Acoustic wave filter and radio frequency module

Abstract

To provide an acoustic wave filter that can reduce deterioration in transmission characteristics and attenuation characteristics.SOLUTION: An acoustic wave filter 100 includes: a piezoelectric substrate 11a; series-arm resonators 101 and 103 formed at the piezoelectric substrate 11a; an external connection terminal 121 disposed at the piezoelectric substrate 11a and connected to an amplifier connection terminal 201; an external connection terminal 122 disposed at the piezoelectric substrate 11a and connected to an amplifier; a wire 13 disposed at the piezoelectric substrate 11a and electrically connecting the external connection terminal 121 to the series-arm resonator 101; a wire 14 disposed at the piezoelectric substrate 11a and electrically connecting the external connection terminal 122 to the series-arm resonator 103; and a shield 12 covering a part of a side surface of the piezoelectric substrate 11a. The shield 12 covers at least a part of an area A2, of the side surface of the piezoelectric substrate 11a, opposing the wire 14 without covering an area A1 opposing the wire 13.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to an acoustic wave filter and a high-frequency module. [Background technology]

[0002] Patent Document 1 discloses that a hole is formed in the ceiling of a shielding case that shields a high-frequency filter, thereby suppressing capacitive coupling and / or inductive coupling between the high-frequency filter and the shielding case, thereby suppressing deterioration of the characteristics of the high-frequency filter. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 10-107471 Summary of the Invention [Problem to be solved by the invention]

[0004] However, with the above-described conventional techniques, it may be difficult to suppress deterioration of the attenuation characteristics due to the shield while suppressing deterioration of the passband characteristics due to coupling between the acoustic wave filter and other components.

[0005] Therefore, the present invention provides an acoustic wave filter and a high-frequency module that can suppress deterioration of the pass characteristics and attenuation characteristics. [Means for solving the problem]

[0006] An acoustic wave filter according to one aspect of the present invention includes a first substrate, a first series arm resonator and a second series arm resonator formed on the first substrate, a first external connection terminal disposed on the first substrate and connected to an antenna connection terminal, a second external connection terminal disposed on the first substrate and connected to an amplifier, a first wiring disposed on the first substrate and electrically connecting the first external connection terminal to the first series arm resonator, a second wiring disposed on the first substrate and electrically connecting the second external connection terminal to the second series arm resonator, and a shield covering a part of a side surface of the first substrate, wherein the shield covers at least a part of a second region of the side surface of the first substrate that faces the second wiring but does not cover a first region that faces the first wiring.

[0007] An acoustic wave filter according to one aspect of the present invention includes a first substrate and a second substrate, a first series arm resonator formed on the first substrate, a second series arm resonator formed on the second substrate, a first external connection terminal disposed on the first substrate and connected to an antenna connection terminal, a second external connection terminal disposed on the second substrate and connected to an amplifier, a third external connection terminal disposed on the first substrate and connected to the second substrate, a fourth external connection terminal disposed on the second substrate and connected to the third external connection terminal, and a shield covering at least a portion of a side surface of the second substrate, wherein the side surface of the first substrate is not covered by the shield. [Effects of the Invention]

[0008] According to the present invention, it is possible to suppress deterioration of the pass characteristics and attenuation characteristics of an acoustic wave filter. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a circuit configuration diagram of a high-frequency module according to a first embodiment. [Figure 2] FIG. 2 is a plan view of the high-frequency module according to the first embodiment. [Figure 3] FIG. 3 is a cross-sectional view of the high-frequency module according to the first embodiment. [Figure 4] FIG. 4 is a cross-sectional view of the acoustic wave filter according to the first embodiment. [Figure 5]FIG. 5 is a cross-sectional view of the acoustic wave filter according to the first embodiment. [Figure 6] FIG. 6 is a front view of the acoustic wave filter according to the first embodiment. [Figure 7] FIG. 7 is a left side view of the acoustic wave filter according to the first embodiment. [Figure 8] FIG. 8 is a right side view of the acoustic wave filter according to the first embodiment. [Figure 9] FIG. 9 is a rear view of the acoustic wave filter according to the first embodiment. [Figure 10] FIG. 10 is a Smith chart for explaining the influence of parasitic capacitance due to a shield. [Figure 11] FIG. 11 is a circuit configuration diagram of a high-frequency module according to the second embodiment. [Figure 12] FIG. 12 is a cross-sectional view of a filter module according to the second embodiment. [Figure 13] FIG. 13 is a circuit configuration diagram of a high-frequency module according to the third embodiment. [Figure 14] FIG. 14 is a cross-sectional view of a filter module according to the third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that the embodiments described below are all comprehensive or specific examples. The numerical values, shapes, materials, components, arrangements and connection forms of the components shown in the following embodiments are merely examples and are not intended to limit the present invention.

[0011] It should be noted that the drawings are schematic diagrams in which emphasis, omission, or adjustment of proportions has been appropriately made to illustrate the present invention, and are not necessarily strictly illustrated, and may differ from the actual shapes, positional relationships, and proportions. In the drawings, the same reference numerals are used to denote substantially the same components, and redundant explanations may be omitted or simplified.

[0012] In the following figures, the x-axis and y-axis are axes that are perpendicular to each other on a plane parallel to the main surface of the substrate. Specifically, if the substrate has a rectangular shape in a plan view, the x-axis is parallel to a first side of the module substrate, and the y-axis is parallel to a second side of the substrate that is perpendicular to the first side. The z-axis is an axis perpendicular to the main surface of the substrate, with its positive direction indicating the upward direction and its negative direction indicating the downward direction.

[0013] In the following explanation, "connected" includes not only direct connection by connection terminals and / or wiring conductors, but also electrical connection via other circuit elements. "C is connected between A and B" means that one end of C is connected to A and the other end of C is connected to B, meaning that C is arranged in series on the path connecting A and B. "Path connecting A and B" means a path made up of a conductor that electrically connects A to B.

[0014] "Terminal" means a point where a conductor within an element terminates. Note that terminal is understood to mean any point on the conductor between elements or the entire conductor, not just a single point, provided the impedance of the conductor between elements is sufficiently low.

