Acoustic Wave Devices

Abstract

To provide an acoustic wave device with low resistance loss. [Solution] The acoustic wave device includes a plurality of resonators provided on a piezoelectric substrate, a pad, and a plurality of wirings, each of the plurality of resonators having an IDT electrode, and the wirings having a busbar-adjacent portion provided in a region extending from a busbar in a direction perpendicular to the acoustic wave propagation direction of the IDT electrode. The busbar-adjacent portion has a connection-side end close to a portion connected to a pad or another resonator in the acoustic wave propagation direction, and a non-connection-side end opposite the pad or the other resonator, the connection-side end having a width in the perpendicular direction greater than the width of the non-connection-side end of the busbar in the perpendicular direction, and the width of the busbar-adjacent portion of the wiring in the perpendicular direction to the acoustic wave propagation direction increases from the non-connection-side end of the busbar to the connection-side end.

Description

[Technical Field]

[0001] The present invention relates to an acoustic wave device in which a plurality of resonators are provided on a piezoelectric substrate. [Background technology]

[0002] For example, an acoustic wave device including a filter using a plurality of SAW (Surface Acoustic Wave) resonators is known as a duplexer for a mobile phone.

[0003] Patent Document 1 discloses an acoustic wave filter device having a plurality of IDT electrodes provided on a piezoelectric substrate, in which the length of a reflector adjacent to the IDT electrode is shortened to secure space, and the secured space is used as an area for forming wiring, thereby widening the wiring width and lowering the wiring resistance, thereby reducing loss. Patent Document 2 discloses an acoustic wave device having a plurality of IDT electrodes with bus bars inclined with respect to the electrode fingers, in which the IDT electrodes form an inclination angle of a positive value exceeding 0° with respect to the propagation direction of the acoustic wave, thereby reducing insertion loss. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2017-195580 A [Patent Document 2] Patent No. 6424962 Summary of the Invention [Problem to be solved by the invention]

[0005] In an acoustic wave device having an IDT electrode and wiring on a piezoelectric substrate, it is necessary to reduce loss by lowering the resistance of the wiring. However, widening the wiring increases the area occupied by the wiring on the piezoelectric substrate, which poses a problem: either the piezoelectric substrate must be enlarged to make the device larger, or, as in the acoustic wave filter device disclosed in Patent Document 1, the area occupied by the reflector on the piezoelectric substrate must be reduced to ensure additional space for the wiring.

[0006] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide an acoustic wave device that reduces the resistance of wiring while ensuring area efficiency. [Means for solving the problem]

[0007] One aspect of the acoustic wave device of the present invention is a device comprising: a piezoelectric substrate; a plurality of resonators provided on the piezoelectric substrate; a pad provided on the piezoelectric substrate; a plurality of wirings for electrically connecting the pads and the plurality of resonators; An acoustic wave device comprising: each of the plurality of resonators includes an IDT electrode having a pair of comb-teeth electrodes facing each other; The comb-tooth electrode is a plurality of electrode fingers provided on the comb-tooth electrode; a bus bar electrically connected to the plurality of electrode fingers, In a plan view, the wiring includes a busbar-adjacent portion that is provided adjacent to the busbar on a side opposite to a side on which the electrode fingers are provided and that is provided in a region that extends from the busbar in a direction perpendicular to a propagation direction of an elastic wave in the IDT electrode, the busbar-adjacent portion has a connection-side end portion that is close to the wiring connected to the pad or another resonator in the elastic wave propagation direction, and a non-connection-side end portion that is an end portion opposite to the pad or the other resonator, a width in the orthogonal direction at the connection side end of the busbar-adjacent portion is larger than a width in the orthogonal direction at the non-connection side end of the busbar-adjacent portion; The width of the busbar-adjacent portion of the wiring in the direction perpendicular to the elastic wave propagation direction is configured to increase gradually or in a stepwise manner from the non-connection side end of the busbar to the connection side end. In this way, the busbar-adjacent portion of the IDT electrode, which is disposed adjacent to the busbar, has a larger width at the connection side end, through which a relatively large current flows, and a smaller width at the non-connection side end, through which a relatively large current does not flow. This makes it possible to reduce the total electrical resistance of the busbar-adjacent portion without significantly increasing the area occupied by the busbar-adjacent portion. Here, "close" in terms of wiring connected to a pad or another resonator means that the wiring is close as a circuit path in terms of the electrical connection relationship.

[0008] As a specific aspect of the above-described aspect, the acoustic wave device of the present invention may further include a resonator among the plurality of resonators, the resonator being provided with two bus bars that are electrically connected to the electrode fingers of the resonator and that face each other; the bus bar adjacent portions are disposed adjacent to the two bus bars, respectively; The two adjacent busbar portions are each of the resonators has a connection end portion that is close to the pad or the other resonator in the wiring in the propagation direction of the elastic wave, and a non-connection end portion that is an end portion opposite to the pad and the other resonator; a width in the orthogonal direction at the connection-side end portion is larger than a width in the orthogonal direction at the non-connection-side end portion of the busbar-adjacent portion; Each of the two busbar adjacent portions is configured to have a width that gradually or stepwise increases from the non-connection side end to the connection side end of the busbar. It is something.

[0009] As a specific aspect of the above-described aspect, the acoustic wave device of the present invention includes, in a plan view, a first resonator and a second resonator among the plurality of resonators provided on the piezoelectric substrate, the first resonator and the second resonator are arranged opposite to each other in the orthogonal direction so as to have a portion where the distance between them is closest and a portion where the distance between them is farthest, the busbar-adjacent portion is a wiring region that electrically connects the first resonator and the second resonator, the busbar-adjacent portion is disposed adjacent to a busbar on the second resonator side of the first resonator and a busbar on the first resonator side of the second resonator, and is a region where these two busbars overlap when viewed from the orthogonal direction, and is a region extending from these two busbars in the orthogonal direction, the busbar adjacent portion is a portion where the distance between the opposing first resonator and the opposing second resonator in the orthogonal direction is the greatest, and the first resonator and the second resonator on the pad or the piezoelectric substrate are connected to each other by wiring at a connection side end portion, and a non-connection side end portion that is on a side where the opposing first resonator and second resonator are close to each other in the orthogonal direction and is opposite to the pad or the other resonator; a width of the non-connection-side end of the busbar-adjacent portion in the orthogonal direction is smaller than a width of the busbar-adjacent portion of the connection-side end in the orthogonal direction, and a width of the connection-side end in the orthogonal direction is larger than a width of the non-connection-side end of the busbar-adjacent portion in the orthogonal direction, The width of the busbar-adjacent portion is configured to increase gradually or in a stepwise manner from the non-connection side end to the connection side end. In this way, a busbar-adjacent portion is provided between the first resonator and the second resonator, and the width of the busbar-adjacent portion near the connection side end where a relatively large current flows, i.e., the side opposite the non-connection side end of the busbar-adjacent portion, is made wider, while the width of the non-connection side end where a relatively large current does not flow is made narrower.As a result, the total electrical resistance of the busbar-adjacent portion can be reduced without significantly increasing the area occupied by the busbar-adjacent portion.

[0010] As a specific aspect of the above-described aspect, the acoustic wave device of the present invention includes a first resonator and a second resonator that are opposed to each other in a plan view among the plurality of resonators provided on the piezoelectric substrate, and The bus bar adjacent portion is a first busbar adjacent portion located adjacent to a busbar of the first resonator on the second resonator side, the first busbar adjacent portion being located adjacent to the busbar of the first resonator on the second resonator side; a second busbar adjacent portion located adjacent to the busbar on the first resonator side among the plurality of busbars of the second resonator; is established, the first busbar-adjacent portion and the second busbar-adjacent portion are not electrically connected to each other, the first busbar adjacent portion and the second busbar adjacent portion are provided in regions of wiring adjacent to a busbar on a second resonator side of the first resonator and a busbar on the first resonator side of the second resonator, the regions overlapping each other when viewed from the orthogonal direction; the first busbar-adjacent portion disposed adjacent to the first resonator has a connection-side end and a non-connection-side end in a propagation direction of an elastic wave of the first resonator, The connection side end is close to the pad on the piezoelectric substrate or to a wiring connected to another resonator, and has a large width in a direction perpendicular to the propagation direction. the non-connection side end is on the opposite side of the piezoelectric substrate from the pad or the other resonator, and has a small width in an orthogonal direction perpendicular to the propagation direction; a width of the first busbar-adjacent portion in the orthogonal direction gradually or stepwise increases from the non-connection side end to the connection side end, the second busbar-adjacent portion disposed adjacent to the second resonator has a connection-side end and a non-connection-side end in a propagation direction of an elastic wave of the second resonator, The connection side end of the second bus bar adjacent portion is close to the pad on the piezoelectric substrate or to a wiring connected to another resonator, and has a large width in a direction perpendicular to the propagation direction. the non-connection side end of the second busbar-adjacent portion is on the opposite side to the pad or the other resonator on the piezoelectric substrate, and has a small width in a direction perpendicular to the propagation direction; a width of the second busbar-adjacent portion in the orthogonal direction gradually or stepwise increases from the non-connection side end to the connection side end, a distance between a connection-side end of the first busbar-adjacent portion and a non-connection-side end of the second busbar-adjacent portion in the propagation direction is closer than a connection-side end of the second busbar-adjacent portion; In the propagation direction, the non-connection side end of the first busbar-adjacent portion is closer to the connection side end of the second busbar-adjacent portion than the non-connection side end of the second busbar-adjacent portion. In this way, the width of each of the first and second busbar-adjacent portions is widest near the connection-side end, where a relatively large current flows, i.e., the side opposite the non-connection-side end of the busbar-adjacent portion, and is narrowest at the non-connection-side end, where a relatively large current does not flow. This reduces the total electrical resistance of the busbar-adjacent portions without significantly increasing the area occupied by the busbar-adjacent portions. Furthermore, by locating the connection-side end of the first busbar-adjacent portion close to the non-connection-side end of the second busbar-adjacent portion, the non-connection-side end of the first busbar-adjacent portion and the connection-side end of the second busbar-adjacent portion are close to each other. This allows the first and second busbar-adjacent portions to be arranged area-efficiently. Therefore, when arranging two resonators, the resistance of the busbar-adjacent portions can be reduced and loss can be suppressed while improving area efficiency.

[0011] In a specific aspect of the acoustic wave device of the present invention, the bus bar is connected to the electrode fingers at an angle in a plan view.

[0012] In a specific aspect of the acoustic wave device of the present invention, the bus bar is formed in a stepped shape in a plan view.

