Elastic wave device

Abstract

The purpose of the present invention is to improve isolation characteristics while achieving a low height. In a first elastic wave filter (1), a first conductor section (3) is interposed between the first elastic wave filter (1) and a second elastic wave filter (2), and is connected to a second functional conductor section (E2) of the second elastic wave filter (2). The first elastic wave filter (1) is provided with: a signal electrode (17) that is disposed on the second main surface (102) of the first piezoelectric substrate (10) and that is connected to the first conductor section (3); a ground electrode (18) disposed on the second main surface (102) of the first piezoelectric substrate (10); and a second conductor part (7) connected to the ground electrode (18). In a plan view from the thickness direction (D1) of the first piezoelectric substrate (10), the ground electrode (18) overlaps the first functional conductor part (E1) and does not overlap the signal electrode (17). The second conductor part (7) is disposed between the first main surface (101) and the second main surface (102) of the first piezoelectric substrate (10), and is separated from the first main surface (101).

Description

Technical Field

[0001] The present invention generally relates to an elastic wave device, and more particularly, to an elastic wave device including a first elastic wave filter and a second elastic wave filter. Background Art

[0002] Patent Document 1 discloses an elastic wave device including a first elastic wave filter, a second elastic wave filter, and a bump (first conductor) connecting the first elastic wave filter and the second elastic wave filter.

[0003] In the elastic wave device disclosed in Patent Document 1, a first elastic wave filter comprises a first substrate (first piezoelectric substrate) having piezoelectricity on at least a portion thereof, and a first functional electrode provided on the first surface (first principal surface) of the first substrate. Furthermore, a second elastic wave filter comprises a second substrate (second piezoelectric substrate) having piezoelectricity on at least a portion thereof, and a second functional electrode provided on the first surface (third principal surface) of the second substrate. Furthermore, the first elastic wave filter comprises a signal terminal (signal electrode) provided on the second surface (second principal surface) of the first substrate and electrically connected to the second functional electrode, a ground terminal (ground electrode), and an insulating film interposed between the ground terminal and the signal terminal in the thickness direction of the first substrate.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: International Publication No. 2018 / 235433 Summary of the Invention

[0007] Problems to be solved by the invention

[0008] In the elastic wave device disclosed in Patent Document 1, although the degradation of the isolation characteristics between the first functional electrode and the signal electrode can be suppressed, it is difficult to achieve a low profile because a ground electrode, an insulating film, and a signal electrode are stacked on the second principal surface of the first piezoelectric substrate.

[0009] An object of the present invention is to provide an elastic wave device that can achieve both a reduced height and improved isolation characteristics.

[0010] Technical solutions to solve problems

[0011] An elastic wave device according to one embodiment of the present invention includes a first elastic wave filter, a second elastic wave filter, and a first conductor. The first elastic wave filter includes a first piezoelectric substrate and a first functional conductor. The first piezoelectric substrate has a first principal surface and a second principal surface that oppose each other. The first functional conductor is disposed on the first principal surface of the first piezoelectric substrate. The second elastic wave filter includes a second piezoelectric substrate and a second functional conductor. The second functional conductor is disposed on the second piezoelectric substrate. The second elastic wave filter is disposed on the first elastic wave filter. The first conductor is interposed between the first and second elastic wave filters. The first conductor is connected to the second functional conductor. The first elastic wave filter includes a signal electrode, a ground electrode, and a second conductor. The signal electrode is disposed on the second principal surface of the first piezoelectric substrate. The signal electrode is connected to the first conductor. The ground electrode is disposed on the second principal surface of the first piezoelectric substrate. The second conductor portion is connected to the ground electrode. When viewed from above in the thickness direction of the first piezoelectric substrate, the ground electrode overlaps with the first functional conductor portion and does not overlap with the signal electrode. The second conductor portion is arranged between the first and second principal surfaces of the first piezoelectric substrate and is separated from the first principal surface.

[0012] Effects of the Invention

[0013] The elastic wave device according to the above-described aspect of the present invention can achieve both a reduced height and improved isolation characteristics. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a cross-sectional view of a main portion of the elastic wave device according to Embodiment 1.

[0015] Figure 2 This is a bottom view of the same elastic wave device as above.

[0016] Figure 3 This is a bottom view of the same elastic wave device, omitting the illustration of the plurality of external connection terminals.

[0017] Figure 4 This is a perspective view of the first elastic wave filter in the same elastic wave device as above, viewed from the bottom surface side.

[0018] Figure 5 This is a bottom view of the second elastic wave filter in the same elastic wave device.

[0019] Figure 6 This is an enlarged view of the main parts of the elastic wave device as above.

[0020] Figure 72 is a cross-sectional view of another main part of the elastic wave device described above.

[0021] Figure 8 This is a circuit diagram of the same elastic wave device as above.

[0022] Figure 9 This is a cross-sectional view of a main portion of an elastic wave device according to Embodiment 2.

[0023] Figure 10 This is a cross-sectional view of a main portion of an elastic wave device according to Embodiment 3.

[0024] Figure 11 This is a cross-sectional view of a main portion of an elastic wave device according to a fourth embodiment.

[0025] Figure 12 2 is a cross-sectional view of another main part of the elastic wave device described above. DETAILED DESCRIPTION

[0026] The figures referenced in the following embodiments 1 to 4 are schematic diagrams, and the sizes and thickness ratios of the components in the figures do not necessarily reflect the actual dimensional ratios. In addition, the following embodiments 1 to 4 are merely one of the various embodiments of the present invention. As long as the objectives of the present invention can be achieved, the following embodiments 1 to 4 can be modified in various ways according to design, etc., and different components of different embodiments can be appropriately combined.

[0027] (Implementation Method 1)

[0028] The following is based on Figures 1 to 8 The elastic wave device 100 according to the first embodiment will be described.

[0029] (1) Summary

[0030] like Figure 1As shown, the elastic wave device 100 according to Embodiment 1 includes a first elastic wave filter 1, a second elastic wave filter 2, and a first conductor portion 3. The first elastic wave filter 1 includes a first piezoelectric substrate 10 and a first functional conductor portion E1. The first piezoelectric substrate 10 has a first principal surface 101 and a second principal surface 102 that are opposed to each other. The first functional conductor portion E1 is arranged on the first principal surface 101 of the first piezoelectric substrate 10. The first functional conductor portion E1 is a conductor portion having a potential different from the ground potential. The second elastic wave filter 2 includes a second piezoelectric substrate 20 and a second functional conductor portion E2. The second functional conductor portion E2 is arranged on the second piezoelectric substrate 20. The second elastic wave filter 2 is arranged on the first elastic wave filter 1. The first conductor portion 3 is interposed between the first elastic wave filter 1 and the second elastic wave filter 2. The first conductor portion 3 is connected to the second functional conductor portion E2. The first elastic wave filter 1 includes a signal electrode 17, a ground electrode 18, and a plurality of second conductor portions 7 (see Figure 1 as well as Figure 6 The signal electrode 17 is arranged on the second principal surface 102 of the first piezoelectric substrate 10. The signal electrode 17 is connected to the first conductor 3. The ground electrode 18 is arranged on the second principal surface 102 of the first piezoelectric substrate 10. The ground electrode 18 is an electrode to which a ground potential is applied.

[0031] Furthermore, in elastic wave device 100, as shown in FIG. Figure 2 as well as Figure 3 As shown, the first elastic wave filter 1 further includes a common electrode 15, a signal electrode 16, and a ground electrode 19. The common electrode 15, the signal electrode 16, and the ground electrode 19 are arranged on the second principal surface 102 of the first piezoelectric substrate 10. Hereinafter, the signal electrode 16 may be referred to as the first signal electrode 16, and the signal electrode 17 may be referred to as the second signal electrode 17. Hereinafter, the ground electrode 18 may be referred to as the first ground electrode 18, and the ground electrode 19 may be referred to as the second ground electrode 19.

[0032] (2) Details

[0033] Below, in reference Figure 8 After describing the circuit configuration of the elastic wave device 100 , the structure of the elastic wave device 100 will be described in more detail.

[0034] (2.1) Circuit structure of elastic wave device

[0035] Elastic wave device 100 is, for example, a duplexer used in a high-frequency front-end circuit of a communication device. The communication device includes an antenna. In elastic wave device 100, for example, first elastic wave filter 1 is a transmission filter, and second elastic wave filter 2 is a reception filter. Common electrode 15 is a signal input / output electrode shared by both the transmission and reception filters. The transmission filter, for example, has a passband in the transmission band of a first communication frequency band. The first communication frequency band is, for example, a communication band conforming to the 3GPP (registered trademark, Third Generation Partnership Project) LTE (registered trademark, Long Term Evolution) standard. The first communication frequency band is, for example, a communication band (e.g., Band 25) used in communications conforming to FDD (Frequency Division Duplex) as a communication method, but is not limited thereto and may also be a communication band used in communications conforming to TDD (Time Division Duplex). The reception filter, for example, has a passband in the reception band of the second communication frequency band. The second communication frequency band is, for example, a communication frequency band of the 3GPP LTE standard or a communication frequency band of the 5G NR standard. The second communication frequency band is a communication frequency band used for communication corresponding to FDD (for example, Band 25), but is not limited thereto and may also be a communication frequency band used for communication corresponding to TDD. The second communication frequency band may be the same as the first communication frequency band or a different communication frequency band.

[0036] (2.1.1) First elastic wave filter

[0037] like Figure 8 As shown, first elastic wave filter 1 is, for example, a ladder-type filter having a plurality (e.g., eleven) of first elastic wave resonators 14. Multiple first elastic wave resonators 14 include, for example, seven series-arm resonators S11, S12, S131, S132, S133, S14, and S15, and four parallel-arm resonators P11, P12, P13, and P14. The seven series-arm resonators S11, S12, S131, S132, S133, S14, and S15 are provided on a first signal path Ru1 (hereinafter also referred to as a series-arm path Ru1) between a common electrode 15 and a first signal electrode 16. Figure 8In the example shown, three of the seven series-arm resonators S11, S12, S131, S132, S133, S14, and S15 are each composed of multiple (two in the illustrated example) split resonators, but the present invention is not limited to this. The multiple split resonators are resonators formed by splitting a single first elastic wave resonator 14, and the split resonators are connected in series with no other first elastic wave resonators 14 between them and no connection nodes to paths containing other first elastic wave resonators 14.