[0015] The "passband of a filter" is defined as the portion of the frequency spectrum transmitted by the filter over which the output power is not attenuated by more than 3 dB below the maximum output power. The upper and lower ends of a bandpass filter's passband are therefore identified as the higher and lower frequencies of the two points where the output power is attenuated by 3 dB below the maximum output power.

[0016] The term "transmission band" refers to a frequency band used for transmission in a communication device, and the term "reception band" refers to a frequency band used for reception in a communication device. For example, in an FDD band, different frequency bands (e.g., an uplink band and a downlink band) are used as the transmission band and the reception band. For example, in a Time Division Duplex (TDD) band, the same frequency band is used as the transmission band and the reception band.

[0017] "Capable of simultaneous communication" means that signals of multiple bands can be transmitted, received, or transmitted and received simultaneously. Band combinations that can be used for simultaneous communication are predefined by standardization organizations (e.g., 3GPP (registered trademark) (3rd Generation Partnership Project) and IEEE (Institute of Electrical and Electronics Engineers)). Examples of simultaneous communication include Carrier Aggregation (CA), E-UTRAN New Radio - Dual Connectivity (EN-DC), New Radio - Dual Connectivity (NR-DC), and New Radio E-UTRAN - Dual Connectivity (NE-DC).

[0018] "A component is disposed on a substrate" includes a component being disposed on the main surface of the substrate and a component being disposed within the substrate. "A component is disposed on the main surface of the substrate" includes a component being disposed in contact with the main surface of the substrate, as well as a component being disposed above the main surface without contacting the main surface (for example, a component being stacked on another component disposed in contact with the main surface). "A component is disposed on the main surface of the substrate" may also include a component being disposed in a recess formed in the main surface. "A component is disposed within the substrate" includes a component being encapsulated within a module substrate, as well as a component being entirely disposed between both main surfaces of the substrate but partially not covered by the substrate, and a component being partially disposed within the substrate.

[0019] The phrase "the shield covers the side surface of the substrate" means that the side surface is blocked by the shield when viewed from the normal direction of the side surface of the substrate. Therefore, the shield does not necessarily have to be in contact with the side surface.

[0020] "A region of the side of the substrate that faces a component (e.g., wiring, a resonator, etc.)" refers to the region of the side of the substrate that is closer to the component out of two parallel sides of the substrate in a planar view, and refers to the region on the side of the substrate that is obtained by orthogonally projecting the component onto a plane parallel to the side, extended in the normal direction (z direction) of the main surface of the substrate.

[0021] Terms indicating the relationship between elements, such as "parallel" and "perpendicular," terms indicating the shape of elements, such as "rectangle," and numerical ranges do not only indicate strict meanings, but also include substantially equivalent ranges, for example, including an error of a few percent.

[0022] (Embodiment 1) A first embodiment will be described. A high-frequency module 300 including an acoustic wave filter 100 according to this embodiment can be used in a communication device for providing wireless connectivity. For example, the high-frequency module 300 can be used in user equipment (UE) in a cellular network (also called a mobile network), such as a mobile phone, a smartphone, a tablet computer, or a wearable device. Another example of the high-frequency module 300 is a communication device for providing wireless connectivity to Internet of Things (IoT) sensor devices, medical / healthcare devices, cars, unmanned aerial vehicles (UAVs) (so-called drones), and automated guided vehicles (AGVs). Another example of the high-frequency module 300 can be used in a communication device for providing wireless connectivity at a wireless access point or a wireless hotspot.

[0023] Here, the circuit configuration of a high-frequency module 300 according to this embodiment will be described with reference to Fig. 1. Fig. 1 is a circuit configuration diagram of a high-frequency module 300 according to this embodiment.

[0024] 1 is an example circuit configuration, and the high-frequency module 300 and the acoustic wave filter 100 can be implemented using any of a wide variety of circuit implementations and circuit technologies. Therefore, the following description of the high-frequency module 300 and the acoustic wave filter 100 should not be construed as limiting.

[0025] [1.1 Circuit configuration of high-frequency module 300] The high-frequency module 300 includes an acoustic wave filter 100, an inductor 200, and an antenna connection terminal 201. The detailed circuit configuration of the acoustic wave filter 100 will be described later.

[0026] The antenna connection terminal 201 is an external connection terminal of the high-frequency module 300. The antenna connection terminal 201 is connected to an antenna (not shown) outside the high-frequency module 300, and is connected to the acoustic wave filter 100 inside the high-frequency module 300.

[0027] The acoustic wave filter 100 is a bandpass filter having a passband that includes the receive band of band A. The acoustic wave filter 100 may be a bandpass filter having a passband that includes the transmit band of band A. The acoustic wave filter 100 is not limited to a bandpass filter. The acoustic wave filter 100 may be a surface acoustic wave (SAW) filter or a bulk acoustic wave (BAW) filter.

[0028] Band A is an example of a first band and is a frequency band for a communication system built using a radio access technology (RAT). Band A is predefined by a standardization organization (e.g., 3GPP and IEEE). Examples of the communication system include a 5GNR (5th Generation New Radio) system, an LTE (Long Term Evolution) system, and a WLAN (Wireless Local Area Network) system.

[0029] The inductor 200 is connected between a path connecting the antenna connection terminal 201 and the acoustic wave filter 100 and ground. The inductor 200 forms, for example, an impedance matching circuit. Note that the impedance matching circuit is not limited to the circuit configuration shown in FIG. 1 . For example, the impedance matching circuit may include an inductor and / or a capacitor connected between the antenna connection terminal 201 and the acoustic wave filter 100 in addition to or instead of the inductor 200, or may include a capacitor connected between the path connecting the antenna connection terminal 201 and the acoustic wave filter 100 and ground.

[0030] The high-frequency module 300 may include a power amplifier and / or a low-noise amplifier, and may include a plurality of acoustic wave filters 100.

[0031] 1.2 Circuit Configuration of Acoustic Wave Filter 100 Next, the circuit configuration of the acoustic wave filter 100 will be described with reference to Fig. 1. The acoustic wave filter 100 includes series arm resonators 101, 102, and 103, parallel arm resonators 111, 112, and 113, and external connection terminals 121, 122, and 123.

