Elastic wave device

Abstract

Provided is an elastic wave device having low loss due to resistance. This elastic wave device is provided with a plurality of resonators, a pad, and a plurality of wirings provided on a piezoelectric substrate. Each of the plurality of resonators has an IDT electrode, and the wiring is provided with a bus bar adjacent portion extending from the bus bar in a direction orthogonal to an elastic wave propagation direction of the IDT electrode. The bus bar adjacent portion has, in the elastic wave propagation direction, a connection-side end portion that is close to a portion connected to a pad or another resonator, and a non-connection-side end portion that is located on the opposite side of the pad or another resonator. The width of the connection-side end portion in the orthogonal direction is larger than the width of the non-connection-side end portion of the bus bar in the orthogonal direction, and the width of the bus bar adjacent portion in the wiring in the orthogonal direction in the elastic wave propagation direction is configured so as to gradually widen from the non-connection-side end portion of the bus bar toward the connection-side end portion.

Description

Technical Field

[0001] This invention relates to an elastic wave device. Background Technology

[0002] For example, as a demultiplexer for mobile phones, there is a known elastic wave device that includes a filter containing multiple surface acoustic wave (SAW) resonators.

[0003] Japanese Patent JP2017195580A (hereinafter referred to as Patent Document 1) discloses an elastic wave filter device with multiple IDT electrodes disposed on a piezoelectric substrate. By shortening the length of the reflector adjacent to the IDT electrodes, space is ensured, and this space is used as the area for forming wiring, thereby increasing the wiring width, reducing wiring resistance, and reducing losses.

[0004] Furthermore, Japanese Patent JP6424962B2 (hereinafter referred to as Patent Document 2) discloses an elastic wave device that includes multiple IDT electrodes with busbars that are tilted relative to the electrode fingers. The IDT electrodes reduce insertion loss by making the direction in which they are connected to the front ends of the multiple electrode fingers present a positive tilt angle of more than 0° relative to the propagation direction of the elastic wave. Summary of the Invention

[0005] In elastic wave devices on piezoelectric substrates with IDT electrodes and wiring, it is required to reduce the resistance of the wiring to minimize losses. However, when attempting to increase the wiring width, the area occupied by the wiring on the piezoelectric substrate also increases, leading to the following problems: either the size of the piezoelectric substrate must be increased, thus making the device larger, or the area occupied by the reflector on the piezoelectric substrate needs to be reduced, as in the elastic wave filter device disclosed in Patent Document 1, to ensure additional space for the wiring. The present invention was made in view of the above-mentioned problems, and aims to provide an elastic wave device that can reduce wiring resistance while ensuring area utilization efficiency.

[0006] One embodiment of the elastic wave device of the present invention comprises: Piezoelectric substrate; Multiple resonators disposed on the piezoelectric substrate; Pads disposed on the piezoelectric substrate; Multiple wirings for making electrical connections between the pads and the plurality of resonators; Each of the plurality of resonators has an IDT electrode comprising a pair of opposing comb electrodes. The comb electrode includes: Multiple electrode fingers disposed on the comb-tooth electrodes; A busbar electrically connected to the plurality of electrodes; In the top view, the wiring is provided with a busbar abutment portion, which is adjacent to the side of the busbar opposite to the electrode finger setting side, and is located in a region extending from the busbar in a perpendicular direction to the elastic wave propagation direction of the IDT electrode; The busbar adjacent portion has a connection side end that is closer to the wiring connected to the pad or other resonator in the direction of elastic wave propagation, and a non-connection side end on the side opposite to the pad or other resonator. The width of the adjacent portion of the busbar in the orthogonal direction at the end on the connecting side is greater than its width in the orthogonal direction at the end on the non-connecting side. The width of the adjacent portion of the busbar in the wiring is formed by gradually or stepwise increasing from the non-connected end of the busbar toward the connected end in the direction of elastic wave propagation.

[0007] In this way, the busbar adjoining portion adjacent to the IDT electrode busbar has an increased width at the connection side end through which a relatively large current flows, and a decreased width at the non-connection side end through which a relatively large current does not flow. This reduces the overall resistance of the busbar adjoining portion without significantly increasing the area occupied by the busbar adjoining portion.

[0008] Here, "closer in wiring connected to pads or other resonators" means that the circuit paths are relatively close in the electrical connection relationship of the wiring.

[0009] In some implementations, wherein: In the plurality of resonators, one of the resonators has two busbars that are electrically connected to the electrodes of the resonator and are arranged opposite to each other; The adjacent portion of the busbar is adjacent to the two busbars mentioned above, respectively; The adjacent portions of the two busbars each have: In the direction of elastic wave propagation, the connection side end that is closer to the wiring connected to the pad or other resonator, and the non-connection side end that is opposite to the pad or other resonator; The orthogonal width at the end of the connecting side is greater than the orthogonal width of the adjacent portion of the busbar at the end of the non-connecting side. The adjacent portions of the two busbars are configured such that their widths in the orthogonal directions gradually or in a stepped manner increase from the non-connecting end of the busbar towards the connecting end.