[0013] In a specific aspect of the above-described aspect of the elastic wave device of the present invention, the width of the busbar-adjacent portion in the orthogonal direction of the non-connection side end is 1 / 3 or less of the width of the connection side end in the orthogonal direction.

[0014] In a specific embodiment of the acoustic wave device of the present invention, the first busbar-adjacent portion and the second busbar-adjacent portion are provided between opposing busbars, and the distance between the opposing busbars is defined as the total width in the orthogonal direction including the first busbar-adjacent portion and the second busbar-adjacent portion, and the total width in the orthogonal direction of the non-connection side ends of the first busbar-adjacent portion and the second busbar-adjacent portion is one-third or less of the total width in the orthogonal direction of the connection side ends of the first busbar-adjacent portion and the second busbar-adjacent portion.

[0015] In a specific embodiment of the acoustic wave device of the present invention, a ladder filter including a plurality of series resonators and a plurality of parallel resonators is provided on the piezoelectric substrate. [Effects of the Invention]

[0016] According to the acoustic wave device of the present invention, the busbar-adjacent portion of the IDT electrode, which is disposed adjacent to the busbar, has a larger width at the connection side end through which a relatively large current flows and a smaller width at the non-connection side end through which a relatively large current does not flow, thereby reducing the total electrical resistance of the busbar-adjacent portion without increasing the area occupied by the busbar-adjacent portion on the piezoelectric substrate. This makes it possible to realize an acoustic wave device in which loss due to wiring resistance is reduced without increasing the area of ​​the piezoelectric substrate and thereby increasing its size. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a plan view illustrating an embodiment of an acoustic wave device according to the present invention. [Figure 2] 2 is an enlarged plan view of a resonator and a portion adjacent to a bus bar in the acoustic wave device of FIG. 1. FIG. [Figure 3] FIG. 3 is a cross-sectional view of the resonator of FIG. 2 taken along line AA'. [Figure 4] 1(a) is a plan view showing an IDT electrode and a portion adjacent to a bus bar according to Example 1. FIG. 1(b) is a view showing a conventional example of an IDT electrode and a portion adjacent to a bus bar for comparison. [Figure 5] 1(a) is a plan view showing the width of each part of Example 1. FIG. 1(b) is a plan view showing the width of each part of a conventional example. [Figure 6] 1(a) is a diagram illustrating an equivalent circuit of Example 1. FIG. 1(b) is a diagram illustrating an equivalent circuit of a conventional example. [Figure 7] 3 is a circuit diagram showing an equivalent circuit of an IDT electrode and a portion adjacent to a bus bar in the resonator of the first embodiment. FIG. [Figure 8] 10 is a graph showing the change in resistance reduction rate with respect to the change in width W1 in Example 1. FIG. [Figure 9] 10 is a diagram showing a change in the resistance reduction rate with respect to a change in width W1 when the resistor R3 of Example 1 is excluded. FIG. [Figure 10] 10(a) is a plan view showing a state in which two resonators are tilted and opposed to each other as Example 2. FIG. 10(b) is a diagram showing a conventional example. [Figure 11] 10A and 10B are plan views illustrating other examples of a resonator and a busbar-adjacent portion constituting an acoustic wave device according to an embodiment of the present invention. [Figure 12] 12 is a cross-sectional view of the resonator of FIG. 11 taken along a line BB'. [Figure 13] 10A and 10B are plan views illustrating other examples of a resonator and a busbar-adjacent portion constituting an acoustic wave device according to an embodiment of the present invention. [Figure 14] 10A and 10B are plan views illustrating other examples of a resonator and a busbar-adjacent portion constituting an acoustic wave device according to an embodiment of the present invention. [Figure 15] 10A and 10B are plan views illustrating other examples of a resonator and a busbar-adjacent portion constituting an acoustic wave device according to an embodiment of the present invention. [Figure 16] 10A and 10B are plan views illustrating other examples of a resonator and a busbar-adjacent portion constituting an acoustic wave device according to an embodiment of the present invention. [Figure 17] 10A and 10B are plan views illustrating other examples of a resonator and a busbar-adjacent portion constituting an acoustic wave device according to an embodiment of the present invention. [Figure 18] 10A and 10B are plan views illustrating other examples of a resonator and a busbar-adjacent portion constituting an acoustic wave device according to an embodiment of the present invention. [Figure 19] 10A and 10B are plan views illustrating other examples of a resonator and a busbar-adjacent portion constituting an acoustic wave device according to an embodiment of the present invention. [Figure 20] 10A and 10B are plan views illustrating other examples of a resonator and a busbar-adjacent portion constituting an acoustic wave device according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0018] <About the acoustic wave device in Figure 1> Fig. 1 is a plan view showing an embodiment of an acoustic wave device of the present invention. As shown in Fig. 1, a plurality of acoustic wave resonators S1 to S5, P1 to P3, wirings 30 to 38, and pads 40 to 43 are formed on a substrate 10 serving as a piezoelectric substrate. A ladder-type filter 1 serving as an acoustic wave device includes series resonators S1 to S5 and parallel resonators P1 to P3.

[0019] For example, lithium tantalate (LiTaO3) is used for the substrate 10 as a piezoelectric substrate. However, the piezoelectric substrate is not limited to this material, and other materials such as lithium niobate (LiNbO3) can also be used.

[0020] The acoustic wave resonators P1 to P3 and S1 to S5 each include an IDT (Interdigital Transistor). The substrate 10 includes electrodes 100a, 120a, 130a, 140a, 150a, 210a, 220a, and 230a, and reflectors 100b, 120b, 130b, 140b, 150b, 210b, 220b, and 230b provided on both sides thereof. The wiring 30 to 38 and the pads 40 to 43 are formed of a metal layer such as a copper layer or a gold layer formed on the substrate 10.

[0021] In the ladder filter 1 serving as an acoustic wave device, the series resonators S1 to S5 are connected in series between a pad 40 serving as an antenna terminal Ant (output terminal) and a pad 42 serving as a transmission terminal Tx (input terminal). The parallel resonators P1 to P3 are connected in parallel between the pad 40 serving as the antenna terminal Ant and the pad 42 serving as a transmission terminal Tx. One end of the parallel resonators P1 to P3 is connected to pads 41 and 43 serving as ground (GND) terminals.

[0022] <Regarding the resonator and the area adjacent to the busbar in Figure 2> 2 is a plan view of a resonator P1 provided on a substrate 10 in the acoustic wave device 1. The resonator P1 includes an IDT electrode 210a and a reflector 210b.

[0023] IDT electrode 210a includes comb-tooth electrodes 212a and 212b, and comb-tooth electrode 212a includes electrode fingers 213a and bus bar 214a. Comb-tooth electrode 212b includes electrode fingers 213b and bus bar 214b. Bus bars 214a and 214b are provided at an angle to electrode fingers 213a and 214b. Bus bars 214a and 214b are also provided at an angle to the propagation direction of surface acoustic waves excited by IDT electrode 210a (X direction in FIG. 2).

[0024] A wiring 36 is provided above the IDT electrode 210a in FIG. 2. A wiring 37 is provided below the IDT electrode 21a. This wiring 36 is provided on the bus bar 214a on the opposite side to the electrode finger 213a, and is electrically connected to the resonator S1, which is another resonator (a resonator other than the resonator P1). The wiring 37 is provided on the bus bar 214b on the opposite side to the electrode finger 213b, and is connected to a pad 41, which is a ground terminal (GND). Note that the resonant frequency f R is determined by P=λ / 2, where λ is the wavelength of the surface acoustic wave propagating through the piezoelectric layer 3 and P is the electrode period of the electrode fingers.

[0025] 2, the busbar-adjacent portion 36a and the busbar-adjacent portion 37a are indicated by diagonal hatching. The busbar-adjacent portion 36a is a partial region of the wiring 36, is disposed adjacent to the busbar 214a, and extends from the busbar 214a in a direction perpendicular to the propagation direction of the surface acoustic wave (the Y direction in FIG. 2, which may hereinafter be referred to as the "orthogonal direction"). That is, the busbar-adjacent portion 36a is a region of the wiring 35 that has the same width as the busbar 214a in the propagation direction (X direction).

[0026] The busbar-adjacent portion 36a has a connection-side end 36b and a non-connection-side end 36c in the propagation direction. The connection-side end 36b is the end electrically closer to the other resonator, resonator P1. The non-connection-side end 36c is the end opposite the connection-side end 36b in the propagation direction, and is an end that is separated from other components such as other wirings, other resonators, or pads, i.e., an end that is not directly connected to other wirings.

[0027] The width W2a of the connection-side end 36b in the orthogonal direction (Y direction) is larger than the width W1a of the non-connection-side end 36c, and the width W1a of the non-connection-side end 36c in the orthogonal direction is smaller than the width W2a of the connection-side end 36b. The width of the busbar-adjacent portion 36a in the orthogonal direction is configured to gradually increase from the non-connection-side end 36c to the connection-side end 36b.

[0028] The busbar-adjacent portion 37a is a part of the wiring 37, and is disposed adjacent to the busbar 214b and extends perpendicularly from the busbar 214b. That is, the busbar-adjacent portion 37a is a region of the wiring 37 that has the same width as the busbar 214b in the propagation direction.

[0029] The busbar-adjacent portion 37a has a connection-side end 37b and a non-connection-side end 37c in the propagation direction. The connection-side end 37b is the end connected to the wiring leading to the pad 43, which is the ground terminal, and is the end closest to these in terms of electrical connection. The non-connection-side end 37c is the end opposite the connection-side end 37b in terms of the propagation direction, and is the end farther away from other components on the substrate 10, such as other wiring or other resonator pads, in terms of electrical connection.

[0030] The width W2a of the connection-side end 36b in the orthogonal direction (Y direction) and the width W1a of the non-connection-side end 36c in the orthogonal direction are the same as the width W2a of the connection-side end 37b in the orthogonal direction (Y direction) and the width W1a of the non-connection-side end 37c in the orthogonal direction. The width W2a of the connection-side end 36b in the orthogonal direction (Y direction) is greater than the width W1a of the non-connection-side end 36c, and the width W1a of the non-connection-side end 36c in the orthogonal direction is smaller than the width W2a of the connection-side end 36b. The busbar-adjacent portion 36a is configured so that its width in the orthogonal direction gradually increases from the non-connection-side end 36c to the connection-side end 36b in the propagation direction.

[0031] Fig. 3 is an AA' cross-sectional view of resonator P1. As shown in Fig. 3, a first metal layer 60 and a second metal layer 61 are formed on substrate 10. As shown in Fig. 3, electrode finger 213b, bus bars 214a and 214b, and electrode finger 213b are formed of first metal layer 60. First metal layer 60 is, for example, an aluminum layer, a titanium layer, or a copper layer, but may be an alloy of these, or another metal may be used, or these metals may be laminated to form a multilayer structure.

