IDT electrode.

[0007] In one embodiment of the present invention, the number of logarithms of the first IDT electrode and the number of logarithms of the fifth IDT electrode are the same.

[0008] In one embodiment of the invention, the number of logarithms of the second IDT electrode is the same as the number of logarithms of the fourth IDT electrode.

[0009] In one embodiment of the invention, the wiring pattern of the bandpass filter has a first metal layer, a second metal layer formed on the first metal layer, and an insulator formed between the first metal layer and the second metal layer. The first metal layer has an island-shaped pattern that is surrounded by and insulated from the signal line of the third IDT electrode. The island-shaped pattern is electrically connected to the ground line of the second IDT electrode and the ground line of the fourth IDT electrode through the second metal layer.

[0010] In one embodiment of the invention, the piezoelectric substrate is bonded to a substrate on a main surface opposite to the surface forming the bandpass filter, the substrate being formed of one of sapphire, silicon, alumina, spinel, and glass.

[0011] In one embodiment of the invention, the bandpass filter is a receiving filter, and the elastic wave device is a duplexer that also includes a transmitting filter.

[0012] In one embodiment of the present invention, the passband frequency of the receiving filter is lower than the passband frequency of the transmitting filter.

[0013] In one embodiment of the invention, the transmitting filter has a plurality of resonators configured in a trapezoidal structure.

[0014] In one embodiment of the invention, the plurality of resonators of the transmitting filter, arranged in a trapezoidal structure, are acoustic thin-film resonators.

[0015] In one embodiment of the present invention, the transmitting filter is formed on the piezoelectric substrate.

[0016] One embodiment of the present invention includes a module comprising the elastic wave device.

[0017] According to the present invention, an elastic wave device using a resonator that is closer to a rectangle, has low loss, and has excellent passband characteristics can be provided. Attached Figure Description

[0018] Other features and effects of the present invention will be clearly presented in the embodiments with reference to the drawings, wherein:

[0019] Figure 1 This is a cross-sectional view of the elastic wave device of the first embodiment.

[0020] Figure 2 This is a schematic diagram of the device chip.

[0021] Figure 3 This is a schematic diagram of the resonance characteristics of the multimode resonators in the first embodiment and the comparative example.

[0022] Figure 4 This is a schematic diagram of the passband characteristics of the bandpass filters of the first embodiment and the comparative example.

[0023] Figure 5 yes Figure 2 A schematic diagram of the structure of the area surrounded by dashed lines.

[0024] Figure 6 This is a schematic diagram of the device chip.

[0025] Figure 7 This is a schematic top view of an elastic surface wave resonator as the elastic wave component.

[0026] Figure 8 This is a schematic cross-sectional view of the elastic wave component, which is a piezoelectric thin film resonator.

[0027] Figure 9 This is a schematic diagram of the passband characteristics of the duplexer in the first embodiment.

[0028] Figure 10 This is a schematic diagram of the device chip in the second embodiment.

[0029] Figure 11 This is a cross-sectional view of a module according to the third embodiment of the present invention. Detailed Implementation

[0030] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0031] (First Embodiment)

[0032] Figure 1 This is a cross-sectional view of the elastic wave device 1 of the first embodiment.

[0033] like Figure 1 As shown, the elastic wave device 1 of the first embodiment includes a wiring substrate 3 and two device chips 5 mounted on the wiring substrate 3. Although the first embodiment exemplifies an elastic wave device that uses one device chip 5 (Rx) as a receiving filter and the other device chip 5 (Tx) as a transmitting filter to form a duplexer, the present invention is also applicable to elastic wave devices with a bandpass filter having one device chip 5, or double duplexers. Furthermore, components capable of implementing duplexer functions can also be formed on a single device chip.

[0034] The wiring substrate 3 may be, for example, a multilayer substrate composed of resin, or a low-temperature co-fired ceramic (LTCC) multilayer substrate formed of several dielectric layers. Furthermore, the wiring substrate 3 includes several external connection terminals 31.