[0032] The external connection terminal 121 is an example of a first external connection terminal. The external connection terminal 121 is connected to the antenna connection terminal 201 outside the acoustic wave filter 100, and is connected to the series arm resonator 101 inside the acoustic wave filter 100.

[0033] The external connection terminal 122 is an example of a second external connection terminal. The external connection terminal 122 is connected to a power amplifier (not shown) and / or a low-noise amplifier (not shown) outside the acoustic wave filter 100, and is connected to the series arm resonator 103 inside the acoustic wave filter 100.

[0034] External connection terminal 123 is connected to ground outside acoustic wave filter 100 and is connected to parallel arm resonators 111 to 113 inside acoustic wave filter 100.

[0035] The series arm resonators 101 to 103 are connected in series between external connection terminals 121 and 122. Specifically, the series arm resonator 101 is an example of a first series arm resonator, and is connected between the external connection terminal 121 and the series arm resonator 102. The series arm resonator 102 is connected between the series arm resonators 101 and 103. The series arm resonator 103 is an example of a second series arm resonator, and is connected between the series arm resonator 102 and the external connection terminal 122.

[0036] The parallel arm resonators 111 to 113 are connected in parallel with one another between a path connecting the external connection terminals 121 and 122 and ground. Specifically, the parallel arm resonator 111 is connected between the path connecting the series arm resonators 101 and 102 and the external connection terminal 123. The parallel arm resonator 112 is connected between the path connecting the series arm resonators 102 and 103 and the external connection terminal 123. The parallel arm resonator 113 is connected between the path connecting the series arm resonator 103 and the external connection terminal 122 and the external connection terminal 123.

[0037] The numbers of series arm resonators and parallel arm resonators included in the acoustic wave filter 100 are not limited to those shown in Fig. 1. For example, the number of series arm resonators and the number of parallel arm resonators included in the acoustic wave filter 100 may each be one. That is, in the acoustic wave filter 100, the first series arm resonator and the second series arm resonator may be the same single series arm resonator.

[0038] [1.3 Mounting example of high frequency module 300] Next, an example of mounting the high-frequency module 300 will be described with reference to Fig. 2 and Fig. 3. Fig. 2 is a plan view of the high-frequency module 300 according to the present embodiment. Fig. 3 is a cross-sectional view of the high-frequency module 300 according to the present embodiment.

[0039] 2 and 3 are exemplary diagrams, and the high frequency module 300 can be implemented using any of a wide variety of circuit implementations and circuit technologies. Therefore, the description of the high frequency module 300 provided below should not be construed as limiting.

[0040] The high-frequency module 300 includes a module substrate 301, an acoustic wave filter 100, and an inductor 200. The acoustic wave filter 100 and the inductor 200 are arranged on a main surface of the module substrate 301.

[0041] The module substrate 301 may be, for example, a low temperature co-fired ceramics (LTCC) substrate or a high temperature co-fired ceramics (HTCC) substrate having a laminated structure of multiple dielectric layers, a component-embedded substrate, a substrate having a redistribution layer (RDL), or a printed circuit board, but is not limited to these.

[0042] The acoustic wave filter 100 includes a substrate 11, a shield 12, and external connection terminals 121 to 123. The external connection terminal 121 is electrically connected to the inductor 200 via wiring 302 on a module substrate 301. Details of the acoustic wave filter 100 will be described later with reference to FIGS.

[0043] The inductor 200 is implemented as a chip inductor. A chip inductor refers to a surface mount device (SMD) that constitutes an inductor. The implementation of the inductor 200 is not limited to a chip inductor. For example, the inductor 200 may be implemented by a wiring pattern formed on the module substrate 301.

[0044] [1.4 Implementation example of acoustic wave filter 100] Next, implementation examples of the acoustic wave filter 100 will be described with reference to FIGS. 4 to 9. FIGS. 4 and 5 are cross-sectional views of the acoustic wave filter 100 according to this embodiment. The cross sections of the acoustic wave filter 100 in FIGS. 4 and 5 are taken along line iv-iv in FIG. 3 and line vv in FIG. 4. FIGS. 6 to 9 are front, left, right, and rear views of the acoustic wave filter 100 according to this embodiment.

[0045] 4 to 9 are exemplary diagrams, and the acoustic wave filter 100 can be implemented using any of a wide variety of circuit implementations and circuit technologies. Therefore, the following description of the acoustic wave filter 100 should not be construed as limiting.

[0046] As shown in FIG. 5, the substrate 11 includes a piezoelectric substrate 11a and a support substrate 11b.

[0047] The piezoelectric substrate 11a is an example of a first substrate and is disposed on the support substrate 11b. The piezoelectric substrate 11a is made of a piezoelectric single crystal or piezoelectric ceramics such as lithium tantalate (LiTaO), lithium niobate (LiNbO), aluminum nitride (AlN), or zinc oxide (ZnO). However, the material of the piezoelectric substrate 11a is not limited to these.

[0048] Series arm resonators 101 to 103 and parallel arm resonators 111 to 113 are formed on the piezoelectric substrate 11a. The series arm resonators 101 to 103 and the parallel arm resonators 111 to 113 are, for example, IDT (Inter Digital Transducer) electrodes formed on the surface of the piezoelectric substrate 11a. The IDT electrodes can generate and detect surface acoustic waves.

[0049] Furthermore, wirings 13, 14, and 15 are formed on the piezoelectric substrate 11a. The wiring 13 electrically connects the series arm resonator 101 to an external connection terminal 121. The wiring 14 electrically connects the series arm resonator 103 to an external connection terminal 122. The wiring 15 electrically connects the parallel arm resonators 111 to 113 to an external connection terminal 123. The wirings 13 to 15 may include bus bar electrodes of IDT electrodes.

[0050] The support substrate 11b is an example of a second substrate and supports the piezoelectric substrate 11a. The support substrate 11b is, for example, a silicon substrate, and has recesses 21 for forming spaces between the series arm resonators 101-103 and the parallel arm resonators 111-113 and the support substrate 11b. In addition, via conductors are formed in the support substrate 11b to electrically connect the wirings 13-15 and the external connection terminals 121-123, respectively.