[0038] Six of the seven series arm resonators S11, S12, S131, S132, S133, S14, and S15 are connected in series along the series arm path Ru1. In the first elastic wave filter 1, the series arm resonators S11, S12, S131, S133, S14, and S15 are arranged in the order of series arm resonator S11, S12, S131, S133, S14, and S15, starting from the first signal electrode 16, along the series arm path Ru1. Furthermore, in the first elastic wave filter 1, the series arm resonator S132 is connected in parallel with the series arm resonator S131. Therefore, six series arm resonators S11, S12, S132, S133, S14, and S15 among the seven series arm resonators S11, S12, S131, S132, S133, S14, and S15 are connected in series.

[0039] The parallel arm resonator P11 is provided on a path Ru11 (parallel arm path Ru11) between the path between the series arm resonators S11 and S12 in the series arm path Ru1 and the ground. The parallel arm resonator P12 is provided on a path Ru12 (parallel arm path Ru12) between the path between the parallel circuit of the series arm resonator S12 and the two series arm resonators S131 and S132 in the series arm path Ru1 and the ground. The parallel arm resonator P13 is provided on a path Ru13 (parallel arm path Ru13) between the path between the series arm resonator S133 and the series arm resonator S14 in the series arm path Ru1 and the ground. The parallel arm resonator P14 is provided on a path Ru14 (parallel arm path Ru14) between the path between the series arm resonator S14 and S15 in the series arm path Ru1 and the ground.

[0040] (2.1.2) Second elastic wave filter

[0041] like Figure 8As shown, the second elastic wave filter 2 is, for example, a ladder-type filter having a plurality (e.g., eight) of second elastic wave resonators 24. The plurality of second elastic wave resonators 24 include, for example, four series arm resonators S21, S22, S23, and S24, and four parallel arm resonators P21, P22, P23, and P24. The four series arm resonators S21, S22, S23, and S24 are provided on a second signal path Ru2 (hereinafter also referred to as a series arm path Ru2) between the common electrode 15 and the second signal electrode 17. Furthermore, three of the four series arm resonators S21, S22, S23, and S24 are each composed of a plurality (two in the illustrated example) of split resonators, but this is not limiting. The plurality of split resonators are resonators formed by splitting one second elastic wave resonator 24 , and are connected in series without any other second elastic wave resonator 24 between the split resonators or with any connection nodes to paths including other second elastic wave resonators 24 .

[0042] Four series arm resonators S21, S22, S23, and S24 are connected in series along the series arm path Ru2. In the second elastic wave filter 2, the series arm resonators S21, S22, S23, and S24 are arranged in this order on the series arm path Ru2, starting from the common electrode 15.

[0043] The parallel arm resonator P21 is provided on a path Ru21 (hereinafter referred to as the parallel arm path Ru21) between the path between the series arm resonators S21 and S22 in the series arm path Ru2 and the ground. The parallel arm resonator P22 is provided on a path Ru22 (hereinafter referred to as the parallel arm path Ru22) between the path between the series arm resonators S22 and S23 in the series arm path Ru2 and the ground. The parallel arm resonator P23 is provided on a path Ru23 (hereinafter referred to as the parallel arm path Ru23) between the path between the series arm resonators S23 and S24 in the series arm path Ru2 and the ground. The parallel arm resonator P24 is provided on a path Ru24 (hereinafter referred to as the parallel arm path Ru24) between the path between the series arm resonator S24 and the second signal electrode 17 in the series arm path Ru2 and the ground.

[0044] (2.2) Structure of elastic wave device

[0045] The following is based on Figures 1 to 7 The structure of elastic wave device 100 will be described.

[0046] like Figure 1As shown, the elastic wave device 100 includes a first elastic wave filter 1, a second elastic wave filter 2, and a first conductor 3. In addition, the elastic wave device 100 further includes a spacer 4 and a plurality of external connection terminals 6 (see FIG. Figure 2 ). Spacer portion 4 is interposed between first elastic wave filter 1 and second elastic wave filter 2. Spacer portion 4 is frame-shaped. Elastic wave device 100 includes a hollow space SP1 surrounded by first elastic wave filter 1, second elastic wave filter 2, and spacer portion 4. Each of the plurality of external connection terminals 6 is, for example, a conductive bump.

[0047] (2.2.1) First elastic wave filter

[0048] The first elastic wave filter 1 is an elastic wave filter using surface acoustic waves. Figure 1 as well as Figure 4 As shown, it includes a first piezoelectric substrate 10 and a plurality of (for example, 11) first functional electrodes 12 that constitute a portion of each of the plurality of (for example, 11) first elastic wave resonators 14. Each of the plurality of first functional electrodes 12 includes an IDT (Interdigital Transducer) electrode. Therefore, each of the plurality of first elastic wave resonators 14 is a SAW (Surface Acoustic Wave) resonator. Among the seven series arm resonators S11, S12, S131, S132, S133, S14, and S15 in the plurality of first elastic wave resonators 14, the three series arm resonators S11, S12, and S15 composed of a plurality of (2) split resonators each include two IDT electrodes. The two IDT electrodes are connected in series with each other via a common bus bar that they share. In addition, as shown Figure 4As shown, the first elastic wave filter 1 includes a plurality (e.g., 28) of first reflectors 13. Furthermore, the first elastic wave filter 1 has a plurality of wiring conductor sections. These include a first wiring conductor section W1, a second wiring conductor section W2, a third wiring conductor section W3, a fourth wiring conductor section W4, a fifth wiring conductor section W5, a sixth wiring conductor section W6, a seventh wiring conductor section W7, an eighth wiring conductor section W8, a ninth wiring conductor section W9, and a plurality of tenth wiring conductor sections (not shown). The first wiring conductor section W1, the second wiring conductor section W2, the third wiring conductor section W3, the fourth wiring conductor section W4, the fifth wiring conductor section W5, the sixth wiring conductor section W6, the seventh wiring conductor section W7, the eighth wiring conductor section W8, and the ninth wiring conductor section W9 are connected to at least one of the plurality of first functional electrodes 12. Furthermore, each of the plurality of tenth wiring conductor sections is connected to at least one of the plurality of first reflectors 13. In the first elastic wave filter 1 , for example, the first functional conductor portion E1 includes a fourth wiring conductor portion W4 . Furthermore, the first elastic wave filter 1 includes a through-hole conductor V1 (hereinafter also referred to as the first through-hole conductor V1 ), a through-hole conductor V2 (hereinafter also referred to as the second through-hole conductor V2 ), a through-hole conductor V3 (hereinafter also referred to as the third through-hole conductor V3 ), and a plurality of through-hole ground via conductors (not shown). Figure 1 is with Figure 6 The sectional view corresponding to the Y1-Y1 line section. Figure 6 In the figure, each first functional electrode 12, each first reflector 13 and each wiring conductor portion is marked with dotted shadows. These shadows do not represent cross sections, but are simply marked for ease of viewing the drawings. Figure 7 is with Figure 6 The sectional view corresponding to the Y1-Y2 line section.

[0049] like Figure 1 As shown, the first piezoelectric substrate 10 has a first principal surface 101 and a second principal surface 102 facing each other in the thickness direction D1 of the first piezoelectric substrate 10. When viewed from above in the thickness direction D1 of the first piezoelectric substrate 10, the outer edge of the first piezoelectric substrate 10 is rectangular (see FIG. Figures 2-4 The thickness H10 of the first piezoelectric substrate 10 is, for example, not less than 50 μm and not more than 200 μm.

[0050] The first piezoelectric substrate 10 includes, for example, a first high-acoustic-velocity supporting substrate 111, a first low-acoustic-velocity film 112 disposed on the first high-acoustic-velocity supporting substrate 111, and a first piezoelectric layer 113 disposed on the first low-acoustic-velocity film 112. The first piezoelectric layer 113 has piezoelectricity. In the first high-acoustic-velocity supporting substrate 111, the acoustic velocity of the bulk wave propagating through the first high-acoustic-velocity supporting substrate 111 is higher than the acoustic velocity of the elastic wave propagating through the first piezoelectric layer 113. The bulk wave propagating through the first high-acoustic-velocity supporting substrate 111 is the lowest-acoustic-velocity bulk wave among the multiple bulk waves propagating through the first high-acoustic-velocity supporting substrate 111. The first low-acoustic-velocity film 112 is a film that makes the acoustic velocity of the bulk wave propagating through the first low-acoustic-velocity film 112 lower than the acoustic velocity of the bulk wave propagating through the first piezoelectric layer 113.

[0051] The material of the first piezoelectric layer 113 includes, for example, lithium tantalate or lithium niobate. For example, assuming that the wavelength of the elastic wave determined by the electrode finger pitch of the IDT electrode included in the first functional electrode 12 is λ, the thickness of the first piezoelectric layer 113 is preferably 3.5λ or less.

[0052] The material of the first high acoustic velocity support substrate 111 includes silicon, for example. In this case, the first high acoustic velocity support substrate 111 is a silicon substrate. The thickness of the silicon substrate is preferably, for example, greater than 10λ and less than 180μm. The resistivity of the silicon substrate is, for example, greater than 1 kΩcm, preferably greater than 2 kΩcm, and more preferably greater than 4 kΩcm. The silicon substrate includes, for example, a body region on the side of the first low acoustic velocity film 112 and a surface region on the side opposite to the first low acoustic velocity film 112. The surface region includes the second principal surface 102 of the first piezoelectric substrate 10. The thickness of the surface region is, for example, greater than 1 nm and less than 700 nm. The body region is a single crystal silicon layer. The single crystal silicon layer is the remaining portion of the single crystal silicon substrate after the surface region is formed on the single crystal silicon substrate. The surface region is, for example, an amorphous silicon layer. The amorphous silicon layer is formed, for example, by degrading the lattice structure of a portion of the single crystal silicon substrate that forms the basis of the first high acoustic velocity support substrate 111. The surface region is formed, for example, by implanting ions of at least one element selected from the group consisting of argon, silicon, oxygen, and carbon into a single crystal silicon substrate. The surface region can also be formed, for example, by irradiating a single crystal silicon substrate with radiation. The material of the first high acoustic velocity support substrate 111 may include, for example, at least one material selected from the group consisting of silicon, aluminum nitride, aluminum oxide, silicon carbide, silicon nitride, sapphire, lithium tantalate, lithium niobate, quartz, alumina, zirconium oxide, cordierite, mullite, steatite, forsterite, magnesium oxide, and diamond.