[0035] The device chip 5 has a bandpass filter formed on it, allowing electrical signals in the desired frequency band to pass through. The device chip 5 (Rx) also has a bandpass filter including a multimode resonator. In the first embodiment, the device chip 5 (Rx) is a receiving filter.

[0036] A trapezoidal filter is formed on the device chip 5(Tx). In the first embodiment, the device chip 5(Tx) is a transmitting filter.

[0037] The device chip 5 can, for example, use a substrate formed of piezoelectric single crystals such as lithium tantalate, lithium niobate, or crystal, or piezoelectric ceramics. Alternatively, as described below, in the case where the bandpass filter uses an acoustic thin-film resonator, a semiconductor substrate such as silicon can be used, or an insulating substrate such as sapphire, alumina, spinel, or glass.

[0038] Furthermore, the device chip 5 can also be a substrate formed by bonding a piezoelectric substrate and a support substrate. The support substrate can be, for example, a sapphire substrate, an alumina substrate, a spinel substrate, or a silicon substrate.

[0039] A plurality of electrode pads 9 are formed on the wiring substrate 3. The electrode pads 9 may, for example, be made of an alloy containing copper. Furthermore, the thickness of the electrode pads 9 is, for example, between 10 μm and 20 μm.

[0040] The encapsulation portion 17 is formed to cover the device chip 5. The encapsulation portion 17 may be formed of an insulator such as a synthetic resin, or a metal may be used. The synthetic resin may be, for example, epoxy resin or polyimide, but is not limited to these. Preferably, the sealing portion 17 may be made of epoxy resin and formed by a low-temperature curing process.

[0041] The device chip 5 is mounted on the wiring substrate 3 via bumps 15 using flip chip bonding technology.

[0042] The bump 15 can be made of gold, for example. The height of the bump 15 is, for example, between 20 μm and 50 μm.

[0043] The electrode pad 9 is electrically connected to the device chip 5 via the bump 15.

[0044] Figure 2 This is a schematic diagram of the structure of device chip 5 (Rx).

[0045] like Figure 2 As shown, the device chip 5 (Rx) has several elastic wave components 52 and several wiring patterns 54.

[0046] The elastic wave assembly 52 includes a multimode resonator 7. The multimode resonator 7 has a first IDT electrode 71, a second IDT electrode 72, a third IDT electrode 73, a fourth IDT electrode 74, and a fifth IDT electrode 75.

[0047] In the first embodiment, the number of logarithms of the first IDT electrode 71 is 18. Furthermore, the number of logarithms of the second IDT electrode 72 is 22. Moreover, the number of logarithms of the third IDT electrode 73 is 96.5. Furthermore, the number of logarithms of the fourth IDT electrode 74 is 22. Furthermore, the number of logarithms of the fifth IDT electrode 75 is 18. In other words, the number of logarithms of the third IDT electrode 73 is greater than the sum of the number of logarithms of the first IDT electrode 71, the second IDT electrode 72, the fourth IDT electrode 74, and the fifth IDT electrode 75.

[0048] The logarithm of the first IDT electrode 71 is 18, the same as that of the fifth IDT electrode 75. Furthermore, the logarithm of the second IDT electrode 72 is 22, the same as that of the fourth IDT electrode 74.

[0049] The wiring pattern 54 has a first metal layer and a second metal layer. Figure 2 (not shown), and an insulator formed between the first metal layer and the second metal layer ( Figure 2 (Not shown). The insulator may, for example, be polyimide. The insulator may be, for example, a thin film with a thickness of 1000 nm.

[0050] The wiring pattern 54 has a three-dimensional wiring section 58, which is wired in a manner in which the first metal layer and the second metal layer are intersected in a three-dimensional manner through the insulator.