[0032] The busbar-adjacent portion 36a of the wiring 36 and the busbar-adjacent portion 36a of the wiring 36 include a first metal layer 60 on the substrate 10 and a second metal layer 61 formed on the first metal layer 60. The second metal layer 61 is, for example, an aluminum layer, a titanium layer, a copper layer, a palladium layer, or a gold layer. An alloy of these metals may be used, or other metals may be employed, or these metals may be configured in multiple layers.

[0033] The substrate 10 as a piezoelectric substrate may be composed of only a piezoelectric substrate, or may be a substrate in which a piezoelectric substrate is attached to a support substrate. The support substrate may be, for example, a spinel substrate, but may also be made of other materials such as a sapphire substrate, silicon substrate, quartz substrate, crystal substrate, alumina substrate, or silicon carbide substrate, as long as it can solve the problems of the present invention. An intermediate layer may also be provided between the support substrate and the piezoelectric substrate. For example, when the intermediate layer is provided for the purpose of increasing the bonding strength between the support substrate 2 and the piezoelectric substrate 3, silicon dioxide (SiO2) or the like is used for the intermediate layer. When the intermediate layer is provided as a layer for increasing the speed of elastic waves, for example, aluminum nitride (AlN) or boron aluminum nitride (B X Al 1-X N) etc. are used.

[0034] In this way, the busbar-adjacent portions 36a and 37a, which are adjacent to the busbars 214a and 214b of the IDT electrode 210a, have a larger width at the connection-side ends 36b and 37b, through which a relatively large current flows, and a smaller width at the non-connection-side ends 36c and 37c, through which a relatively large current does not flow because they are not connected to other wiring. This reduces the total electrical resistance of the busbar-adjacent portions 36a and 37a without significantly increasing the area occupied by the busbar-adjacent portions 36a and 37a on the substrate 10. This makes it possible to reduce losses due to electrical resistance while maintaining the area occupied by the resonator P1. This also makes it possible to reduce losses due to electrical resistance in the acoustic wave device 1.

[0035] In the present embodiment, the widths of the connection-side ends 36b, 37b of the busbar-adjacent portions 36a, 37a of the IDT electrode 210a are increased and the widths of the non-connection-side ends 36c, 36c are decreased, but the width of the connection-side end (36b, 37b) of only one of the busbar-connected portions of the busbar-adjacent portions 36a, 37a may be increased and the width of the non-connection-side end (36c, 37c) may be decreased. Note that, although straight lines are shown at the positions of the connection-side ends 35b, 36b of the busbar-adjacent portions 36a, 37a of the wirings 36, 37, these straight lines indicate the outline of the hatching and do not indicate the boundaries of the shapes or materials.

[0036] <About the simulation> Simulations were performed to confirm the loss reduction due to the electrical resistance of the resonator P1. FIG. 4(a) is a plan view showing an IDT electrode and a busbar-adjacent portion according to Example 1. FIG. 4(b) is a plan view showing a conventional example of an IDT electrode and a busbar-adjacent portion for comparison. In this application, the region in Example 1 in FIG. 4(a), from boundary line 71 to boundary line 72, where electrode fingers 76 and busbars 73 are arranged, is referred to as the IDT electrode arrangement region 70. In FIG. 4(a), busbar-adjacent portions 74 and 75 electrically connected to wirings 78 and 79 are provided above and below the IDT electrode arrangement region 70. In this simulation, the busbar-adjacent portions 74 and 75 play the same role as the busbar-adjacent portions 36a and 37a in the resonator P1 of FIG. 2.

[0037] 4(b), the IDT electrode of the conventional example is provided in an IDT electrode arrangement region 80, which is an area from boundary line 81 to boundary line 83, in which electrode fingers 86 and bus bars 83 are arranged. Above and below the IDT electrode arrangement region 80, bus bar adjacent portions 84 and 85, which are electrically connected to wiring 87 and 88, are provided.

[0038] 4(a), the electrode fingers 76, the busbar 73, and the busbar-adjacent portions 74 and 75 are provided with a first metal layer 60, similar to the cross-sectional view of FIG. 3. The busbar-adjacent portions 74 and 75 are provided with a laminated structure of the first metal layer 60 and the second metal layer 61. The busbar-adjacent portions 36a and 37a in FIG. 2 and the busbar-adjacent portions 74 and 75 in FIG. 4(a) have in common the shape, in a plan view, of a trapezoid with the connection side end as the bottom side and the non-connection side end as the top side. Therefore, if it can be confirmed that Example 1 in FIG. 4(a) has a reduced loss due to resistance compared to the conventional example in FIG. 4(b), it can also be confirmed that there is a reduced loss due to resistance in the resonator P1 and the busbar-adjacent portions 36a and 37a in FIG. 2.

[0039] FIG. 5(a) is a diagram illustrating the widths of each portion of the first embodiment, which includes an IDT electrode arrangement region 70 and busbar-adjacent portions 74 and 75. As shown in FIG. 5(a), the outline of the IDT electrode arrangement region 70 is shown in simplified form. As shown in FIGS. 4(a) and 5(a), the upper and lower sides 71 and 72 of the IDT electrode arrangement region 70 are lines that indicate the boundaries between the busbar 73 and the busbar-adjacent portions 74 and 75. The busbar-adjacent portion 74 is provided in a direction perpendicular to the propagation direction of the upper side (boundary line) 71. The busbar-adjacent portion 75 is provided in a direction perpendicular to the lower side (boundary line) 72.

[0040] 5(b) is a diagram illustrating the widths of the IDT electrode arrangement region 80 and the conventional widths of the adjacent busbar portions 84 and 85. The outline of the IDT electrode arrangement region 80 is shown.

[0041] The difference in configuration between Example 1 in FIG. 5(a) and the conventional example in FIG. 5(b) will be described. In both Example 1 in FIG. 5(a) and the conventional example in FIG. 5(b), the overall shape has a width W5 in the orthogonal direction and a length L in the propagation direction of the resonant wave. Therefore, the occupied areas of the IDT electrode arrangement regions 70 and 80 and the busbar-adjacent portions 74, 75, 84, and 85 on the substrate are the same for Example 1 and the conventional example. If the occupied areas are the same and the loss due to resistance in Example 1 is lower than the loss due to resistance in Conventional Example 1, this means that a reduction in loss due to resistance has been confirmed while maintaining the area, and therefore the effect of Embodiment 1 has been confirmed.

[0042] The width W4 in the orthogonal direction of the side 72 of the IDT electrode arrangement region 70 of Example 1 in FIG. 5(a) is the same as the width W4 in the orthogonal direction of the side 89 of the IDT electrode arrangement region 80 in FIG. 5(b).

[0043] 5(a), the orthogonal width of the connection side ends 74a, 75a of the busbar-adjacent portions 74, 75 is W1. The orthogonal width of the non-connection side ends 74b, 75b of the busbar-adjacent portions 74, 75 is W2. The widths of the busbar-adjacent portions 84, 85 in the conventional example are all W0. Therefore, the orthogonal widths of the connection side ends 84a, 85a and non-connection side ends 84b, 85b are also W0.

[0044] The common simulation conditions for the first embodiment and the conventional example are as follows: The resonator is Resonant frequency fr: 2[GHz], Electromechanical coupling coefficient k2: 8%, Capacitance C: 0.5[pF], Qr, the quality factor at the resonant frequency: 1000 It was assumed that: Based on the above assumptions, the series resistance of the resonator during series resonance is 2.25 [Ω] It was calculated as follows.

[0045] Based on these, the IDT electrodes were designed, and the bus bar adjacent portions 74, 75 and the bus bar adjacent portions 84, 85 were assumed to have the same sheet resistivity, which was set to 0.025 [Ω] / □ (ohms per square).

[0046] In addition, in the conventional example, the width of the connection side end 84a and the width of the non-connection side end 84b of the busbar-adjacent portions 84, 85 are both W0 = 10 [μm], and the width of the connection side end 85a and the width of the non-connection side end 85b of the busbar-adjacent portion 85 are both W0 = 10 [μm].

[0047] For these, while keeping the areas of Example 1 and the conventional example constant, where W1 is the orthogonal width of connection-side end 74a of busbar-adjacent portion 74 and the orthogonal width of connection-side end 75a of busbar-adjacent portion 75, and W2 is the orthogonal width of non-connection-side end 74b of busbar-adjacent portion 75 and the orthogonal width of non-connection-side end 74b of busbar-adjacent portion 75, only W1 and W2 were varied, with W1 + W2 = W0 × 2 = 20 μm, and a simulation was performed to examine the change in electrical resistance. The width in the propagation direction of the IDT electrodes, busbar-adjacent portions 74, 75, and busbar-adjacent portions 84, 85 was set to L = 400 μm.

[0048] Fig. 7 shows equivalent circuits of Example 1 and the conventional example in a simulation. Fig. 6(a) is a diagram illustrating the equivalent circuit of Example 1 in Fig. 5(a). Fig. 6(b) is a diagram illustrating the equivalent circuit of the conventional example in Fig. 5(b).

[0049] For Example 1, an equivalent circuit was created by dividing the propagation direction into eight parts, as shown in Fig. 6(a). Fig. 6(a) shows the equivalent circuit including resistors R11 to R18, R21 to R28, and R3, and input / output terminals Port1 and Port2. Resistors R11 to R18 are obtained by replacing busbar-adjacent portion 74 with eight resistors. Resistors R21 to R28 are obtained by replacing busbar-adjacent portion 75 with eight resistors. The multiple resistors R3 correspond to the resistances of electrode finger 76. Note that the resistances of busbar-adjacent portions 74 and 75 were calculated using the sheet resistivity described above based on the area divided into eight parts.

[0050] As in Example 1, the conventional example was divided into eight parts in the propagation direction to create an equivalent circuit 88, as shown in FIG. 6(b). FIG. 6(b) shows resistors R11 to R18, R21 to R28, and R3 of the equivalent circuit, as well as input and output terminals Port1 and Port2. Resistors R11 to R18 are obtained by replacing busbar-adjacent portion 84 with eight resistors. R21 to R28 are obtained by replacing busbar-adjacent portion 85 with eight resistors. The multiple resistors R3 correspond to the resistances of the IDT electrode having electrode fingers 86 and busbar 73. Note that although the same symbols are used for resistors in Example 1 and the conventional example, this does not mean that they have the same resistance values.

[0051] As described above, the resistor equivalent circuit 88 in FIG. 7 was created by dividing it into eight parts.

