Multiplexer

Abstract

To provide a multiplexer that achieves both improvement of power resistance reliability and suppression of deterioration in isolation characteristics.SOLUTION: Of resonators forming a reception filter connected to a path between a common terminal Ant and a reception terminal Rx, a series resonator S21 and a parallel resonator P21 are provided on a substrate 10, and series resonators S22 and S23 and a parallel resonator P22 are provided on a substrate 20 mounted on the substrate 10. Of resonators connected to a path between the common terminal Ant and a transmission terminal Tx and forming a transmission filter, series resonators S11 and S12 and a parallel resonator P11 are provided on the substrate 10, and a series resonator S13 and a parallel resonator P12 are provided on the substrate 20. Among the series resonators S11, S12, and S21 and the parallel resonators P11 and P21 provided on the substrate 10, a resonator closest to the reception terminal Rx in plan view is the parallel resonator P21.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a multiplexer.

Background Art

[0002] For miniaturization, it is known to mount two substrates on which filters are formed such that the surfaces on which the filters are formed face each other with a gap therebetween (for example, Patent Document 1). At this time, by forming a transmission filter on the lower substrate, it is known that the heat dissipation property of the transmission filter is enhanced and the power endurance reliability is improved (for example, Patent Document 1). Also, it is known to make the electrode fingers of IDTs (Interdigital Transducers) formed opposite to each other on two opposite substrates non-parallel (for example, Patent Document 2). Thereby, deterioration of isolation characteristics is suppressed. Further, the transmission filter and the reception filter are each divided into two sub-filters, and the two sub-filters constituting the transmission filter are formed so as to face each of the two opposite substrates, and the two sub-filters constituting the reception filter are formed so as to face each of the two opposite substrates (for example, Patent Document 3). Thereby, deterioration of isolation characteristics is suppressed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, Patent Documents 1 to 3 still have room for improvement in achieving both improved power withstand reliability and suppression of deterioration in isolation characteristics.

[0005] This invention has been made in view of the above problems, and aims to achieve both improved power withstand reliability and suppression of deterioration of isolation characteristics. [Means for solving the problem]

[0006] The present invention comprises: a first substrate having a first surface and a second surface opposite to the first surface; a second substrate having a third surface and mounted on the first substrate with an air gap between it and the first surface; a transmitting filter having a common terminal, a transmitting terminal, and a receiving terminal provided on the second surface, and a plurality of first elastic wave resonators connected to a first path between the common terminal and the transmitting terminal, some of the plurality of first elastic wave resonators being provided on the first surface and the remainder being provided on the third surface; and a receiving filter having a plurality of second elastic wave resonators connected to a second path between the common terminal and the receiving terminal, some of the plurality of second elastic wave resonators being provided on the first surface and the remainder being provided on the third surface, wherein the resonator closest to the receiving terminal in a plan view among the portion of the first elastic wave resonators provided on the first surface and the portion of the second elastic wave resonators provided on the first surface is a second elastic wave resonator. The plurality of second elastic wave resonators include a plurality of second series resonators connected in series to the second path, and a plurality of second parallel resonators, one end of which is connected to each of the plurality of first nodes on the second path and the other end of which is connected to ground, wherein the second elastic wave resonator closest to the receiving terminal is the second parallel resonator that is electrically connected closest to the common terminal among the plurality of second parallel resonators by being connected to the first node that is located closest to the common terminal among the plurality of first nodes. It is a multiplexer.

[0007] In the above configuration, in a plan view, the second elastic wave resonator closest to the receiving terminal can be provided on the shortest distance between the first elastic wave resonator closest to the receiving terminal among the first elastic wave resonators provided on the first surface and the receiving terminal.

[0008] In the above configuration, the first elastic wave resonator and the second elastic wave resonator provided on the first surface, among which the resonator closest to the transmitting terminal in a plan view, can be configured to be the first elastic wave resonator.

[0009] In the above configuration, the plurality of first elastic wave resonators are a plurality of first series resonators connected in series to the first path, and one end is connected to the first path Each of the multiple second nodes above It includes a plurality of first parallel resonators connected to one end and the other end connected to ground, and some of the first elastic wave resonators provided on the first surface are among the plurality of first series resonators On the first path A first series resonator electrically connected closest to the transmitting terminal, By connecting to the second node located closest to the transmission terminal among the plurality of second nodes, The configuration may include the first parallel resonator among the plurality of first parallel resonators that is electrically connected closest to the transmitting terminal.

[0010] In the above configuration, the remaining first elastic wave resonator provided on the third surface is one of the plurality of first series resonators. On the first path The first series resonator electrically connected closest to the common terminal, By connecting to the second node located closest to the common terminal among the plurality of second nodes, The configuration may include the first parallel resonator among the plurality of first parallel resonators that is electrically connected closest to the common terminal.

[0013] In the above configuration ,before The remaining second elastic wave resonator located on the third surface is one of the plurality of second series resonators. On the aforementioned second path A second series resonator electrically connected closest to the receiving terminal, By connecting to the first node located closest to the receiving terminal among the plurality of first nodes, The configuration may include the second parallel resonator among the plurality of second parallel resonators that is electrically connected closest to the receiving terminal.

[0014] In the above configuration, the second elastic wave resonator closest to the receiving terminal can be configured such that at least a portion of it overlaps with the receiving terminal in a plan view.

[0015] In the above configuration, a shield layer can be provided between the portion of the first elastic wave resonators and the portion of the second elastic wave resonators provided on the first surface, the remaining first elastic wave resonators and the remaining second elastic wave resonators provided on the third surface, and connected to ground.

Advantages of the Invention

[0016] According to the present invention, it is possible to achieve both an improvement in power resistance reliability and a suppression of deterioration in isolation characteristics.