[0051] The elastic wave component 52 and the wiring pattern 54 are formed, for example, of suitable metals or alloys such as silver, aluminum, copper, titanium, and palladium. Furthermore, the metal pattern of the elastic wave component 52 and the wiring pattern 54 can be a multilayer metal film structure composed of multiple stacked metal layers. The thickness of the elastic wave component 52 and the wiring pattern 54 is, for example, between 150 nm and 400 nm.

[0052] The wiring pattern 54 has wiring that forms the input pad In, the output pad Out, and the ground pad GND. Furthermore, the wiring pattern 54 is electrically connected to the elastic wave assembly 52.

[0053] like Figure 2 As shown, the third IDT electrode 73 is electrically connected to the elastic wave assembly 52 of the output pad Out via direct electrical connection, and is electrically connected to the output pad Out via the three-dimensional wiring portion 58.

[0054] like Figure 2 As shown, the bandpass filter can be formed by setting multiple elastic wave components 52. The bandpass filter is designed to allow only electrical signals in the desired frequency band from the electrical signals input from the input pad In to pass through.

[0055] The electrical signal input from the input pad In will pass through the bandpass filter, and the electrical signal that meets the expected frequency band will be output from the output pad Out.

[0056] The electrical signal output from the output pad Out passes through the bump 15 and the electrode pad 9, and is output from the external connection terminal 31 of the wiring board 3.

[0057] Figure 3 This is a schematic diagram of the resonance characteristics of the multimode resonators in the first embodiment and the comparative example.

[0058] The solid lines illustrate the resonance characteristics of the multimode resonator 7 of the elastic wave device in the first embodiment. The dashed lines illustrate the resonance characteristics of the multimode resonator in the comparative example. In the comparative example's multimode resonator, the number of pairs of the first IDT electrode is 18, the number of pairs of the second IDT electrode is 22, the number of pairs of the third IDT electrode is 78.5, the number of pairs of the fourth IDT electrode is 22, and the number of pairs of the fifth IDT electrode is 18. Other conditions are the same as those in the multimode resonator of the first embodiment.

[0059] like Figure 3 As shown, although the first embodiment and the comparative example have the same passband characteristics, the first embodiment has better attenuation characteristics in the frequency range where the passband is higher than 820MHz.

[0060] Figure 4 This is a schematic diagram of the passband characteristics of the bandpass filters of the first embodiment and the comparative example.

[0061] The solid line waveform illustrates the pass-through characteristics of the bandpass filter in the elastic wave device of the first embodiment. The dashed line waveform illustrates the pass-through characteristics of the comparative example. The bandpass filter of the comparative example uses a filter with the following characteristics: Figure 3 The bandpass filter of the multimode resonator shown is a comparative example of the resonant characteristics. Other conditions are the same as those of the bandpass filter in the first embodiment.

[0062] like Figure 4 As shown, regarding the passband characteristics, although the first embodiment and the comparative example have the same passband characteristics, it can be found that the attenuation characteristics of the first embodiment are better in the frequency range where the passband is higher than 820MHz.

[0063] In other words, according to the present invention, an elastic wave device using a multimode resonator that is closer to a rectangle, has low loss, and has excellent passband characteristics can be provided.

[0064] Figure 5 yes Figure 2 A diagram illustrating the structure of the area surrounded by dashed lines.

[0065] like Figure 5 As shown, a first metal layer 54M1 is formed on the device chip 5(Rx). Furthermore, the first metal layer 54M1 has an island-shaped pattern IP that is surrounded by and insulated from the signal line L73 of the third IDT electrode 73.

[0066] The device chip 5(Rx) also has a ground line GL for the second IDT electrode 72 and the fourth IDT electrode 74. Furthermore, the device chip 5(Rx) also has a second metal layer 54M2 electrically connected to the ground line GL and the island pattern IP. An insulator 56 is provided between the second metal layer 54M2 and the signal line L73.

[0067] In this way, the signal line L73, the insulator 56 and the second metal layer 54M2 can form a three-dimensional wiring section 58.