[0052] The current flow in FIG. 6(a) will now be described. When current I1 enters the connection-side end 74a of the busbar-adjacent portion 74 from Port 1, current I4 passes through the connection-side end 75a of the busbar-adjacent portion 75 and flows to Port 2. Since a current flows through each of the eight resistors R3, the current flowing through the busbar-adjacent portion 74 branches off at the branching point with resistor R3 as it moves from the connection-side end 74a to the non-connection-side end 74b. Therefore, current I2 flowing through resistor R18 is smaller than current I1. Similarly, current I4 flowing through Port 2 is the same as current I1 flowing through Port 1. However, in the busbar-adjacent portion 75, current from resistor R3 joins the current flowing through resistor R3 as it moves from the non-connection-side end 75b to the connection-side end 75a. Therefore, current I3 flowing through resistor R21 located at the non-connection-side end 75b is smaller than current I4 flowing through the connection-side end 75a. In this way, by increasing the width of the portion where a large current flows and decreasing the width of the portion where a small current flows, the resistance value is reduced without increasing the area.

[0053] When the simulation was performed in this way, the simulation results shown in Table 1 were obtained.

[0054] [Table 1] Table 1 shows the results of the simulation, and FIG. 8 is a graph showing the resistance reduction rate (resistance reduction rate) of Example 1 relative to the conventional example (W1 = 10) by comparing the resistance value when the width W1 is changed with the resistance value of the conventional example (W1 = 10). In Table 1, W1 = W2 = 10 μm, which is the same width as the conventional example. As described above, when W1 is the width of the connection-side end 74a of the busbar-adjacent portion 74 and the width of the connection-side end 75a of the busbar-adjacent portion 75 in the orthogonal direction, and W2 is the width of the non-connection-side end 74b of the busbar-adjacent portion 75 in the orthogonal direction, and W2 is the width of the non-connection-side end 75b of the busbar-adjacent portion 75 in the orthogonal direction, W1 was increased and W2 was decreased under the condition of W1 + W2 = 20 μm, and the resistance value was calculated. As described above, in Table 1, a decrease in the resistance value from Port 1 to Port 2 of the equivalent circuit 88 was observed as W1 increased. 8, when the width W2 of the non-connection end is 5 μm and the width W1 of the connection end is 15 μm, i.e., when the width W2 of the non-connection end is 1 / 3 of the width W1 of the connection end, the reduction rate of the resistance value is -3.99%, which is preferable. When the width W2 of the non-connection end is 4 μm and the width W1 of the connection end is 16 μm, i.e., when the width W2 of the non-connection end is 1 / 4 of the width W1 of the connection end, the reduction rate of the resistance value is -4.49%, which is even more preferable.

[0055] [Table 2]

[0056] Furthermore, the resistance values ​​obtained by excluding all resistance values ​​of the multiple resistors R3 corresponding to the IDT electrode having the electrode fingers 46 and the busbar 73 (see FIG. 4(a)) from the resistance values ​​from Port 1 to Port 2 in the equivalent circuit 88 are shown in Table 2. FIG. 9 is a graph showing the resistance reduction rate (resistance reduction rate) of the embodiment and the conventional example (W1 = W2 = 10) when the width W1 is changed based on Table 2. As shown in Table 2, increasing the width W1 of the connection-side ends 74a and 75a and decreasing the width W2 of the non-connection-side ends 74b and 75b reduces the resistance value regardless of the resistance R3. The resistance reduction rate in Table 2 is significantly lower than that in Table 1. This indicates that the resistance is reduced when the shape of the busbar-adjacent portion in a plan view is a trapezoid with the connection-side ends 74a and 75a as the bottom edge and the non-connection-side ends 74b and 75b as the top edge.

[0057] These results show that if the sheet resistivity of the wiring near the busbars of the IDT electrodes is uniform, the resistivity will similarly decrease, and therefore, even in the embodiment of Figure 2, it was found that the busbar-adjacent portions 36a, 37a can reduce loss due to resistance by increasing the width of the connection-side ends 36b, 37b and reducing the width of the non-connection-side ends 36c, 37c. Furthermore, as described above, it is preferable that the orthogonal width of the non-connection-side ends 36c, 37c be one-third or less of that of the connection-side ends 36b, 37b, as this greatly reduces loss due to resistance, and it is even more preferable that it be one-quarter or less, as this greatly reduces loss due to resistance.

[0058] In this way, the IDT electrode and the busbar-adjacent portion of Example 1 (W1>10 μm) can reduce loss due to resistance without increasing the area compared to the IDT electrode and the busbar-adjacent portion of the conventional example (W1=10 μm), thereby realizing an acoustic wave device with low loss.

[0059] FIG. 10(a) is a plan view showing a state in which two resonators are tilted and opposed to each other as a second embodiment. FIG. 10(b) is a plan view showing a state in which two resonators are parallel and opposed to each other as a second conventional embodiment. In FIG. 10(a), an IDT electrode arrangement region 90, where electrode fingers and bus bars are arranged, has tilted upper and lower edges 90a and 90b. The upper and lower edges 90a and 90b are boundary lines between the bus bars and adjacent-busbar portions 94, 92, similar to the boundary lines 71 and 72 in FIG. 4(a). In FIG. 10(a), a bus bar adjacent portion 94 is provided above the upper edge 90a. Bus bar adjacent portions 92, 93 are provided below the lower edge 90b. In FIG. 10(a), an IDT electrode arrangement region 91, including tilted upper and lower edges 91a and 91b, is provided below the adjacent-busbar portion 93. A busbar-adjacent portion 93 is provided on the upper side 91a. A busbar-adjacent portion 95 is provided below the lower side 91b. The busbar-adjacent portion 92 and the busbar-adjacent portion 93 are integral and continuously connected. The busbar-adjacent portion 92 and the busbar-adjacent portion 93 each have a connection-side end 98 and a non-connection-side end 97. The connection-side end 98 is the end connected to another resonator or pad, and has an orthogonal width W7. The non-connection-side end 97 is the end away from another resonator or pad, and has an orthogonal width W8. The width W8 of the non-connection-side end 97 is smaller than the width W7 of the connection-side end 98. The overall orthogonal width, including these two IDT electrode arrangement regions and the busbar-adjacent portion, is W6, and the width in the propagation direction is L2. From the results of the above simulation, it is clear that since the width W7 of the connection side end 98 is larger than the width W8 of the non-connection side end 97, the busbar adjacent portions 92, 93 have a lower resistance value than the busbar adjacent portions 112, 113 of Conventional Example 2 in Figure 10(b).

[0060] In this way, by making the width W8 of the non-connection side end 97 smaller than the width W7 of the connection side end 98, the resistance values ​​of the busbar adjacent portions 92 and 93 can be reduced, and an acoustic wave device with low loss due to resistance values ​​can be realized.

[0061] In FIG. 10(b), the IDT electrode arrangement region 110 and the IDT electrode arrangement region 111 of Conventional Example 2 face each other without tilting. The IDT electrode arrangement region 110 includes an upper side 110a and a lower side 110b, and the IDT electrode arrangement region 111 includes an upper side 111a and a lower side 111b. These upper side 110a, lower side 110b, upper side 111a, and lower side 111b are all parallel. The busbar-adjacent portion 112 and the busbar-adjacent portion 113 are integrally formed, and their width at their end 114 is W9. The overall width of the two IDT electrode arrangement regions and the busbar-adjacent portion of Example 2 in FIG. 10(a) is W6, and the overall width of the two IDT electrode arrangement regions and the busbar-adjacent portion of Conventional Example 2 in FIG. 10(b) is W6, which are the same width. Furthermore, the width in the propagation direction of both is L, which is the same. Therefore, the areas of the two IDT electrode regions 90, 91 and the busbar-adjacent portions 92 to 95 in Example 2 are not increased compared to those in Conventional Example 2. Furthermore, the width of the busbar-adjacent portions 92, 93, which are generated by diagonally opposing the two IDT electrode regions 90, 91, can be made larger than the width W8 of the non-connection-side end 97 to the width W7 of the connection-side end 98, thereby realizing an acoustic wave device including two resonators with reduced loss due to resistance value.

[0062] In Example 2 shown in FIG. 10( a), the busbar-adjacent portions 92 and 93 are integral and continuously connected. However, even in an example where the busbar-adjacent portions 92 and 93 are separated and not electrically connected at the dashed line 99, the loss due to resistance in each of the busbar-adjacent portions 92 and 93 can be reduced without increasing the area, compared to an example where the busbar-adjacent portions 112 and 113 are not electrically connected and are slightly separated at the dashed line 107 in FIG. 10( b). Similar to the simulation results described above, the trapezoidal shape of the busbar-adjacent portions 92 and 93 in Example 2 clearly reduces their resistance. Furthermore, the width W8 is preferably equal to or less than one-third of the width W7, and more preferably equal to or less than one-quarter of the width W7.

[0063] <Regarding the resonator and the adjacent busbar in Figure 11> 11 is an enlarged plan view showing an example of the resonators P2 and P3 provided on the substrate 10 in the acoustic wave device 1. As shown in Fig. 11, the resonator P2 as the first resonator and the resonator P3 as the second resonator are not parallel, and are therefore arranged facing each other in the orthogonal direction so that there are portions where the distances between them are closest and farthest. In other words, the resonators P2 and P3 face each other at an angle.

[0064] The resonator P2 includes an IDT electrode 220a and a reflector 220b. The IDT electrode 220a includes comb-shaped electrodes 222a and 222b. The comb-shaped electrode 222a includes electrode fingers 223a and a busbar 224a (the busbar 224a on the side of the resonator P3 as the second resonator in the resonator P2 as the first resonator). The comb-shaped electrode 222b includes electrode fingers 223b and a busbar 224b. The busbars 224a and 224b are provided at an angle to the electrode fingers 223a and 223b. The busbars 224a and 224b are also provided at an angle to the propagation direction (X direction in FIG. 11 ) of the surface acoustic wave excited by the IDT electrode 220a.

[0065] The resonator P3 includes an IDT electrode 230a and a reflector 230b. The IDT electrode 230a includes comb-tooth electrodes 232a and 232b. The comb-tooth electrode 232a includes electrode fingers 233a and a bus bar 234a. The comb-tooth electrode 232b includes electrode fingers 233b and a bus bar 234b (the bus bar 234b on the side of the resonator P2 as the first resonator in the resonator P3 as the second resonator). The bus bars 234a and 234b are provided at an angle to the electrode fingers 233a and 233b. The bus bars 234a and 234b are also provided at an angle to the propagation direction of the surface acoustic wave excited by the IDT electrode 230a.

[0066] Since the resonators P2 and P3 are opposed to each other at an angle, the opposed bus bars 224a and 234b are not parallel to each other.