[0010] In some implementations, wherein: Among the plurality of resonators disposed on the piezoelectric substrate, there are a first resonator and a second resonator that are opposite to each other in a top view; The first resonator and the second resonator are arranged opposite each other in the orthogonal direction, such that the distance between them exists at positions of minimum and maximum. The adjacent portion of the busbar is the wiring area that electrically connects the first resonator and the second resonator; The busbar adjoining portion is adjacent to the busbar of the first resonator facing the second resonator and the busbar of the second resonator facing the first resonator. Furthermore, the regions where the two busbars overlap when viewed from the orthogonal direction, and the regions extending from these two busbars in the orthogonal direction; The busbar adjacent portion includes: the side furthest from the first resonator and the second resonator in the orthogonal direction, and the connection side end that is relatively close to the pad or other resonators disposed on the piezoelectric substrate in the wiring connection; And the non-connected end opposite the pad or other resonator, located between the first and second resonators and closer in the orthogonal direction; The orthogonal width of the adjacent portion of the busbar at the non-connecting end is smaller than the orthogonal width at the connecting end. Furthermore, the width of the connecting end in the orthogonal direction is greater than the width of the adjacent portion of the busbar in the orthogonal direction at the non-connecting end; The width of the adjacent portion of the busbar gradually or in a stepped manner increases from the non-connecting end toward the connecting end.

[0011] In this way, a busbar adjoining portion is provided between the first resonator and the second resonator, and the width of the busbar adjoining portion near the connected side end through which a relatively large current flows—that is, the side opposite to the non-connected side end—is increased, while the width of the non-connected side end through which a relatively small current flows is decreased, thereby reducing the overall resistance of the busbar adjoining portion without significantly increasing the occupied area of ​​the busbar adjoining portion.

[0012] In some implementations, wherein: Among the plurality of resonators disposed on the piezoelectric substrate, there are a first resonator and a second resonator that are opposite to each other in a top view; As an adjacent part of the busbar, it is provided with: The first busbar adjoining portion of the busbar located on the side of the second resonator among the multiple busbars adjacent to the first resonator; The second busbar adjoining portion of the busbar located on the side of the first resonator among the multiple busbars adjacent to the second resonator; The first busbar adjacent portion and the second busbar adjacent portion are electrically insulated from each other; The first busbar adjoining portion and the second busbar adjoining portion are respectively disposed in the wiring extending from the busbar of the first resonator toward the second resonator and the busbar of the second resonator toward the first resonator, and are located in the area that overlaps with each other when viewed from the orthogonal direction; The first busbar adjoining portion adjacent to the first resonator has a connected end and a non-connected end in the elastic wave propagation direction of the first resonator. The connection end is located in a wiring region close to the pads or other resonators disposed on the piezoelectric substrate, and has a larger width in the direction perpendicular to the propagation direction. The non-connected end is located on the side opposite to the pad or other resonator, and has a smaller width in the direction perpendicular to the propagation direction. The width of the adjacent portion of the first busbar in the orthogonal direction gradually or stepwise increases from the non-connecting end toward the connecting end; The second busbar adjoining portion adjacent to the second resonator has a connecting end and a non-connecting end in the elastic wave propagation direction of the second resonator. The connection end is located in a wiring region close to the pads or other resonators disposed on the piezoelectric substrate, and has a large width in the direction perpendicular to the propagation direction. The non-connected end is located on the side opposite to the pad or other resonator, and has a smaller width in the direction perpendicular to the propagation direction. The width of the adjacent portion of the second busbar in the orthogonal direction gradually or stepwise increases from the non-connecting end toward the connecting end; In the propagation direction, the distance between the connecting end of the first busbar adjacent portion and the non-connecting end of the second busbar adjacent portion is smaller than the position of the connecting end of the second busbar adjacent portion. In the propagation direction, the distance between the non-connecting end of the first busbar adjacent portion and the connecting end of the second busbar adjacent portion is less than the position of the non-connecting end of the second busbar adjacent portion.

[0013] In this way, regarding the first busbar adjacent portion and the second busbar adjacent portion, the width is increased near the connection side end through which a relatively large current flows, that is, on the side opposite to the non-connection side end, while the width is decreased at the non-connection side end through which a large current does not flow. This reduces the overall resistance of the busbar adjacent portion without significantly increasing the area occupied by the busbar adjacent portion.

[0014] Furthermore, by placing the connecting end of the first busbar adjacent portion close to the non-connecting end of the second busbar adjacent portion, and placing the non-connecting end of the first busbar adjacent portion close to the connecting end of the second busbar adjacent portion, an efficient area configuration of the first and second busbar adjacent portions is achieved. Therefore, when arranging two resonators, not only can area efficiency be improved, but the resistance value of the busbar adjacent portions can also be reduced, thereby suppressing losses.

[0015] In some embodiments, the busbar is connected to the electrode finger at an angle in a top view.

[0016] In some embodiments, the busbar appears stepped in a top view.

[0017] In some embodiments, the width of the adjacent portion of the busbar in the orthogonal direction at the non-connecting end is less than 1 / 3 of the orthogonal width at the connecting end.

[0018] In some embodiments, a first busbar adjoining portion and a second busbar adjoining portion are provided between the busbars arranged opposite each other. The distance between the relatively arranged busbars is taken as the total width in the orthogonal direction, including the adjacent portions of the first busbar and the second busbar. The total width of the first busbar adjacent portion and the second busbar adjacent portion in the orthogonal direction at their non-connecting side ends is less than 1 / 3 of the total width of the first busbar adjacent portion and the second busbar adjacent portion in the orthogonal direction at their connecting side ends.

[0019] In some embodiments, the piezoelectric substrate is provided with a stepped filter comprising multiple series resonators and multiple parallel resonators.

[0020] In some embodiments, the width of the adjacent portion of the busbar in the orthogonal direction at the non-connecting end is less than 1 / 4 of the width of the connecting end in the orthogonal direction.

[0021] According to the elastic wave device of the present invention, since the busbar adjacent to the IDT electrode is provided with a busbar abutment portion, and the busbar abutment portion 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 small current flows, the overall resistance of the busbar abutment portion can be reduced without increasing the area occupied by the busbar abutment portion on the piezoelectric substrate. Therefore, an elastic wave device that reduces losses caused by wiring resistance can be realized without increasing the area of ​​the piezoelectric substrate. Attached Figure Description

[0022] Figure 1 This is a top view showing one embodiment of the elastic wave device of the present invention.

