Multiplexer

Abstract

To provides a multiplexer that improves isolation characteristics.SOLUTION: A multiplexer includes a substrate 10 having a first surface and a second surface facing the first surface, a first filter that is provided on the first surface of the substrate 10 and connected between a common terminal Ant and a first signal terminal, a second filter that is provided on the first surface of the substrate 10 and connected between the common terminal Ant and a second signal terminal, an annular metal layer 20 that is provided on the first surface of the substrate 10 and surrounding the first filter and the second filter, a ground terminal Gnd1 provided on the second surface of the substrate, and a ground via wiring 16a that is provided between the area where the first filter is provided and the area where the second filter is provided, which penetrates the substrate 10 and connects the annular metal layer 20 and the ground terminal Gnd1.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a multiplexer, for example a multiplexer having multiple filters. [Background technology]

[0002] An acoustic wave device is known in which a frame is provided to surround a filter provided on a substrate, and a lid is provided on the frame to seal the filter in a gap (for example, Patent Document 1). It is also known to join a substrate provided with a transmitting filter and a substrate provided with a receiving filter so that the surfaces on which the filters are provided face each other with a gap between them. It is also known to provide a ground pattern on the surface on which the transmitting filter is provided, between the transmitting filter and a pad that transmits a receiving signal (for example, Patent Document 2). A multiplexer in which a transmitting filter and a receiving filter are mounted on a multilayer substrate is also known (for example, Patent Document 3). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-152612 A [Patent Document 2] JP 2017-204827 A [Patent Document 3] JP 2019-205065 A Summary of the Invention [Problem to be solved by the invention]

[0004] In a multiplexer, for example, it is required to improve isolation between a transmission terminal and a reception terminal.

[0005] The present invention has been made in consideration of the above problems, and has an object to improve isolation characteristics. [Means for solving the problem]

[0006] The present invention relates to a semiconductor device comprising: a substrate having a first surface and a second surface opposite to the first surface; a common terminal, a first signal terminal, and a second signal terminal provided on the second surface of the substrate; and a first filter provided on the first surface of the substrate and connected between the common terminal and the first signal terminal; a first signal via wiring that penetrates the substrate and connects the first filter and the first signal terminal; a second filter provided on the first surface of the substrate and connected between the common terminal and the second signal terminal; a second signal via wiring that penetrates the substrate and connects the second filter and the second signal terminal; a ring-shaped metal layer provided on a first surface of the substrate and surrounding the first filter and the second filter; a ground terminal provided on a second surface of the substrate; and a ground via wiring provided between a region in which the first filter is provided and a region in which the second filter is provided, penetrating the substrate and connecting the ring-shaped metal layer and the ground terminal. a metal lid provided on the annular metal layer, electrically connected to the annular metal layer, and sealing the first filter and the second filter in a gap; the first signal terminal and the second signal terminal are provided on the second surface without overlapping the annular metal layer in a plan view. The planar shape of the annular metal layer is substantially rectangular, the first signal via wiring and the second signal via wiring are provided near both ends of one side of the substantially rectangular shape, the ground via wiring connects the one side of the annular metal layer to the ground terminal, and the first filter and the second filter directly face the metal lid via the gap. It is a multiplexer.

[0008] In the aforementioned configuration, the ground via wiring may be configured to be unconnected to the first filter and the second filter on the first surface.

[0010] In the above configuration, the configuration can include a first ground terminal and a second ground terminal provided on the second surface, and a first ground via wiring and a second ground via wiring that penetrate the substrate and connect the annular metal layer to the first ground terminal and the second ground terminal, respectively, near both ends of the side opposite the one side.

[0011] In the above configuration, the first filter can be a ladder-type filter including a first series resonator and a first parallel resonator, and the first ground terminal can be connected to the first parallel resonator among the first parallel resonators that is electrically closest to the common terminal, and the second filter can be a ladder-type filter including a second series resonator and a second parallel resonator, and the second ground terminal can be connected to the second parallel resonator among the second parallel resonators that is electrically closest to the common terminal.

[0012] The annular metal layer may be configured to be grounded only through the ground via wiring, the first ground via wiring, and the second ground via wiring.

[0013] In the above configuration, the substrate may include a support substrate and a piezoelectric layer provided on the support substrate, the annular metal layer may be provided on the support substrate from which the piezoelectric layer has been removed, and the first filter and the second filter may be provided on the piezoelectric layer.

[0014] In the above configuration, the first filter and the second filter may be provided on a single piezoelectric layer.