[0067] A wiring 33 is provided between the resonator P2 and the resonator P3. The wiring 33 electrically connects the opposing bus bar 224a and bus bar 234b with a pad 41 serving as a ground terminal. The wiring 33 is provided above the IDT electrode 220a of the resonator P2 in FIG. 11. A wiring bus bar adjacent portion 33a is provided on the wiring 33 on the opposite side to the electrode fingers 223a of the bus bar 224a and the opposite side to the electrode fingers 233b of the bus bar 234b.

[0068] In Fig. 11, busbar-adjacent portion 33a is indicated by diagonal hatching. Busbar-adjacent portion 33a is a partial region of wiring 33, and is disposed adjacent to busbar 224a and busbar 234b, extending from busbar 224a and busbar 234b in the perpendicular direction (Y direction in Fig. 11). In other words, busbar-adjacent portion 33a is a region of wiring 33 that has the same width as busbar 24a in the propagation direction (X direction). Busbar-adjacent portion 33a is a region of wiring 33 where opposing busbar 224a and busbar 234b overlap when viewed from the perpendicular direction (the portion where the busbars are positioned at the same position in the propagation direction).

[0069] The busbar-adjacent portion 33a has a connection-side end 33b and a non-connection-side end 33c in the propagation direction. The connection-side end 33b is the end electrically closer to the pad 41. The non-connection-side end 33c is the end opposite the connection-side end 33b in the propagation direction (X direction), and is electrically separated from other components such as other wirings, other resonators, or pads, i.e., is not directly connected to other wirings.

[0070] The width W2b of the connection-side end 33b of the busbar-adjacent portion 33a in the orthogonal direction (Y direction) is larger than the width W1b of the non-connection-side end 33c. The width of the busbar-adjacent portion 33a in the orthogonal direction is configured to gradually increase from the non-connection-side end 33c to the connection-side end 33b.

[0071] Fig. 12 is a BB' cross-sectional view of the resonators P2 and P3 of Fig. 11. As shown in Fig. 11, a first metal layer 60 and a second metal layer 61 are formed on a substrate 10. As shown in Fig. 11, the electrode finger 223b, the bus bars 224a, 224b, 234a, 234b, and the electrode finger 233b are formed of the first metal layer 60. The first metal layer 60 is, for example, an aluminum layer, a titanium layer, or a copper layer, but may also be an alloy of these, or may be formed by laminating these metals to form a multilayer structure.

[0072] The busbar-adjacent portion 33a of the wiring 33, the wiring 31, and the wiring 34 each include a first metal layer 60 on the substrate 10, and a second metal layer 61 formed on the first metal layer 60. The second metal layer 61 is, for example, an aluminum layer, a titanium layer, a copper layer, a palladium layer, or a gold layer. An alloy of these metals may also be used, or these metals may be configured in multiple layers.

[0073] In this manner, the busbar-adjacent portion 33a adjacent to the busbars 224a and 234b has a large width W2b at the connection-side end 33b, through which a relatively large current flows, and a small width W1b at the non-connection-side end 33c, through which a relatively large current does not flow because it is not connected to other wiring. This reduces the total electrical resistance of the busbar-adjacent portion. This reduces loss due to electrical resistance without increasing the area required for the resonators P2 and P3. This reduces loss due to electrical resistance throughout the entire acoustic wave device 1. To reduce the resistance of the busbar-adjacent portion 33a, the width W1b is preferably equal to or less than one-third of the width W2b, and more preferably equal to or less than one-quarter of the width W2b.

[0074] <Regarding the resonator and the adjacent busbar in Figure 13> As shown in Fig. 13, the resonators P2 and P3 may be disposed diagonally opposite each other and offset in the propagation direction (X direction). In the wiring 33 of Fig. 13, the busbar-adjacent portion 33a2 is the portion indicated by diagonal hatching. The busbar-adjacent portion 33a2 is a partial region of the wiring 33, and is disposed adjacent to the busbar 224a and the busbar 234b. When the busbars 224a and 234b are offset in the propagation direction in the orthogonal direction as shown in Fig. 13, the region where the busbars 224a and 234b overlap when viewed from the orthogonal direction (Y direction) (regions at the same position in the X direction) is defined as the busbar-adjacent portion 33a2.

[0075] The width W2c of the connection-side end 33b2 of the busbar-adjacent portion 33a2 in the orthogonal direction (Y direction) is greater than the width W1c of the non-connection-side end 33c2. At the connection-side end 33b2, the orthogonal width of the busbar-adjacent portion 33a2 (the orthogonal distance between the busbar 224a and the busbar 234b at the connection-side end 33b2) is greatest. The orthogonal width of the busbar-adjacent portion 33a is configured to gradually increase from the non-connection-side end 33c2 to the connection-side end 33b2. From the viewpoint of reducing the resistance of the busbar-adjacent portion 33a2, the width W1c is preferably equal to or less than one-third of the width W2c, and more preferably equal to or less than one-quarter of the width W2c.

[0076] In this way, the busbar-adjacent portion 33a2, which is located adjacent to the busbars 224a and 234b, has a larger width at the connection-side end 33b2, through which a relatively large current flows, and a smaller width at the non-connection-side end 33c2, through which a relatively large current does not flow because it is not connected to other wiring. This reduces the total electrical resistance of the busbar-adjacent portion. This makes it possible to reduce losses due to electrical resistance while maintaining the area required for the resonators P2 and P3. This also reduces losses due to electrical resistance throughout the acoustic wave device 1.

[0077] <Regarding the resonator and the adjacent busbar in Figure 14> 14 is an enlarged plan view showing another example of the resonator S3 and the resonator P1 provided on the substrate 10 in the acoustic wave device 1. As shown in Fig. 14, the resonator S3 as the first resonator and the resonator P1 as the second resonator are not parallel, and are therefore arranged facing each other in the orthogonal direction so that there are portions where the distances between them are closest and farthest. In other words, the resonator S3 and the resonator P1 face each other at an angle.

[0078] Between the resonator S3 and the resonator P1, a bus bar adjacent portion 35a and a bus bar adjacent portion 36a are provided separately.

[0079] As described above, the resonator P1 includes the IDT electrode 210a and the reflector 210b. The IDT electrode 210a includes comb-shaped electrodes 212a and 212b, and the comb-shaped electrode 212a includes electrode fingers 213a and a busbar 214a. The comb-shaped electrode 212b includes electrode fingers 213b and a busbar 214b.

[0080] The resonator S3 includes an IDT electrode 130a and a resonator 130b. The resonator IDT 130a includes comb-shaped electrodes 132a and 132b, and the comb-shaped electrode 132a includes electrode fingers 133a and a bus bar 134a. The comb-shaped electrode 132b includes electrode fingers 133b and a bus bar 134b. The bus bars 134a and 134b are provided at an angle to the electrode fingers 133a and 134b.

[0081] Wiring 35 and wiring 36 are provided between resonator S3 and resonator P1. Wiring 35 electrically connects busbar 134b of resonator S3 to resonators P2 and S2 (see FIG. 1) which are resonators other than resonator S3 and resonator P1. A busbar-adjacent portion 35a serving as a first busbar-adjacent portion is provided on wiring 35 on the opposite side of electrode finger 133a on the busbar 134a side and on the opposite side of electrode finger 133b on busbar 134b.

[0082] 14, the busbar-adjacent portion 35a on the resonator S3 side is indicated by diagonal hatching. The busbar-adjacent portion 35a is a partial region of the wiring 35, and is disposed adjacent to the busbar 134b of the resonator S3 and extends from the busbar 134b in the orthogonal direction (the Y direction in FIG. 11). The busbar-adjacent portion 35a is a region of the wiring 35 where the opposing busbar 214a and busbar 134b overlap when viewed in the orthogonal direction.

[0083] The wiring 36 electrically connects the bus bar 214a to the resonators S1 and S2 (see FIG. 1) other than the resonators S3 and P1. The wiring 36 is provided with a bus bar adjacent portion 36a on the opposite side of the electrode finger 213b connected to the bus bar 214b, and on the opposite side of the electrode finger 233b in the bus bar 134b.

[0084] 14, the busbar-adjacent portion 36a on the resonator P1 side is indicated by diagonal lines. The busbar-adjacent portion 36a is a partial region of the wiring 36, and is disposed adjacent to the busbar 214a and extends from the busbar 214a in the orthogonal direction (the Y direction in FIG. 11). The busbar-adjacent portion 36a is a region of the wiring 36 where the opposing busbar 214a and busbar 134b overlap when viewed in the orthogonal direction.

[0085] The busbar-adjacent portion 35a of the wiring 35 on the resonator S3 side and the busbar-adjacent portion 36a of the wiring 36 on the resonator P1 side are separated and disposed adjacent to each other with a distance D therebetween.

[0086] The busbar-adjacent portions 35a and 36a have connection-side ends 35b and 36b and non-connection-side ends 35c and 36c, respectively, in the propagation direction. The connection-side ends 35b and 36b are ends electrically closer to the other resonator, i.e., resonator S1 or resonator S2 (see FIG. 1). The non-connection-side ends 35c and 36c are ends opposite the connection-side ends 35b and 36b in the propagation direction (X direction) and are electrically separated from other components such as other wirings, other resonators, or pads, i.e., are not directly connected to other wirings.

[0087] Regarding the distance between the resonators, i.e., the distance between the busbar 134b on the resonator S3 side and the busbar 214a on the resonator P1 side, a width W2d, which is the distance in the orthogonal direction (Y direction) between the busbar 134b and the busbar 214a at the connection-side ends 35b and 36b of the busbar-adjacent portions 35a and 36a in the propagation direction (X direction), is greater than a width W1d, which is the distance in the orthogonal direction between the busbar 134b and the busbar 214a at the non-connection-side ends 36c and 36c in the propagation direction. The orthogonal distance between the opposing busbars 134b and 214a, i.e., the total width in the orthogonal direction including the busbar-adjacent portion 35a, the interval D, and the busbar-adjacent portion 36a, is configured to gradually increase from the non-connection-side ends 36b and 36b to the connection-side ends 36c and 36c (in the propagation direction).

[0088] In this way, the busbar-adjacent portions 35a and 36a, which are located adjacent to the busbar 134b and the busbar 214a, have larger widths at the connection-side ends 35b and 36b, through which a relatively large current flows, and smaller widths at the non-connection-side ends 35c and 36c, through which a relatively large current does not flow because they are not connected to other wiring. This reduces the total electrical resistance of the busbar-adjacent portions. This makes it possible to reduce losses due to electrical resistance without increasing the area required for the resonators P2 and P3. This also reduces losses due to electrical resistance throughout the entire acoustic wave device 1.