Brief Description of the Drawings

[0017] [Figure 1] FIG. 1 is a circuit diagram of the multiplexer according to Embodiment 1. [Figure 2] FIG. 2 is a cross-sectional view of the multiplexer according to Embodiment 1. [Figure 3] FIG. 3(a) is a plan view when the elastic wave resonator is a surface acoustic wave resonator, and FIG. 3(b) is a cross-sectional view when the elastic wave resonator is a piezoelectric thin film resonator. [Figure 4] FIGS. 4(a) to 4(c) are plan views of the substrate in Embodiment 1. [Figure 5] FIGS. 5(a) to 5(c) are plan views of the substrate in the comparative example. [Figure 6] FIG. 6(a) is a plan view for explaining the problems occurring in the multiplexer according to the comparative example, and FIG. 6(b) is a plan view for explaining the effects of the multiplexer according to Embodiment 1. [Figure 7] FIG. 7 is a circuit diagram of the multiplexer according to Embodiment 2. [Figure 8] FIGS. 8(a) to 8(c) are plan views of the substrate in Embodiment 2. [Figure 9] FIG. 9 is a cross-sectional view of the multiplexer according to Embodiment 3.

Modes for Carrying Out the Invention

[0018] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

Embodiment

[0019] Figure 1 is a circuit diagram of the multiplexer 100 according to Embodiment 1. As shown in Figure 1, a transmit filter 50 is connected between the common terminal Ant and the transmit terminal Tx. A receive filter 60 is connected between the common terminal Ant and the receive terminal Rx. The passband of the transmit filter 50 and the passband of the receive filter 60 do not overlap. The transmit filter 50 outputs the transmit band signal of the high-frequency signal input to the transmit terminal Tx to the common terminal Ant, suppressing signals in other frequency bands. The receive filter 60 outputs the receive band signal of the high-frequency signal input to the common terminal Ant to the receive terminal Rx, suppressing signals in other frequency bands.

[0020] The transmit filter 50 is a ladder-type filter. The transmit filter 50 comprises series resonators S11 to S13 connected in series between the transmit terminal Tx and the common terminal Ant, and parallel resonators P11 and P12 connected in parallel between the transmit terminal Tx and the common terminal Ant. The series resonators S11 to S13 are provided in the series path 52 between the transmit terminal Tx and the common terminal Ant. One end of the parallel resonators P11 and P12 is connected to the series path 52, and the other end is connected to the ground terminal Gnd.

[0021] The receiving filter 60 is a ladder-type filter. The receiving filter 60 comprises series resonators S21 to S23 connected in series between the common terminal Ant and the receiving terminal Rx, and parallel resonators P21 and P22 connected in parallel between the common terminal Ant and the receiving terminal Rx. The series resonators S21 to S23 are provided in the series path 62 between the common terminal Ant and the receiving terminal Rx. One end of the parallel resonators P21 and P22 is connected to the series path 62, and the other end is connected to the ground terminal Gnd.

[0022] Figure 2 is a cross-sectional view of a multiplexer 100 according to Embodiment 1. As shown in Figure 2, a substrate 20 is mounted on a substrate 10, and a lid 30 is mounted on the substrate 20. The substrate 10 comprises a support substrate 11 and a piezoelectric substrate 12 bonded to the support substrate 11. Similarly, the substrate 20 comprises a support substrate 21 and a piezoelectric substrate 22 bonded to the support substrate 21. The support substrates 11 and 21 are, for example, sapphire substrates, spinel substrates, alumina substrates, quartz substrates, or silicon substrates. The piezoelectric substrates 12 and 22 are, for example, lithium tantalate substrates or lithium niobate substrates.

[0023] An elastic wave resonator 13 and wiring 14 are provided on the upper surface 10a of the substrate 10. A terminal 15 is provided on the lower surface 10b of the substrate 10. Terminal 15 is a footpad for connecting the elastic wave resonators 13 and 23 to the outside. Via wiring 16 is provided that penetrates the substrate 10. Via wiring 16 electrically connects wiring 14 and terminal 15. Wiring 14, terminal 15, and via wiring 16 are metal layers such as a copper layer, an aluminum layer, or a gold layer. Terminal 15 includes a common terminal Ant, a transmit terminal Tx, a receive terminal Rx, and a ground terminal Gnd.

[0024] Elastic wave resonators 23 and wiring 24 are provided on the upper surface 20a of the substrate 20. A shielding layer 28 is provided on the lower surface 20b of the substrate 20. The shielding layer 28 has the function of shielding electromagnetic waves between elastic wave resonators 13 and elastic wave resonators 23. Via wiring 26 is provided penetrating the substrate 20. The via wiring 26 is electrically connected to wiring 14 via pillars 17. The wiring 24 and via wiring 26 are metal layers such as copper, aluminum, or gold. The shielding layer 28 includes conductive metal layers such as copper, silver, tungsten, aluminum, or titanium, or magnetic metal layers such as iron, nickel, or iron-nickel alloy layers (Kovar layers). The thickness of the shielding layer 28 is preferably equal to or greater than the skin thickness of the electromagnetic waves to be shielded. The pillars 17 are metal layers including, for example, copper, gold, silver, or aluminum.

[0025] The upper surface 10a of substrate 10 and the lower surface 20b of substrate 20 face each other with an air gap 32 in between. A sealing portion 34a is provided between substrate 10 and substrate 20 so as to surround the elastic wave resonator 13 and the wiring 14. The sealing portion 34a seals the elastic wave resonator 13 and the wiring 14 in the air gap 32. The sealing portion 34a is a metal layer including, for example, a nickel layer, a copper layer, or a gold layer. The sealing portion 34a is electrically connected to terminal 15, which becomes the ground terminal Gnd, via via wiring 16. The shielding layer 28 is electrically connected to the sealing portion 34a and is electrically connected to terminal 15, which becomes the ground terminal Gnd.

[0026] The lid 30 and the upper surface 20a of the substrate 20 face each other with a gap 33 in between. A sealing portion 34b is provided between the substrate 20 and the lid 30 so as to surround the elastic wave resonator 23 and the wiring 24. The sealing portion 34b seals the elastic wave resonator 23 and the wiring 24 in the gap 33. The lid 30 is, for example, an insulating plate such as a sapphire substrate or a metal plate such as a Kovar substrate. The sealing portion 34b is a metal layer including, for example, a nickel layer, a copper layer, or a gold layer. The sealing portion 34b may be electrically connected to the shield layer 28 by via wiring 26 that penetrates the substrate 20. This allows the sealing portion 34b and the lid 30 to be electrically connected to the ground terminal Gnd.