[0051] The shield 12 is a metal film formed by, for example, sputtering and connected to ground. The shield 12 can suppress capacitive coupling (electric field coupling) and / or inductive coupling (magnetic field coupling) between components inside the acoustic wave filter 100 and components outside the acoustic wave filter 100.

[0052] 6 to 9, the shield 12 partially covers the side surfaces of the piezoelectric substrate 11a and the support substrate 11b. More specifically, the shield 12 does not cover at least areas A1, A3, A5, and A7 of the side surfaces of the piezoelectric substrate 11a and the support substrate 11b, but covers at least areas A2, A4, A6, and A8. Note that the shield 12 only needs to cover at least a portion of area A2, and does not necessarily have to cover areas A4, A6, and A8. The shield 12 may also cover areas A3, A5, and A7.

[0053] Region A1 is an example of a first region and is a region of the side surface of the piezoelectric substrate 11a facing the wiring 13. Region A2 is an example of a second region and is a region of the side surface of the piezoelectric substrate 11a facing the wiring 14. Region A3 is an example of a third region and is a region of the side surface of the piezoelectric substrate 11a facing the series arm resonator 101. Region A4 is an example of a fourth region and is a region of the side surface of the piezoelectric substrate 11a facing the series arm resonator 103.

[0054] Region A5 is an example of a fifth region and is a region of the side surface of the support substrate 11b facing the wiring 13. Region A6 is an example of a sixth region and is a region of the side surface of the support substrate 11b facing the wiring 14. Region A7 is an example of a seventh region and is a region of the side surface of the support substrate 11b facing the series arm resonator 101. Region A8 is an example of an eighth region and is a region of the side surface of the support substrate 11b facing the series arm resonator 103.

[0055] Inductor 200 is arranged closer to region A1 than to region A2, closer to region A3 than to region A4, closer to region A5 than to region A6, and closer to region A7 than to region A8.

[0056] The external connection terminals 121 to 123 are formed on the main surface of the support substrate 11b opposite to the piezoelectric substrate 11a (the lower surface in FIG. 5). The external connection terminals 121 to 123 are electrically connected to input / output terminals and ground terminals of the module substrate 301. The external connection terminals 121 to 123 are, for example, copper electrodes or solder electrodes.

[0057] [1.5 Effect of parasitic capacitance due to shield 12] Next, the influence of the parasitic capacitance due to the shield 12 will be described with reference to FIG. 10 . FIG. 10 is a Smith chart for illustrating the influence of the parasitic capacitance due to the shield 12. In FIG. 10 , impedance 401 represents the impedance in the reception band of band A (the pass band of the acoustic wave filter 100) when the acoustic wave filter 100 is viewed from the antenna connection terminal 201 without the shield 12. Impedance 402 represents the impedance in the reception band of band A when the acoustic wave filter 100 is viewed from the antenna connection terminal 201 with the shield 12 present. Impedance 403 represents the impedance in the reception band of band B, which allows simultaneous communication with band A, when the acoustic wave filter 100 is viewed from the antenna connection terminal 201 without the shield 12 present. Impedance 404 represents the impedance in the reception band of band B when the acoustic wave filter 100 is viewed from the antenna connection terminal 201 with the shield 12 present.

[0058] In the acoustic wave filter 100 with the shield 12, parasitic capacitance occurs between the wiring and the resonator and the shield 12, causing the impedance 401 to shift to the impedance 402. To match the impedance 402, the inductance value of the inductor 200 must be reduced, which increases loss in the pass band.

[0059] Although the present embodiment has been described with reference to a case where the inductor 200 is connected between the ground and a path connecting the antenna connection terminal 201 and the acoustic wave filter 100, the same applies to a case where the inductor 200 is connected between the antenna connection terminal 201 and the acoustic wave filter 100. Specifically, an increase in the parasitic capacitance of the acoustic wave filter 100 requires an increase in the inductance value of the inductor 200, which increases loss in the pass band.

[0060] Furthermore, when the impedance 403 shifts to the impedance 404, signals of band B, which can be communicated simultaneously with band A, tend to leak into the path of the acoustic wave filter 100, degrading isolation. Therefore, from the viewpoint of parasitic capacitance, it is preferable that the area of ​​the acoustic wave filter 100 covered by the shield 12 is small.

[0061] On the other hand, if the acoustic wave filter 100 does not have the shield 12, capacitive coupling and / or inductive coupling occurs between the inductor 200 or the like and the acoustic wave filter 100, degrading the attenuation characteristics of the acoustic wave filter 100. Therefore, from the viewpoint of capacitive coupling and / or inductive coupling, it is preferable that the area of ​​the acoustic wave filter 100 that is covered by the shield 12 be as large as possible.

[0062] [1.6 Summary] As described above, the acoustic wave filter 100 according to this preferred embodiment includes the piezoelectric substrate 11a, the series arm resonators 101 and 103 formed on the piezoelectric substrate 11a, the external connection terminal 121 disposed on the piezoelectric substrate 11a and connected to the antenna connection terminal 201, the external connection terminal 122 disposed on the piezoelectric substrate 11a and connected to an amplifier, the wiring 13 disposed on the piezoelectric substrate 11a and electrically connecting the external connection terminal 121 to the series arm resonator 101, the wiring 14 disposed on the piezoelectric substrate 11a and electrically connecting the external connection terminal 122 to the series arm resonator 103, and the shield 12 covering a portion of the side surface of the piezoelectric substrate 11a. The shield 12 covers at least a portion of an area A2 of the side surface of the piezoelectric substrate 11a that faces the wiring 14, but does not cover an area A1 that faces the wiring 13.