[0015] In the above configuration, the pass band of the first filter and the pass band of the second filter may not overlap. Effect of the Invention

[0016] According to the present invention, the isolation characteristics can be improved. [Brief description of the drawings]

[0017] [Figure 1] FIG. 1 is a circuit diagram of a multiplexer according to a first embodiment. [Diagram 2] 2(a) and 2(b) are plan views of the multiplexer according to the first embodiment. [Diagram 3] FIG. 3 is a cross-sectional view taken along line AA in FIG. 2(a) and FIG. 2(b). [Figure 4] FIG. 4(a) is a plan view of the acoustic wave resonator in the first embodiment, and FIG. 4(b) is a cross-sectional view of another acoustic wave resonator in the first embodiment. [Diagram 5] FIG. 5 is a cross-sectional view of a multiplexer in accordance with a first comparative example. [Figure 6] FIG. 6 is a plan view of the multiplexer in sample A. As shown in FIG. [Figure 7]7(a) to 7(c) are plan views of multiplexers in samples B to D, respectively. [Figure 8] FIG. 8 is a diagram showing the isolation characteristics of samples A and B. [Figure 9] 9(a) and 9(b) are top views of the current density on the underside of the lid in samples A and B, respectively. [Figure 10] FIG. 10 is a diagram showing the isolation characteristics of samples A to C. [Figure 11] 11(a) and 11(b) are top views of the current density on the underside of the lid in samples A and C, respectively. [Figure 12] FIG. 12 is a diagram showing the isolation characteristics of samples A, B and D. [Figure 13] 13(a) and 13(b) are top views of the current density on the underside of the lid in samples A and D, respectively. [Figure 14] FIG. 14 is a plan view of the multiplexer in sample E. FIG. [Figure 15] FIG. 15 is a diagram showing the isolation characteristics of samples E and F. [Figure 16] FIG. 16(a) is a circuit diagram of a multiplexer according to a first modification of the first embodiment, and FIG. 16(b) is a plan view of the multiplexer according to the first modification of the first embodiment. [Figure 17] FIG. 17(a) is a circuit diagram of a multiplexer according to a second modification of the first embodiment, and FIG. 17(b) is a plan view of the multiplexer according to the second modification of the first embodiment. [Figure 18] FIG. 18 is a cross-sectional view of a multiplexer according to a third modification of the first embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

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

[0019] Fig. 1 is a circuit diagram of a multiplexer according to a first embodiment. As shown in Fig. 1, a transmission filter 30 is connected between a common terminal Ant and a transmission terminal Tx. A reception filter 32 is connected between the common terminal Ant and a reception terminal Rx. The transmission filter 30 passes signals in a pass band among the high-frequency signals input to the transmission terminal Tx to the common terminal Ant and suppresses signals of other frequencies. The reception filter 32 passes signals in a pass band among the high-frequency signals input to the common terminal Ant to the reception terminal Rx and suppresses signals of other frequencies.

[0020] 2(a) and 2(b) are plan views of the multiplexer according to the first embodiment. FIG. 3 is a cross-sectional view taken along the line AA of FIG. 2(a) and FIG. 2(b). FIG. 2(a) illustrates the substrate 10, the wirings 13a-13c, 14a-14c, the via wirings 15a-15c, 16a-16c, the annular metal layer 20, the transmit filter 30, and the receive filter 32. FIG. 2(b) is a plan view of the lower surface of the substrate 10 seen through from above, illustrating the substrate 10, the via wirings 15a-15c, 16a-16c, and the terminal 18. The normal direction of the substrate 10 is defined as the Z direction, the arrangement direction of the transmit filter 30 and the receive filter 32 is defined as the X direction, and the direction perpendicular to the X direction and the Y direction is defined as the Y direction.

[0021] As shown in FIG. 2(a) to FIG. 3, the substrate 10 has a support substrate 10b and a piezoelectric layer 10a bonded directly or indirectly to the support substrate 10b. The piezoelectric layer 10a is not provided in the region where the via wirings 15a to 15c and 16a to 16c are provided and in the region where the annular metal layer 20 is provided. The acoustic wave resonators 12a and 12b are provided on the piezoelectric layer 10a. The acoustic wave resonators 12a and 12b form the transmission filter 30 and the reception filter 32, respectively. The wirings 13a to 13c and 14a to 14c and the annular metal layer 20 are provided on the substrate 10. The wiring 14a is electrically connected to the transmission filter 30, the wiring 14b is electrically connected to the reception filter 32, and the wiring 14c is electrically connected to the transmission filter 30 and the reception filter 32. The wirings 13a to 13c are electrically connected to the annular metal layer 20.

[0022] Via wirings 15a to 15c and 16a to 16c are provided so as to penetrate the support substrate 10b. Terminals 18 are provided on the lower surface of the substrate 10. The terminals 18 include a common terminal Ant, a transmitting terminal Tx, a receiving terminal Rx, and ground terminals Gnd1 to Gnd5. The via wiring 15a connects the wiring 14a to the transmitting terminal Tx, the via wiring 15b connects the wiring 14b to the receiving terminal Rx, and the via wiring 15c connects the wiring 14c to the common terminal Ant. The via wiring 15 connects the grounds of the transmitting filter 30 and the receiving filter 32 to the ground terminals Gnd2 to Gnd5. The via wirings 16a to 16c connect the wirings 13a to 13c to the ground terminals Gnd1 to Gnd3, respectively. The lid 22 is bonded onto the annular metal layer 20, and seals the transmitting filter 30 and the receiving filter 32 in the gap 24.