[0027] Examples of elastic wave resonators 13 and 23 will be described using Figures 3(a) and 3(b). Figure 3(a) is a plan view when the elastic wave resonators 13 and 23 are surface acoustic wave resonators. As shown in Figure 3(a), an IDT (Interdigital Transducer) 40 and a reflector 41 are formed on the piezoelectric substrates 12 and 22. The IDT 40 comprises a pair of opposing comb-shaped electrodes 42a. The comb-shaped electrodes 42a comprises a plurality of electrode fingers 42b and a busbar 42c connecting the plurality of electrode fingers 42b. The reflector 41 is provided on both sides of the IDT 40. The IDT 40 excites surface acoustic waves in the piezoelectric substrates 12 and 22. The IDT 40 and the reflector 41 are formed of, for example, an aluminum film or a copper film. As shown in Figure 2, piezoelectric substrates 12 and 22 may be bonded to support substrates 11 and 21, respectively, or the support substrates 11 and 21 may not be provided, and substrates 10 and 20 may consist of piezoelectric substrates 12 and 22 individually. An insulating film such as a silicon oxide film or an aluminum oxide film may be provided between the support substrates 11 and 21 and the piezoelectric substrates 12 and 22. A protective film or temperature compensation film may be provided on substrates 10 and 20 to cover the IDT 40 and the reflector 41.

[0028] Figure 3(b) is a cross-sectional view of the case where the elastic wave resonators 13 and 23 are piezoelectric thin-film resonators. As shown in Figure 3(b), a piezoelectric film 46 is provided on the substrates 10 and 20. A lower electrode 45 and an upper electrode 47 are provided so as to sandwich the piezoelectric film 46. A gap 49 is formed between the lower electrode 45 and the substrates 10 and 20. The region where the lower electrode 45 and the upper electrode 47 face each other with at least a portion of the piezoelectric film 46 in between is the resonance region 48. The lower electrode 45 and the upper electrode 47 within the resonance region 48 excite elastic waves in the thickness longitudinal vibration mode within the piezoelectric film 46. The substrates 10 and 20 are, for example, sapphire substrates, spinel substrates, alumina substrates, glass substrates, quartz substrates, or silicon substrates. The lower electrode 45 and the upper electrode 47 are, for example, metal films such as ruthenium films. The piezoelectric film 46 is, for example, an aluminum nitride film. Instead of the gap 49, an acoustic reflective film that reflects elastic waves may be provided.

[0029] The elastic wave resonators 13 and 23 include electrodes for exciting elastic waves. Therefore, as shown in Figure 2, elastic wave resonators 13 are covered by a gap 32 and elastic wave resonators 23 are covered by a gap 33 so as not to hinder the excitation of elastic waves.

[0030] Figures 4(a) to 4(c) are plan views of the substrates 10 and 20 in Embodiment 1. Figure 4(a) is a plan view of the top surface 20a of substrate 20 as seen from above, Figure 4(b) is a plan view of the top surface 10a of substrate 10 as seen from above, and Figure 4(c) is a plan view of the bottom surface 10b of substrate 10 as seen from above. In Figures 4(a) and 4(b), hatching is added to the wiring 14 and 24 for clarity. In Figure 4(b), the transmit terminal Tx and receive terminal Rx formed on the bottom surface 10b of substrate 10 are shown with dotted lines.

[0031] As shown in Figure 4(a), an elastic wave resonator 23 and wiring 24 are provided on the upper surface 20a of the substrate 20. The elastic wave resonator 23 is a surface acoustic wave resonator comprising an IDT 40 and a reflector 41. The wiring 24 is connected to the elastic wave resonator 23. A sealing portion 34b is provided on the periphery of the substrate 20. The elastic wave resonator 23 includes a series resonator S13 and a parallel resonator P12 that constitute the transmitting filter 50, and series resonators S22, S23 and a parallel resonator P22 that constitute the receiving filter 60.

[0032] As shown in Figure 4(b), an elastic wave resonator 13 and wiring 14 are provided on the upper surface 10a of the substrate 10. The elastic wave resonator 13 is a surface acoustic wave resonator comprising an IDT 40 and a reflector 41. The wiring 14 is connected to the elastic wave resonator 13. A sealing portion 34a is provided on the periphery of the substrate 10. The elastic wave resonator 13 includes series resonators S11, S12 and a parallel resonator P11 that constitute the transmitting filter 50, and series resonators S21 and a parallel resonator P21 that constitute the receiving filter 60.

[0033] As shown in Figure 4(c), a plurality of terminals 15 are provided on the lower surface 10b of the substrate 10. The plurality of terminals 15 include a common terminal Ant, a transmit terminal Tx, a receive terminal Rx, and a ground terminal Gnd. The lower surface 10b has sides 18a and 18b facing each other, and sides 18c and 18d facing each other. The common terminal Ant is provided near the center of one of the pair of opposing sides 18a and 18b of the lower surface 10b, while the transmit terminal Tx and the receive terminal Rx are provided near both ends of the other side 18b, respectively. That is, the transmit terminal Tx is provided near the corner of sides 18b and 18c, and the receive terminal Rx is provided near the corner of sides 18b and 18d. In this way, the common terminal Ant, the transmit terminal Tx, and the receive terminal Rx are provided in positions where the distance between them is large.

[0034] As shown in Figures 4(a) to 4(c), the series resonators S11 to S13 constituting the transmit filter 50 are connected in series between the transmit terminal Tx and the common terminal Ant by wiring 14, via wiring 16, pillar 17, wiring 24, and via wiring 26, while the parallel resonators P11 and P12 are connected in parallel between the transmit terminal Tx and the common terminal Ant. Similarly, the series resonators S21 to S23 constituting the receive filter 60 are connected in series between the common terminal Ant and the receive terminal Rx by wiring 14, via wiring 16, pillar 17, wiring 24, and via wiring 26, while the parallel resonators P21 and P22 are connected in parallel between the common terminal Ant and the receive terminal Rx.