[0023] Figure 2 yes Figure 1 An enlarged top view of the resonator and the adjacent part of the busbar in the elastic wave device shown.

[0024] Figure 3 yes Figure 2 A cross-sectional view of the resonator along line A-A'.

[0025] Figure 4 (a) is a top view showing the adjacent portion of the IDT electrode and busbar in Embodiment 1; (b) is a diagram showing a conventional example of the adjacent portion of the IDT electrode and busbar for comparison.

[0026] Figure 5 (a) is a top view showing the width of each part in Example 1; (b) is a top view showing the width of each part in the conventional example.

[0027] Figure 6 (a) is a diagram illustrating the equivalent circuit of Example 1; (b) is a diagram illustrating the equivalent circuit of the conventional example.

[0028] Figure 7 This is a circuit diagram showing the equivalent circuit of the IDT electrode and the adjacent part of the busbar of the resonator in Embodiment 1.

[0029] Figure 8 This is a graph showing the change in resistance reduction rate corresponding to the change in width W1 in Example 1.

[0030] Figure 9 This is a graph showing the change in resistance reduction rate corresponding to the change in width W1 when excluding resistor R3 in Example 1.

[0031] Figure 10 (a) is a top view of two resonators set up relative to each other in an inclined manner as in Example 2; (b) is a diagram showing a conventional example.

[0032] Figure 11This is a top view showing other examples of the resonator and busbar adjacent portion constituting one embodiment of the elastic wave device of the present invention.

[0033] Figure 12 for Figure 11 B-B' cross-sectional view of the resonator.

[0034] Figure 13 This is a top view showing other examples of the resonator and busbar adjacent portion constituting one embodiment of the elastic wave device of the present invention.

[0035] Figure 14 This is a top view showing other examples of the resonator and busbar adjacent portion constituting one embodiment of the elastic wave device of the present invention.

[0036] Figure 15 This is a top view showing other examples of the resonator and busbar adjacent portion constituting one embodiment of the elastic wave device of the present invention.

[0037] Figure 16 This is a top view showing other examples of the resonator and busbar adjacent portion constituting one embodiment of the elastic wave device of the present invention.

[0038] Figure 17 This is a top view showing other examples of the resonator and busbar adjacent portion constituting one embodiment of the elastic wave device of the present invention.

[0039] Figure 18 This is a top view showing other examples of the resonator and busbar adjacent portion constituting one embodiment of the elastic wave device of the present invention.

[0040] Figure 19 This is a top view showing other examples of the resonator and busbar adjacent portion constituting one embodiment of the elastic wave device of the present invention.

[0041] Figure 20 This is a top view showing other examples of the resonator and busbar adjacent portion constituting one embodiment of the elastic wave device of the present invention.

[0042] Figure label: 1. Elastic wave devices (filters) 10. Substrate (piezoelectric substrate) 21a IDT electrode 7 Electrode Finger Wiring 30, 31, 32, 33, 34, 36, 36, 37, 38 36a, 37a Busbar Adjacent Sections 36b, 37b Connecting side ends 36c, 37c Non-connecting end Pads 40, 41, 42, 43 70, 80 IDT electrode arrangement area 200 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 resonators. Detailed Implementation

[0043] <About Figure 1 The elastic wave device shown > Figure 1 This is a top view illustrating one embodiment of the elastic wave device of the present invention. (See attached image.) Figure 1 As shown, multiple elastic wave resonators S1 to pad S5, pads P1 to pad P3, wiring 30 to wiring 38, and pads 40 to pad 43 are formed on the substrate 10, which serves as a piezoelectric substrate. The stepped filter 1, which serves as an elastic wave device, includes series resonators S1 to series resonators S5 and parallel resonators P1 to parallel resonators P3.

[0044] The substrate 10, which serves as the piezoelectric substrate, can be, for example, lithium tantalate (LiTaO3). However, the material of the piezoelectric substrate is not limited to this, and other materials such as lithium niobate (LiNbO3) can also be used.

[0045] The elastic wave resonators P1 to P3 and S1 to S5 respectively have IDT (Interdigital Transducer) electrodes 100a, 120a, 130a, 140a, 150a, 210a, 220a, and 230a, and reflectors 100b, 120b, 130b, 140b, 150b, 210b, 220b, and 230b disposed on both sides thereof.

[0046] The wiring 30-38 and the pads 40-43 are composed of metal layers such as copper or gold layers formed on the substrate 10.

[0047] In the stepped filter 1, which serves as an elastic wave device, series resonators S1 to S5 are connected in series between pad 40, which serves as the antenna terminal Ant (or output terminal), and pad 42, which serves as the transmitting terminal Tx (or input terminal). Parallel resonators P1 to P3 are connected in parallel between the antenna terminal Ant (pad 40) and the transmitting terminal Tx (pad 42). One end of the parallel resonators P1 to P3 is connected to pads 41 and 43, which serve as ground (GND) terminals.

[0048] <About Figure 2 The resonator and busbar adjacent section shown > Figure 2 This is a top view of the resonator P1 disposed on the substrate 10 in the elastic wave device 1. The resonator P1 includes an IDT electrode 210a and a reflector 210b.

[0049] The IDT electrode 210a includes comb-tooth electrodes 212a and 212b. Comb-tooth electrode 212a includes electrode fingers 213a and a busbar 214a, and comb-tooth electrode 212b includes electrode fingers 213b and a busbar 214b. The busbars 214a and 214b are inclined relative to the electrode fingers 213a and 213b, and also inclined relative to the propagation direction of the elastic surface wave excited by the IDT electrode 210a. Figure 2 The X direction (in the image) is set at an angle.