[0063] In this configuration, at least a portion of the region A2 facing the wiring 14 is covered by the shield 12, thereby suppressing coupling between the wiring 14 and other components (e.g., the inductor 200) and thereby suppressing degradation of the attenuation characteristics. In particular, if the inductor 200 is coupled to the wiring 14, most of the acoustic wave filter 100 is skipped, significantly reducing attenuation. Therefore, covering the region A2 with the shield 12 is highly effective in suppressing degradation of the attenuation characteristics. On the other hand, since the region A1 facing the wiring 13 is not covered by the shield 12, parasitic capacitance generated between the shield 12 and the wiring 13 can be suppressed more effectively than when the entire side surface of the piezoelectric substrate 11a is covered by the shield 12. Therefore, a decrease in the inductance value of the inductor 200 for impedance matching can be suppressed, and an increase in loss can be suppressed. Note that even if the inductor 200 is coupled to the wiring 13, attenuation can be obtained by the resonator between the wiring 13 and the external connection terminal 122, and the effect on degradation of the attenuation characteristics is small. As described above, according to the acoustic wave filter 100, by effectively arranging the shield 12 on the side surface of the piezoelectric substrate 11a, it is possible to suppress deterioration of the pass characteristics and attenuation characteristics.

[0064] Furthermore, for example, in the acoustic wave filter 100 according to this preferred embodiment, the shield 12 does not have to cover the region A3 of the side surface of the piezoelectric substrate 11a that faces the series arm resonator 101.

[0065] In this case, the region A3 facing the series arm resonator 101 is not covered by the shield 12, and therefore, the parasitic capacitance generated between the shield 12 and the series arm resonator 101 can be reduced more than when the entire side surface of the piezoelectric substrate 11a is covered by the shield 12. This makes it possible to prevent a decrease in the inductance value of the inductor 200 for impedance matching, and to prevent an increase in loss. Even if the inductor 200 and the series arm resonator 101 are coupled, a certain degree of attenuation can be obtained between the series arm resonator 101 and the external connection terminal 122, and the impact on degradation of the attenuation characteristics is low.

[0066] Furthermore, for example, in the acoustic wave filter 100 according to this preferred embodiment, the shield 12 may cover at least a part of a region A4 that faces the series arm resonator 103 on the side surface of the piezoelectric substrate 11a.

[0067] In this case, the shield 12 covers at least a portion of the region A4 facing the series arm resonator 103, thereby suppressing coupling between the series arm resonator 103 and other components (e.g., the inductor 200) and suppressing deterioration of the attenuation characteristics. In particular, if the inductor 200 and the series arm resonator 103 are coupled together, most of the acoustic wave filter 100 is skipped, resulting in a significant decrease in attenuation. Therefore, covering the region A4 with the shield 12 is highly effective in suppressing deterioration of the attenuation characteristics. Covering the region A4 with the shield 12 is highly effective in suppressing deterioration of the attenuation characteristics.

[0068] For example, the acoustic wave filter 100 according to this embodiment may further include a support substrate 11b, the piezoelectric substrate 11a may be disposed on the support substrate 11b, and the shield 12 may cover at least a portion of an area A6 on the side surface of the support substrate 11b that faces the wiring 14, but may not cover an area A5 that faces the wiring 13.

[0069] In this configuration, at least a portion of the region A6 facing the wiring 14 is covered by the shield 12, thereby suppressing coupling between the wiring 14 and other components (e.g., the inductor 200) and thereby suppressing degradation of the attenuation characteristics. In particular, if the inductor 200 is coupled to the wiring 14, most of the acoustic wave filter 100 is skipped, significantly reducing attenuation. Therefore, covering the region A6 with the shield 12 is highly effective in suppressing degradation of the attenuation characteristics. Covering the region A6 with the shield 12 is also highly effective in suppressing degradation of the attenuation characteristics. On the other hand, since the region A5 facing the wiring 13 is not covered by the shield 12, parasitic capacitance generated between the shield 12 and the wiring 13 can be suppressed more effectively than when the entire side surface of the piezoelectric substrate 11a is covered by the shield 12. Therefore, a decrease in the inductance value of the inductor 200 for impedance matching can be suppressed, and an increase in loss can be suppressed. Even if the inductor 200 is coupled to the wiring 13, attenuation can be obtained between the wiring 13 and the external connection terminal 122, and the impact on degradation of the attenuation characteristics is low. As described above, the acoustic wave filter 100 can suppress deterioration of the pass characteristics and attenuation characteristics.

[0070] Furthermore, for example, in the acoustic wave filter 100 according to this preferred embodiment, the shield 12 does not have to cover an area A7 of the side surface of the support substrate 11b that faces the series arm resonator 101.

[0071] In this case, the region A7 facing the series arm resonator 101 is not covered by the shield 12, and therefore, the parasitic capacitance generated between the shield 12 and the series arm resonator 101 can be reduced more than when the entire side surface of the piezoelectric substrate 11a is covered by the shield 12. This prevents a decrease in the inductance value of the inductor 200 for impedance matching, and prevents an increase in loss. Even if the inductor 200 and the series arm resonator 101 are coupled, a certain degree of attenuation can be obtained between the series arm resonator 101 and the external connection terminal 122, and the impact on degradation of the attenuation characteristics is low.

[0072] Furthermore, for example, in the acoustic wave filter 100 according to this preferred embodiment, the shield 12 may cover at least a part of a region A8 that faces the series arm resonator 103 on the side surface of the support substrate 11b.

[0073] In this case, the shield 12 covers at least a portion of the region A8 facing the series arm resonator 103, thereby suppressing coupling between the series arm resonator 103 and other components (e.g., the inductor 200) and thereby suppressing deterioration of the attenuation characteristics. In particular, if the inductor 200 and the series arm resonator 103 are coupled together, most of the acoustic wave filter 100 is skipped, resulting in a significant decrease in attenuation. Therefore, covering the region A8 with the shield 12 is highly effective in suppressing deterioration of the attenuation characteristics. Covering the region A8 with the shield 12 is highly effective in suppressing deterioration of the attenuation characteristics.

[0074] Furthermore, for example, the acoustic wave filter 100 according to this embodiment may have a pass band that includes the reception band of band A, and the amplifier may be a low-noise amplifier.

[0075] This allows the acoustic wave filter 100 to be used as a receiving filter.

[0076] Furthermore, for example, the acoustic wave filter 100 according to this embodiment may have a pass band that includes the transmission band of band A, and the amplifier may be a power amplifier.

[0077] This allows the acoustic wave filter 100 to be used as a transmission filter.

[0078] Furthermore, for example, the acoustic wave filter 100 according to this embodiment may be a surface acoustic wave filter or a bulk acoustic wave filter.