[0023] The planar shape of the substrate 10 and the annular metal layer 20 is substantially rectangular. The transmitting terminal Tx and the receiving terminal Rx are provided near both ends of one of the four sides of the rectangle of the annular metal layer 20, a side 60. The common terminal Ant is provided near the center of the side 62, which is one of the four sides of the rectangle and faces the side 60. In this way, the transmitting terminal Tx, the receiving terminal Rx, and the common terminal Ant are arranged at the vertices of a triangle, thereby improving the isolation characteristics between the terminals. The wiring 13a is connected near the center of the side 60 of the annular metal layer 20. As a result, the via wiring 16a electrically connects the center of the side 60 of the annular metal layer 20 to the ground terminal Gnd1. The wirings 13b and 13c are connected near both ends of the side 62 of the annular metal layer 20. As a result, the via wirings 16b and 16c electrically connect the ends of the side 62 of the annular metal layer 20 to the ground terminals Gnd2 and Gnd3, respectively.

[0024] The support substrate 10b is, for example, a sapphire substrate, a spinel substrate, an alumina substrate, a glass substrate, a quartz substrate, or a silicon substrate. The piezoelectric layer 10a is, for example, a piezoelectric substrate such as a lithium tantalate substrate, a lithium niobate substrate, or a quartz substrate. The wirings 13a-13c, 14a-14c, the via wirings 15a-15c, 16a-16c, the terminal 18, and the annular metal layer 20 are, for example, metal layers such as a copper layer, a gold layer, an aluminum layer, or a nickel layer. The lid 22 is, for example, a metal plate such as Kovar.

[0025] Another insulating layer may be provided between the support substrate 10b and the piezoelectric layer 10a. For example, a temperature compensation film having a temperature coefficient of elastic constant whose sign is opposite to that of the temperature coefficient of elastic constant of the piezoelectric layer 10a may be provided between the support substrate 10b and the piezoelectric layer 10a. A boundary layer in which the sound velocity of the bulk wave is faster than the sound velocity of the bulk wave of the temperature compensation film may be provided between the support substrate 10b and the temperature compensation film. The temperature compensation film is, for example, a silicon oxide film, and the boundary layer is, for example, an aluminum oxide film.

[0026] FIG. 4(a) is a plan view of an acoustic wave resonator in the first embodiment, and FIG. 4(b) is a cross-sectional view of another acoustic wave resonator in the first embodiment. In the example of FIG. 4(a), the acoustic wave resonators 12a and 12b are surface acoustic wave resonators. An IDT (Interdigital Transducer) 40 and a reflector 42 are provided on the upper surface of a substrate 10. The IDT 40 has a pair of comb-shaped electrodes 40a facing each other. The comb-shaped electrode 40a has a plurality of electrode fingers 40b and a bus bar 40c connecting the plurality of electrode fingers 40b. The reflectors 42 are provided on both sides of the IDT 40. The IDT 40 excites a surface acoustic wave in the substrate 10. The substrate 10 may be a support substrate 10b and a piezoelectric layer 10a as shown in FIG. 3, or may be a piezoelectric substrate. The IDT 40 and the reflector 42 are formed of, for example, an aluminum film, a copper film, or a molybdenum film. A protective film or a temperature compensation film may be provided on the substrate 10 so as to cover the IDT 40 and the reflector 42. The acoustic wave resonators 12a and 12b may be boundary acoustic wave resonators or Lamb wave resonators.

[0027] In the example of FIG. 4(b), the acoustic wave resonators 12a and 12b are piezoelectric thin film resonators. A piezoelectric film 46 is provided on a substrate 10. A lower electrode 44 and an upper electrode 48 are provided to sandwich the piezoelectric film 46. A gap 45 is formed between the lower electrode 44 and the substrate 10. A region where the lower electrode 44 and the upper electrode 48 face each other with at least a part of the piezoelectric film 46 sandwiched therebetween is a resonance region 47. The lower electrode 44 and the upper electrode 48 in the resonance region 47 excite an acoustic wave in a thickness longitudinal vibration mode in the piezoelectric film 46. The substrate 10 is, for example, a sapphire substrate, a spinel substrate, an alumina substrate, a glass substrate, a quartz substrate, or a silicon substrate. The lower electrode 44 and the upper electrode 48 are, for example, metal films such as ruthenium films. The piezoelectric film 46 is, for example, an aluminum nitride film. An acoustic reflection film may be provided instead of the gap 45.

[0028] [Comparative Example 1] Fig. 5 is a cross-sectional view of a multiplexer according to Comparative Example 1, which corresponds to the cross section AA in Fig. 2(a) and Fig. 2(b). As shown in Fig. 5, via wiring 16a is not provided in Comparative Example 1. The other configurations are the same as those in Example 1, and therefore the description will be omitted.