[0053] The material of the first low-acoustic-velocity film 112 includes, for example, silicon oxide. The material of the first low-acoustic-velocity film 112 is not limited to silicon oxide. The material of the first low-acoustic-velocity film 112 can also be, for example, silicon oxide, glass, silicon oxynitride, tantalum oxide, a compound containing fluorine, carbon, or boron added to silicon oxide, or a material primarily composed of any of the above materials. The thickness of the first low-acoustic-velocity film 112 is preferably, for example, 2λ or less.

[0054] A plurality of (eg, 11) first functional electrodes 12 (see Figure 1 as well as Figure 4 ) are arranged on the first principal surface 101 of the first piezoelectric substrate 10. As described above, each of the plurality of first functional electrodes 12 includes an IDT electrode. The plurality of first functional electrodes 12 are conductive. Examples of materials for the plurality of first functional electrodes 12 include aluminum, copper, platinum, gold, silver, titanium, nickel, chromium, molybdenum, tungsten, tantalum, magnesium, iron, or alloys primarily composed of any of these metals. Furthermore, the plurality of first functional electrodes 12 may also have a structure in which a plurality of metal films comprising these metals or alloys are stacked. Furthermore, the plurality of first functional electrodes 12 may, for example, include a stacked film comprising a first metal film comprising a titanium film formed on the first principal surface 101 of the first piezoelectric substrate 10 and a second metal film comprising an aluminum film formed on the first metal film. The first metal film functions as a bonding film. The material of the first metal film is titanium, but is not limited thereto; for example, it may also be chromium or nickel-chromium. The material of the second metal film is aluminum, but is not limited thereto; for example, it may also include aluminum and copper. The thickness of the first metal film is thinner than that of the second metal film. The thickness of each of the plurality of first functional electrodes 12 is, for example, 150 nm.

[0055] In the elastic wave device 100 according to the first embodiment, the plurality of first functional electrodes 12 (see Figure 4 ) The seven first functional electrodes 12 corresponding to the seven series arm resonators S11, S12, S131, S132, S133, S14, and S15 are conductor portions having a potential different from the ground potential.

[0056] Multiple (e.g., 28) first reflectors 13 are arranged on the first principal surface 101 of the first piezoelectric substrate 10. In the elastic wave device 100, two first reflectors 13 are arranged adjacent to each of the multiple IDT electrodes. The two first reflectors 13 reflect elastic waves in the direction of propagation determined by the IDT electrode located between the two first reflectors 13. Each of the multiple first reflectors 13 is, for example, a grid reflector. Each of the multiple first reflectors 13 is conductive. Each of the multiple first reflectors 13 is a conductor portion at a potential different from the ground potential, or a conductor portion at the ground potential. The potential of each first reflector 13 corresponding to the seven series arm resonators S11, S12, S131, S132, S133, S14, and S15 is assigned a potential different from the ground potential. The material of the multiple first reflectors 13 is, for example, the same as that of the multiple first functional electrodes 12. The thickness of the plurality of first reflectors 13 is, for example, the same as the thickness of the plurality of first functional electrodes 12. The thickness of each of the plurality of first reflectors 13 is, for example, 150 nm.

[0057] A plurality of wiring conductor portions are arranged on the first principal surface 101 of the first piezoelectric substrate 10. Figure 4 As shown, the first wiring conductor portion W1 is connected to the series arm resonator S11 and the second through-hole conductor V2, and includes a first signal path Ru1 (see Figure 8 The second wiring conductor portion W2 is connected to two series arm resonators S11 and S12 and one parallel arm resonator P11, and includes a first signal path Ru1 (see Figure 8 ) and a portion of the parallel arm path Ru11 (refer to Figure 8 The third wiring conductor portion W3 is connected to three series arm resonators S12, S131, and S132 and one parallel arm resonator P12, and includes a first signal path Ru1 (see Figure 8 ) and a portion of the parallel arm path Ru12 (refer to Figure 8 The fourth wiring conductor portion W4 is connected to the three series arm resonators S131, S132, and S133, and includes the first signal path Ru1 (see Figure 8 The fifth wiring conductor portion W5 is connected to two series arm resonators S133 and S14 and one parallel arm resonator P13, and includes a first signal path Ru1 (see Figure 8 ) and a portion of the parallel arm path Ru13 (refer to Figure 8 The sixth wiring conductor portion W6 is connected to two series arm resonators S14 and S15 and one parallel arm resonator P14, and includes a first signal path Ru1 (see Figure 8 ) and a portion of the parallel arm path Ru14 (refer to Figure 8The seventh wiring conductor portion W7 is connected to the series arm resonator S15 and the first through-hole conductor V1 and includes the first signal path Ru1 (see Figure 8 The eighth wiring conductor portion W8 is connected to the three parallel arm resonators P11, P13, and P14, and includes three parallel arm paths Ru11, Ru13, and Ru14 (see Figure 8 ) are part of each. The ninth wiring conductor portion W9 is connected to the parallel arm resonator P12 and includes a parallel arm path Ru12 (see Figure 8 ) part.

[0058] In addition, if Figure 1 as well as Figure 4 As shown, the first elastic wave filter 1 includes a first metal portion 11 and a relay electrode 8 disposed on a first principal surface 101 of a first piezoelectric substrate 10. When viewed from above in the thickness direction D1 of the first piezoelectric substrate 10, the first metal portion 11 is in the shape of a rectangular frame extending along the outer edge of the first piezoelectric substrate 10. When viewed from above in the thickness direction D1 of the first piezoelectric substrate 10, as shown in FIG. Figure 4 As shown in FIG. 1 , the first metal portion 11 surrounds the plurality of first functional electrodes 12, the plurality of first reflectors 13, the plurality of wiring conductor portions, and the relay electrode 8. Figure 4 As shown, the eighth and ninth wiring conductors W8 and W9 of the first to ninth wiring conductors W1 to W9 of the plurality of wiring conductors are connected to the first metal portion 11. Therefore, the eighth and ninth wiring conductors W8 and W9 are wiring conductors at ground potential. The relay electrode 8 is conductive. The relay electrode 8 is used to connect the second elastic wave filter 2 (see FIG. 1 ). Figure 1 ) and the conductor portion connected to the second signal electrode 17, forming a second signal path Ru2 (refer to Figure 8 ). Figure 4 As shown, when viewed from above in the thickness direction D1 of the first piezoelectric substrate 10, the relay electrode 8 is surrounded by the first metal portion 11 and the eighth wiring conductor portion W8. The relay electrode 8 is separated from the first metal portion 11 and the eighth wiring conductor portion W8 and is electrically insulated from the first metal portion 11 and the eighth wiring conductor portion W8. The first metal portion 11 and the eighth wiring conductor portion W8 are conductor portions at ground potential.

[0059] Furthermore, the first through-hole conductor V1, the second through-hole conductor V2, the third through-hole conductor V3, and the plurality of through-ground via conductors penetrate the first piezoelectric substrate 10 in the thickness direction D1 of the first piezoelectric substrate 10. Each of the first through-hole conductor V1, the second through-hole conductor V2, the third through-hole conductor V3, and the plurality of through-ground via conductors is, for example, cylindrical in shape. When viewed from above in the thickness direction D1 of the first piezoelectric substrate 10, each of the first through-hole conductor V1, the second through-hole conductor V2, the third through-hole conductor V3, and the plurality of through-ground via conductors is circular in shape. When viewed from above in the thickness direction D1 of the first piezoelectric substrate 10, the first through-hole conductor V1, the second through-hole conductor V2, the third through-hole conductor V3, and the plurality of through-ground via conductors are arranged inside the rectangular frame-shaped first metal portion 11. The first through-via conductor V1 , the second through-via conductor V2 , and the third through-via conductor V3 are separated from each other in a direction along the inner peripheral edge of the first metal portion 11 in a plan view in the thickness direction D1 of the first piezoelectric substrate 10 .

[0060] When viewed from above in the thickness direction D1 of the first piezoelectric substrate 10, Figure 3 As shown, the first through-hole conductor V1 overlaps with the common electrode 15. More specifically, when viewed from above in the thickness direction D1 of the first piezoelectric substrate 10, the entire first through-hole conductor V1 overlaps with a portion of the common electrode 15. The first through-hole conductor V1 is in contact with the common electrode 15 and is electrically connected to the common electrode 15. In addition, when viewed from above in the thickness direction D1 of the first piezoelectric substrate 10, as shown in FIG. Figure 4 As shown, the first through-hole conductor V1 overlaps a portion of the seventh wiring conductor portion W7. The first through-hole conductor V1 is in contact with the seventh wiring conductor portion W7 and is electrically connected to the seventh wiring conductor portion W7.

[0061] In addition, when viewed from above in the thickness direction D1 of the first piezoelectric substrate 10, Figure 3 As shown, the second through-hole conductor V2 overlaps with the first signal electrode 16. More specifically, when viewed from above in the thickness direction D1 of the first piezoelectric substrate 10, the entire second through-hole conductor V2 overlaps with a portion of the first signal electrode 16. The through-hole conductor V2 is in contact with the first signal electrode 16 and is electrically connected to the first signal electrode 16. In addition, when viewed from above in the thickness direction D1 of the first piezoelectric substrate 10, as shown in FIG. Figure 4 As shown, the second through-hole conductor V2 overlaps a portion of the first wiring conductor portion W1. The second through-hole conductor V2 is in contact with the first wiring conductor portion W1 and is electrically connected to the first wiring conductor portion W1.

[0062] In addition, when viewed from above in the thickness direction D1 of the first piezoelectric substrate 10, Figure 3 As shown in FIG. 1 , the third through-hole conductor V3 overlaps with the second signal electrode 17. More specifically, when viewed from above in the thickness direction D1 of the first piezoelectric substrate 10, the entire third through-hole conductor V3 overlaps with a portion of the second signal electrode 17. The third through-hole conductor V3 is in contact with the second signal electrode 17 and is electrically connected to the second signal electrode 17. In addition, when viewed from above in the thickness direction D1 of the first piezoelectric substrate 10, as shown in FIG. Figure 4 As shown, the third through-hole conductor V3 overlaps a portion of the relay electrode 8. The third through-hole conductor V3 is in contact with the relay electrode 8 and is electrically connected to the relay electrode 8.

[0063] The plurality of through-ground via conductors are connected to, for example, the first ground electrode 18 or the second ground electrode 19 in a plan view from the thickness direction D1 of the first piezoelectric substrate 10 .