[0050] exist Figure 2 The IDT electrode 210a shown has a wiring 36 above it and a wiring 37 below it. Wiring 36 is located on the opposite side of busbar 214a relative to electrode finger 213a and is electrically connected to other resonators (i.e., resonators other than resonator P1) S1. Wiring 37 is located on the opposite side of busbar 214b relative to electrode finger 213b and is connected to pad 41, which serves as a ground terminal (GND). Furthermore, the resonant frequency fR is determined by the relationship P = λ / 2 between the wavelength λ of the elastic surface wave propagating in the piezoelectric layer 3 and the electrode period P of the electrode finger.

[0051] exist Figure 2 In the diagram, busbar adjacent portions 36a and 37a are indicated by diagonal shading. Busbar adjacent portion 36a is a portion of the wiring 36, adjacent to busbar 214a, and extending from busbar 214a in a direction orthogonal to the direction of elastic surface wave propagation (i.e.,...). Figure 2 The area extending in the Y direction (hereinafter also referred to as the "orthogonal direction") of the wiring 36 is the area in the wiring 36 that has the same width as the busbar 214a in the propagation direction (X direction).

[0052] The adjacent portion 36a of the busbar has a connecting end portion 36b and a non-connecting end portion 36c in the propagation direction.

[0053] The connection end 36b is the end on the side of electrical connection that is close to other resonators (i.e., resonators other than P1).

[0054] The non-connection end 36c is the end opposite to the connection end 36b in the propagation direction. It is the end that is far away from other wiring, other resonators or pads and other components, that is, the end that is not directly connected to other wiring.

[0055] The width W2a of the connecting end 36b in the orthogonal direction (Y direction) is greater than the width W1a of the non-connecting end 36c, and the width W1a of the non-connecting end 36c in the orthogonal direction is less than the width W2a of the connecting end 36b. The width of the adjacent portion 36a of the busbar in the orthogonal direction gradually (slowly) widens from the non-connecting end 36c toward the connecting end 36b.

[0056] The busbar adjacency portion 37a is a part of the wiring 37 that is adjacent to the busbar 214b and extends from the busbar 214b in a perpendicular direction. In other words, the busbar adjacency portion 37a is a region of the wiring 37 that has the same width as the busbar 214b in the propagation direction.

[0057] The busbar adjacent portion 37a has a connecting end 37b and a non-connecting end 37c in the propagation direction. The connecting end 37b is the wiring side connected to the pad 43, which serves as a ground terminal, i.e., the end that is closer to the pad in terms of electrical connection. The non-connecting end 37c is the end opposite to the connecting end 37b in the propagation direction, and is the end that is further away from other wiring, other resonators, pads, and other components disposed on the substrate 10 in terms of electrical connection.

[0058] The width W2a of the connecting end 36b in the orthogonal direction (Y direction) and the width W1a of the non-connecting end 36c in the orthogonal direction are the same as the width W2a of the connecting end 37b in the orthogonal direction (Y direction) and the width W1a of the non-connecting end 37c in the orthogonal direction. The width W2a of the connecting end 36b in the orthogonal direction is greater than the width W1a of the non-connecting end 36c, and the width W1a of the non-connecting end 36c in the orthogonal direction is less than the width W2a of the connecting end 36b. The width of the adjacent portion 36a of the busbar gradually (slowly) widens in the orthogonal direction from the non-connecting end 36c toward the connecting end 36b in the propagation direction.

[0059] Figure 3 This is a cross-sectional view of resonator P1 along line A'. Figure 3 As shown, a first metal layer 60 and a second metal layer 61 are formed on the substrate 10.

[0060] like Figure 3 As shown, electrode finger 213b and busbars 214a and 214b are formed by a first metal layer 60. The first metal layer 60 may be, for example, an aluminum layer, a titanium layer, or a copper layer, or an alloy of these metals, or other metals, or multiple layers of the above metals may be stacked to form a multilayer structure.

[0061] The busbar adjacent portion 36a of wiring 36 and the busbar adjacent portion 37a of wiring 37 have a first metal layer 60 formed 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, and a gold layer. Alloys of these metals or other metals may also be used, and the above metals may be configured into a multilayer structure.

[0062] The substrate 10, serving as the piezoelectric substrate, can be composed solely of the piezoelectric substrate, or it can be a structure in which the piezoelectric substrate is attached to a support substrate. The support substrate can be, for example, a spinel substrate, but it can also be a sapphire substrate, silicon substrate, quartz substrate, crystal substrate, alumina substrate, or silicon carbide substrate, etc., as long as it solves the problem of the present invention. Furthermore, an intermediate layer can be provided between the support substrate and the piezoelectric substrate. If the intermediate layer is provided to improve the bonding strength between the support substrate 2 and the piezoelectric substrate 3, then the intermediate layer can be made of a material such as silicon dioxide (SiO2). If the intermediate layer is provided as a high-speed transmission layer for elastic waves, then aluminum nitride (AlN) or aluminum boron nitride (BXAl₋) can be used. x Materials such as N).

[0063] Thus, the busbar abutment portions 36a and 37a of the busbars 214a and 214b adjacent to the IDT electrode 210a are wider at the connection-side ends 36b and 37b where a relatively large current flows, and narrower at the non-connection-side ends 36c and 37c where a relatively small current flows due to their lack of connection with other wiring. Therefore, the overall resistance of the busbar abutment portions 36a and 37a can be reduced without significantly increasing the area occupied by the busbar abutment portions 36a and 37a on the substrate 10. Therefore, while maintaining the same area occupied by the resonator P1, losses caused by resistance can be reduced. Consequently, losses caused by resistance in the elastic wave device 1 can also be reduced.