[0029] In the comparative example 1, due to the capacitive coupling between the transmitting terminal Tx and the annular metal layer 20 sandwiching the substrate 10, the transmitting signal leaks from the transmitting terminal Tx to the annular metal layer 20 through the substrate 10 as shown by the arrow 50 in FIG. 5. The transmitting signal leaks from the annular metal layer 20 to the lid 22 as shown by the arrow 51. When the lid 22 is a metal plate, the transmitting signal propagates to the lid 22 as shown by the arrow 52. Due to the capacitive coupling between the transmitting filter 30 and the lid 22 sandwiching the gap 24, the signal leaks from the transmitting filter 30 to the lid 22 through the gap 24 as shown by the arrow 53. Due to the capacitive coupling between the lid 22 and the receiving filter 32 sandwiching the gap 24, the high-frequency signal propagating through the lid 22 leaks to the receiving filter 32 as shown by the arrow 56. The signal of the lid 22 leaks to the annular metal layer 20 as shown by the arrow 57, and leaks to the receiving terminal Rx through the substrate 10 as shown by the arrow 58. When the lid 22 is an insulating plate, the strength of the high frequency signal propagating through the lid 22 is small, but the high frequency signal reaches the receiving terminal Rx from the transmitting terminal Tx via the annular metal layer 20. As a result, a part of the transmitting signal input to the transmitting terminal Tx leaks to the receiving terminal Rx, degrading the isolation characteristics. In particular, if the thickness of the supporting substrate 10b is, for example, 100 μm or less and the thickness of the gap 24 is, for example, 100 μm or less in order to miniaturize the multiplexer, the capacitive coupling between the substrate 10 and the gap 24 becomes large, and the isolation characteristics are particularly degraded.

[0030] 3, the annular metal layer 20 between the transmit filter 30 and the receive filter 32 is grounded via the wiring 13a. As a result, as indicated by arrow 54, a high-frequency signal propagating through the lid 22 reaches the wiring 13a via the annular metal layer 20, and then reaches the ground terminal Gnd1 via the via wiring 16a as indicated by arrow 55. Furthermore, when the lid 22 is an insulating plate, the high-frequency signal propagating through the annular metal layer 20 reaches the ground terminal Gnd1 via the wiring 13a and the via wiring 16a. As a result, the amount of high-frequency signal leaking from the transmit terminal Tx to the receive terminal Rx is reduced, improving the isolation characteristics.

[0031] [simulation] The isolation characteristics were simulated for samples A to D. FIG. 6 is a plan view of the multiplexer in sample A. As shown in FIG. 6, the transmit filter 30 is a ladder-type filter, and includes series resonators S11 to S13 and parallel resonators P11 to P14. The series resonators S11 to S13 are provided in a series path between a common terminal Ant and a transmit terminal Tx. One end of the parallel resonators P11 to P14 is connected to the series path, and the other end is connected to ground terminals Gnd2 and Gnd4. The series resonators S11 to S13 and the parallel resonators P11 to P14 are acoustic wave resonators 12a shown in FIG. 4(a), and are connected to each other by wiring 14a.

[0032] The receiving filter 32 is a ladder type filter and includes series resonators S21 to S25 and parallel resonators P21 to P24. The series resonators S21 to S25 are provided in a series path between a common terminal Ant and a receiving terminal Rx. One end of the parallel resonators P21 to P24 is connected to the series path, and the other end is connected to ground terminals Gnd3 and Gnd5. The series resonators S21 to S25 and the parallel resonators P21 to P24 are the elastic wave resonators 12b shown in FIG. 4(a) and are connected by a wiring 14b. The propagation direction of the elastic waves of the series resonators S11 to S13, S21 to S25, the parallel resonators P11 to P14, and P21 to P24 is the X direction.

[0033] The via wiring 16a connects the wiring 13a connected to the annular metal layer 20 to the ground terminal Gnd1 between the region where the transmit filter 30 is provided and the region where the receive filter 32 is provided. The via wiring 16b connects the wiring 13b connected to the corner (the +X end of the side 62) of the annular metal layer 20 to the ground terminal Gnd2. The parallel resonator P11, which is closest to the common terminal Ant, among the parallel resonators P11 to P14, is connected to the ground terminal Gnd2. The via wiring 16c connects the wiring 13c connected to the corner (the -X end of the side 62) of the annular metal layer 20 to the ground terminal Gnd3. The parallel resonator P21, which is closest to the common terminal Ant, among the parallel resonators P21 to P24, is connected to the ground terminal Gnd3.

[0034] The via wiring 15a connects the wiring 14a connected to the transmit filter 30 to the transmit terminal Tx. The via wiring 15b connects the wiring 14b connected to the receive filter 32 to the receive terminal Rx. The via wiring 15c connects the wiring 14c connected to the transmit filter 30 and the receive filter 32 to a common terminal Ant. The via wiring 15 connects one ends of the parallel resonators P11 to P14 and P21 to P24 to ground terminals Gnd2 to Gnd5.

[0035] 7(a) to 7(c) are plan views of multiplexers in samples B to D, respectively. As shown in FIG. 7(a), via wiring 16a is not provided in sample B. The other configurations are the same as those of sample A. As shown in FIG. 7(b), via wiring 16b is not provided in sample C. The other configurations are the same as those of sample A. As shown in FIG. 7(c), via wiring 16c is not provided in sample D. The other configurations are the same as those of sample A. Sample B corresponds to a comparative example, and samples A, C and D correspond to Example 1.