[0035] As shown in Figure 4(b), the series resonator S21 and parallel resonator P21 constituting the receiving filter 60 are located on the upper surface 10a of the substrate 10, closer to the side corresponding to the edge 18d of the lower surface 10b of the substrate 10, than the series resonators S11, S12, and parallel resonator P11 constituting the transmitting filter 50. In a plan view, at least a portion of the parallel resonator P21 overlaps with the receiving terminal Rx, and it is located closer to the receiving terminal Rx than the series resonators S11, S12, and parallel resonator P11. In other words, in a plan view, the series resonators S11, S12, and parallel resonator P11 are located further from the receiving terminal Rx than the parallel resonator P21.

[0036] The parallel resonator P21 is the resonator located closest to the receiving terminal Rx in a plan view among all the series resonators S11, S12, S21 and parallel resonators P11, P21 provided on the upper surface 10a of the substrate 10. On the other hand, among the series resonators S11, S12 and parallel resonators P11 that constitute the transmitting filter 50 provided on the upper surface 10a of the substrate 10, the resonator located closest to the receiving terminal Rx in a plan view is the series resonator S11. Here, "located closest to the receiving terminal Rx in a plan view" means that the shortest distance between it and the receiving terminal Rx in a plan view is the shortest. The series resonator S11 is also the resonator located closest to the transmitting terminal Tx among the series resonators S11, S12 and parallel resonators P11 that constitute the transmitting filter 50 provided on the upper surface 10a of the substrate 10. In a plan view, at least a portion of the parallel resonator P21 is located between the receiving terminal Rx and the shortest distance L between the series resonator S11 and the series resonator S11.

[0037] In the resonators constituting the transmitting filter 50, the series resonators S11 and S12 provided on the upper surface 10a of the substrate 10 overlap at least partially with the parallel resonator P12 and the series resonator S13 provided on the upper surface 20a of the substrate 20, respectively. In the resonators constituting the receiving filter 60, the series resonators S21 and P21 provided on the upper surface 10a of the substrate 10 overlap at least partially with the series resonators S22 and S23 provided on the upper surface 20a of the substrate 20, respectively. Thus, in the multiple resonators constituting the transmitting filter 50, at least one of the multiple resonators provided on the upper surface 10a of the substrate 10 and at least one of the multiple resonators provided on the upper surface 20a of the substrate 20 overlap at least partially. The same applies to the multiple resonators constituting the receiving filter 60.

[0038] [Manufacturing method] An example of a method for manufacturing an elastic wave device according to Example 1 will be described. First, substrates 10 and 20 are formed separately. Substrate 10 is formed by bonding a piezoelectric substrate 12 to the surface of a support substrate 11, and then thinning the piezoelectric substrate 12 to a desired thickness by polishing or grinding. For bonding the support substrate 11 and the piezoelectric substrate 12, for example, a direct bonding method using room-temperature bonding is used by activating the surface of the support substrate 11 and the surface of the piezoelectric substrate 12. Next, the piezoelectric substrate 12 is etched to process it into a desired shape. After that, via wiring 16 is formed on the support substrate 11, an elastic wave resonator 13 is formed on the piezoelectric substrate 12, and wiring 14 connected to the elastic wave resonator 13 is formed. Next, a sealing portion 34a is formed on the periphery of substrate 10, and pillars 17 are formed on the wiring 14. Generally known methods are used for forming the elastic wave resonator 13, wiring 14, via wiring 16, pillars 17, and sealing portion 34a.

[0039] Similarly to the substrate 20, via wiring 26 is formed on the support substrate 21 joined to the piezoelectric substrate 22 using the same method as for the substrate 10. An elastic wave resonator 23 is formed on the piezoelectric substrate 22, wiring 24 is formed to connect to the elastic wave resonator 23, and a sealing portion 34b is formed on the periphery of the substrate 20. Then, a lid 30 is mounted on the sealing portion 34b. As a result, the elastic wave resonator 23 and wiring 24 are sealed in the gap 33 formed between the substrate 20 and the lid 30. Next, the substrate 20 is thinned to the desired thickness by polishing or grinding, and then a shield layer 28 is formed on the lower surface 20b of the substrate 20.

[0040] Next, the substrate 20 is mounted on the sealing portion 34b of the substrate 10 and the pillar 17. As a result, the elastic wave resonator 13 formed on the substrate 10 is sealed in the gap 32 formed between the substrate 10 and the substrate 20. After that, the substrate 10 is thinned to a desired thickness by polishing or grinding, and then a plurality of terminals 15 are formed on the lower surface 10b of the substrate 10.

[0041] [Comparative Example] The circuit diagram and cross-sectional view of the multiplexer 500 in the comparative example are the same as those in Figures 1 and 2 of Example 1, so their explanation is omitted. Figures 5(a) to 5(c) are plan views of the substrates 10 and 20 in the comparative example. Figure 5(a) is a plan view of the top surface 20a of substrate 20 seen from above, Figure 5(b) is a plan view of the top surface 10a of substrate 10 seen from above, and Figure 5(c) is a plan view of the bottom surface 10b of substrate 10 seen from above. In Figures 5(a) and 5(b), hatching is added to the wiring 14 and 24 for clarity. Also, in Figure 5(b), the transmit terminal Tx and receive terminal Rx formed on the bottom surface 10b of substrate 10 are shown with dotted lines.

[0042] As shown in Figures 5(a) to 5(c), the elastic wave resonator 23 provided on the upper surface 20a of the substrate 20 includes series resonators S21 to S23 and parallel resonators P21 and P22 that constitute the receiving filter 60. The elastic wave resonator 13 provided on the upper surface 10a of the substrate 10 includes series resonators S11 to S13 and parallel resonators P11 and P12 that constitute the transmitting filter 50. The other configurations are the same as those in Figures 4(a) to 4(c) of Embodiment 1, so their description is omitted.

[0043] Thus, the comparative example differs from Example 1 in that all of the series resonators S11 to S13 and parallel resonators P11 and P12 constituting the transmitting filter 50 are provided on the upper surface 10a of the substrate 10, and all of the series resonators S21 to S23 and parallel resonators P21 and P22 constituting the receiving filter 60 are provided on the upper surface 20a of the substrate 20.