[0064] In the first elastic wave filter 1, as Figure 2 as well as Figure 3 As shown, the common electrode 15, the first signal electrode 16, the second signal electrode 17, the first ground electrode 18, and the second ground electrode 19 are arranged on the second principal surface 102 of the first piezoelectric substrate 10. The common electrode 15, the first signal electrode 16, the second signal electrode 17, the first ground electrode 18, and the second ground electrode 19 are conductive. The first ground electrode 18 and the second ground electrode 19 are, for example, electrodes electrically connected to a ground electrode of a circuit board included in the communication device and thus given a ground potential. The material of the common electrode 15, the first signal electrode 16, the second signal electrode 17, the first ground electrode 18, and the second ground electrode 19 includes, for example, copper. The common electrode 15, the first signal electrode 16, the second signal electrode 17, the first ground electrode 18, and the second ground electrode 19 each have a structure in which a plurality of metal films including metals or alloys are stacked, but the present invention is not limited to this and may also be a metal film including metals or alloys. The common electrode 15, the first signal electrode 16, the second signal electrode 17, the first ground electrode 18, and the second ground electrode 19 have the same thickness. The metal film farthest from the second main surface 102 among the plurality of metal films is a plated film formed by wet plating, for example.

[0065] like Figure 2 as well as Figure 3As shown, the common electrode 15, the first signal electrode 16, the second signal electrode 17, the first ground electrode 18, and the second ground electrode 19 are separated from each other on the second principal surface 102 of the first piezoelectric substrate 10. When viewed from above in the thickness direction D1 of the first piezoelectric substrate 10, the common electrode 15, the first signal electrode 16, the second signal electrode 17, the first ground electrode 18, and the second ground electrode 19 are separated from each other. The common electrode 15, the first signal electrode 16, the second signal electrode 17, the first ground electrode 18, and the second ground electrode 19 have the same thickness. The thickness of the common electrode 15, the first signal electrode 16, the second signal electrode 17, the first ground electrode 18, and the second ground electrode 19 is thicker than the thickness of each first functional electrode 12 and the thickness of each first reflector 13.

[0066] When viewed from above in the thickness direction D1 of the first piezoelectric substrate 10, Figure 3 As shown, the common electrode 15, the first signal electrode 16, and the second signal electrode 17 are each rectangular in shape, for example. The outer edge 120 of the second principal surface 102 of the first piezoelectric substrate 10 is rectangular and has a first side 121, a second side 122, a third side 123, and a fourth side 124. The first side 121, the second side 122, the third side 123, and the fourth side 124 are arranged in this order along the outer edge 120 of the second principal surface 102. The common electrode 15 is arranged at a corner near the intersection of the first side 121 and the fourth side 124 of the second principal surface 102 of the first piezoelectric substrate 10. The first signal electrode 16 is arranged at a corner near the intersection of the first side 121 and the second side 122 of the second principal surface 102 of the first piezoelectric substrate 10. The second signal electrode 17 is arranged near the midpoint of the third side 123 of the second principal surface 102 of the first piezoelectric substrate 10 .

[0067] like Figure 1 as well as Figure 6 As shown in FIG. 1 , when viewed from above in the thickness direction D1 of the first piezoelectric substrate 10 , the first ground electrode 18 overlaps with the first functional conductor E1 and does not overlap with the second signal electrode 17 . Figure 2 As shown in FIG. 1 , the first ground electrode 18 includes a first ground portion 181, a second ground portion 182, and a third ground portion 183. Figure 6 As shown, when viewed from above in the thickness direction D1 of the first piezoelectric substrate 10, the first ground portion 181 overlaps with the first functional conductor portion E1 and surrounds the second signal electrode 17. When viewed from above in the thickness direction D1 of the first piezoelectric substrate 10, the first ground portion 181 is, for example, the third side 123 of the second principal surface 102 of the first piezoelectric substrate 10 (see FIG. Figure 3) side is open, and surrounds the portion of the second signal electrode 17 located inside the first metal portion 11. When viewed from above in the thickness direction D1 of the first piezoelectric substrate 10, the first ground portion 181 may surround the second signal electrode 17 over the entire circumference. However, it is sufficient to surround the portion of the second signal electrode 17 located inside the spacer portion 4, and it is not necessary to surround the second signal electrode 17 over the entire circumference. Figure 2 as well as Figure 3 As shown, the second ground portion 182 is connected to the first ground portion 181 and is arranged along the third side 123 and the second side 122 of the second main surface 102. The third ground portion 183 is connected to the first ground portion 181 and is arranged along the third side 123 and the fourth side 124 of the second main surface 102.

[0068] When viewed from above in the thickness direction D1 of the first piezoelectric substrate 10, the area of ​​the first ground electrode 18 is larger than the areas of the common electrode 15, the first signal electrode 16, and the second signal electrode 17. Furthermore, when viewed from above in the thickness direction D1 of the first piezoelectric substrate 10, the area of ​​the second ground electrode 19 is larger than the areas of the common electrode 15, the first signal electrode 16, and the second signal electrode 17. When viewed from above in the thickness direction D1 of the first piezoelectric substrate 10, the area of ​​the first ground electrode 18 is larger than the area of ​​the second ground electrode 19. The common electrode 15, the first signal electrode 16, and the second signal electrode 17 are rectangular when viewed from above in the thickness direction D1 of the first piezoelectric substrate 10, but are not limited to this and may also be circular, for example.

[0069] A plurality of (for example, 14) second conductors 7 (see Figure 1 as well as Figure 6) is arranged between the first principal surface 101 and the second principal surface 102 of the first piezoelectric substrate 10. When viewed from above in the thickness direction D1 of the first piezoelectric substrate 10, the plurality of second conductor portions 7 each have, for example, a rectangular shape. When viewed from above in the thickness direction D1 of the first piezoelectric substrate 10, the plurality of second conductor portions 7 overlap with the first ground electrode 18. The plurality of second conductor portions 7 are connected to the first ground electrode 18. More specifically, the plurality of second conductor portions 7 are in contact with the first ground electrode 18 and are electrically connected to the first ground electrode 18. The plurality of second conductor portions 7 may be integral with the first ground electrode 18 or may not be integral with the first ground electrode 18. When the plurality of second conductor portions 7 are integral with the first ground electrode 18, they are formed of the same material as the first ground electrode. When they are not integral with the first ground electrode 18, they are formed of, for example, a material different from that of the ground electrode. Furthermore, the plurality of second conductor portions 7 are separated from the first principal surface 101 of the first piezoelectric substrate 10. In other words, the plurality of second conductor portions 7 do not reach the first principal surface 101 of the first piezoelectric substrate 10. Furthermore, the plurality of second conductor portions 7 are separated from the first functional conductor portion E1. When viewed from above in the thickness direction D1 of the first piezoelectric substrate 10, the plurality of second conductor portions 7 are arranged, for example, to surround the second signal electrode 17. Figure 1 As shown, the plurality of second conductor portions 7 are arranged to suppress capacitive coupling between the first functional conductor portion E1 of the first elastic wave filter 1, which is arranged on the first principal surface 101 of the first piezoelectric substrate 10, and the second signal electrode 17, which is arranged on the second principal surface 102 of the first piezoelectric substrate 10 and connected to the second functional conductor portion E2 of the second elastic wave filter 2. More specifically, at least one of the plurality of second conductor portions 7 is arranged so as to overlap with the first functional conductor portion E1 when viewed from above in the thickness direction D1 of the first piezoelectric substrate 10. To distinguish the plurality (14) of second conductor portions 7, they are referred to as the plurality of second conductor portions 7A to 7N (see FIG. 1 ). Figure 6 ), the seven second conductor portions 7G to 7M overlap with the first functional conductor portion E1 (fourth wiring conductor portion W4) when viewed from above in the thickness direction D1 of the first piezoelectric substrate 10. The first elastic wave filter 1 does not necessarily need to include multiple second conductor portions 7; it only needs to include at least one second conductor portion 7. Alternatively, the first elastic wave filter 1 may include a single second conductor portion 7 surrounding the second signal electrode 17, rather than multiple second conductor portions 7.

[0070] From the perspective of suppressing leakage of high-frequency signals from the first functional conductor portion E1 to the second conductor portions 7 and suppressing a decrease in the manufacturing yield of the elastic wave device 100, the length L7 of each second conductor portion 7 in the thickness direction D1 of the first piezoelectric substrate 10 (see Figure 1) is equal to or less than the thickness of the first high acoustic velocity supporting substrate 111, for example, the thickness H10 of the first piezoelectric substrate 10 (see Figure 1 ). The length L7 of each second conductor portion 7 is less than 80% of the thickness H10 of the first piezoelectric substrate 10, preferably less than 70%, more preferably more than 40% and less than 60%. In addition, the lower limit of the length L7 of each second conductor portion 7 is more than 10% of the thickness H10 of the first piezoelectric substrate 10, preferably more than 30%, more preferably more than 40%. In addition, the length L7 of each second conductor portion 7 may also be the same as the thickness of the first high acoustic velocity supporting substrate 111. In this case, when a recess is formed from the second main surface 102 of the first piezoelectric substrate 10 to the predetermined formation area of ​​each second conductor portion 7 by etching technology during manufacturing, the first low acoustic velocity film 112 can be used as an etching stopper, thereby improving the accuracy of the length L7 of each second conductor portion 7.

[0071] Multiple external connection terminals 6 (see Figure 1 as well as Figure 2 ) are each, for example, a spherical conductive bump. The conductive bump is made of, for example, solder, copper, or gold. Figure 2 As shown, the plurality of external connection terminals 6 are arranged in a direction along the outer edge 120 of the second principal surface 102 of the first piezoelectric substrate 10 when viewed from above in the thickness direction D1 of the first piezoelectric substrate 10. The plurality of external connection terminals 6 include a common terminal 65 connected to the common electrode 15, a first signal terminal 66 connected to the first signal electrode 16, a second signal terminal 67 connected to the second signal electrode 17, a plurality of first ground terminals 68 connected to the first ground electrode 18, and a plurality of second ground terminals 69 connected to the second ground electrode 19.