[0036] The simulation conditions are as follows. Multiplexer: Multiplexer for LTE (Long Term Evolution) Band 7 Support substrate 10b: sapphire substrate with a thickness of 70 μm Piezoelectric layer 10a: 42° Y-cut X-propagation lithium tantalate with a thickness of 2.4 μm Wirings 13a to 13c, 14a to 14c: from the substrate 10 side, a titanium film having a thickness of 50 nm, an aluminum film having a thickness of 100 nm, a titanium film having a thickness of 200 nm, and a gold film having a thickness of 1 μm. Via wiring 15, 15a to 15c, 16a to 16c: copper layer with a diameter of 40 μm Annular metal layer 20: From the substrate 10 side, a nickel layer having a thickness of 2.5 μm, and a copper layer having a thickness of 17.5 μm and a width of 23 μm Lid 22: 30 μm thick Kovar

[0037] Fig. 8 is a diagram showing the isolation characteristics of samples A and B. As shown in Fig. 8, the transmission band 34 of the LTE band 7 is 2500 MHz to 2570 MHz, and the reception band 36 is 2620 MHz to 2690 MHz. In bands lower than 2470 MHz, the transmission band 34, the reception band 36, and bands higher than 2750 MHz, the isolation characteristics of sample A are better than those of sample B. High-frequency power with a voltage of 1 V and a frequency of 2400 MHz (dashed line 38a) was applied to the transmission terminal Tx, and the current density on the underside of the lid 22 was simulated.

[0038] 9(a) and 9(b) are top views of the current density on the underside of the lid in samples A and B, respectively. The region where the high frequency power current density is 7.2 A / m or more is shown with dark hatching, the region where the current density is between 1.7 A / m and 7.2 A / m is shown with slightly darker hatching, the region where the current density is between 0.42 A / m and 1.7 A / m is shown with light hatching, and the region where the current density is 0.42 A / m or less is shown in white. The transmit filter 30 and receive filter 32 are shown with thin solid lines. The same applies to the following figures.

[0039] 9(b), in sample B, the high frequency power supplied to the transmitting terminal Tx propagates through the transmitting filter 30 toward the common terminal Ant. The high frequency power leaks to the lid 22, which overlaps with the region from the transmitting terminal Tx of the transmitting filter 30 to the common terminal Ant, and the high frequency power in the lid 22 increases. Furthermore, as indicated by arrows 52a to 52c, the high frequency power propagates throughout the lid 22. As a result, the high frequency power in the entire lid 22 increases.

[0040] As shown in FIG. 9(a), in sample A, a via wiring 16a is provided. Therefore, the high frequency power directed toward the receiving terminal Rx as indicated by an arrow 52d is grounded via the via wiring 16a and the annular metal layer 20 in its vicinity. This reduces the high frequency power propagating diagonally from the transmitting terminal Tx through the lid 22 as indicated by an arrow 52b. This reduces the high frequency power in the region of the lid 22 that overlaps with the receiving filter 32 as indicated by an area 64. Therefore, in sample A, the high frequency power reaching the receiving terminal Rx via the lid 22 and the annular metal layer 20 is reduced compared to sample B, which is considered to improve the isolation characteristics.

[0041] Fig. 10 is a diagram showing the isolation characteristics of samples A to C. As shown in Fig. 10, in bands lower than 2470 MHz and in the transmission band 34, the isolation characteristics of sample C are comparable to those of sample A. In bands higher than 2750 MHz, the isolation characteristics of sample C are slightly better than those of sample A. In the reception band 36, the isolation characteristics of sample C are slightly worse than those of sample A. High-frequency power with a voltage of 1 V and a frequency of 2700 MHz (dashed line 38b) was applied to the transmission terminal Tx, and the current density of the high-frequency power on the underside of the lid 22 was simulated.

[0042] 11(a) and 11(b) are top views of the current density on the underside of the lid in samples A and C, respectively. As shown in FIG. 11(a), in sample A, the high-frequency power can be suppressed in a region 64 of the lid 22 that overlaps with the receiving filter 32, similar to FIG. 9(a). As shown in FIG. 11(b), in sample C, the high-frequency power propagates diagonally from the transmitting terminal Tx through the lid 22, as indicated by an arrow 52b. This increases the high-frequency power in the region of the lid 22 that overlaps with the receiving filter 32, degrading the isolation characteristics.

[0043] As shown in FIG. 10, sample C has better isolation characteristics than sample B. However, as shown in FIGS. 11(a) and 11(b), there is leakage of high-frequency power into the area overlapping with the receiving filter 32, and the isolation characteristics in the receiving band 36 are slightly worse than those of sample A.

[0044] Fig. 12 is a diagram showing the isolation characteristics of samples A, B, and D. As shown in Fig. 12, in bands lower than 2470 MHz, reception band 36, and bands higher than 2750 MHz, the isolation characteristics of sample D are comparable to those of sample A. In transmission band 34, the isolation characteristics of sample D are comparable to those of sample B and worse than those of sample A. High-frequency power with a voltage of 1 V and a frequency of 2550 MHz (dashed line 38c) was applied to the transmission terminal Tx, and the current density of the high-frequency power on the underside of the lid 22 was simulated.