[0044] Figure 6(a) is a plan view illustrating the problems that arise with the multiplexer 500 according to the comparative example, and Figure 6(b) is a plan view illustrating the effects of the multiplexer 100 according to Example 1. As shown in Figure 6(a), most of the high-frequency signal input to the transmitting terminal Tx flows to the common terminal Ant as indicated by arrow 70. At this time, if the series resonator S13 is located near the receiving terminal Rx, the electromagnetic field coupling between the series resonator S13 and the receiving terminal Rx becomes strong, and the signal may leak from the series resonator S13 to the receiving terminal Rx as indicated by arrow 72. This degrades the isolation characteristics.

[0045] In Example 1, as shown in Figure 6(b), most of the high-frequency signal input to the transmitting terminal Tx flows to the common terminal Ant as indicated by arrow 74. Of all the series resonators S11, S12, S21 and parallel resonators P11, P21 provided on the upper surface 10a of the substrate 10, the resonator closest to the receiving terminal Rx in a plan view is the parallel resonator P21 that constitutes the receiving filter 60. For this reason, the series resonators S11, S12 and the parallel resonator P11 that constitute the transmitting filter 50 are provided at a distance from the receiving terminal Rx in a plan view. For example, in a plan view, the parallel resonator P21 overlaps with the receiving terminal Rx, and the distance between the parallel resonator P21 and the receiving terminal Rx is zero. If the shortest distances between the receiving terminal Rx and the series resonators S11, S12, S21 and the parallel resonator P11 are L1, L2, L3, and L4, then the distance to the receiving terminal Rx decreases in the order of series resonator S12, parallel resonator P11, series resonator S11, and series resonator S21.

[0046] In this way, by positioning the series resonators S11, S12 and the parallel resonator P11 that constitute the transmitting filter 50 away from the receiving terminal Rx, the electromagnetic field coupling between the series resonator S11, which is closest to the receiving terminal Rx among the series resonators S11, S12 and the parallel resonator P11, and the receiving terminal Rx is weakened, and signal leakage from the series resonator S11 to the receiving terminal Rx is suppressed. Therefore, the deterioration of the isolation characteristics is suppressed.

[0047] Furthermore, by providing a parallel resonator P21 on the shortest distance L1 between the series resonator S11 and the receiving terminal Rx, electromagnetic waves from the series resonator S11 are blocked by the parallel resonator P21, further suppressing the deterioration of the isolation characteristics. In addition, because the resonator provided between the series resonator S11 and the receiving terminal Rx is a parallel resonator P21, electromagnetic waves from the series resonator S11 are more easily grounded through the parallel resonator P21 and the wiring 14. Therefore, even if a signal leaks from the series resonator S11 to the parallel resonator P21, the leakage signal is less likely to be transmitted to the receiving terminal Rx. As a result, the deterioration of the isolation characteristics is further suppressed.

[0048] As described above, according to Embodiment 1, as shown in Figures 4(a) and 4(b), some of the series resonators S11, S12 and parallel resonators P11 and P12 (first elastic wave resonators) that constitute the transmitting filter 50 are provided on the upper surface 10a of the substrate 10, while the remaining series resonators S13 and parallel resonators P12 are provided on the upper surface 20a of the substrate 20. Some of the series resonators S21 and parallel resonators P21 and P22 (second elastic wave resonators) that constitute the receiving filter 60 are provided on the upper surface 10a of the substrate 10, while the remaining series resonators S22, S23 and parallel resonators P22 are provided on the upper surface 20a of the substrate 20. Furthermore, of all the series resonators S11, S12, S21 and parallel resonators P11, P21 provided on the upper surface 10a of the substrate 10, the resonator closest to the receiving terminal Rx in a plan view is the parallel resonator P21 that constitutes the receiving filter 60. As a result, as explained in Figure 6(b), the series resonators S11, S12 and parallel resonator P11 that constitute the transmitting filter 50 are provided away from the receiving terminal Rx, so signal leakage from the series resonators S11, S12 and parallel resonator P11 to the receiving terminal Rx is suppressed. Therefore, the deterioration of the isolation characteristics is suppressed. In addition, since the series resonators S11, S12 and parallel resonator P11 that constitute the transmitting filter 50 are provided on the upper surface 10a of the substrate 10, the heat dissipation of the series resonators S11, S12 and parallel resonator P11 is improved, and the power withstand reliability is improved.

[0049] Furthermore, according to Example 1, as shown in Figure 4(b), in a plan view, the parallel resonator P21 constituting the receiving filter 60 is located on the shortest distance L between the series resonator S11, which is closest to the receiving terminal Rx, and the receiving terminal Rx, among the series resonators S11, S12, and parallel resonator P11 that constitute the transmitting filter 50. As a result, as explained in Figure 6(b), electromagnetic waves from the series resonator S11 are blocked by the parallel resonator P21, thereby suppressing the deterioration of the isolation characteristics.

[0050] Furthermore, according to Example 1, as shown in Figure 4(b), among all the series resonators S11, S12, S21 and parallel resonators P11, P21 provided on the upper surface 10a of the substrate 10, the resonator closest to the transmitting terminal Tx in a plan view is the series resonator S11 that constitutes the transmitting filter 50. As a result, electromagnetic field coupling between the transmitting terminal Tx and the series resonators S21 and parallel resonators P21 that constitute the receiving filter 60 is suppressed, thereby suppressing the deterioration of the isolation characteristics.

[0051] Furthermore, according to Example 1, as shown in Figure 4(b), among all the series resonators S11, S12, S21 and parallel resonators P11, P21 provided on the upper surface 10a of the substrate 10, the resonator closest to the receiving terminal Rx is the parallel resonator P21 that constitutes the receiving filter 60. As a result, as explained in Figure 6(b), even if a signal leaks from the series resonator S11 to the parallel resonator P21, the leakage signal is suppressed from being transmitted to the receiving terminal Rx, and the deterioration of the isolation characteristics is suppressed.