[0072] (2.2.2) Second elastic wave filter

[0073] The second elastic wave filter 2 is an elastic wave filter using surface acoustic waves. Figure 1 as well as Figure 5 As shown, it includes a second piezoelectric substrate 20 and a plurality of (e.g., 8) second functional electrodes 22 that constitute a portion of each of the plurality of (e.g., 8) second elastic wave resonators 24. The plurality of second functional electrodes 22 each include an IDT electrode. Therefore, the plurality of second elastic wave resonators 24 are each SAW resonators. Of the four series arm resonators S21, S22, S23, S24 in the plurality of second elastic wave resonators 24, the three series arm resonators S21, S23, S24 composed of a plurality of (2) split resonators each include two IDT electrodes. The two IDT electrodes are connected in series with each other via a common bus bar that they share. In addition, as shown in FIG. Figure 5As shown, the second elastic wave filter 2 includes a plurality (e.g., 22) of second reflectors 23. Furthermore, the second elastic wave filter 2 has a plurality of wiring conductor sections. These include an 11th wiring conductor section W11, a 12th wiring conductor section W12, a 13th wiring conductor section W13, a 14th wiring conductor section W14, a 15th wiring conductor section W15, a 16th wiring conductor section W16, a 17th wiring conductor section W17, an 18th wiring conductor section W18, and a plurality of 19th wiring conductor sections (not shown). The 11th wiring conductor section W11, the 12th wiring conductor section W12, the 13th wiring conductor section W13, the 14th wiring conductor section W14, the 15th wiring conductor section W15, the 16th wiring conductor section W16, the 17th wiring conductor section W17, and the 18th wiring conductor section W18 are connected to at least one second functional electrode 22 among the plurality of second functional electrodes 22. Furthermore, each of the plurality of nineteenth wiring conductor portions is connected to at least one of the plurality of second reflectors 23. In the second elastic wave filter 2, for example, the second functional conductor portion E2 includes the fifteenth wiring conductor portion W15.

[0074] like Figure 1 As shown, the second piezoelectric substrate 20 has a third principal surface 201 and a fourth principal surface 202 that are opposed to each other in the thickness direction D1 of the first piezoelectric substrate 10. The third principal surface 201 of the second piezoelectric substrate 20 is opposed to the first principal surface 101 of the first piezoelectric substrate 10. The second functional conductor portion E2 is disposed on the third principal surface 201 of the second piezoelectric substrate 20. When viewed from above in the thickness direction D1 of the first piezoelectric substrate 10, the outer edge 220 of the second piezoelectric substrate 20 (see FIG. 2 ) is substantially the same as that of the first piezoelectric substrate 10. Figure 5 ) is rectangular in shape.

[0075] The second piezoelectric substrate 20 includes, for example, a second high-acoustic-velocity supporting substrate 211, a second low-acoustic-velocity film 212 disposed on the second high-acoustic-velocity supporting substrate 211, and a second piezoelectric layer 213 disposed on the second low-acoustic-velocity film 212. The second piezoelectric layer 213 has piezoelectricity. In the second high-acoustic-velocity supporting substrate 211, the acoustic velocity of the bulk wave propagating through the second high-acoustic-velocity supporting substrate 211 is higher than the acoustic velocity of the elastic wave propagating through the second piezoelectric layer 213. Here, the bulk wave propagating through the second high-acoustic-velocity supporting substrate 211 is the lowest-acoustic-velocity bulk wave among the multiple bulk waves propagating through the second high-acoustic-velocity supporting substrate 211. The second low-acoustic-velocity film 212 is a film that makes the acoustic velocity of the bulk wave propagating through the second low-acoustic-velocity film 212 lower than the acoustic velocity of the bulk wave propagating through the second piezoelectric layer 213.

[0076] The material of the second piezoelectric layer 213 includes, for example, lithium tantalate or lithium niobate.

[0077] The material of the second high acoustic velocity support substrate 211 includes silicon, for example. In this case, the second high acoustic velocity support substrate 211 is a silicon substrate. The thickness of the silicon substrate is preferably, for example, not less than 10λ and not more than 180μm. The resistivity of the silicon substrate is, for example, not less than 1kΩcm, preferably not less than 2kΩcm, and more preferably not less than 4kΩcm. The material of the second high acoustic velocity support substrate 211 may include, for example, at least one material selected from the group consisting of silicon, aluminum nitride, aluminum oxide, silicon carbide, silicon nitride, sapphire, lithium tantalate, lithium niobate, quartz, alumina, zirconium oxide, cordierite, mullite, steatite, forsterite, magnesium oxide, and diamond.

[0078] The material of the second low-acoustic-velocity film 212 includes, for example, silicon oxide. The material of the second low-acoustic-velocity film 212 is not limited to silicon oxide. The material of the second low-acoustic-velocity film 212 may also be, for example, silicon oxide, glass, silicon oxynitride, tantalum oxide, a compound containing silicon oxide with fluorine, carbon, or boron added, or a material primarily composed of any of the above materials.

[0079] like Figure 5 As shown, multiple (e.g., eight) second functional electrodes 22 are arranged on the third principal surface 201 of the second piezoelectric substrate 20. As described above, each of the multiple second functional electrodes 22 comprises an IDT electrode. The multiple second functional electrodes 22 are electrically conductive. Examples of materials for the multiple second functional electrodes 22 include aluminum, copper, platinum, gold, silver, titanium, nickel, chromium, molybdenum, tungsten, tantalum, magnesium, iron, or alloys primarily composed of any of these metals. Alternatively, the multiple second functional electrodes 22 may have a structure comprising a stack of multiple metal films comprising these metals or alloys. Furthermore, the multiple second functional electrodes 22 may comprise, for example, a stacked film comprising a first metal film comprising titanium formed on the third principal surface 201 of the second piezoelectric substrate 20 and a second metal film comprising aluminum formed on the first metal film. The first metal film functions as an adhesion film. The material of the first metal film is titanium, but is not limited to this; for example, it may also be chromium or nickel-chromium. The material of the second metal film is aluminum, but is not limited to this; for example, it may also be aluminum and copper. The thickness of the first metal film is thinner than the thickness of the second metal film. The thickness of each of the plurality of second functional electrodes 22 is, for example, 150 nm.

[0080] In elastic wave device 100 according to Embodiment 1, four second functional electrodes 22 corresponding to four series arm resonators S21 , S22 , S23 , and S24 among the plurality of second functional electrodes 22 are conductor portions having a potential different from the ground potential.

[0081] like Figure 5As shown, multiple (e.g., 22) second reflectors 23 are arranged on the third principal surface 201 of the second piezoelectric substrate 20. In the elastic wave device 100, two second reflectors 23 are arranged adjacent to the IDT electrodes included in each of the multiple second functional electrodes 22. The two second reflectors 23 reflect elastic waves in the direction of propagation determined by the IDT electrode located between the two second reflectors 23. Each of the multiple second reflectors 23 is, for example, a grid reflector. Each of the multiple second reflectors 23 is conductive. Each of the multiple second reflectors 23 is a conductor portion at a potential different from the ground potential, or a conductor portion at the ground potential. Each second reflector 23 corresponding to the four series arm resonators S21, S22, S23, and S24 is assigned a potential different from the ground potential. The material of the multiple second reflectors 23 is, for example, the same as that of the multiple second functional electrodes 22. The thickness of the plurality of second reflectors 23 is, for example, the same as the thickness of the plurality of second functional electrodes 22. The thickness of each of the plurality of second reflectors 23 is, for example, 150 nm.

[0082] A plurality of wiring conductor portions are arranged on the third main surface 201 of the second piezoelectric substrate 20. Figure 5 As shown, the eleventh wiring conductor portion W11 is connected to the series arm resonator S21 and the third conductor portion 9, and includes a second signal path Ru2 (see Figure 8 ) part. The third conductor portion 9 is connected to the first through-hole conductor V1 (see Figure 3 as well as Figure 4 ) and the common electrode 15 (refer to Figure 3 as well as Figure 4 ) is electrically connected. The 12th wiring conductor portion W12 is connected to the two series arm resonators S21 and S22 and the one parallel arm resonator P21, and includes a second signal path Ru2 (see Figure 8 ) and a portion of the parallel arm path Ru21 (refer to Figure 8 ) part. The 13th wiring conductor portion W13 is connected to the two series arm resonators S22 and S23 and the one parallel arm resonator P22, and includes the second signal path Ru2 (refer to Figure 8 ) and a portion of the parallel arm path Ru22 (refer to Figure 8 ) part. The 14th wiring conductor portion W14 is connected to the two series arm resonators S23 and S24 and the one parallel arm resonator P23, and includes the second signal path Ru2 (refer to Figure 8 ) and a portion of the parallel arm path Ru23 (refer to Figure 8 The fifteenth wiring conductor portion W15 is connected to the series arm resonator S24, the parallel arm resonator P24, and the first conductor portion 3, and includes a second signal path Ru2 (see Figure 8) and a portion of the parallel arm path Ru24 (refer to Figure 8 ) part. The 16th wiring conductor portion W16 is connected to the parallel arm resonator P21 and includes a parallel arm path Ru21 (refer to Figure 8 ) part. The 17th wiring conductor portion W17 is connected to the parallel arm resonator P22 and includes a parallel arm path Ru22 (refer to Figure 8 ) part. The 18th wiring conductor portion W18 is connected to the two parallel arm resonators P23 and P24, and includes parallel arm paths Ru23 and Ru24 (see Figure 8 ) their respective parts.

[0083] In addition, if Figure 1 as well as Figure 5 As shown, the second elastic wave filter 2 includes a second metal portion 21 disposed on the third principal surface 201 of the second piezoelectric substrate 20. When viewed from above in the thickness direction D1 of the second piezoelectric substrate 20, the second metal portion 21 is in the shape of a rectangular frame along the outer edge of the second piezoelectric substrate 20. When viewed from above in the thickness direction D1 of the first piezoelectric substrate 10, as shown in FIG. Figure 5 As shown, the second metal portion 21 surrounds the plurality of second functional electrodes 22, the plurality of second reflectors 23, and the plurality of wiring conductor portions. The 16th to 18th wiring conductor portions W16 to W18 of the 11th to 18th wiring conductor portions W11 to W18 of the plurality of wiring conductor portions are connected to the second metal portion 21. When viewed from above in the thickness direction D1 of the first piezoelectric substrate 10, the second metal portion 21 overlaps the first metal portion 11 of the first elastic wave filter 1.