[0068] The third IDT electrode 73 of this invention has a large width, which causes the insulator 56 to peel off. Therefore, the inventors divided the wiring connecting the third IDT electrode 73 and solved the problem of insulator 56 peeling off by setting up multiple three-dimensional wirings.

[0069] And, as Figure 5 As shown, three three-dimensional wiring portions 58 can be formed after forming two island-shaped pattern IPs, or two three-dimensional wiring portions 58 can be formed after forming one island-shaped pattern IP. When forming one island-shaped pattern IP, its length can be increased as needed.

[0070] Here, depending on the thickness and area of ​​the insulator 56, the three-dimensional wiring portion 58 has parasitic capacitance formed between the second metal layer 54M2 of the signal line L73 and the ground line GL, which may affect the characteristics of the bandpass filter. The thicker the insulator 56, the smaller the parasitic capacitance, but it is also easier to peel off. Furthermore, the larger the area of ​​the insulator 56, the less difficult it is to peel off, but the parasitic capacitance will increase.

[0071] Furthermore, extending the length of the island pattern IP can reduce parasitic capacitance; however, excessive extension will narrow the wiring pattern 54 of the signal line L73, and the problem of increased impedance must be considered.

[0072] According to the structural design of the present invention, optimal design can be achieved while preventing characteristic degradation caused by the peeling of the insulator 56 and parasitic capacitance. The structural design of the present invention provides an elastic wave device with high design freedom and excellent characteristics.

[0073] Figure 6 This is a schematic diagram of the structure of device chip 5 (Tx).

[0074] like Figure 6 As shown, the elastic wave component 52 and the wiring pattern 54 are formed on the device chip 5 (Tx).

[0075] The elastic wave component 52 and the wiring pattern 54 can be formed of suitable metals or alloys such as silver, aluminum, copper, titanium, and palladium. Furthermore, the metal pattern of the elastic wave component 52 and the wiring pattern 54 can be, for example, a multilayer metal film composed of multiple stacked metal layers. The thickness of the elastic wave component 52 and the wiring pattern 54 is, for example, between 150 nm and 400 nm.

[0076] The wiring pattern 54 has wiring that constitutes the input pad In, the output pad Out, and the ground pad GND. Furthermore, the wiring pattern 54 is electrically connected to the elastic wave assembly 52.

[0077] like Figure 6 As shown, the bandpass filter is constructed by forming multiple elastic wave components 52. Each elastic wave component 52 has multiple resonators arranged in a trapezoidal structure, which are series resonators and / or parallel resonators. The bandpass filter is designed to allow only electrical signals from the input electrical signal pad In that conform to the desired frequency band to pass through.

[0078] The electrical signal input from the input pad In will pass through the bandpass filter, and the electrical signal that meets the expected frequency band will be output from the output pad Out.

[0079] The electrical signal output from the output pad Out passes through the bump 15 and the electrode pad 9, and is output from the external connection terminal 31 of the wiring board 3.

[0080] Figure 7 This is a schematic top view of the elastic wave component 52 as an elastic surface wave resonator.

[0081] like Figure 7As shown, the device chip 5 is equipped with an IDT (Interdigital Transducer) 52a capable of exciting elastic surface waves and a reflector 52b. The IDT 52a has a pair of comb-shaped electrodes 52c. The comb-shaped electrodes 52c are arranged opposite to each other. The comb-shaped electrodes 52c have several electrode fingers 52d and several busbars 52e connecting the electrode fingers 52d. The reflector 52b is disposed on both sides of the IDT 52a.

[0082] The IDT 52a and the reflector 52b are formed, for example, of an alloy of aluminum and copper. The IDT 52a and the reflector 52b are, for example, thin films with a thickness between 150 nm and 400 nm. The IDT 52a and the reflector 52b can also be other metals, such as titanium, palladium, silver, or alloys containing the aforementioned metals, and can also be formed from these alloys. Furthermore, the IDT 52a and the reflector 52b can also be a multilayer metal film structure composed of multiple stacked metal layers.