[0089] Width W1d, which is the distance between busbar 134b and busbar 214a in the orthogonal direction (Y direction) at the positions of non-connection-side ends 35c and 36c in the propagation direction, is preferably 1 / 3, and more preferably 1 / 4, of width W2d, which is the distance between busbar 134b and busbar 214a in the orthogonal direction at the positions of connection-side ends 35b and 36b of busbar-adjacent portions 35a and 36a in the propagation direction (X direction). This is because a larger ratio of these widths can further reduce loss due to resistance.

[0090] <Regarding the resonator and the adjacent busbar in Figure 15> FIG. 15 is a plan view showing another example of resonators and busbar-adjacent portions provided on the substrate 10 in the acoustic wave device 1. The resonators S3A and P1A in FIG. 15 are a modified example in which the resonators in FIG. 14 are arranged at different positions in the propagation direction (X direction). As shown in FIG. 15, the resonator S3A as the first resonator and the resonator P1A as the second resonator are opposed to each other in a diagonally perpendicular direction. The resonators S3A and P1A are also arranged at different positions in the propagation direction (X direction). In the example of the resonators and busbar-adjacent portions shown in FIG. 15, components having the same names and functions as those in the example of the resonators and busbar-adjacent portions in FIG. 14 are designated by the same reference numerals and will not be described again.

[0091] Between the resonator S3A and the resonator P1A, a wiring 35 and a wiring 36 are provided. Between the resonator S3A and the resonator P1A, a busbar-adjacent portion 35a2 and a busbar-adjacent portion 36a2 are provided separately. The busbar-adjacent portion 35a2 is a region of the wiring 35 where the opposing busbars 214a and 134b overlap in the orthogonal direction. The busbar-adjacent portion 36a2 is a region of the wiring 36 where the opposing busbars 214a and 134b overlap in the orthogonal direction.

[0092] The ends of the wiring 35 and the wiring 36 in the propagation direction are connection-side ends 35b2 and 36b2 and non-connection-side ends 35c2 and 36c2. The connection-side ends 35b2 and 36b2 are ends electrically close to a resonator or pad other than the resonator S3A or the resonator P1A. The non-connection-side ends 35c2 and 36c2 are ends electrically separated from other components such as other wirings, other resonators, or pads, i.e., ends not directly connected to other wirings.

[0093] Regarding the distance between the resonators, i.e., the distance between the busbar 134b and the busbar 214a, a width W2e, which is the distance between the busbar 134b and the busbar 214a in the orthogonal direction (Y direction) at the connection-side ends 35b2 and 36b2 of the busbar-adjacent portions 35a2 and 36a2 in the propagation direction (X direction), is greater than a width W1e, which is the distance between the busbar 134b and the busbar 214a in the orthogonal direction at the non-connection-side ends 35c2 and 36c2 in the propagation direction. The orthogonal distance between the busbar 134b and the busbar 214a, i.e., the total width in the orthogonal direction including the busbar-adjacent portion 35a, the interval D, and the busbar-adjacent portion 36a, is configured to gradually increase in width from the non-connection-side ends 35b2 and 36b2 to the connection-side ends 35c2 and 36c2 in the propagation direction.

[0094] In this way, the busbar-adjacent portions 35a and 36a, which are adjacent to the busbar 134b and the busbar 214a, have larger widths at the connection-side ends 35b and 36b, through which a relatively large current flows, and smaller widths at the non-connection-side ends 35c and 36c, which are not connected to other wiring and therefore do not flow a relatively large current. This reduces the total electrical resistance of the busbar-adjacent portions 35a and 36a. This makes it possible to reduce losses due to electrical resistance without increasing the area of ​​the substrate required for occupying the resonators S3A and P1A. This also reduces losses due to electrical resistance throughout the entire acoustic wave device 1.

[0095] The width W1e, which is the distance between the busbar 134b and the busbar 214a in the orthogonal direction (Y direction) at the non-connection-side ends 35c and 36c in the propagation direction, is preferably 1 / 3, and more preferably 1 / 4, of the width W2e, which is the distance between the busbar 134b and the busbar 214a in the orthogonal direction at the connection-side ends 35b2 and 36b2 of the busbar-adjacent portions 35a2 and 36a2 in the propagation direction (X direction). This is because a larger ratio between the two can further reduce losses due to resistance. Therefore, it is possible to reduce losses due to electrical resistance throughout the acoustic wave device 1.

[0096] <Regarding the resonator and the adjacent busbar in Figure 16> 16 is a plan view illustrating an example of a resonator and a busbar-adjacent portion in which busbars are formed in a stepped shape, which are provided in the acoustic wave device 1. The resonator 300 in FIG. 16 includes an IDT electrode 300a and a reflector 300b, and is connected to wiring 308 and wiring 309. The IDT electrode 300a is a comb-shaped electrode having electrode fingers 307a and 307b.

[0097] IDT electrode 300a includes stepped bus bars 301a and 301b that are stepped in the orthogonal direction (Y direction). Stepped bus bar 301a includes first step 302a, second step 303a, and third step 304a. Stepped bus bar 301b includes first step 302b, second step 303b, and third step 304b. In this embodiment, bus bars 301a and 302b have a three-step configuration, but the number of steps may be four or more, or may be a two-step configuration.

[0098] The wirings 308 and 309 are provided with busbar adjacent portions 308a and 309a that are adjacent to the busbars 301a and 301b in the regions extending in the Y direction from the busbars 301a and 301b.

[0099] The widths of the busbar-adjacent portions 308a, 309a adjacent to the first stages 302a, 302b, the second stages 303a, 303b, and the third stages 304a, 304b of the busbars 301a, 301b increase stepwise to W1f, W2f, and W3f, respectively. The connection-side ends 308b, 309b close to the other resonators or pads have a width W3f, which is larger than the width W1f of the non-connection-side ends 308c, 309c opposite the other resonators or pads.

[0100] In this way, the busbar-adjacent portions 308a, 309a, which are disposed adjacent to the busbars 301a, 301b, have a larger width at the connection-side ends 308b, 309b, through which a relatively large current flows, and a smaller width at the non-connection-side ends 308c, 309c, through which a relatively large current does not flow because they are not connected to other wiring, thereby reducing the total electrical resistance of the busbar-adjacent portions 308a, 309a. This makes it possible to reduce losses due to electrical resistance without increasing the area on the substrate required for the resonator 300 to occupy.

[0101] Note that only one of the adjacent busbar portions 308a, 309a may be configured so that the width increases stepwise to W1f, W2f, and W3f, respectively, and the other may have a different shape.

[0102] <Regarding the resonator and the adjacent busbar in Figure 17> Fig. 17 is a plan view showing another example of a resonator and a busbar-adjacent portion provided in the acoustic wave device 1. As shown in Fig. 17, two resonators 400 and 500, each having a stepped busbar, are provided opposite each other. As shown in Fig. 17, the resonator 400 includes an IDT electrode 400a and a reflector 400b, and is connected to a wiring 408 and a wiring 600.

[0103] IDT electrode 400a is a comb-shaped electrode and includes electrode fingers 407 and bus bars 401a and 401b. IDT electrode 400a of resonator 400 includes stepped bus bars 401a and 401b with steps in the orthogonal direction (Y direction). Stepped bus bar 401a includes first step 402a, second step 403a, and third step 404a. Stepped bus bar 401b includes first step 402b, second step 403b, and third step 404b.

[0104] The resonator 500 includes an IDT electrode 500a and a reflector 500b, and is connected to a wiring 508 and a wiring 600. The IDT electrode 500a is a comb-shaped electrode and includes electrode fingers 507 and bus bars 501a and 501b.

[0105] IDT electrode 500a of resonator 500 includes stepped bus bars 501a and 501b with steps in the orthogonal direction (Y direction). Stepped bus bar 501a includes first step 502a, second step 503a, and third step 504a. Stepped bus bar 501b includes first step 502b, second step 503b, and third step 504b.

[0106] In the wiring 600, in a region extending in the Y direction to the bus bars 401b and 501a, a bus bar adjacent portion 600a is provided adjacent to these bus bars 401b and 501a.

[0107] The widths of the busbar-adjacent portion 600a adjacent to the first stages 402b and 502a, the second stages 403b and 503a, and the third stages 404b and 504a of the busbars 401b and 501a in the orthogonal direction increase stepwise in the propagation direction (X direction) to W1g, W2g, and W3g, respectively. The connection-side end 600b, which is closer to other resonators or pads along the wiring path, has a width W3g, which is larger than the width W1g of the non-connection-side end 600c, which is the end opposite the other resonators or pads. The width W1g is preferably equal to or smaller than one-third of the width W3g, and more preferably equal to or smaller than one-quarter of the width W3g. This is because a larger ratio of the widths W1g and W3g significantly reduces loss due to electrical resistance.

[0108] In this way, the busbar-adjacent portion 600a, which is disposed adjacent to the busbars 401b and 501a, has a larger width at the connection-side end 600b, through which a relatively large current flows, and a smaller width at the non-connection-side end 600c, through which a relatively large current does not flow because the busbar is not connected to other wiring. This reduces the total electrical resistance of the busbar-adjacent portion 600a. Therefore, in an acoustic wave device including the resonators 400 and 500, it is possible to reduce losses due to electrical resistance without increasing the area required for the resonators 400 and 500.

[0109] <Regarding the resonator and the adjacent busbar in Figure 18> 18 is a plan view showing another example of two resonators and a busbar-adjacent portion constituting the acoustic wave device 1, as a modification in which the positional relationship in the propagation direction (X direction) of the resonators 400 and 500 in Fig. 17 is changed. In the example of the resonators 400, 500 and the busbar-adjacent portion 601a in Fig. 18, components having the same names and roles as those in the example of the resonators 400, 500 and the busbar-adjacent portion 600a in Fig. 17 are designated by the same reference numerals, and their descriptions are omitted.

[0110] 18, the resonator 400 and the resonator 500 are provided facing each other in the orthogonal direction. The resonator 400 and the resonator 500 are located at different positions in the propagation direction (X direction). A wiring 601 is provided between the resonator 400 and the resonator 500.

[0111] The wiring 601 has a busbar-adjacent portion 601a in a region where the busbars 401b and 501a overlap (are at the same position in the X direction) when viewed from the orthogonal direction (Y direction), and extends from the busbar 401a to the busbar 501a in the orthogonal direction (Y direction). The busbar-adjacent portion 601a is adjacent to the busbar 401b and the busbar 501a.