[0079] This makes it possible to obtain the above-mentioned effects with a surface acoustic wave filter or a bulk acoustic wave filter.

[0080] Moreover, the high-frequency module 300 according to this embodiment includes a module substrate 301, an acoustic wave filter 100 disposed on the module substrate 301, and an inductor 200 disposed on the module substrate 301 and electrically connected to an external connection terminal 121 of the acoustic wave filter 100.

[0081] This makes it possible to achieve the effects of the acoustic wave filter 100 in a high-frequency module 300 in which the inductor 200 is connected to the acoustic wave filter 100.

[0082] Furthermore, for example, in the high-frequency module 300 according to this embodiment, the inductor 200 may be disposed closer to the region A1 than to the region A2.

[0083] This allows the distance between the inductor 200 and the wiring 14 to be longer than the distance between the inductor 200 and the wiring 13, thereby further suppressing the coupling between the inductor 200 and the wiring 14.

[0084] (Embodiment 2) Next, a second embodiment will be described. This embodiment differs from the first embodiment in that the acoustic wave filters are mounted separately on separate substrates. The following describes the second embodiment, focusing on the differences from the first embodiment, with reference to the drawings.

[0085] 2.1 Circuit Configuration of the High-Frequency Module 300A and the Acoustic Wave Filter 100A 11 is a circuit diagram of a high-frequency module 300A according to this embodiment. Note that FIG. 11 illustrates an exemplary circuit configuration, and the high-frequency module 300A and the acoustic wave filter 100A can be implemented using any of a wide variety of circuit implementations and circuit technologies. Therefore, the following description of the high-frequency module 300A and the acoustic wave filter 100A should not be construed as limiting.

[0086] The high-frequency module 300A includes an acoustic wave filter 100A, an inductor 200, and an antenna connection terminal 201.

[0087] Similar to the acoustic wave filter 100 according to the first embodiment, the acoustic wave filter 100A is a bandpass filter having a passband that includes the reception band of band A. The acoustic wave filter 100A includes series arm resonators 101, 102, and 103, parallel arm resonators 111, 112, and 113, and external connection terminals 121, 122, and 123. The acoustic wave filter 100A is divided into two filter modules, a filter module 1001A, and a filter module 1002A.

[0088] The filter module 1001A includes series arm resonators 101 and 102, a parallel arm resonator 111, and external connection terminals 121, 123, and 124.

[0089] The external connection terminal 124 is an example of a third external connection terminal, and is connected to the external connection terminal 125 of the filter module 1002A outside the filter module 1001A, and is connected to the series arm resonator 102 inside the filter module 1001A.

[0090] The filter module 1002A includes a series arm resonator 103, parallel arm resonators 112 and 113, and external connection terminals 122, 123, and 125.

[0091] The external connection terminal 125 is an example of a fourth external connection terminal, and is connected to the external connection terminal 124 of the filter module 1001A outside the filter module 1002A, and is connected to the series arm resonator 103 inside the filter module 1002A.

[0092] [2.2 Implementation example of acoustic wave filter 100A] Next, an implementation example of the acoustic wave filter 100A will be described with reference to FIG. 12. FIG. 12 is a cross-sectional view of filter modules 1001A and 1002A according to this embodiment. Note that FIG. 12 is an exemplary diagram, and the acoustic wave filter 100A can be implemented using any of a wide variety of circuit implementations and circuit technologies. Therefore, the following description of the filter modules 1001A and 1002A should not be construed as limiting.

[0093] The filter module 1001A includes a substrate 11A1, which is an example of a first substrate. On the substrate 11A1, series arm resonators 101 and 102, a parallel arm resonator 111, and wirings 13, 15, and 16 are formed. The wiring 16 electrically connects the series arm resonator 102 to an external connection terminal 124. Note that the side surfaces of the substrate 11A1 are not covered with a shield.

[0094] The filter module 1002A includes a substrate 11A2, which is an example of a second substrate. The substrate 11A2 is provided with a series arm resonator 103, parallel arm resonators 112 and 113, and wirings 14, 15, and 17. The side surfaces of the substrate 11A2 are covered with a shield 12A. The wiring 17 electrically connects the series arm resonator 103 to an external connection terminal 125. In this embodiment, the entire side surface of the substrate 11A2 is covered with the shield 12A, but part of the side surface of the substrate 11A2 does not have to be covered with the shield 12A.

[0095] The number of series arm resonators and the number of parallel arm resonators included in each of filter module 1001A and filter module 1002A are not limited to the numbers shown in FIG.

[0096] [2.3 Summary] As described above, the acoustic wave filter 100A according to this preferred embodiment includes the substrates 11A1 and 11A2, the series arm resonator 101 formed on the substrate 11A1, the series arm resonator 103 formed on the substrate 11A2, the external connection terminal 121 disposed on the substrate 11A1 and connected to the antenna connection terminal 201, the external connection terminal 122 disposed on the substrate 11A2 and connected to an amplifier, the external connection terminal 124 disposed on the substrate 11A1 and connected to the substrate 11A2, the external connection terminal 125 disposed on the substrate 11A2 and connected to the external connection terminal 124, and the shield 12A covering at least a portion of the side surface of the substrate 11A2, and the side surface of the substrate 11A1 is not covered by the shield.

[0097] This allows the side surfaces to be covered or not to be covered for each substrate, simplifying the manufacturing process of the acoustic wave filter 100A.

[0098] (Embodiment 3) Next, a third embodiment will be described. The third embodiment differs from the second embodiment in that the high-frequency module includes two acoustic wave filters having different passbands. The following describes the third embodiment, focusing on the differences from the second embodiment, with reference to the drawings.

[0099] 3.1 Circuit Configuration of High-Frequency Module 300B and Acoustic Wave Filter 100B FIG. 13 is a circuit diagram of a high-frequency module 300B according to this embodiment. Note that FIG. 13 illustrates an exemplary circuit configuration, and the high-frequency module 300B and the acoustic wave filters 100A and 100B can be implemented using any of a wide variety of circuit implementations and circuit technologies. Therefore, the following description of the high-frequency module 300B and the acoustic wave filters 100A and 100B should not be construed as limiting.