[0064] In this embodiment, regarding the busbar adjacent portions 36a and 37a of the IDT electrode 210a, the width of the connecting side ends 36b and 37b is set to be larger, and the width of the non-connecting side ends 36c and 37c is set to be smaller. However, this structure can also be implemented only for either the busbar adjacent portions 36a and 37a, that is, only the connecting side ends (36b and 37b) of one of the busbar adjacent portions is set to be larger, and the non-connecting side ends (36c and 37c) is set to be smaller. In addition, in the wiring 36 and 37, although the positions of the connecting side ends 35b and 36b of the busbar adjacent portions 36a and 37a are represented by straight lines, these straight lines only represent the outline of the shaded area and do not represent the boundary of the shape or material.

[0065] <About Simulation> To confirm the effect of the resonator P1 on reducing losses due to resistance, a simulation was performed. Figure 4 (a) is a top view of Embodiment 1 showing the IDT electrode and the adjacent part of the bus bar. Figure 4 (b) is a top view of the conventional IDT electrode and the adjacent portion of the busbar for comparison. In this application, Figure 4 The region between boundary line 71 and boundary line 72 in (a), that is, the region where electrode finger 76 and bus bar 73 are configured, is called IDT electrode configuration region 70.

[0066] exist Figure 4 In (a), the upper and lower parts of the IDT electrode configuration area 70 are respectively provided with busbar adjacent parts 74 and 75 that are electrically connected to the wiring 78 and 79.

[0067] In this simulation, the adjacent parts 74 and 75 of the busbar are... Figure 2 The adjacent portions 36a and 37a of the busbar of the resonator P1 serve the same function.

[0068] Figure 4 (b) In the conventional example shown, the IDT electrode is disposed in the region from boundary line 81 to boundary line 83, which is the IDT electrode configuration region 80 where electrode fingers 86 and busbars 83 are disposed. Above and below the IDT electrode configuration region 80, busbar adjacency portions 84 and 85, which are electrically connected to wiring 87 and 88, are respectively disposed.

[0069] In addition, Figure 4 In Embodiment 1 shown in (a), the structure of the electrode finger 76, the busbar 73, and the adjacent portions 74 and 75 of the busbar are similar to those of the present invention. Figure 3 The cross-sectional view shown is the same, wherein the electrode finger 76 and the bus bar 73 are composed of the first metal layer 60, and the adjacent portions 74 and 75 of the bus bar have a stacked structure of the first metal layer 60 and the second metal layer 61.

[0070] Figure 2 The adjacent portions 36a and 37a of the busbar in the middle Figure 4 In (a), the adjacent portions 74 and 75 of the busbar have the same shape in the top view; both are trapezoidal structures with the connecting end as the bottom and the non-connecting end as the top. Therefore, as long as it can be confirmed... Figure 4 (a) Compared to Example 1 shown in Figure 1 Figure 4 (b) shows that the conventional example has reduced losses due to resistance, which confirms this. Figure 2 The resonator P1 shown and its adjacent busbars 36a and 37a can also reduce the loss caused by resistance.

[0071] Figure 5(a) A schematic diagram illustrating the width of each portion in Embodiment 1, which includes the IDT electrode configuration area 70 and the busbar adjacent portions 74, 75. As... Figure 5 As shown in (a), the outline of the IDT electrode configuration region 70 is represented in a simplified manner. Figure 4 (a) and Figure 5 As shown in (a), the upper edge 71 and lower edge 72 of the IDT electrode configuration area 70 are lines representing the boundaries of the busbar 73 and the busbar adjacent portions 74 and 75. Among them, the busbar adjacent portion 74 is provided in the direction perpendicular to the propagation direction on the upper edge (boundary line) 71; and the busbar adjacent portion 75 is provided in the direction perpendicular to the lower edge (boundary line) 72.

[0072] Figure 5 (b) A schematic diagram illustrating the width of each portion in a conventional example including the IDT electrode configuration region 80 and the busbar adjacent portions 84, 85. The figure shows the outline of the IDT electrode configuration region 80.

[0073] The following explanation Figure 5 Example 1 shown in (a) and Figure 5 (b) shows the structural differences between the traditional examples. Figure 5 Example 1 of (a) and Figure 5 (b) The conventional example is identical in overall shape, with a width of W5 in the orthogonal direction and a length of L in the propagation direction of the resonant wave. Therefore, in both Example 1 and the conventional example, the IDT electrode configuration regions 70 and 80, as well as the adjacent busbar portions 74, 75, 84, and 85, occupy the same area on the substrate. If, with the same occupied area, the loss caused by resistance in Example 1 is less than the loss caused by resistance in the conventional example, it indicates that a reduction in resistance-induced loss is achieved while maintaining the same area, thus confirming the effectiveness of Example 1.

[0074] Figure 5 (a) The width W4 of the side portion 72 of the IDT electrode configuration region 70 in the orthogonal direction of Example 1 is... Figure 5 (b) The side portion 89 of the IDT electrode configuration region 80 has the same width W4 in the orthogonal direction.

[0075] Figure 5 In (a) the connecting ends 74a and 75a of the busbar adjacent portions 74 and 75 have a width of W1 in the orthogonal direction, and the non-connecting ends 74b and 75b of the busbar adjacent portions 74 and 75 have a width of W2 in the orthogonal direction. In the conventional example, the widths of the busbar adjacent portions 84 and 85 are both W0. Therefore, the widths of the connecting ends 84a and 85a and the non-connecting ends 84b and 85b in the orthogonal direction are all W0.