[0084] (2.2.3) Spacer

[0085] like Figure 1 as well as Figure 7 As shown, the spacer portion 4 is interposed between the first elastic wave filter 1 and the second elastic wave filter 2 in the thickness direction D1 of the first piezoelectric substrate 10. More specifically, the spacer portion 4 is interposed between the first metal portion 11 of the first elastic wave filter 1 and the second metal portion 21 of the second elastic wave filter 2. The spacer portion 4 has a rectangular frame shape. The material of the spacer portion 4 includes, for example, at least one of a metal and solder. In the elastic wave device 100, the first metal portion 11 of the first elastic wave filter 1 and the second metal portion 21 of the second elastic wave filter 2 are bonded via the spacer portion 4. In other words, in the elastic wave device 100, the spacer portion 4 forms the bonding portion that bonds the first elastic wave filter 1 and the second elastic wave filter 2. In the elastic wave device 100, the second metal portion 21 is electrically connected to the first metal portion 11. Alternatively, the first metal portion 11 and the second metal portion 21 may be directly bonded without the spacer portion 4.

[0086] (2.2.4) First conductor and third conductor

[0087] The first conductor 3 (see Figure 1 as well as Figure 5 ) and the third conductor 9 (refer to Figure 5 ) is interposed between the first elastic wave filter 1 and the second elastic wave filter 2 in the thickness direction D1 of the first piezoelectric substrate 10. The first conductor portion 3 and the third conductor portion 9 have electrical conductivity.

[0088] When viewed from above in the thickness direction D1 of the first piezoelectric substrate 10, the first conductor portion 3 overlaps with the relay electrode 8 of the first elastic wave filter 1. Furthermore, when viewed from above in the thickness direction D1 of the first piezoelectric substrate 10, the first conductor portion 3 overlaps with the second functional conductor portion E2 of the second elastic wave filter 2. The first conductor portion 3 is interposed between the second functional conductor portion E2 of the second elastic wave filter 2 and the relay electrode 8 of the first elastic wave filter 1. Therefore, in the elastic wave device 100, the second functional conductor portion E2 of the second elastic wave filter 2 and the relay electrode 8 are connected via the first conductor portion 3. Thus, in the elastic wave device 100, the series arm resonator S24 (see FIG. 2 ) of the second elastic wave filter 2 is connected to the relay electrode 8. Figure 5 ) is connected to the second signal electrode 17 (see Figure 1 as well as Figure 3 ) electrical connection.

[0089] When viewed from above in the thickness direction D1 of the first piezoelectric substrate 10, the third conductor portion 9 (see Figure 5 ) and the seventh wiring conductor portion W7 of the first elastic wave filter 1 (see Figure 4 ) and the first through-hole conductor V1 (refer to Figure 4 ) overlap. In addition, when viewed from above in the thickness direction D1 of the first piezoelectric substrate 10, the third conductor portion 9 overlaps with the eleventh wiring conductor portion W11 (see Figure 5 ) overlap. The third conductor portion 9 is interposed between the 11th wiring conductor portion W11 of the second elastic wave filter 2 and the 7th wiring conductor portion W7 of the first elastic wave filter 1. Therefore, in the elastic wave device 100, the series arm resonator S21 (see Figure 5 ) and the first through-hole conductor V1 (refer to Figure 4) are connected via the 11th wiring conductor portion W11, the third conductor portion 9, and the seventh wiring conductor portion W7. Thus, in the elastic wave device 100, the series arm resonator S21 of the second elastic wave filter 2 is connected to the common electrode 15 (see FIG. 1 ) via the 11th wiring conductor portion W11, the third conductor portion 9, the seventh wiring conductor portion W7, and the first through-hole conductor V1. Figure 3 ) electrical connection.

[0090] (3) Effect

[0091] An elastic wave device 100 according to Embodiment 1 includes a first elastic wave filter 1, a second elastic wave filter 2, and a first conductor 3. The first elastic wave filter 1 includes a first piezoelectric substrate 10 and a first functional conductor E1. The first piezoelectric substrate 10 has a first principal surface 101 and a second principal surface 102 that face each other. The first functional conductor E1 is disposed on the first principal surface 101 of the first piezoelectric substrate 10. The second elastic wave filter 2 includes a second piezoelectric substrate 20 and a second functional conductor E2. The second functional conductor E2 is disposed on the second piezoelectric substrate 20. The second elastic wave filter 2 is disposed on the first elastic wave filter 1. The first conductor 3 is interposed between the first and second elastic wave filters 1 and 2. The first conductor 3 is connected to the second functional conductor E2. The first elastic wave filter 1 further includes a signal electrode 17, a ground electrode 18, and a second conductor 7. The signal electrode 17 is disposed on the second principal surface 102 of the first piezoelectric substrate 10. The signal electrode 17 is connected to the first conductor portion 3. The ground electrode 18 is arranged on the second principal surface 102 of the first piezoelectric substrate 10. The second conductor portion 7 is connected to the ground electrode 18. When viewed from above in the thickness direction D1 of the first piezoelectric substrate 10, the ground electrode 18 overlaps with the first functional conductor portion E1 and does not overlap with the signal electrode 17. The second conductor portion 7 is arranged between the first principal surface 101 and the second principal surface 102 of the first piezoelectric substrate 10 and is separated from the first principal surface 101.

[0092] The elastic wave device 100 according to Embodiment 1 achieves both a low profile and improved isolation characteristics. More specifically, in the elastic wave device 100 according to Embodiment 1, when viewed from above in the thickness direction D1 of the first piezoelectric substrate 10, the ground electrode 18 disposed on the second principal surface 102 of the first piezoelectric substrate 10 overlaps with the first functional conductor portion E1 and does not overlap with the signal electrode 17. Consequently, the elastic wave device 100 according to Embodiment 1 can achieve a low profile. Furthermore, in the elastic wave device 100 according to Embodiment 1, the first elastic wave filter 1 includes the second conductor portion 7 connected to the ground electrode 18. The second conductor portion 7 is disposed between the first principal surface 101 and the second principal surface 102 of the first piezoelectric substrate 10 and is separated from the first principal surface 101. Thus, in the elastic wave device 100 according to Embodiment 1, a first parasitic capacitance is formed between the first functional conductor portion E1 and the second conductor portion 7, and a second parasitic capacitance is formed between the second conductor portion 7 and the signal electrode 17, resulting in the first and second parasitic capacitances being connected in series. Consequently, the elastic wave device 100 according to Embodiment 1 can reduce the capacitance of the parasitic capacitance between the first functional conductor portion E1 and the signal electrode 17, thereby improving the isolation between the first functional conductor portion E1 of the first elastic wave filter 1 and the signal electrode 17 connected to the second elastic wave filter 2. Consequently, the elastic wave device 100 according to Embodiment 1 can achieve improved isolation characteristics. Furthermore, the elastic wave device 100 according to Embodiment 1 can improve the filter characteristics of both the first elastic wave filter 1 and the second elastic wave filter 2. Specifically, the elastic wave device 100 according to Embodiment 1 can improve the attenuation characteristics on the high-frequency side of the passband (e.g., the transmission band corresponding to Band 25) of the first elastic wave filter 1. Furthermore, elastic wave device 100 according to Embodiment 1 can improve the attenuation characteristics on the low-frequency side of the passband (eg, the reception band corresponding to Band 25 ) of second elastic wave filter 2 .

[0093] Furthermore, in the elastic wave device 100 according to the first embodiment, the second conductor portion 7 overlaps the first functional conductor portion E1 when viewed from above in the thickness direction D1 of the first piezoelectric substrate 10. This facilitates the formation of parasitic capacitance between the first functional conductor portion E1 and the signal electrode 17, and between the first functional conductor portion E1 and the second conductor portion 7, making it easier to reduce the capacitance value of the parasitic capacitance between the first functional conductor portion E1 and the signal electrode 17.

[0094] (Implementation Method 2)

[0095] Reference Figure 9The elastic wave device 100A according to the second embodiment will be described. The elastic wave device 100A according to the second embodiment is similar to the elastic wave device 100 according to the first embodiment (see Figure 1 ) The same components are marked with the same figure numbers and the description is omitted.

[0096] (1) Structure

[0097] In the elastic wave device 100A according to the second embodiment, the first functional conductor portion E1 overlaps with the ground electrode 18 and the signal electrode 17 when viewed from above in the thickness direction D1 of the first piezoelectric substrate 10. More specifically, a portion of the first functional conductor portion E1 overlaps with a portion of the ground electrode 18, and another portion of the first functional conductor portion E1 overlaps with a portion of the signal electrode 17.

[0098] (2) Effect

[0099] Since the elastic wave device 100A according to the second embodiment includes the second conductor portion 7 , capacitive coupling between the first functional conductor portion E1 and the signal electrode 17 can be suppressed in a structure in which the first functional conductor portion E1 and the signal electrode 17 overlap when viewed from above in the thickness direction D1 of the first piezoelectric substrate 10 .

[0100] (Implementation Method 3)

[0101] Reference Figure 10 The elastic wave device 100B according to the third embodiment will be described. The elastic wave device 100B according to the third embodiment is similar to the elastic wave device 100 according to the first embodiment (see Figure 1 ) The same components are marked with the same figure numbers and the description is omitted.

[0102] (1) Structure

[0103] In the elastic wave device 100B according to Embodiment 3, when viewed from above in the thickness direction D1 of the first piezoelectric substrate 10, the first functional conductor portion E1 overlaps with the ground electrode 18 and does not overlap with the second conductor portion 7. In the elastic wave device 100B, when viewed from above in the thickness direction D1 of the first piezoelectric substrate 10, the distance L2 between the second conductor portion 7 and the signal electrode 17 is shorter than the distance L1 between the first functional conductor portion E1 and the signal electrode 17. In other words, in the elastic wave device 100B, when viewed from above in the thickness direction D1 of the first piezoelectric substrate 10, the first functional conductor portion E1, the second conductor portion 7, and the signal electrode 17 are arranged in this order.

[0104] (2) Effect

[0105] Regarding the elastic wave device 100B involved in embodiment 3, when viewed from above in the thickness direction D1 of the first piezoelectric substrate 10, the distance L2 between the second conductor portion 7 and the signal electrode 17 is shorter than the distance L1 between the first functional conductor portion E1 and the signal electrode 17, so that the capacitive coupling between the first functional conductor portion E1 and the signal electrode 17 can be further suppressed.

[0106] (Implementation Method 4)

[0107] Reference Figure 11 as well as Figure 12 An elastic wave device 100C according to a fourth embodiment will be described. Regarding the elastic wave device 100C according to the fourth embodiment, the elastic wave device 100C is different from the elastic wave device 100 according to the first embodiment (see Figure 1 ) The same components are marked with the same figure numbers and the description is omitted.

[0108] (1) Structure

[0109] An elastic wave device 100C according to the fourth embodiment differs from the elastic wave device 100 according to the first embodiment in that it further includes a shield electrode 5 .