[0083] Figure 8 This is a schematic cross-sectional view of the elastic wave component 52, which is a piezoelectric thin film resonator.

[0084] like Figure 8 As shown, a piezoelectric film 62 is provided on the chip substrate 60. The piezoelectric film 62 is sandwiched between a lower electrode 64 and an upper electrode 66. 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 elastic waves in the piezoelectric film 62 in a thickness longitudinal vibration mode.

[0085] The chip substrate 60 is, for example, a semiconductor substrate such as silicon, or it can also be an insulating substrate such as sapphire, alumina, spinel, or glass. The piezoelectric film 62 can be, for example, aluminum nitride. The lower electrode 64 and the upper electrode 66 can be, for example, metals such as ruthenium.

[0086] The elastic wave component 52 can achieve the desired characteristics of a bandpass filter and can be appropriately applied to multimode filters or trapezoidal filters.

[0087] Figure 9 This is a schematic diagram of the band domain characteristics of the duplexer in the first embodiment.

[0088] like Figure 9As shown, in the first embodiment, the frequency of the passband Rx of the receiving filter of the duplexer is lower than the frequency of the passband Tx of the transmitting filter. In a duplexer with the frequency relationship described above, the high-frequency side of the receiving filter's passband Rx must be drastically suppressed. Generally, it is difficult to drastically suppress the high-frequency side of the passband of a multimode filter. However, according to the present invention, a duplexer with the above frequency relationship can obtain good passband characteristics for both the receiving filter and the transmitting filter.

[0089] (Second Embodiment)

[0090] Figure 10 This is a schematic diagram of the structure of the device chip 105 in the second embodiment.

[0091] like Figure 10 As shown, a receiving filter RxBPF and a transmitting filter TxBPF are formed on a device chip 105. This allows for the provision of an elastic wave device serving as a duplexer on a single device chip.

[0092] like Figure 10 As shown, the input terminal In(Rx) of the receiving filter RxBPF and the output terminal Out(Tx) of the transmitting filter TxBPF are the same terminal. Furthermore, the output terminal Out(Rx) of the receiving filter RxBPF and the input terminal In(Tx) of the transmitting filter TxBPF can be positioned at the furthest points from each other on the device chip 105. This reduces interference between the receiving filter RxBPF and the transmitting filter TxBPF and improves the characteristics of the duplexer.

[0093] Furthermore, in the design of the receive filter RxBPF and the transmit filter TxBPF on a single device chip, in order to ensure that the receive filter RxBPF can suppress electrical signals outside the passband in a space-saving manner, it can be a multimode filter, and in order to ensure power resistance, the transmit filter TxBPF can be a trapezoidal filter.

[0094] The other structures are the same as those in the first embodiment, so descriptions are omitted.

[0095] (Third Embodiment)

[0096] Next, a third embodiment, which is another embodiment of the present invention, will be described.

[0097] Figure 11 This is a cross-sectional view of module 100 according to the third embodiment of the present invention.

[0098] like Figure 11As shown, the elastic wave device 1 is provided on the main surface of the wiring board 130. The elastic wave device 1 can be, for example, a duplexer as described in the first embodiment or the second embodiment. The wiring board 130 includes a plurality of external connection terminals 131. The external connection terminals 131 can be mounted to the main printed circuit board of a predetermined mobile communication terminal.

[0099] An inductor 111 is provided on the main surface of the wiring board 130 to achieve impedance matching. The inductor 111 may be an integrated passive device (IPD). The module 100 seals multiple electronic components, including the elastic wave device 1, through a sealing portion 117.

[0100] The wiring board 130 contains an integrated circuit component (IC). The integrated circuit component (IC) includes a switching circuit and a low-noise amplifier, which are not shown in the figure.