[0076] As a common simulation condition for Example 1 and the conventional example, the parameters of the resonator are set as follows: Resonant frequency fr: 2 [GHz] Electromechanical coupling coefficient k2: 8% Capacitor C: 0.5 pF Q value Qr at the resonant frequency: 1000 Based on the above assumptions, the series resistance at series resonance is calculated to be 2.25 [Ω].

[0077] The IDT electrode is designed based on the above conditions, and it is assumed that the adjacent portions 74 and 75 of the busbar and the adjacent portions 84 and 85 of the busbar have the same sheet resistivity, and the sheet resistivity is set to 0.025 [Ω] / □ (ohms per square).

[0078] In addition, in the conventional example, the width of the connecting end 84a and the non-connecting end 84b of the busbar adjacent portions 84 and 85 is W0 = 10 [μm], and the width of the connecting end 85a and the non-connecting end 85b of the busbar adjacent portion 85 is also W0 = 10 [μm].

[0079] Under the above conditions, in order not to change the total area of ​​Embodiment 1 and the conventional example, the width of the connecting end 74a of the busbar adjacent portion 74 and the connecting end 75a of the busbar adjacent portion 75 in the orthogonal direction is set to W1, and the width of the non-connecting end 74b of the busbar adjacent portion 74 and the non-connecting end 75 of the busbar adjacent portion 75 in the orthogonal direction is set to W2. Furthermore, W1 + W2 = W0 × 2 = 20 [μm]. Only the values ​​of W1 and W2 were changed, and the resistance change was simulated. The width of the IDT electrode, the busbar adjacent portions 74 and 75, and the busbar adjacent portions 84 and 85 in the propagation direction is set to L = 400 [μm].

[0080] Figure 7 The equivalent circuit diagrams for Example 1 and the conventional example used for simulation are shown below. Figure 6 (a) is used to illustrate Figure 5 (a) A diagram of the equivalent circuit of Embodiment 1 shown. Figure 6 (b) is used for explanation Figure 5 (b) is a diagram of the equivalent circuit of the conventional example.

[0081] Regarding Example 1, as Figure 6 As shown in (a), the structure is divided into 8 segments in the propagation direction, and an equivalent circuit is constructed accordingly. Figure 6(a) includes resistors R11-R18, R21-R28, and R3 in the equivalent circuit, as well as Port1 and Port2 as input / output terminals. Resistors R11-R18 are modeled by equivalently representing busbar adjacent portion 74 as eight resistors. Resistors R21-R28 are modeled by equivalently representing busbar adjacent portion 75 as eight resistors. The multiple resistors R3 correspond to the resistance of electrode fingers 76. Regarding busbar adjacent portions 74 and 75, the resistance of each segment is calculated based on dividing their area into eight equal parts and applying the aforementioned thin-layer resistance values.

[0082] Similar to Example 1, regarding the conventional example, such as Figure 6 As shown in (b), the propagation direction is divided into 8 segments, and an equivalent circuit 200 is constructed. Figure 6 (b) includes resistors R11-R18, R21-R28, and R3 in the equivalent circuit, as well as Port1 and Port2 as input / output terminals. Resistors R11-R18 are the model after the busbar adjacent portion 84 is equivalent to eight resistors, and resistors R21-R28 are the model after the busbar adjacent portion 85 is equivalent to eight resistors. The multiple resistors R3 correspond to the resistor portions of the IDT electrodes having electrode fingers 86 and busbar 73. Furthermore, although the same reference numerals are used for the resistors shown in Embodiment 1 and the conventional example, this does not mean that their resistance values ​​are the same.

[0083] As mentioned above, by dividing the structure into 8 segments, a Figure 7 The resistor equivalent circuit 200 is shown.

[0084] The following explanation Figure 6 (a) illustrates the current flow. When current I1 enters the connecting end 74a of the busbar adjoining section 74 from Port1, current I4 flows to Port2 through the connecting end 75a of the busbar adjoining section 75. At this time, since there are eight resistors R3, current flows through each of these resistors. Therefore, the current flowing through the busbar adjoining section 74 will branch at the node where it branches with resistor R3 as it moves from the connecting end 74a to the non-connecting end 74b. As a result, the current I2 flowing through resistor R18 is less than the current I1. Similarly, although the current I4 flowing into Port2 is equal to the current I1 flowing out of Port1, in the busbar adjoining section 75, current from resistor R3 continuously flows in along the path from the non-connecting end 75b to the connecting end 75a. Therefore, the current I3 flowing through resistor R21 at the non-connecting end 75b is less than the current I4 flowing through the final connecting end 75a. Therefore, by setting a larger width in areas with higher current and a smaller width in areas with lower current, the overall resistance value can be reduced without increasing the area.

[0085] After performing the simulation in the above manner, the simulation results are shown in Table 1.

[0086] [Table 1]

[0087] Table 1 shows the simulation results. Figure 8 This is a graph comparing the resistance value when the width W1 changes with the resistance value of the conventional example (W1 = 10), used to represent the resistance reduction rate (i.e., resistance decrease rate) of Example 1 relative to the conventional example. In Table 1, W1 = W2 = 10 μm, which has the same width as the conventional example.

[0088] As described above, the width of the connecting end 74a of the busbar adjacent portion 74 and the connecting end 75a of the busbar adjacent portion 75 in the orthogonal direction is set to W1, and the width of the non-connecting end 74b of the busbar adjacent portion 74 and the non-connecting end 75b of the busbar adjacent portion 75 in the orthogonal direction is set to W2. With W1 + W2 = 20 μm as a premise, W1 is gradually increased and W2 is decreased, and the resistance value is calculated accordingly.