[0110] Shield electrode 5 is disposed between first elastic wave filter 1 and second elastic wave filter 2 . More specifically, shield electrode 5 is disposed in hollow space SP1 surrounded by first piezoelectric substrate 10 of first elastic wave filter 1 , second piezoelectric substrate 20 of second elastic wave filter 2 , and spacer 4 .

[0111] The shield electrode 5 is disposed between the first functional conductor portion E1 and the second functional conductor portion E2 in the thickness direction D1 of the first piezoelectric substrate 10. The shield electrode 5 includes, for example, a first shield portion 51 that separates the first elastic wave filter 1 and the second elastic wave filter 2 in the thickness direction D1 of the first piezoelectric substrate 10, and a second shield portion 52 that connects the second elastic wave filter 2 and the first shield portion 51 (see FIG. Figure 7 The shielding electrode 5 is made of a metal. The elastic wave device 100C includes a cavity SP2 formed between the shielding electrode 5 and the second elastic wave filter 2. The cavity SP2 can be formed using, for example, a sacrificial layer etching technique. The shielding electrode 5 is connected to, for example, the second metal portion 21 of the second elastic wave filter 2. Thus, the shielding electrode 5 is electrically connected to the first ground electrode 18 and the second ground electrode 19. Furthermore, the second shielding portion 52 is not limited to a structure connecting the second elastic wave filter 2 and the first shielding portion 51. For example, the second elastic wave filter 1 and the first shielding portion 51 may be connected, and the structure may also be connected to the first metal portion 11.

[0112] In the thickness direction D1 of the first piezoelectric substrate 10, the first functional conductor portion E1 and the second functional conductor portion E2 overlap with the shield electrode 5. In the elastic wave device 100C, when viewed from above in the thickness direction D1 of the first piezoelectric substrate 10, a portion of the shield electrode 5 overlaps with the entire first functional conductor portion E1. However, this is not limiting; a portion of the shield electrode 5 may overlap with a portion of the first functional conductor portion E1. Furthermore, in the elastic wave device 100C, when viewed from above in the thickness direction D1 of the first piezoelectric substrate 10, a portion of the shield electrode 5 overlaps with a portion of the second functional conductor portion E2. However, this is not limiting; a portion of the shield electrode 5 may overlap with the entire second functional conductor portion E2.

[0113] (2) Effect

[0114] In the elastic wave device 100C according to the fourth embodiment, the first functional conductor portion E1 and the second functional conductor portion E2 overlap with the shield electrode 5 in the thickness direction D1 of the first piezoelectric substrate 10. Thus, the elastic wave device 100C according to the fourth embodiment can improve the isolation between the first functional conductor portion E1 and the second functional conductor portion E2.

[0115] (Variation)

[0116] Each of the plurality of second conductor portions 7 may have a shape other than a rectangle, for example, a circular shape, when viewed from above in the thickness direction D1 of the first piezoelectric substrate 10 .

[0117] The first elastic wave filter 1 does not necessarily need to include a plurality of second conductor portions 7; it only needs to include at least one second conductor portion 7. Furthermore, the first elastic wave filter 1 may include a single second conductor portion 7 surrounding the second signal electrode 17, instead of a plurality of second conductor portions 7.

[0118] Furthermore, as described above, when the first high acoustic velocity support substrate 111 is a silicon substrate, the first elastic wave filter 1 may further include, for example, an electrically insulating film interposed between the common electrode 15, the first signal electrode 16, the second signal electrode 17, the first ground electrode 18, and the second ground electrode 19, and the first high acoustic velocity support substrate 111. Furthermore, the electrically insulating film may be provided in a third region of the second principal surface 102 of the first piezoelectric substrate 10, excluding the first region overlapping with the first ground electrode 18 and the second region overlapping with the second ground electrode 19. Furthermore, the electrically insulating film may be provided between the first through via conductor V1, the second through via conductor V2, the third through via conductor V3, and each of the plurality of through ground via conductors, and the first high acoustic velocity support substrate 111. The material of the electrically insulating film includes, for example, silicon oxide.

[0119] Furthermore, in the elastic wave device 100 , the second functional conductor E2 may be arranged on the fourth principal surface 202 of the second piezoelectric substrate 20 instead of on the third principal surface 201 .

[0120] Furthermore, instead of having the through via conductor V3 connecting the first conductor portion 3 and the signal electrode 17 , the first elastic wave filter 1 may have a side electrode that is arranged across the first principal surface 101 , the side surface, and the second principal surface 102 of the first piezoelectric substrate 10 and connects the first conductor portion 3 and the signal electrode 17 .

[0121] The first piezoelectric substrate 10 is not limited to a laminated substrate including the first high-acoustic-velocity supporting substrate 111, the first low-acoustic-velocity film 112, and the first piezoelectric layer 113, but may be, for example, a first piezoelectric substrate such as a lithium tantalate substrate or a lithium niobate substrate.

[0122] The second piezoelectric substrate 20 is not limited to a laminated substrate including the second high-acoustic-velocity supporting substrate 211, the second low-acoustic-velocity film 212, and the second piezoelectric layer 213. For example, the second piezoelectric substrate may be a lithium tantalate substrate or a lithium niobate substrate.

[0123] Furthermore, the first piezoelectric substrate 10 may also have a structure including a first high-acoustic-velocity film interposed between a silicon substrate and a first low-acoustic-velocity film 112. The first high-acoustic-velocity film is a film in which the acoustic velocity of the bulk wave propagating through the first high-acoustic-velocity film is higher than the acoustic velocity of the elastic wave propagating through the first piezoelectric layer 113. Furthermore, the second piezoelectric substrate 20 may also have a structure including a second high-acoustic-velocity film interposed between a silicon substrate and a second low-acoustic-velocity film 212. The second high-acoustic-velocity film is a film in which the acoustic velocity of the bulk wave propagating through the second high-acoustic-velocity film is higher than the acoustic velocity of the elastic wave propagating through the second piezoelectric layer 213. The materials of the first high-acoustic-velocity film and the second high-acoustic-velocity film are, for example, silicon nitride.

[0124] Furthermore, the first piezoelectric substrate 10 may include, for example, a first adhesive layer interposed between the first low-acoustic-velocity film 112 and the first piezoelectric layer 113. The first adhesive layer may include, for example, a resin (epoxy resin, polyimide resin). Furthermore, the second piezoelectric substrate 20 may include, for example, a second adhesive layer interposed between the second low-acoustic-velocity film 212 and the second piezoelectric layer 213. The second adhesive layer may include, for example, a resin (epoxy resin, polyimide resin). Furthermore, the first elastic wave filter 1 may further include a first protective film disposed on the first piezoelectric layer 113 and covering the plurality of first functional electrodes 12 and the plurality of first reflectors 13. The material of the first protective film may be, for example, silicon oxide. Furthermore, the second elastic wave filter 2 may further include a second protective film disposed on the second piezoelectric layer 213 and covering the plurality of second functional electrodes 22 and the plurality of second reflectors 23. The material of the second protective film may be, for example, silicon oxide.

[0125] Furthermore, each of the first elastic wave filter 1 and the second elastic wave filter 2 is not limited to a ladder-type filter, and may be, for example, a T-type filter.

[0126] Furthermore, each of the first elastic wave filter 1 and the second elastic wave filter 2 may be an elastic wave filter utilizing, for example, boundary acoustic waves, plate waves, or the like.

[0127] The circuit configurations of elastic wave devices 100, 100A, 100B, and 100C are not limited to those described above. Figure 8 Furthermore, elastic wave devices 100 , 100A, 100B, and 100C are not limited to a configuration in which first elastic wave filter 1 is a transmission filter and second elastic wave filter 2 is a reception filter. Alternatively, first elastic wave filter 1 may be a reception filter and second elastic wave filter 2 may be a transmission filter.

[0128] (Way)

[0129] In this specification, the following aspects are disclosed.

[0130] The elastic wave device (100; 100A; 100B; 100C) according to the first embodiment comprises a first elastic wave filter (1), a second elastic wave filter (2), and a first conductor portion (3). The first elastic wave filter (1) comprises a first piezoelectric substrate (10) and a first functional conductor portion (E1). The first piezoelectric substrate (10) has a first principal surface (101) and a second principal surface (102) facing each other. The first functional conductor portion (E1) is arranged on the first principal surface (101) of the first piezoelectric substrate (10). The second elastic wave filter (2) comprises a second piezoelectric substrate (20) and a second functional conductor portion (E2). The second functional conductor portion (E2) is arranged on the second piezoelectric substrate (20). The second elastic wave filter (2) is arranged on the first elastic wave filter (1). The first conductor portion (3) is interposed between the first elastic wave filter (1) and the second elastic wave filter (2). The first conductor portion (3) is connected to the second functional conductor portion (E2). The first elastic wave filter (1) has a signal electrode (17), a ground electrode (18) and a second conductor portion (7). The signal electrode (17) is arranged on the second main surface (102) of the first piezoelectric substrate (10). The signal electrode (17) is connected to the first conductor portion (3). The ground electrode (18) is arranged on the second main surface (102) of the first piezoelectric substrate (10). The second conductor portion (7) is connected to the ground electrode (18). When viewed from above in the thickness direction (D1) of the first piezoelectric substrate (10), the ground electrode (18) overlaps with the first functional conductor portion (E1) and does not overlap with the signal electrode (17). The second conductor portion (7) is arranged between the first main surface (101) and the second main surface (102) of the first piezoelectric substrate (10) and is separated from the first main surface (101).

[0131] According to this embodiment, it is possible to achieve both a lower height and an improvement in isolation characteristics.

[0132] In the elastic wave device (100; 100A; 100C) according to the second embodiment, in the first embodiment, the second conductor portion (7) overlaps the first functional conductor portion (E1) when viewed from above in the thickness direction (D1) of the first piezoelectric substrate (10).

[0133] According to this method, parasitic capacitance is easily formed between the first functional conductor part (E1) and the signal electrode (17), and between the first functional conductor part (E1) and the second conductor part (7), making it easy to reduce the capacitance value of the parasitic capacitance between the first functional conductor part (E1) and the signal electrode (17).

[0134] In the elastic wave device (100A) according to the third aspect, in the first aspect, the first functional conductor portion (E1) overlaps with the signal electrode (17) when viewed from above in the thickness direction (D1) of the first piezoelectric substrate (10).