[0045] 13(a) and 13(b) are top views of the current density on the underside of the lid in samples A and D, respectively. Comparing Fig. 13(a) and Fig. 13(b), in sample D, high frequency power propagates from near the common terminal Ant to near the receiving terminal Rx, as indicated by arrow 52e. As a result, the high frequency power in the lid 22 near the receiving terminal Rx is greater than that in region 64 of sample A.

[0046] As shown in FIG. 12, sample D has better isolation characteristics than sample B. However, as shown in FIGS. 13(a) and 13(b), there is leakage of high-frequency power into the area overlapping with the receiving filter 32, resulting in worse isolation characteristics in the transmission band 34 than sample A.

[0047] As in the above simulation samples A, C, and D, by providing the via wiring 16a between the transmit filter 30 and the receive filter 32, the isolation characteristics can be improved compared to sample B. The via wirings 16b and 16c are not necessarily provided, but providing them can further improve the isolation characteristics.

[0048] FIG. 14 is a plan view of a multiplexer in sample E. As shown in FIG. 14, in the transmission filter 30, the series resonators S11 to S13 are connected in series between the common terminal Ant and the transmission terminal Tx, and the parallel resonators P11 to P14 are connected in parallel. In the reception filter 32, the series resonators S21 to S25 are connected in series between the common terminal Ant and the reception terminal Rx, and the parallel resonators P21 to P24 are connected in parallel. The propagation direction of the acoustic waves in the series resonators S11 to S13, S21 to S25, the parallel resonators P11 to P14, and P21 to P24 is the Y direction. The other configurations are the same as those of sample A. A simulation was also performed on a sample F that is the same as sample E except that the via wiring 16a is not provided. Sample F corresponds to Comparative Example 1.

[0049] Fig. 15 is a diagram showing the isolation characteristics of samples E and F. As shown in Fig. 15, in the transmission band 34, the isolation characteristics of sample E are better than those of sample F. Even if the arrangement within the chip is changed as in samples E and F, the isolation characteristics of Example 1 are improved compared to Comparative Example 1.

[0050] [Modification 1 of Example 1] Fig. 16(a) is a circuit diagram of a multiplexer according to a first modification of the first embodiment. As shown in Fig. 16(a), in the first modification of the first embodiment, a transmission filter 30a is connected between a common terminal Ant and a transmission terminal Tx1, and a transmission filter 30b is connected between the common terminal Ant and a transmission terminal Tx2. A reception filter 32 is connected between the common terminal Ant and a reception terminal Rx. The transmission filters 30a and 30b are, for example, transmission filters for the LTE band 13 and the LTE band 17, respectively. The reception filter 32 is, for example, a reception filter shared by the LTE band 13 and the LTE band 17.

[0051] FIG. 16(b) is a plan view of a multiplexer according to the first modification of the first embodiment. As shown in FIG. 16(b), the transmission filter 30a is provided on the side 62, and the transmission filter 30b is provided on the side 60. The wiring 14d and the via wiring 15d connecting the transmission filter 30a and the transmission terminal Tx1 are provided near the center of the side 61 on the +X side between the sides 60 and 62. The wiring 14a and the via wiring 15a connecting the transmission filter 30b and the transmission terminal Tx2 are provided near the ends of the sides 60 and 61. The wiring 14c connects the transmission filters 30a, 30b and the reception filter 32. The other configurations are the same as those of the first embodiment, and the description will be omitted. As in the first modification of the first embodiment, the multiplexer may be a triplexer.

[0052] [Modification 2 of Example 1] FIG. 17(a) is a circuit diagram of a multiplexer according to a second modification of the first embodiment. As shown in FIG. 17(a), in the second modification of the first embodiment, a transmission filter 30a is connected between a common terminal Ant and a transmission terminal Tx1, and a transmission filter 30b is connected between the common terminal Ant and a transmission terminal Tx2. A reception filter 32a is connected between the common terminal Ant and a reception terminal Rx1, and a reception filter 32b is connected between the common terminal Ant and a reception terminal Rx2. The transmission filters 30a and 30b are, for example, transmission filters for the LTE band 13 and the LTE band 17, respectively. The reception filters 32a and 32b are, for example, reception filters for the LTE band 13 and the LTE band 17, respectively.

[0053] FIG. 17(b) is a plan view of a multiplexer according to the second modification of the first embodiment. As shown in FIG. 17(b), the receiving filter 32a is provided on the side 62, and the receiving filter 32b is provided on the side 60. The wiring 14e and the via wiring 15e connecting the receiving filter 32a and the receiving terminal Rx1 are provided near the center of the side 63 on the -X side between the sides 60 and 62. The wiring 14b and the via wiring 15b connecting the receiving filter 32b and the receiving terminal Rx2 are provided near the ends of the sides 60 and 63. The wiring 14c connects the transmitting filters 30a and 30b and the receiving filters 32a and 32b. The other configurations are the same as those of the first modification of the first embodiment, and the description thereof will be omitted. As in the second modification of the first embodiment, the multiplexer may be a quadplexer.