[0100] The high-frequency module 300B includes acoustic wave filters 100A and 100B, an inductor 200, and an antenna connection terminal 201.

[0101] The acoustic wave filter 100B is a bandpass filter having a passband that includes the reception band of band B, which allows simultaneous communication with band A. The acoustic wave filter 100B may be a bandpass filter having a passband that includes the transmission band of band B. The acoustic wave filter 100B is not limited to a bandpass filter. Band B is an example of a second band, and, like band A, is a frequency band for a communication system established using a RAT, and is defined in advance by a standardization organization or the like.

[0102] The acoustic wave filter 100B includes series arm resonators 104, 105, and 106, parallel arm resonators 114, 115, and 116, and external connection terminals 123 and 128.

[0103] The external connection terminal 128 is connected to a power amplifier (not shown) and / or a low-noise amplifier (not shown) outside the acoustic wave filter 100B, and is connected to the series arm resonator 106 inside the acoustic wave filter 100B.

[0104] The series arm resonators 104 to 106 are connected in series between the external connection terminals 121 and 128. Specifically, the series arm resonator 104 is connected between the external connection terminal 121 and the series arm resonator 105. The series arm resonator 105 is connected between the series arm resonators 104 and 106. The series arm resonator 106 is connected between the series arm resonator 105 and the external connection terminal 128.

[0105] The parallel arm resonators 114 to 116 are connected in parallel with each other between a path connecting the external connection terminals 121 and 128 and the ground. Specifically, the parallel arm resonator 114 is connected between the path connecting the series arm resonators 104 and 105 and the external connection terminal 123. The parallel arm resonator 115 is connected between the path connecting the series arm resonators 105 and 106 and the external connection terminal 123. The parallel arm resonator 116 is connected between the path connecting the series arm resonator 106 and the external connection terminal 128 and the external connection terminal 123.

[0106] A portion of the acoustic wave filter 100A and a portion of the acoustic wave filter 100B are mounted on a filter module 1001B, and the other portion of the acoustic wave filter 100A and the other portion of the acoustic wave filter 100B are mounted on a filter module 1002B.

[0107] The filter module 1001B includes series arm resonators 101, 102, 104, and 105, parallel arm resonators 111 and 114, and external connection terminals 121, 123, 124, and 126.

[0108] The external connection terminal 126 is connected to an external connection terminal 127 of the filter module 1002B outside the filter module 1001B, and is connected to the series arm resonator 105 inside the filter module 1001B.

[0109] The filter module 1002B includes series arm resonators 103 and 106, parallel arm resonators 112, 113, 115 and 116, and external connection terminals 122, 123, 125, 127 and 128.

[0110] The external connection terminal 127 is connected to the external connection terminal 126 of the filter module 1001B outside the filter module 1002B, and is connected to the series arm resonator 106 inside the filter module 1002B.

[0111] The numbers of series arm resonators and parallel arm resonators included in each of the acoustic wave filters 100A and 100B are not limited to those shown in FIG.

[0112] [3.2 Implementation examples of acoustic wave filters 100A and 100B] Next, an implementation example of the acoustic wave filters 100A and 100B will be described with reference to FIG. 14 . FIG. 14 is a cross-sectional view of filter modules 1001B and 1002B according to this embodiment. Note that FIG. 14 is an exemplary diagram, and the acoustic wave filters 100A and 100B can be implemented using any of a wide variety of circuit implementations and circuit technologies. Therefore, the following description of the filter modules 1001B and 1002B should not be construed as limiting.

[0113] The filter module 1001B includes a substrate 11B1, which is an example of a first substrate. On the substrate 11B1, series arm resonators 101, 102, 104, and 105, parallel arm resonators 111 and 114, and wirings 13, 15, 16, and 18 are formed. The wiring 13 electrically connects the series arm resonators 101 and 104 to an external connection terminal 121. The wiring 18 electrically connects the series arm resonator 105 to an external connection terminal 126. Note that the side surfaces of the substrate 11B1 are not covered with a shield.

[0114] The filter module 1002B includes a substrate 11B2, which is an example of a second substrate. The substrate 11B2 is provided with a series arm resonator 103, parallel arm resonators 112 and 113, and wirings 14, 15, 17, 19, and 20. The wiring 19 electrically connects the series arm resonator 106 to an external connection terminal 127. The wiring 20 electrically connects the series arm resonator 106 to an external connection terminal 128. The side surfaces of the substrate 11B2 are covered with a shield 12B. In this embodiment, the entire side surface of the substrate 11B2 is covered with the shield 12B, but some of the side surfaces of the substrate 11B2 may not be covered with the shield 12B.

[0115] The number of series arm resonators and the number of parallel arm resonators included in each of filter module 1001B and filter module 1002B are not limited to the numbers shown in FIG.

[0116] (Other embodiments) Although the acoustic wave filter and high-frequency module according to the present invention have been described above based on the embodiments, the acoustic wave filter and high-frequency module according to the present invention are not limited to the above embodiments. The present invention also includes other embodiments realized by combining any of the components in the above embodiments, modifications obtained by applying various modifications to the above embodiments that would occur to those skilled in the art without departing from the spirit of the present invention, and various devices incorporating the above acoustic wave filter or high-frequency module.

[0117] For example, in the circuit configurations of the various circuits according to the above embodiments, other circuit elements and wiring may be inserted between the paths connecting the circuit elements and signal paths disclosed in the drawings.

[0118] The characteristics of the acoustic wave filter and the high-frequency module described based on the above-described embodiments will be described below.

[0119] <1> a first substrate; a first series arm resonator and a second series arm resonator formed on the first substrate; a first external connection terminal disposed on the first substrate and connected to an antenna connection terminal; a second external connection terminal disposed on the first substrate and connected to an amplifier; a first wiring arranged on the first substrate and electrically connecting the first external connection terminal to the first series arm resonator; a second wiring disposed on the first substrate and electrically connecting the second external connection terminal to the second series arm resonator; a shield covering a part of a side surface of the first substrate, the shield covers at least a part of a second region of the side surface of the first substrate that faces the second wiring, and does not cover a first region that faces the first wiring; Acoustic wave filters.