[0135] According to this method, in a structure in which the first functional conductor portion (E1) and the signal electrode (17) overlap when viewed from above in the thickness direction (D1) of the first piezoelectric substrate (10), capacitive coupling between the first functional conductor portion (E1) and the signal electrode (17) can be suppressed.

[0136] In the elastic wave device (100B) involved in the fourth embodiment, in the first embodiment, when viewed from above in the thickness direction (D1) of the first piezoelectric substrate (10), the distance (L2) between the second conductor portion (7) and the signal electrode (17) is shorter than the distance (L1) between the first functional conductor portion (E1) and the signal electrode (17).

[0137] According to this embodiment, the capacitive coupling between the first functional conductor portion (E1) and the signal electrode (17) can be further suppressed.

[0138] In the elastic wave device (100; 100A; 100B; 100C) according to the fifth embodiment, in any one of the first to fourth embodiments, the second piezoelectric substrate (20) has a third principal surface (201) and a fourth principal surface (202) facing each other. The third principal surface (201) of the second piezoelectric substrate (20) faces the first principal surface (101) of the first piezoelectric substrate (10). The second functional conductor portion (E2) is arranged on the third principal surface (201) of the second piezoelectric substrate (20).

[0139] According to this embodiment, the wiring length between the second functional conductor portion (E2) and the signal electrode (17) can be shortened.

[0140] The elastic wave device (100C) according to the sixth embodiment, in the fifth embodiment, further comprises a shielding electrode (5). The shielding electrode (5) is arranged between the first elastic wave filter (1) and the second elastic wave filter (2). In the thickness direction (D1) of the first piezoelectric substrate (10), the first functional conductor portion (E1) and the second functional conductor portion (E2) overlap with the shielding electrode (5).

[0141] According to this aspect, the isolation between the first functional conductor portion ( E1 ) and the second functional conductor portion ( E2 ) can be improved.

[0142] In the elastic wave device (100C) according to the seventh embodiment, in the sixth embodiment, the first elastic wave filter (1) further includes a second ground electrode (19) that is different from the first ground electrode (18) serving as the ground electrode (18). The second ground electrode (19) is disposed on the second principal surface (102) of the first piezoelectric substrate (10). The shielding electrode (5) is electrically connected to the first ground electrode (18) and the second ground electrode (19).

[0143] According to this embodiment, the shielding performance of the shielding electrode (5) can be improved.

[0144] In the elastic wave device (100; 100A; 100B; 100C) according to the eighth embodiment, in any one of the first to seventh embodiments, the first elastic wave filter (1) further includes a through-hole conductor (V3). The through-hole conductor (V3) penetrates the first piezoelectric substrate (10) and connects the first conductor portion (3) and the signal electrode (17).

[0145] According to this method, the wiring length between the first conductor portion (3) and the signal electrode (17) can be shortened.

[0146] In the elastic wave device (100; 100A; 100B; 100C) according to the ninth embodiment, in any one of the first to eighth embodiments, one of the first elastic wave filter (1) and the second elastic wave filter (2) is a transmission filter, and the other of the first elastic wave filter (1) and the second elastic wave filter (2) is a reception filter. The first elastic wave filter (1) further includes a common electrode (15) disposed on the second principal surface (102) of the first piezoelectric substrate. The common electrode (15) is a signal input / output electrode common to the transmission filter and the reception filter.

[0147] According to this aspect, the isolation between the transmission filter and the reception filter can be improved.

[0148] Description of Reference Numerals

[0149] 1: First elastic wave filter;

[0150] 10: first piezoelectric substrate;

[0151] 101: 1st main surface;

[0152] 102: 2nd main surface;

[0153] 120: outer edge;

[0154] 121: side 1;

[0155] 122: Side 2;

[0156] 123: 3rd side;

[0157] 124: 4th side;

[0158] 111: first high-acoustic-velocity supporting substrate;

[0159] 112: 1st low sound velocity membrane;

[0160] 113: first piezoelectric layer;

[0161] 11: 1st Metal Division;

[0162] 12: first functional electrode;

[0163] 13: 1st reflector;

[0164] 14: 1st elastic wave resonator;

[0165] 15: common electrode;

[0166] 16: signal electrode (first signal electrode);

[0167] 17: signal electrode (second signal electrode);

[0168] 18: ground electrode (first ground electrode);

[0169] 181: 1st grounding portion;

[0170] 182: second grounding portion;

[0171] 183: 3rd grounding part;

[0172] 19: second ground electrode;

[0173] 2: Second elastic wave filter;

[0174] 20: second piezoelectric substrate;

[0175] 201: The third main surface;

[0176] 202: 4th main surface;

[0177] 211: second high-acoustic-velocity supporting substrate;

[0178] 212: 2nd low sound velocity membrane;

[0179] 213: second piezoelectric layer;

[0180] 220: outer edge;

[0181] 21: 2nd Metal Division;

[0182] 22: second functional electrode;

[0183] 23: 2nd reflector;

[0184] 3: The first conductor part;

[0185] 4: spacer part;

[0186] 5: shielding electrode;

[0187] 51: 1st shielding part;

[0188] 6: External connection terminal;

[0189] 65: Common terminal;

[0190] 66: 1st signal terminal;

[0191] 67: Second signal terminal;

[0192] 68: First ground terminal;

[0193] 69: Second ground terminal;

[0194] E1: first functional conductor part;

[0195] 7: Second conductor part;

[0196] 8: relay electrode;

[0197] 9: The third conductor;

[0198] 100, 100A, 100B, 100C: elastic wave devices;

[0199] E2: second functional conductor part;

[0200] H10: thickness;

[0201] L1: distance;

[0202] L2: distance;

[0203] L7: length;

[0204] P11, P12, P13, P14: parallel arm resonators;

[0205] P21, P22, P23, P24: parallel arm resonators;

[0206] Ru1: first signal path (serial arm path);

[0207] Ru11: path (parallel arm path);

[0208] Ru12: path (parallel arm path);

[0209] Ru13: path (parallel arm path);

[0210] Ru14: path (parallel arm path);

[0211] Ru2: second signal path (serial arm path);

[0212] Ru21: path (parallel arm path);

[0213] Ru22: path (parallel arm path);

[0214] Ru23: path (parallel arm path);

[0215] Ru24: path (parallel arm path);

[0216] S11, S12, S14, S15: series arm resonators;

[0217] S131, S132, S133: series arm resonators;

[0218] S21, S22, S23, S24: series arm resonators;

[0219] SP1: hollow space;

[0220] SP2: hollow;

[0221] V1: through-hole conductor (first through-hole conductor);

[0222] V2: through-hole conductor (second through-hole conductor);

[0223] V3: through-hole conductor (the third through-hole conductor);

[0224] W1: 1st wiring conductor part;

[0225] W2: second wiring conductor portion;

[0226] W3: 3rd wiring conductor part;

[0227] W4: 4th wiring conductor portion;

[0228] W5: 5th wiring conductor portion;

[0229] W6: 6th wiring conductor portion;

[0230] W7: 7th wiring conductor part;

[0231] W8: 8th wiring conductor portion;

[0232] W9: 9th wiring conductor portion;

[0233] W11: 11th wiring conductor portion;

[0234] W12: 12th wiring conductor portion;

[0235] W13: 13th wiring conductor portion;

[0236] W14: 14th wiring conductor portion;

[0237] W15: 15th wiring conductor portion;

[0238] W16: 16th wiring conductor portion;

[0239] W17: 17th wiring conductor portion;

[0240] W18: 18th wiring conductor portion.

Claims

1. An elastic wave device comprising: A first elastic wave filter includes a first piezoelectric substrate having a first main surface and a second main surface facing each other, and a first functional conductor portion disposed on the first main surface of the first piezoelectric substrate; a second elastic wave filter including a second piezoelectric substrate and a second functional conductor portion disposed on the second piezoelectric substrate, and disposed on the first elastic wave filter; and a first conductor portion interposed between the first elastic wave filter and the second elastic wave filter and connected to the second functional conductor portion; The first elastic wave filter comprises: a signal electrode disposed on the second main surface of the first piezoelectric substrate and connected to the first conductor; a ground electrode disposed on the second main surface of the first piezoelectric substrate; and a second conductor portion connected to the ground electrode, In a plan view from the thickness direction of the first piezoelectric substrate, the ground electrode overlaps with the first functional conductor portion and does not overlap with the signal electrode. The second conductor portion is disposed between the first principal surface and the second principal surface of the first piezoelectric substrate and is separated from the first principal surface.

2. The elastic wave device according to claim 1, wherein: The second conductor portion overlaps the first functional conductor portion in a plan view in the thickness direction of the first piezoelectric substrate.

3. The elastic wave device according to claim 1, wherein: The first functional conductor portion overlaps the signal electrode in a plan view in the thickness direction of the first piezoelectric substrate.

4. The elastic wave device according to claim 1, wherein: In a plan view in the thickness direction of the first piezoelectric substrate, a distance between the second conductor portion and the signal electrode is shorter than a distance between the first functional conductor portion and the signal electrode.

5. The elastic wave device according to any one of claims 1 to 4, wherein: The second piezoelectric substrate has a third main surface and a fourth main surface facing each other. The third principal surface of the second piezoelectric substrate faces the first principal surface of the first piezoelectric substrate. The second functional conductor portion is arranged on the third main surface of the second piezoelectric substrate.

6. The elastic wave device according to claim 5, wherein: The elastic wave device further includes a shield electrode disposed between the first elastic wave filter and the second elastic wave filter. The first functional conductor portion and the second functional conductor portion overlap the shield electrode in the thickness direction of the first piezoelectric substrate.

7. The elastic wave device according to claim 6, wherein: The first elastic wave filter further includes a second ground electrode different from the first ground electrode serving as the ground electrode. The second ground electrode is arranged on the second main surface of the first piezoelectric substrate. The shield electrode is electrically connected to the first ground electrode and the second ground electrode.

8. The elastic wave device according to any one of claims 1 to 7, wherein: The first elastic wave filter further includes a through via conductor that penetrates the first piezoelectric substrate and connects the first conductor portion and the signal electrode.

9. The elastic wave device according to any one of claims 1 to 8, wherein: One of the first elastic wave filter and the second elastic wave filter is a transmission filter, and the other of the first elastic wave filter and the second elastic wave filter is a reception filter. The first elastic wave filter further includes a common electrode disposed on the second main surface of the first piezoelectric substrate. The common electrode is a signal input and output electrode common to the transmission filter and the reception filter.

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