[0054] [Modification 3 of Example 1] Fig. 18 is a cross-sectional view of a multiplexer according to Modification 3 of Example 1. As shown in Fig. 18, acoustic wave resonator 12a forming transmission filter 30 and acoustic wave resonator 12b forming reception filter 32 are provided on substrate 10. Acoustic wave resonators 12a and 12b are the piezoelectric thin film resonators shown in Fig. 4(b). The other configurations are the same as those of Example 1, and description thereof will be omitted. As in Modification 3 of Example 1, acoustic wave resonators 12a and 12b may be piezoelectric thin film resonators.

[0055] According to the first embodiment and its modified example, a transmitting filter 30 (first filter) connected between a common terminal Ant and a transmitting terminal Tx (first signal terminal), and a receiving filter 32 (second filter) connected between the common terminal Ant and a receiving terminal Rx (second signal terminal) are provided on the upper surface (first surface) of the substrate 10. The annular metal layer 20 is provided on the first surface of the substrate 10 and surrounds the transmitting filter 30 and the receiving filter 32. The via wiring 16a (grounding via wiring) is provided between the region where the transmitting filter 30 is provided and the region where the receiving filter 32 is provided, penetrates the substrate 10, and connects the annular metal layer 20 and the ground terminal Gnd1 provided on the lower surface (second surface) of the substrate 10. This makes it possible to suppress leakage of a high-frequency signal input to the transmitting terminal Tx to the receiving terminal Rx via the annular metal layer 20, thereby improving isolation characteristics.

[0056] The lid 22 is provided on the annular metal layer 20 and is electrically connected to the annular metal layer 20, sealing the transmit filter 30 and the receive filter 32 in the gap 24. If the lid 22 is a metal lid, a high-frequency signal leaking from the transmit filter 30 to the lid 22 propagates through the lid 22 and reaches the receive terminal Rx, causing degradation of isolation characteristics. As in the simulation samples A, C, and D, by providing the via wiring 16a, it is possible to suppress high-frequency signals leaking from the transmit filter 30 to the lid 22 and from the lid 22 to the receive filter 32. This makes it possible to further improve the isolation characteristics.

[0057] The via wiring 16a is not connected to the transmit filter 30 and the receive filter 32 on the upper surface (the surface on which the transmit filter 30 and the receive filter 32 are provided) of the substrate 10. This makes it possible to suppress leakage of high-frequency signals from the ground of the transmit filter 30 to the ground of the receive filter 32 via the wiring 13a.

[0058] The via wiring 15a (first signal via wiring) penetrates the substrate 10 and connects the transmitting filter 30 and the transmitting terminal Tx. The via wiring 15b (second signal via wiring) penetrates the substrate 10 and connects the receiving filter 32 and the receiving terminal Rx. The annular metal layer 20 is substantially rectangular, and the via wirings 15a and 15b are provided near both ends of a side 60 of the substantially rectangular shape, and the via wiring 16a connects the side 60 of the annular metal layer 20 to the ground terminal Gnd1. This allows a high-frequency signal leaking from the transmitting terminal Tx to the receiving terminal Rx through the annular metal layer 20 to be grounded through the via wiring 16a. In addition, a high-frequency signal propagating through the lid 22 can be grounded through the side 60 of the annular metal layer 20. This further improves the isolation characteristics. Note that the planar shape of the annular metal layer 20 being substantially rectangular allows the corners to be curved and the sides to be curved to the extent of manufacturing errors. Moreover, the vicinity of both ends of side 60 is permitted to be about 1 / 4 of the length of side 60 away from the end of side 60 .

[0059] The via wiring 16b (first ground via wiring) and the via wiring 16c (second ground via wiring) connect the annular metal layer 20 to the ground terminal Gnd2 (first ground terminal) and the ground terminal Gnd3 (second ground terminal), respectively, near both ends of the side 62 facing the side 60. This allows the annular metal layer 20 to be grounded at a position away from the via wiring 16a. This allows high-frequency signals propagating through the annular metal layer 20 and the lid 22 to be grounded, improving isolation characteristics. Note that the vicinity of both ends of the side 62 is allowed to be about ¼ of the length of the side 62 away from the end of the side 62.

[0060] The transmit filter 30 is a ladder-type filter including series resonators S11 to S13 (first series resonators) and parallel resonators P11 to P14 (first parallel resonators), and the ground terminal Gnd2 is connected to the parallel resonator P11 that is electrically closest to the common terminal Ant. The receive filter 32 is a ladder-type filter including series resonators S21 to S25 (second series resonators) and parallel resonators P21 to P24 (second parallel resonators), and the ground terminal Gnd3 is connected to the parallel resonator P21 that is electrically closest to the common terminal Ant. The via wiring 16b allows high-frequency signals leaking from the transmit terminal Tx to the common terminal Ant to be grounded. Also, the via wiring 16c allows high-frequency signals leaking from the transmit terminal Tx to the receive terminal Rx via the common terminal Ant to be grounded.