[0052] Furthermore, according to Example 1, as shown in Figure 4(b), the parallel resonator P21, which is electrically connected closest to the common terminal Ant among the parallel resonators P21 and P22 constituting the receiving filter 60, is the resonator closest to the receiving terminal Rx. When a signal leaks from the transmitting filter 50 to the parallel resonator P21, which is electrically connected closest to the common terminal Ant among the parallel resonators P21 and P22 constituting the receiving filter 60, the leaked signal is transmitted to the receiving terminal Rx via the series resonators S22 and S23, as shown in Figure 1, so the intensity of the leaked signal when it reaches the receiving terminal Rx is reduced. Therefore, by making the parallel resonator P21, which is electrically connected closest to the common terminal Ant among the parallel resonators P21 and P22 constituting the receiving filter 60, the resonator closest to the receiving terminal Rx, the deterioration of the isolation characteristics is suppressed.

[0053] Furthermore, according to Example 1, as shown in Figure 4(a), the series resonator S23, which is the series resonator S21 to S23 constituting the receiving filter 60 and is electrically connected closest to the receiving terminal Rx, and the parallel resonator P22, which is the parallel resonators P21 and P22 and is electrically connected closest to the receiving terminal Rx, are provided on the upper surface 20a of the substrate 20. If a signal leaks from the transmitting filter 50 to the series resonator S23 and the parallel resonator P22, which are electrically connected closest to the receiving terminal Rx among the resonators constituting the receiving filter 60, the intensity of the leaked signal when it reaches the receiving terminal Rx will be large, thus having a significant impact on the isolation characteristics. Therefore, by providing the series resonator S23 and the parallel resonator P22, which have a significant impact on the isolation characteristics, on the upper surface 20a of the substrate 20, the wiring distance between the series resonator S23 and the parallel resonator P22 and the receiving terminal Rx becomes longer, the intensity of the leaked signal is weakened, and thus the deterioration of the isolation characteristics is suppressed.

[0054] Furthermore, according to Example 1, as shown in Figure 4(b), the parallel resonator P21 located closest to the receiving terminal Rx overlaps with the receiving terminal Rx in a plan view, at least a portion of which overlaps. This allows for miniaturization of the multiplexer 100. From the viewpoint of miniaturizing the multiplexer 100, it is preferable that 1 / 4 or more of the parallel resonator P21 overlaps with the receiving terminal Rx, more preferably that 1 / 3 or more overlaps with the receiving terminal Rx, and even more preferably that 1 / 2 or more overlaps with the receiving terminal Rx. In addition, from the viewpoint of miniaturizing the multiplexer 100, at least a portion of the series resonator S11 located closest to the transmitting terminal Tx in a plan view may overlap with the transmitting terminal Tx.

[0055] Furthermore, according to Example 1, as shown in Figure 4(b), the series resonator S11, which is the series resonator S11 to S13 constituting the transmitting filter 50 and is electrically connected closest to the transmitting terminal Tx, and the parallel resonator P11, which is the parallel resonator P11 and P12 and is electrically connected closest to the transmitting terminal Tx, are provided on the upper surface 10a of the substrate 10. The series resonator S11 and the parallel resonator P11, which are electrically connected closest to the transmitting terminal Tx, are subjected to large amounts of power and generate a large amount of heat. Therefore, by providing the series resonator S11 and the parallel resonator P11 on the upper surface 10a of the substrate 10, heat dissipation is improved and power withstand reliability is improved.

[0056] Furthermore, according to Example 1, as shown in Figure 4(a), the series resonator S13, which is the series resonator S11 to S13 constituting the transmitting filter 50 and is electrically connected closest to the common terminal Ant, and the parallel resonator P12, which is the parallel resonator P11 and P12 and is electrically connected closest to the common terminal Ant, are provided on the upper surface 20a of the substrate 20. The series resonator S13 and the parallel resonator P12 generate less heat than the other resonators of the transmitting filter 50, so they can be provided on the upper surface 20a of the substrate 20. In addition, when the high-frequency signal input to the transmitting terminal Tx is transmitted to the series resonator S13 and the parallel resonator P12, which are electrically connected closest to the common terminal Ant, it is attenuated by the resonator between them. For this reason, even if a signal leaks from the series resonator S13 and the parallel resonator P12 to the receiving filter 60, the impact on the isolation characteristics is relatively small.

[0057] Furthermore, according to Embodiment 1, as shown in Figure 2, a shielding layer 28 connected to ground is provided between the elastic wave resonator 13 provided on the upper surface 10a of the substrate 10 and the elastic wave resonator 23 provided on the upper surface 20a of the substrate 20. This suppresses electromagnetic field coupling between the series resonators S11, S12, S21 and parallel resonators P11, P21 provided on the upper surface 10a of the substrate 10 and the series resonators S13, S22, S23 and parallel resonators P12, P22 provided on the upper surface 20a of the substrate 20.

[0058] Furthermore, according to Example 1, as shown in Figures 4(a) and 4(b), the series resonator S13 and parallel resonator P12 of the transmitting filter 50 are provided on the upper surface 20a of the substrate 20, while the series resonators S11 and S12 and the parallel resonator P11 are provided on the upper surface 10a of the substrate 10. In this way, by dividing the resonators constituting the transmitting filter 50 in roughly half and arranging them on the substrate 10 and the substrate 20, the multiplexer 100 is miniaturized. In order to miniaturize the multiplexer 100, it is preferable that the number of resonators of the transmitting filter 50 provided on the upper surface 10a of the substrate 10 and the number of resonators of the transmitting filter 50 provided on the upper surface 20a of the substrate 20 are the same or differ by one. The same applies to the receiving filter 60. Furthermore, from the standpoint of miniaturizing the multiplexer 100, it is preferable that the total number of resonators of the transmitting filter 50 and receiving filter 60 provided on the upper surface 20a of the substrate 20 is the same as or differs by one from the total number of resonators of the transmitting filter 50 and receiving filter 60 provided on the upper surface 10a of the substrate 10.