[0120] <2> the shield does not cover a third region of the side surface of the first substrate that faces the first series arm resonator. <1> The acoustic wave filter according to claim 1.

[0121] <3> the shield covers at least a part of a fourth region of the side surface of the first substrate that faces the second series arm resonator. <1> or <2> The acoustic wave filter according to claim 1.

[0122] <4> the acoustic wave filter further includes a second substrate; the first substrate is disposed on the second substrate; the shield covers at least a part of a sixth region of the side surface of the second substrate that faces the second wiring, and does not cover a fifth region that faces the first wiring; <1> ~ <3> 10. The acoustic wave filter according to claim 9, wherein:

[0123] <5> the shield does not cover a seventh region of the side surface of the second substrate that faces the first series arm resonator. <4> The acoustic wave filter according to claim 1.

[0124] <6> the shield covers at least a part of an eighth region of a side surface of the second substrate that faces the second series arm resonator. <4> or <5> The acoustic wave filter according to claim 1.

[0125] <7> the acoustic wave filter has a passband that includes a first band reception band; the amplifier is a low noise amplifier; <1> ~ <6> 10. The acoustic wave filter according to claim 9, wherein:

[0126] <8> the acoustic wave filter has a passband that includes a first transmission band; the amplifier is a power amplifier; <1> ~ <6> 10. The acoustic wave filter according to claim 9, wherein:

[0127] <9> The acoustic wave filter is a surface acoustic wave filter or a bulk acoustic wave filter. <1> ~ <8> 10. The acoustic wave filter according to claim 9, wherein:

[0128] <10> a module substrate; The module substrate is disposed <1> ~ <9> an acoustic wave filter according to any one of the preceding items; an inductor disposed on the module substrate and electrically connected to the first external connection terminal of the acoustic wave filter; High frequency module.

[0129] <11> The inductor is disposed closer to the first region than to the second region. <10> The high-frequency module according to claim 1.

[0130] <12> a first substrate and a second substrate; a first series arm resonator formed on the first substrate; a second series arm resonator formed on the second substrate; a first external connection terminal disposed on the first substrate and connected to an antenna connection terminal; a second external connection terminal disposed on the second substrate and connected to an amplifier; a third external connection terminal disposed on the first substrate and connected to the second substrate; a fourth external connection terminal disposed on the second substrate and connected to the third external connection terminal; a shield covering at least a portion of a side surface of the second substrate; The side surface of the first substrate is not covered with a shield. Acoustic wave filters. [Industrial Applicability]

[0131] The present invention can be widely used as a high-frequency module disposed in the front end of communication devices such as mobile phones. [Explanation of symbols]

[0132] 11, 11A1, 11A2, 11B1, 11B2 board 11a Piezoelectric substrate 11b Support board 12, 12A, 12B Shield 13, 14, 15, 16, 17, 18, 19, 20, 302 Wiring 21 Recess 100, 100A, 100B acoustic wave filters 101, 102, 103, 104, 105, 106 Series arm resonators 111, 112, 113, 114, 115, 116 Parallel arm resonators 121, 122, 123, 124, 125, 126, 127, 128 External connection terminals 200 inductor 201 Antenna connection terminal 300, 300A, 300B High Frequency Module 301 Module Board 401, 402, 403, 404 Impedance 1001A, 1001B, 1002A, 1002B Filter Modules A1, A2, A3, A4, A5, A6, A7, A8 area

Claims

1. a first substrate; a first series arm resonator and a second series arm resonator formed on the first substrate; a first external connection terminal disposed on the first substrate and connected to an antenna connection terminal; a second external connection terminal disposed on the first substrate and connected to an amplifier; a first wiring disposed on the first substrate and electrically connecting the first external connection terminal to the first series arm resonator; a second wiring disposed on the first substrate and electrically connecting the second external connection terminal to the second series arm resonator; a shield covering a part of a side surface of the first substrate, the shield covers at least a part of a second region of a side surface of the first substrate that faces the second wiring, and does not cover a first region that faces the first wiring; Acoustic wave filters.

2. the shield does not cover a third region of the side surface of the first substrate that faces the first series arm resonator. The acoustic wave filter according to claim 1 .

3. the shield covers at least a part of a fourth region of a side surface of the first substrate that faces the second series arm resonator. The acoustic wave filter according to claim 1 or 2.

4. the acoustic wave filter further includes a second substrate; the first substrate is disposed on the second substrate; the shield covers at least a part of a sixth region of the side surface of the second substrate that faces the second wiring, and does not cover a fifth region that faces the first wiring; The acoustic wave filter according to claim 1 or 2.

5. the shield does not cover a seventh region of the side surface of the second substrate that faces the first series arm resonator. The acoustic wave filter according to claim 4 .

6. the shield covers at least a part of an eighth region of a side surface of the second substrate, the eighth region facing the second series arm resonator. The acoustic wave filter according to claim 4 .

7. the acoustic wave filter has a pass band that includes a first band reception band; the amplifier is a low noise amplifier; The acoustic wave filter according to claim 1 or 2.

8. the acoustic wave filter has a passband that includes a first transmission band; the amplifier is a power amplifier; The acoustic wave filter according to claim 1 or 2.

9. The acoustic wave filter is a surface acoustic wave filter or a bulk acoustic wave filter. The acoustic wave filter according to claim 1 or 2.

10. a module substrate; an acoustic wave filter according to claim 1 or 2, which is disposed on the module substrate; an inductor disposed on the module substrate and electrically connected to the first external connection terminal of the acoustic wave filter; High frequency module.

11. The inductor is disposed closer to the first region than to the second region. The high frequency module according to claim 10.

12. a first substrate and a second substrate; a first series arm resonator formed on the first substrate; a second series arm resonator formed on the second substrate; a first external connection terminal disposed on the first substrate and connected to an antenna connection terminal; a second external connection terminal disposed on the second substrate and connected to an amplifier; a third external connection terminal disposed on the first substrate and connected to the second substrate; a fourth external connection terminal disposed on the second substrate and connected to the third external connection terminal; a shield covering at least a portion of a side surface of the second substrate, The side surface of the first substrate is not covered with a shield. Acoustic wave filters.

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