[0089] As shown in Table 1, the resistance values ​​from Port1 to Port2 in the equivalent circuit 200 decrease with increasing W1. Figure 8 It can also be seen that when the width W2 of the non-connected end is 5μm and the width W1 of the connected end is 15μm, that is, when W2 is 1 / 3 of W1, the resistance reduction rate is -3.99%, which can be considered a relatively ideal state.

[0090] Furthermore, when the width W2 of the non-connected end is 4μm and the width W1 of the connected end is 16μm, that is, when W2 is 1 / 4 of W1, the resistance reduction rate is -4.49%, which is even better.

[0091] [Table 2]

[0092] In addition, it will include electrode fingers 46 and busbar 73 (see Figure 4 The resistance values ​​of all resistors R3 corresponding to the IDT electrodes of (a) are excluded from the total resistance values ​​of Port1 to Port2 in the equivalent circuit 200, and the resulting resistance values ​​are shown in Table 2. Figure 9 The chart is based on Table 2 and shows the rate of resistance reduction (resistance reduction rate) of the embodiment relative to the conventional example (W1 = W2 = 10) when the width W1 is changed.

[0093] As shown in Table 2, when the width W1 of the connecting ends 74a and 75a increases and the width W2 of the non-connecting ends 74b and 75b decreases, the resistance value decreases regardless of whether resistor R3 is included. Furthermore, since the resistance reduction rate in Table 2 is significantly lower than that in Table 1, it can be concluded that as long as the shape of the adjacent portion of the busbar in the top view is a trapezoidal structure with the connecting ends 74a and 75a as the bottom and the non-connecting ends 74b and 75b as the top, an effective reduction in resistance can be achieved.

[0094] Based on the above results, it can be seen that in the wiring near the busbar of the IDT electrode, if the resistivity of the thin film is uniform, the resistance value can also be reduced. Therefore, in Figure 2 In the illustrated embodiment, even if the widths of the connecting-side ends 36b and 37b of the busbar adjacent portions 36a and 37a are set to be relatively large, and the widths of the non-connecting-side ends 36c and 37c are set to be relatively small, losses caused by resistance can still be reduced. Furthermore, as described above, if the width of the non-connecting-side ends 36c and 37c in the orthogonal direction does not exceed 1 / 3 of the width of the connecting-side ends 36b and 37b, losses caused by resistance can be significantly reduced, which is ideal; if it is further reduced to less than 1 / 4, the reduction effect on resistance loss is even more significant, which is even more ideal.

[0095] As described above, the IDT electrode and busbar adjacent portion in Example 1 (W1 > 10 μm) can effectively reduce the loss due to the resistance value without increasing the area, thus realizing a low-loss elastic wave device.

[0096] Figure 10 (a) shows the state in which the two resonators are tilted and opposite each other in a top view as in Example 2. Figure 10 (b) shows the state where the two resonators are parallel and opposite each other in the top view, as in the traditional example 2. Figure 10 In (a), the area where the electrode fingers and busbars are configured, namely the IDT electrode configuration area 90, has an inclined upper side 90a and a lower side 90b. This upper side 90a and lower side 90b, along with... Figure 4 Boundary line 71 shown in (a) is similar to boundary line 72, and is the boundary line between the busbar and the adjacent portions 94, 92 of the busbar. Figure 10In (a), a busbar abutment portion 94 is provided above the upper side 90a, and busbar abutment portions 92 and 93 are provided below the lower side 90b. Below the busbar abutment portion 93, there is an IDT electrode configuration region 91 including the inclined upper side 91a and lower side 91b. The busbar abutment portion 93 is located above the upper side 91a, and the busbar abutment portion 95 is located below the lower side 91b. The busbar abutment portions 92 and 93 are an integral structure and are continuously connected. In the busbar abutment portions 92 and 93, there is a connection side end 98 and a non-connection side end 97. The connection side end 98 is the end facing other resonators or pads, and its width in the orthogonal direction is W7; the non-connection side end 97 is the end away from other resonators or pads, and its width in the orthogonal direction is W8. The width W8 of the non-connection side end 97 is smaller than the width W7 of the connection side end 98. Furthermore, the overall structure, including the two IDT electrode configuration areas and the busbar adjoining portion, has a width of W6 in the orthogonal direction and a width of L2 in the propagation direction. According to the simulation results, since the width W7 of the connecting end 98 is greater than the width W8 of the non-connecting end 97, the resistance values ​​of the busbar adjoining portions 92 and 93 are significantly higher than those of the connecting end 97. Figure 10 (b) shows that the adjacent portions 112 and 113 of the busbar in the conventional example 2 are lower.

[0097] As described above, 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 portion 92 and the busbar adjacent portion 93 can also be reduced, thereby realizing an elastic wave device with less loss due to resistance value.

[0098] Figure 10 In the conventional example 2 shown in (b), the IDT electrode configuration area 110 and the IDT electrode configuration area 111 are arranged opposite each other in a non-tilted state. The IDT electrode configuration area 110 includes an upper edge 110a and a lower edge 110b, and the IDT electrode configuration area 111 includes an upper edge 111a and a lower edge 111b. These boundary lines 110a, 110b, 111a, and 111b are all parallel. The busbar adjacent portion 112 and the busbar adjacent portion 113 are integral structures, and the width at its end 114 is W9. Figure 10 (a) The overall width of the two IDT electrode configuration areas and the adjacent portion of the busbar in Example 2 is W6, while Figure 10(b) In the conventional example 2, the overall width of the two IDT electrode configuration regions and the busbar adjoining portion is also W6, which is the same. Furthermore, their lengths in the propagation direction are also L, which is also the same. Therefore, the overall area of ​​the two IDT electrode configuration regions 90 and 91 and the busbar adjoining portions 92-95 in Example 2 is not increased. Furthermore, by using the structure formed by tilting the two IDT electrode configuration regions 90 and 91 opposite each other, the width W7 of the connecting end 98 of the busbar adjoining portions 92 and 93 can be made greater than the width W8 of the non-connecting end 97, thus enabling the realization of an elastic wave device containing two resonators with low loss due to resistance.