[0112] The busbar-adjacent portion 601a has a connection-side end 601b and a non-connection-side end 601c in the propagation direction. The connection-side end 601b is the end electrically closer to other resonators (resonators other than the resonators 400 and 500) or pads in terms of wiring connection. The connection-side end 601b is located at the same position in the propagation direction (X direction) as the end 501d of the busbar 501a. The non-connection-side end 601c is located on the opposite side of the connection-side end 601b in the propagation direction (X direction) and is electrically separated from other components such as other wirings, other resonators, or pads. In other words, the non-connection-side end 601c is not directly connected to other wirings. The non-connection-side end 601c is located at the same position in the propagation direction (X direction) as the end 401c of the busbar 401b.

[0113] The widths of the busbar-adjacent portion 601a, which are adjacent to the first stages 402b and 502a, the second stages 403b and 503a, and the third stages 404b and 504a of the busbars 401b and 501a, respectively, in the orthogonal direction gradually increase in a stepwise manner to W1h, W2h, and W3h in the propagation direction (X direction). The connection-side end 601b, which is closer to the other resonators or pads, has a width W3h, which is larger than the width W1h of the non-connection-side end 601c, which is the end opposite the other resonators or pads. The width W1h is preferably equal to or less than one-third of the width W3h, and more preferably equal to or less than one-quarter of the width W3h. This is because a larger ratio of the widths W1g and W3g significantly reduces loss due to electrical resistance.

[0114] In this way, the busbar-adjacent portion 601a, which is disposed adjacent to the busbars 401b and 501a, has a larger width at the connection-side end 601b, through which a relatively large current flows, and a smaller width at the non-connection-side end 601c, through which a relatively large current does not flow because the busbar is not connected to other wiring, thereby reducing the total electrical resistance of the busbar-adjacent portion 600a. Therefore, in an acoustic wave device including the resonators 400 and 500, it is possible to reduce losses due to electrical resistance without increasing the area required for the resonators 400 and 500.

[0115] <Regarding the resonator and the adjacent busbar in Figure 19> Fig. 19 is a plan view showing another example of two resonators and a busbar-adjacent portion in which busbars are formed in a stepped shape, which are provided in an acoustic wave device. Components having the same names and functions as the resonators and the busbar-adjacent portion in Fig. 17 are given the same reference numerals and their descriptions are omitted.

[0116] In FIG. 19, the resonator 400 and the resonator 500 are provided facing each other in the orthogonal direction. The resonator 400 and the resonator 500 are at the same position in the propagation direction (X direction). Between the resonator 400 as the first resonator and the resonator 500 as the second resonator, a wiring 602 and a wiring 603 are provided. The wiring 602 and the wiring 603 are provided adjacent to each other, separated by a distance D, and are not directly electrically connected.

[0117] The wiring 602 is electrically connected to the bus bar 401b and other resonators (resonators other than the resonators 400 and 500) or pads (not shown). The wiring 603 is electrically connected to the bus bar 501a and other resonators (resonators other than the resonators 400 and 500) or pads (not shown).

[0118] 19, busbar-adjacent portion 602a and busbar-adjacent portion 603a are indicated by diagonal hatching. In wiring 602, busbar-adjacent portion 602a is provided in a region extending from busbar 401b in the Y direction, as a first busbar-adjacent portion provided adjacent to busbar 401b. In the wiring 603, in a region extending from the bus bar 501a in the Y direction, a bus bar adjacent portion 603a is provided as a second bus bar adjacent portion provided adjacent to the bus bar 501a.

[0119] The range in the propagation direction (X direction) of busbar adjacent portion 602a and busbar adjacent portion 603a is the range in which busbars 401b and 501a overlap when viewed from the orthogonal direction (Y direction) (the range in which the busbars are positioned at the same location in the X direction). In this embodiment, end 401c of busbar 401b and end 501c of busbar 501a are at the same position in the propagation direction. Also, end 401d of busbar 401b and end 501d of busbar 501a are at the same position in the propagation direction.

[0120] The busbar-adjacent portion 602a has a connection-side end 602b and a non-connection-side end 602c in the propagation direction (X direction). The connection-side end 602b is the end electrically closer to other resonators, such as resonators other than the resonators 400 and 500, or to pads. The connection-side end 602b is located at the same position as the end 401d of the busbar 401b in the propagation direction. The non-connection-side end 602c is located on the opposite side of the connection-side end 602b in the propagation direction and is electrically separated from other components, such as other wiring, other resonators, or pads, i.e., is not directly connected to other wiring. The non-connection-side end 602c is located at the same position as the end 401c of the busbar 401b in the propagation direction.

[0121] The width of busbar-adjacent portion 602a, which is the first busbar-adjacent portion, in the orthogonal direction of portions adjacent to first stage 402b, second stage 403b, and third stage 404b of busbar 401b increases stepwise in the propagation direction (X direction). Also, connection-side end 601b, which is closer to other resonators or pads, has a larger width in the orthogonal direction (Y direction) than non-connection-side end 601c, which is the end opposite to other resonators or pads.

[0122] The width of busbar-adjacent portion 603a, which serves as the second busbar-adjacent portion, in the orthogonal direction of portions adjacent to first stage 502a, second stage 503a, and third stage 504a of busbar 501a increases stepwise in the propagation direction (X direction). Also, connection-side end 603b, which is closer to other resonators or pads, is wider than non-connection-side end 603c, which is the end opposite to the other resonators or pads.

[0123] In FIG. 19, the width in the orthogonal direction of busbar adjacent portion 602a, busbar adjacent portion 603a, and the distance D therebetween, i.e., the distance in the orthogonal direction between busbars 401b and 501a, increases stepwise from first stage 402b, 502a to second stage 403b, 503a and third stage 404b, 504a, to W1i, W2i, and W3i, respectively, as one moves in the propagation direction (X direction).

[0124] Furthermore, the width in the orthogonal direction, including busbar-adjacent portion 602a, busbar-adjacent portion 603a, and the distance D between them, is W3i at the connection-side end (same position as end 401d of busbar 401a in the propagation direction) that is closer to the other resonators or pads, and is larger than width W1i at the non-connection-side end (same position as end 401c of busbar 401a in the propagation direction) that is the end opposite to the other resonators or pads. Furthermore, width W1i is preferably 1 / 3 or less of width W3i, and more preferably 1 / 4 or less of width W3i. This is because a larger ratio between widths W1g and W3g significantly reduces loss due to electrical resistance.

[0125] In this way, the busbar-adjacent portions 602a, 603a, which are disposed adjacent to the busbars 401b, 501a, have a larger width at the connection-side ends 602b, 603b, through which a relatively large current flows, and a smaller width at the non-connection-side ends 602c, 603c, through which a relatively large current does not flow because they are not connected to other wiring, thereby reducing the total electrical resistance of the busbar-adjacent portions 602a, 603a. Therefore, in an acoustic wave device including the resonators 400 and 500, it is possible to reduce losses due to electrical resistance without increasing the area of ​​the resonators 400 and 500 on the substrate.

[0126] <Regarding the resonator and the adjacent busbar in Figure 20> Fig. 20 is a plan view showing another example of two resonators and a busbar-adjacent portion, each having a stepped busbar, that constitute an acoustic wave device. The example of the two resonators and the busbar-adjacent portion in Fig. 20 is a modification in which the positions of the resonators in Fig. 19 in the propagation direction are changed to be different. In Fig. 20, components that have the same names and functions as those in the example of the resonators and the busbar-adjacent portion in Fig. 19 are designated by the same reference numerals, and their description will be omitted.

[0127] 20, a resonator 400 as a first resonator and a resonator 500 as a second resonator are provided facing each other in a direction perpendicular to each other. The resonators 400 and 500 are located at different positions in the propagation direction (X direction). Wiring 604 and wiring 605 are provided between the resonators 400 and 500. Although the wiring 604 and wiring 605 are provided adjacent to each other, they are separated by a distance D and are not directly electrically connected.

[0128] The wiring 604 is electrically connected to the bus bar 401 and other resonators (resonators other than the resonators 400 and 500) or pads (not shown). The wiring 605 is electrically connected to the bus bar 501a and other resonators (resonators other than the resonators 400 and 500) or pads (not shown).

[0129] 20, busbar-adjacent portion 604a and busbar-adjacent portion 605a are indicated by diagonal hatching. In wiring 604, busbar-adjacent portion 604a is provided as a first busbar adjacent to busbar 401b in a region extending from busbar 401b in the Y direction.

[0130] In a region of wiring 605 extending from bus bar 501a in the Y direction, bus bar adjacent portion 600a is provided as a second bus bar adjacent to bus bar 501a.

[0131] The range in the propagation direction (X direction) of busbar-adjacent portion 604a as the first busbar-adjacent portion and busbar-adjacent portion 605a as the second busbar-adjacent portion is the range in which busbars 401b and 501a overlap when viewed from the perpendicular direction (Y direction) (i.e., the part in which both are at the same position in the propagation direction).

[0132] In this example, bus bar 401b has end 401c and end 401d in the propagation direction, and bus bar 501a has end 501c and end 501d in the propagation direction.

[0133] The busbar-adjacent portion 604a as the first busbar-adjacent portion has a connection-side end 604b and a non-connection-side end 604c in the propagation direction. The connection-side end 604b is the end electrically closer to a resonator other than the above-described resonator 400 and resonator 500 or a pad as a wiring path. The connection-side end 604b is located at the same position in the propagation direction as the end 401d of the busbar 401b.

[0134] The non-connection side end 604c of the busbar-adjacent portion 604a is the end opposite the connection side end 604b in the propagation direction (X direction) and is electrically isolated from other components such as other wirings, other resonators, or pads. In other words, the connection side end 604b is the end that is not directly connected to other wirings. The non-connection side end 604c is located at the same position as the end 501c of the busbar 501a in the propagation direction.

[0135] The width of the busbar-adjacent portion 604a, which is the first busbar-adjacent portion, in the orthogonal direction of the portions adjacent to the first, second, and third stages 402b, 403b, and 404b of the busbar 401b increases stepwise in the propagation direction (X direction). Also, the connection-side end 604b, which is closer to the other resonators or pads as a wiring path, has a larger width in the orthogonal direction (Y direction) than the non-connection-side end 604c, which is the end opposite to the other resonators or pads.

[0136] The busbar-adjacent portion 605a as the second busbar-adjacent portion has a connection-side end 605b and a non-connection-side end 605c in the propagation direction. The connection-side end 605b is the end electrically closer to another resonator, such as a resonator other than the above-described resonator 400 or resonator 500, or to a pad as a wiring path. The connection-side end 605b is located at the same position in the propagation direction as the end 401d of the busbar 401b.