[0061] Providing a large number of via wirings connected to the annular metal layer 20 increases the size of the multiplexer. Therefore, as in samples A and E of Example 1 and modified examples 1 to 3 of Example 1, the annular metal layer 20 is grounded only through the via wirings 16a to 16c among the via wirings that penetrate the substrate 10. This allows the via wirings to be provided in the most effective locations for improving the isolation characteristics, thereby improving the isolation characteristics. Since the via wirings are not provided in locations that are not very effective in improving the isolation characteristics, miniaturization is possible.

[0062] As in the first embodiment and its first and second modifications, the substrate 10 includes a support substrate 10b and a piezoelectric layer 10a provided on the support substrate 10b. The annular metal layer 20 is provided on the support substrate 10b from which the piezoelectric layer 10a has been removed, and the transmit filter 30 and the receive filter 32 are provided on the piezoelectric layer 10a. This makes it possible to prevent the piezoelectric layer 10a from being damaged by the stress of the annular metal layer 20. The transmit filter 30 and the receive filter 32 are provided on the single piezoelectric layer 10a. This makes it possible to miniaturize the multiplexer. As in the third modification of the first embodiment, the acoustic wave resonators 12a and 12b may be piezoelectric thin film resonators. The substrate 10 may also be a piezoelectric substrate.

[0063] The pass band of the transmit filter 30 does not overlap with the pass band of the receive filter 32. In this case, isolation between the pass bands becomes an issue. Therefore, it is preferable to provide the via wiring 16a.

[0064] In the first embodiment and its modified example, the multiplexer has a transmit filter and a receive filter, but the multiplexer may have only a plurality of transmit filters or only a plurality of receive filters. The multiplexer may have at least one of a filter for a band of an FDD (Frequency Division Duplex) system and a filter for a band of a TDD (Time Division Duplex) system. The transmit filter 30 and the receive filter 32 may be multimode filters.

[0065] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to such specific embodiments, and various modifications and variations are possible within the scope of the gist of the present invention described in the claims. [Explanation of symbols]

[0066] 10 Substrate 10a Piezoelectric layer 10b Support board 12a, 12b Acoustic wave resonator 13a~13c, 14a~14e Wiring 15a~15e, 16a~16c Via wiring 18 Terminals 20 Circular metal layer 22 Lid 30, 30a, 30b Transmit Filter 32, 32a, 32b Receive filters 60~63 sides

Claims

1. A substrate having a first surface and a second surface opposite to the first surface; a common terminal, a first signal terminal, and a second signal terminal provided on a second surface of the substrate; a first filter provided on a first surface of the substrate and connected between the common terminal and the first signal terminal; a first signal via wiring that penetrates the substrate and connects the first filter and the first signal terminal; a second filter provided on the first surface of the substrate and connected between the common terminal and the second signal terminal; a second signal via wiring that penetrates the substrate and connects the second filter and the second signal terminal; an annular metal layer provided on a first surface of the substrate and surrounding the first filter and the second filter; a ground terminal provided on a second surface of the substrate; a ground via wiring provided between a region in which the first filter is provided and a region in which the second filter is provided, penetrating the substrate and connecting the annular metal layer and the ground terminal; a metal lid provided on the annular metal layer, electrically connected to the annular metal layer, and sealing the first filter and the second filter in a gap; Equipped with the first signal terminal and the second signal terminal are provided on the second surface without overlapping the annular metal layer in a plan view, a planar shape of the annular metal layer is substantially rectangular, the first signal via wiring and the second signal via wiring are provided near both ends of one side of the substantially rectangular shape, and the ground via wiring connects the one side of the annular metal layer to the ground terminal; The first filter and the second filter are directly opposed to the metal lid with the gap therebetween.

2. The multiplexer according to claim 1 , wherein the ground via wiring is not connected to the first filter and the second filter on the first surface.

3. a first ground terminal and a second ground terminal provided on the second surface; 3. A multiplexer as described in claim 1 or 2, comprising a first ground via wiring and a second ground via wiring that penetrate the substrate and connect the annular metal layer to the first ground terminal and the second ground terminal, respectively, near both ends of the side opposite the one side.

4. the first filter is a ladder-type filter including a first series resonator and a first parallel resonator, the first ground terminal being connected to the first parallel resonator that is electrically closest to the common terminal among the first parallel resonators; 4. The multiplexer according to claim 3, wherein the second filter is a ladder-type filter including a second series resonator and a second parallel resonator, and the second ground terminal is connected to the second parallel resonator that is electrically closest to the common terminal among the second parallel resonators.

5. 5. The multiplexer according to claim 3, wherein the annular metal layer is grounded only through the ground via wiring, the first ground via wiring, and the second ground via wiring.

6. The substrate includes a support substrate and a piezoelectric layer provided on the support substrate, The multiplexer according to claim 1 , wherein the annular metal layer is provided on the support substrate from which the piezoelectric layer has been removed, and the first filter and the second filter are provided on the piezoelectric layer.

7. 7. The multiplexer of claim 6, wherein the first filter and the second filter are provided on a single piezoelectric layer.

8. 8. The multiplexer according to claim 1, wherein the passband of the first filter and the passband of the second filter do not overlap.

Images