[0059] Furthermore, according to Example 1, as shown in Figures 4(a) and 4(b), parallel resonators P11 and P22, which constitute the transmit filter 50 or the receive filter 60, are provided between the series resonators S12 and S13 that constitute the transmit filter 50 and the series resonators S21 and S22 that constitute the receive filter 60. This arrangement suppresses the deterioration of the isolation characteristics. [Examples]

[0060] Figure 7 is a circuit diagram of the multiplexer 200 according to Embodiment 2. As shown in Figure 7, the transmit filter 50 connected between the transmit terminal Tx and the common terminal Ant is a ladder-type filter, the same as in Embodiment 1, and includes series resonators S11 to S13 and parallel resonators P11 and P12. The receive filter 60a connected between the common terminal Ant and the receive terminal Rx includes a series resonator S21, a vertically coupled double-mode resonator DMS, and a series resonator S22 connected in series between the common terminal Ant and the receive terminal Rx, and a parallel resonator P21 connected in parallel between the common terminal Ant and the receive terminal Rx. The series resonators S21, DMS, and S22 are provided in the series path 62 between the common terminal Ant and the receive terminal Rx. One end of the parallel resonator P21 is connected to the series path 62, and the other end is connected to the ground terminal Gnd. The longitudinally coupled dual-mode resonator (DMS) includes multiple elastic wave resonators P1 to P3. One end of the central elastic wave resonator P2, on the common terminal Ant side, is connected to a series path 62, and the other end is connected to the ground terminal Gnd. One end of the receiving terminal Rx side of the elastic wave resonators P1 and P3, which are located on either side of elastic wave resonator P2, is connected to a series path 62, and the other end is connected to the ground terminal Gnd.

[0061] The cross-sectional view of the multiplexer 200 according to Example 2 is the same as that of Figure 2 in Example 1, so its description is omitted. Figures 8(a) to 8(c) are plan views of the substrates 10 and 20 in Example 2. Figure 8(a) is a plan view of the top surface 20a of substrate 20 seen from above, Figure 8(b) is a plan view of the top surface 10a of substrate 10 seen from above, and Figure 8(c) is a plan view of the bottom surface 10b of substrate 10 seen from above in perspective. In Figures 8(a) and 8(b), hatching is added to the wiring 14 and 24 for clarity. Also, in Figure 8(b), the transmitting terminal Tx and receiving terminal Rx formed on the bottom surface 10b of substrate 10 are shown with dotted lines.

[0062] As shown in Figures 8(a) to 8(c), an elastic wave resonator 23 and wiring 24 are provided on the upper surface 20a of the substrate 20. The elastic wave resonator 23 includes a series resonator S13 and a parallel resonator P12 that constitute the transmitting filter 50, and a longitudinally coupled double-mode resonator DMS and a series resonator S22 that constitute the receiving filter 60a. An elastic wave resonator 13 and wiring 14 are provided on the upper surface 10a of the substrate 10. The elastic wave resonator 13 includes series resonators S11, S12 and a parallel resonator P11 that constitute the transmitting filter 50, and a series resonator S21 and a parallel resonator P21 that constitute the receiving filter 60a. The other configurations are the same as in Figures 4(a) to 4(c) of Embodiment 1, so their description is omitted.

[0063] According to Embodiment 2, of the series resonators S11 to S13 and parallel resonators P11 and P12 that constitute the transmitting filter 50, some of the series resonators S11 and S12 and the parallel resonator P11 are provided on the upper surface 10a of the substrate 10, while the remaining series resonator S13 and the parallel resonator P12 are provided on the upper surface 20a of the substrate 20. Of the series resonators S21 and S22, the longitudinally coupled double-mode resonator DMS, and the parallel resonator P21 that constitute the receiving filter 60a, some of the series resonators S21 and the parallel resonator P21 are provided on the upper surface 10a of the substrate 10, while the remaining series resonator S22 and the longitudinally coupled double-mode resonator DMS are provided on the upper surface 20a of the substrate 20. Furthermore, of all the series resonators S11, S12, S21 and parallel resonators P11, P21 provided on the upper surface 10a of the substrate 10, the resonator closest to the receiving terminal Rx in a plan view is the parallel resonator P21 of the receiving filter 60a. As a result, similar to Example 1, the power withstand reliability is improved and the deterioration of the isolation characteristics is suppressed.

[0064] Furthermore, according to Example 2, the series resonator S22 and the vertically coupled dual-mode resonator DMS constituting the receiving filter 60a are provided on the upper surface 20a of the substrate 20, while the series resonator S21 and the parallel resonator P21 are provided on the upper surface 10a of the substrate 10. By arranging the resonators constituting the receiving filter 60a separately on substrates 10 and 20 in this way, the multiplexer 200 can be miniaturized. In order to miniaturize the multiplexer 200, it is preferable that the number of series resonators and parallel resonators provided on the same substrate as the vertically coupled dual-mode resonator DMS in the receiving filter 60a is less than the number of series resonators and parallel resonators provided on the other substrate. Also, it is preferable that the total number of series resonators and parallel resonators of the transmitting filter 50 and the receiving filter 60a provided on the same substrate as the vertically coupled dual-mode resonator DMS is less than the total number of series resonators and parallel resonators of the transmitting filter 50 and the receiving filter 60a provided on the other substrate. [Examples]

[0065] The circuit diagram of the multiplexer 300 according to Example 3 is the same as that of Figure 1 of Example 1, so its description is omitted. Figure 9 is a cross-sectional view of the multiplexer 300 according to Example 3. As shown in Figure 9, an elastic wave resonator 23 and wiring 24 are provided on the lower surface 20b of a substrate 20, which faces the upper surface 10a of a substrate 10 on which an elastic wave resonator 13 and wiring 14 are provided. The shield layer 28 is provided between the upper surface 10a of the substrate 10 and the lower surface 20b of the substrate 20, and between the elastic wave resonator 13 and the elastic wave resonator 23. An opening is provided in the shield layer 28, and the pillar 17 passes through the opening. An insulating resin film 35 is provided between the pillar 17 and the shield layer 28. As a result, the pillar 17 and the shield layer 28 are electrically insulated. The pillar 17 is connected between the wiring 14 and the wiring 24. The upper surface 10a of the substrate 10 and the shield layer 28 face each other with an air gap 32a in between. The elastic wave resonator 13 and wiring 14 are sealed in the air gap 32a by a sealing portion 34a provided between the substrate 10 and the shield layer 28. The lower surface 20b of the substrate 20 and the shield layer 28 face each other with an air gap 33a in between. The elastic wave resonator 23 and wiring 24 are sealed in the air gap 33a by a sealing portion 34b provided between the substrate 20 and the shield layer 28. The other configurations are the same as in Figure 2 of Embodiment 1, so their description is omitted. Note that if a sufficient distance can be secured between the shield layer 28 and the pillar 17, the resin film 35 may not be provided, and insulation may be provided with the air gap in between. In this case, the air gaps 32a and 33a are in communication.