[0137] The non-connection side end 605c of the busbar-adjacent portion 605a is the end opposite the connection side end 605b in the propagation direction and is electrically isolated from other components such as other wirings, other resonators, or pads. In other words, the connection side end 605b is the end that is not directly connected to other wirings. The non-connection side end 605c is located at the same position as the end 501c of the busbar 501a in the propagation direction (X direction).

[0138] In busbar-adjacent portion 605a as the second busbar-adjacent portion, the width in the orthogonal direction of portions adjacent to first stage 502a, second stage 503a, and third stage 504a of busbar 501a increases stepwise in the propagation direction (X direction). Also, the width of connection-side end 605b, which is close to other resonators or pads, is wider than the width of non-connection-side end 605c, which is the end opposite to other resonators or pads.

[0139] 20, busbar-adjacent portion 604a and busbar-adjacent portion 605a are spaced apart by distance D. The total width in the orthogonal direction including busbar-adjacent portion 604a, busbar-adjacent portion 605a, and distance D therebetween (i.e., the distance in the orthogonal direction between busbars 401b and 501a) increases stepwise from first stage 402b and 502a to second stage 403b and 503a and third stage 404b and 504a in that order, as they proceed in the propagation direction (X direction), to W1j, W2j, and W3j, respectively. Note that the "distance in the orthogonal direction between opposing busbars 401b and 501a" refers to the "width between the ends of busbar-adjacent portion 604a and busbar-adjacent portion 605a in the orthogonal direction."

[0140] The total width of busbar-adjacent portion 604a and busbar-adjacent portion 605a, including distance D, is width W3j at connection-side end 604b and connection-side end 605b (same position as end 401d of busbar 401a in the propagation direction), which is larger than width W1j at non-connection-side end 604c and non-connection-side end 605c (same position as end 401c of busbar 401a in the propagation direction). Width W1j is preferably equal to or smaller than one-third of width W3j, and more preferably equal to or smaller than one-quarter of width W3j. This is because a larger ratio between widths W1j and W3j results in a greater effect of reducing loss due to electrical resistance.

[0141] In this way, the busbar-adjacent portions 604a, 605a, which are disposed adjacent to the busbars 401b, 501a, have a larger width at the connection-side ends 604b, 605b, through which a relatively large current flows, and a smaller width at the non-connection-side ends 604c, 605c, through which a relatively large current does not flow because they are not connected to other wiring, thereby reducing the total electrical resistance of the busbar-adjacent portions 604a, 605a. Therefore, in an acoustic wave device including the resonators 400 and 500, it is possible to reduce losses due to electrical resistance without increasing the area of ​​the resonators 400 and 500 on the substrate.

[0142] In these embodiments, examples have been described in which a ladder-type filter is used as the acoustic wave device, but other filters may also be used, for example, a receiving filter equipped with a DMS.

[0143] Furthermore, the drawings used in the above explanation are schematic, and the dimensions and ratios on the drawings do not necessarily correspond to those of the actual product.

[0144] The present invention has been described above, but when specifically implementing the present invention as an acoustic wave device, it is not limited to the above-described embodiments, and various modifications and additions are possible within the scope of the gist of the present invention. [Explanation of symbols]

[0145] 1. Acoustic wave devices (filters) 10 Substrate (piezoelectric substrate) 21a IDT electrode 7 electrode fingers 30, 31, 32, 33, 34, 36, 36, 37, 38 Wiring 36a, 37a Busbar adjacent section 36b, 37b Connection side end 36c, 37c Non-connection end 40, 41, 42, 43 Pads 70,80 IDT electrode placement area 88 Equivalent Circuit 210a IDT electrode 210b reflector 212a Comb electrode 213a Electrode finger 214a busbar S1,S2,S3,S4,S5,P1,P2,P3 elastic wave resonator,

Claims

1. a piezoelectric substrate; a plurality of resonators provided on the piezoelectric substrate; a pad provided on the piezoelectric substrate; a plurality of wirings for electrically connecting the pads and the plurality of resonators; An acoustic wave device comprising: each of the plurality of resonators includes an IDT electrode having a pair of comb-teeth electrodes facing each other; The comb-tooth electrode is a plurality of electrode fingers provided on the comb-tooth electrode; a bus bar electrically connected to the plurality of electrode fingers, In a plan view, the wiring includes a busbar-adjacent portion that is provided adjacent to the busbar on a side opposite to a side on which the electrode fingers are provided and that is provided in a region that extends from the busbar in a direction perpendicular to a propagation direction of an elastic wave in the IDT electrode, the busbar-adjacent portion has a connection-side end portion that is close to the pad or the other resonator in the wiring in the elastic wave propagation direction, and a non-connection-side end portion that is an end portion opposite to the pad or the other resonator, a width in the orthogonal direction at the connection side end of the busbar-adjacent portion is larger than a width in the orthogonal direction at the non-connection side end of the busbar-adjacent portion; The width of the busbar-adjacent portion of the wiring in the direction perpendicular to the elastic wave propagation direction is configured to increase gradually or stepwise from the non-connection side end of the busbar to the connection side end. Acoustic Wave Devices

2. one of the plurality of resonators is provided with two bus bars that are electrically connected to the electrode fingers of the resonator and that face each other; the bus bar adjacent portions are provided adjacent to the two bus bars, respectively; The two adjacent busbar portions are each of the resonators has a connection end portion that is close to the wiring connected to the pad or another resonator in the propagation direction of the elastic wave, and a non-connection end portion that is an end portion opposite to the pad and the other resonator; a width in the orthogonal direction at the connection-side end portion is larger than a width in the orthogonal direction at the non-connection-side end portion of the busbar-adjacent portion; Each of the two busbar adjacent portions is configured to have a width that gradually or stepwise increases from the non-connection side end to the connection side end of the busbar. The acoustic wave device according to claim 1 .

3. The resonators provided on the piezoelectric substrate include a first resonator and a second resonator in a plan view, the first resonator and the second resonator are arranged to face each other in the orthogonal direction so as to have a portion where the distance between them is closest and a portion where the distance between them is farthest, the busbar-adjacent portion is a wiring region that electrically connects the first resonator and the second resonator, the busbar-adjacent portion is disposed adjacent to a busbar on the second resonator side of the first resonator and a busbar on the first resonator side of the second resonator, and is a region where these two busbars overlap when viewed from the orthogonal direction, and extends from these two busbars in the orthogonal direction; the busbar adjacent portion is a portion where the distance between the first resonator and the second resonator facing each other in the orthogonal direction is the greatest, and the first resonator and the second resonator on the pad or the piezoelectric substrate are connected to each other by wiring at a connection side end portion that is close to the other resonators; a non-connection side end portion that is on a side where the first resonator and the second resonator that face each other are close to each other in the orthogonal direction and is opposite to the pad or the other resonator, a width of the non-connection-side end of the busbar-adjacent portion in the orthogonal direction is smaller than a width of the busbar-adjacent portion of the connection-side end in the orthogonal direction, and a width of the connection-side end in the orthogonal direction is larger than a width of the non-connection-side end of the busbar-adjacent portion in the orthogonal direction, The width of the busbar-adjacent portion is configured to increase gradually or in a stepwise manner from the non-connection side end to the connection side end. The acoustic wave device according to claim 1 .

4. Among the plurality of resonators provided on the piezoelectric substrate, a first resonator and a second resonator are provided which face each other in a plan view, The bus bar adjacent portion is a first busbar adjacent portion located adjacent to a busbar of the first resonator on the second resonator side, the first busbar adjacent portion being located adjacent to the busbar of the first resonator on the second resonator side; a second busbar adjacent portion located adjacent to a busbar of the second resonator on the first resonator side, the second busbar adjacent portion being located adjacent to the busbar of the second resonator on the first resonator side; is established, the first busbar-adjacent portion and the second busbar-adjacent portion are not electrically connected to each other, the first busbar adjacent portion and the second busbar adjacent portion are provided in regions of wiring adjacent to a busbar on a second resonator side of the first resonator and a busbar on the first resonator side of the second resonator, the regions overlapping each other when viewed from the orthogonal direction; the first busbar-adjacent portion disposed adjacent to the first resonator has a connection-side end and a non-connection-side end in a propagation direction of an elastic wave of the first resonator, The connection side end is close to the pad on the piezoelectric substrate or to a wiring connected to another resonator, and has a large width in a direction perpendicular to the propagation direction. the non-connection side end is on the opposite side of the piezoelectric substrate from the pad or the other resonator, and has a small width in an orthogonal direction perpendicular to the propagation direction; a width of the first busbar-adjacent portion in the orthogonal direction gradually or stepwise increases from the non-connection side end to the connection side end, the second busbar-adjacent portion disposed adjacent to the second resonator has a connection-side end and a non-connection-side end in a propagation direction of an elastic wave of the second resonator, The connection side end of the second bus bar adjacent portion is close to the pad on the piezoelectric substrate or to a wiring connected to another resonator, and has a large width in a direction perpendicular to the propagation direction. the non-connection side end of the second busbar-adjacent portion is on the opposite side to the pad or the other resonator on the piezoelectric substrate, and has a small width in a direction perpendicular to the propagation direction; a width of the second busbar-adjacent portion in the orthogonal direction gradually or stepwise increases from the non-connection side end to the connection side end, a distance between a connection-side end of the first busbar-adjacent portion and a non-connection-side end of the second busbar-adjacent portion in the propagation direction is closer than a connection-side end of the second busbar-adjacent portion; In the propagation direction, a non-connection side end of the first busbar-adjacent portion is closer to a connection side end of the second busbar-adjacent portion than to a non-connection side end of the second busbar-adjacent portion. The acoustic wave device according to claim 1 .

5. The bus bar is connected to the electrode fingers obliquely in a plan view. The acoustic wave device according to any one of claims 1 to 4.

6. The bus bar is formed in a stepped shape in a plan view. The acoustic wave device according to claim 1 .

7. The width of the non-connection side end of the bus bar adjacent portion in the orthogonal direction is 1 / 3 or less of the width of the connection side end in the orthogonal direction. The acoustic wave device according to claim 1 .

8. The first busbar-adjacent portion and the second busbar-adjacent portion are provided between opposing busbars, and the distance between the opposing busbars is defined as a total width in the orthogonal direction including the first busbar-adjacent portion and the second busbar-adjacent portion, and the total width in the orthogonal direction of the non-connection side ends of the first busbar-adjacent portion and the second busbar-adjacent portion is ⅓ or less of the total width in the orthogonal direction of the connection side ends of the first busbar-adjacent portion and the second busbar-adjacent portion. The acoustic wave device according to claim 4 .

9. A ladder filter including a plurality of series resonators and a plurality of parallel resonators is provided on the piezoelectric substrate. The acoustic wave device according to any one of claims 1 to 4.

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