[0101] Other structures are omitted because they are repetitive with the content of the first and second embodiments.

[0102] According to the above embodiments of the present invention, an elastic wave device using a multimode resonator that is closer to a rectangle, has low loss, and has excellent passband characteristics can be provided, as well as a module including the elastic wave device.

[0103] It should be noted that, of course, the present invention is not limited to the embodiments described above, but also includes all embodiments that can achieve the purpose of the present invention.

[0104] Furthermore, while at least one embodiment has been described above, it should be understood that various changes, modifications, or improvements can be readily conceived by those skilled in the art. These changes, modifications, or improvements are intended to be part of this disclosure and fall within the scope of the invention. It should be understood that the embodiments of the methods or apparatus described herein are not limited to the architecture and arrangement of the constituent components described above or shown in the accompanying drawings. Methods and apparatus can be installed or implemented in other embodiments. The embodiments described are for illustrative purposes only and are not intended to be limiting. Moreover, the descriptions or terms used herein are for illustrative purposes only and are not intended to be limiting. The use of "comprising," "possessing," "having," "including," and variations thereof herein means to include the items listed below, their equivalents, and additional items. The term "or," or any term used in the description of "or," can be interpreted as meaning one, more than one, or all of the descriptive terms. The terms front, back, left, right, top, bottom, up, down, and horizontal are used for convenience of description and are not intended to limit the position and spatial configuration of any constituent component in this invention. Therefore, the above description and accompanying drawings are merely illustrative.

Claims

1. An elastic wave device, characterized in that... The filter includes a piezoelectric substrate and a bandpass filter formed on the piezoelectric substrate and including a resonator. The resonator has a first IDT electrode, a second IDT electrode, a third IDT electrode, a fourth IDT electrode, and a fifth IDT electrode. The first to fifth IDT electrodes are all electrically connected to an electrical signal input to an input pad. The number of pairs of the third IDT electrode is greater than the number of pairs of the first IDT electrode. The number of pairs of the second IDT electrode, the fourth IDT electrode, and the fifth IDT electrode is the sum of the number of pairs of the first IDT electrode and the fifth IDT electrode. The reflectors of the first IDT electrode and the fifth IDT electrode are adjacent to each other.

2. The elastic wave device according to claim 1, characterized in that: The number of logarithms of the first IDT electrode is the same as the number of logarithms of the fifth IDT electrode.

3. The elastic wave device according to claim 1, characterized in that: The number of logarithms of the second IDT electrode is the same as the number of logarithms of the fourth IDT electrode.

4. The elastic wave device according to claim 1, characterized in that: The wiring pattern of the bandpass filter has a first metal layer, a second metal layer formed on the first metal layer, and an insulator formed between the first metal layer and the second metal layer. The first metal layer has an island pattern that is surrounded by and insulated from the signal line of the third IDT electrode. The island pattern is electrically connected to the ground line of the second IDT electrode and the ground line of the fourth IDT electrode through the second metal layer.

5. The elastic wave device according to claim 1, characterized in that: The piezoelectric substrate is bonded to a substrate on a main surface opposite to the surface forming the bandpass filter, the substrate being formed of one of sapphire, silicon, alumina, spinel, and glass.

6. The elastic wave device according to claim 1, characterized in that: The bandpass filter is a receiving filter, and the elastic wave device is a duplexer that also includes a transmitting filter.

7. The elastic wave device according to claim 6, characterized in that: The passband frequency of the receiving filter is lower than that of the transmitting filter.

8. The elastic wave device according to claim 6, characterized in that: The transmitting filter has multiple resonators configured in a ladder structure.

9. The elastic wave device according to claim 8, characterized in that: The multiple resonators of the transmitting filter, arranged in a trapezoidal structure, are thin-film resonators.

10. The elastic wave device according to claim 6, characterized in that: The transmitting filter is formed on the piezoelectric substrate.

11. A module comprising the elastic wave device according to any one of claims 1 to 7.

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