[0066] The arrangement of the elastic wave resonator 13 provided on the upper surface 10a of the substrate 10 is the same as in Figure 4(b) of Embodiment 1, and the arrangement of the elastic wave resonator 23 provided on the lower surface 20b of the substrate 20 is the same as in Figure 4(a) of Embodiment 1, so their illustration and description are omitted.

[0067] The elastic wave resonator 23 and wiring 24 provided on the substrate 20 may be provided on the upper surface 20a of the substrate 20 opposite to the substrate 10, as shown in Figure 2, or on the lower surface 20b on the substrate 10 side, as shown in Figure 9.

[0068] The number of series resonators, parallel resonators, and longitudinally coupled dual-mode resonators in each filter in Examples 1 to 3 can be set as appropriate. In Examples 1 to 3, a duplexer is shown as an example of a multiplexer, but a triplexer or quadplexer may also be used.

[0069] Although embodiments of the present invention have been described in detail above, the present invention is not limited to these specific embodiments, and various modifications and changes are possible within the scope of the gist of the present invention as described in the claims. [Explanation of Symbols]

[0070] 10, 20 circuit boards 10a, 20a top surface 10b, 20b bottom side 11, 21 Support substrate 12, 22 Piezoelectric substrate 13, 23 Elastic wave resonators 14, 24 Wiring 15 terminals Via wiring 16, 26 17 Pillar 28 Shield layer 30 Lid 32, 32a, 33, 33a void 34a, 34b Sealing part 50 Sending Filters 52 Series Path 60, 60a receiving filter 62 Series Path 100, 200, 300, 500 Multiplexer S11~S13, S21~S23 series resonator P11, P12, P21, P22 parallel resonator Ant Common Terminal Tx Transmitter Terminal Rx receiving terminal Gnd Ground terminal DMS (Dual-Mode Resonator)

Claims

1. A first substrate having a first surface and a second surface opposite to the first surface, A second substrate having a third surface and mounted on the first substrate with a gap between it and the first surface, The second surface is provided with a common terminal, a transmitting terminal, and a receiving terminal, The device has a plurality of first elastic wave resonators connected to a first path between the common terminal and the transmitting terminal, some of which are provided on the first surface and the rest on the third surface, and a transmitting filter. A receiving filter comprising: having a plurality of second elastic wave resonators connected to a second path between the common terminal and the receiving terminal, some of the plurality of second elastic wave resonators provided on the first surface and the remainder provided on the third surface, wherein the resonator closest to the receiving terminal in a plan view among the portion of first elastic wave resonators provided on the first surface and the portion of second elastic wave resonators provided on the first surface is a second elastic wave resonator; The plurality of second elastic wave resonators include a plurality of second series resonators connected in series to the second path, and a plurality of second parallel resonators, one end of which is connected to each of the plurality of first nodes on the second path and the other end of which is connected to ground. A multiplexer in which the second elastic wave resonator closest to the receiving terminal is connected to the first node among the plurality of first nodes that is located closest to the common terminal, thereby being the second parallel resonator among the plurality of second parallel resonators that is electrically connected closest to the common terminal.

2. The multiplexer according to claim 1, wherein, in a plan view, the second elastic wave resonator closest to the receiving terminal is provided on the shortest distance between the first elastic wave resonator closest to the receiving terminal among the part of the first elastic wave resonators provided on the first surface and the receiving terminal.

3. The multiplexer according to claim 1 or 2, wherein, among the portion of the first elastic wave resonators and the portion of the second elastic wave resonators provided on the first surface, the resonator closest to the transmitting terminal in a plan view is the first elastic wave resonator.

4. The plurality of first elastic wave resonators include a plurality of first series resonators connected in series to the first path, and a plurality of first parallel resonators, one end of which is connected to each of a plurality of second nodes on the first path and the other end of which is connected to ground. The multiplexer according to any one of claims 1 to 3, wherein the part of the first elastic wave resonators provided on the first surface includes a first series resonator that is electrically connected to the transmitting terminal closest to the first path among the plurality of first series resonators, and a first parallel resonator that is electrically connected to the transmitting terminal closest to the plurality of first parallel resonators by being connected to a second node that is located closest to the transmitting terminal among the plurality of second nodes.

5. The multiplexer according to claim 4, wherein the remaining first elastic wave resonators provided on the third surface include a first series resonator that is electrically connected to the common terminal closest to the first path among the plurality of first series resonators, and a first parallel resonator that is electrically connected to the common terminal closest to the plurality of first parallel resonators by being connected to a second node that is located closest to the common terminal among the plurality of second nodes.

6. The multiplexer according to any one of claims 1 to 5, wherein the remaining second elastic wave resonator provided on the third surface includes a second series resonator that is electrically connected to the receiving terminal closest to the second path among the plurality of second series resonators, and a second parallel resonator that is electrically connected to the receiving terminal closest to the plurality of second parallel resonators by being connected to the first node that is located closest to the receiving terminal among the plurality of first nodes.

7. The multiplexer according to any one of claims 1 to 6, wherein the second elastic wave resonator closest to the receiving terminal overlaps with the receiving terminal in at least a portion of it in a plan view.

8. A multiplexer according to any one of claims 1 to 7, comprising a shield layer provided between the portion of the first elastic wave resonators and the portion of the second elastic wave resonators provided on the first surface, the remaining first elastic wave resonators and the remaining second elastic wave resonators provided on the third surface, and connected to ground.

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