[0099] In addition, Figure 10 In Embodiment 2 shown in (a), although an example is presented where the busbar adjacent portion 92 and the busbar adjacent portion 93 are integrally and continuously connected, even in a structure where they are not electrically connected and are slightly separated at the position shown by the dashed line 99, compared to Figure 10 In (b), the conventional example, indicated by the dashed line 107, where the busbar adjacent portions 112 and 113 are not electrically connected and are slightly separated, still reduces the losses caused by resistance in the busbar adjacent portions 92 and 93 respectively, without increasing the area. Similar to the simulation results above, since the busbar adjacent portions 92 and 93 in this embodiment 2 have a trapezoidal structure, their resistance can obviously be reduced. Furthermore, it is ideal if the width W8 does not exceed 1 / 3 of the width W7; even more ideally, it is even better if W8 does not exceed 1 / 4 of W7.

[0100] <About Figure 11 The resonator and busbar adjacent part in the middle > Figure 11 This is an enlarged top view of an example of resonators P2 and P3 disposed on substrate 10 in elastic wave device 1. Figure 11 As shown, resonator P2, which is the first resonator, and resonator P3, which is the second resonator, are not arranged in parallel. Instead, they are arranged opposite each other in a way that minimizes the shortest distance between them and maximizes the distance between them in the orthogonal direction. In other words, resonator P2 and resonator P3 are tilted opposite each other.

[0101] Resonator P2 includes an IDT electrode 220a and a reflector 220b. The IDT electrode 220a includes comb electrodes 222a and 222b. The comb electrode 222a includes electrode fingers 223a and a bus bar 224a (in resonator P2, which is the bus bar 224a located on the side of the second resonator P3); the comb electrode 222b includes electrode fingers 223b and a bus bar 224b. Both bus bars 224a and 224b are arranged at an angle on one side of the electrode fingers 223a and 223b. Furthermore, the bus bars 224a and 224b are also positioned relative to the propagation direction of the elastic surface wave excited by the IDT electrode 220a. Figure 11 The X direction (in the middle) is arranged at an angle.

[0102] Resonator P3 includes an IDT electrode 230a and a reflector 230b. The IDT electrode 230a includes comb electrodes 232a and 232b. The comb electrode 232a includes electrode fingers 233a and busbars 234a; the comb electrode 232b includes electrode fingers 233b and busbars 234b (in resonator P3, which is the busbar 234b located on the side of the first resonator P2). Busbars 234a and 234b are arranged at an angle relative to the electrode fingers 233a and 233b. Furthermore, busbars 234a and 234b are also arranged at an angle relative to the propagation direction of the elastic surface wave excited by the IDT electrode 230a.

[0103] Since resonators P2 and P3 are tilted opposite each other, their oppositely arranged busbars 224a and 234b are not parallel.

[0104] A wiring 33 is provided between resonators P2 and P3. This wiring 33 electrically connects the opposing busbars 224a and 234b, as well as the pad 41, which serves as a ground terminal. Figure 11 In this circuit, wiring 33 is disposed above the IDT electrode 220a of the resonator P2. In this wiring 33, a busbar adjacent portion 33a is provided on the side opposite to the electrode finger 223a of the busbar 224a and on the side opposite to the electrode finger 233b of the busbar 234b.

[0105] exist Figure 11 In the diagram, the adjacent portion 33a of the busbar is indicated by a diagonal shading. The adjacent portion 33a is a region within the wiring 33, adjacent to busbars 224a and 234b, and extending from busbars 224a and 234b in a perpendicular direction (…). Figure 11 (Extends in the Y direction).

[0106] In other words, the busbar adjoining portion 33a is the region in wiring 33 that has the same width as busbar 224a in the propagation direction (X direction). This busbar adjoining portion 33a is located in wiring 33 in the region where busbars 224a and 234b overlap when viewed from the orthogonal direction (i.e., the part where the busbars are in the same position in the propagation direction).

[0107] The busbar adjacent portion 33a includes a connecting end 33b and a non-connecting end 33c in the propagation direction. The connecting end 33b is the end closest to the pad 41, and is closer to the pad 41 in terms of electrical connection. The non-connecting end 33c is the end opposite to the connecting end 33b in the propagation direction (X direction), and is the end away from other wiring, other resonators, or other components such as pads, that is, the end that is not directly connected to other wiring.

[0108] The width W2b of the connecting end 33b of the busbar adjacent portion 33a in the orthogonal direction (Y direction) is greater than the width W1b of the non-connecting end 33c. The width of the busbar adjacent portion 33a in the orthogonal direction gradually increases from the non-connecting end 33c to the connecting end 33b.

[0109] Figure 12 yes Figure 11 The diagram shows the B-B' cross-sectional view of resonators P2 and P3. Figure 11 As shown, a first metal layer 60 and a second metal layer 61 are formed on the substrate 10. Figure 11 As shown, electrode finger 223b, busbars 224a, 224b, 234a, 234b, and electrode finger 233b are composed of a first metal layer 60. The first metal layer 60 may be, for example, an aluminum layer, a titanium layer, or a copper layer, or an alloy thereof, or a multilayer structure composed of these metal layers.

[0110] The busbar adjacent portion 33a, wiring 31, and wiring 34 of wiring 33 are composed of a first metal layer 60 formed on the substrate 10 and a second metal layer 61 formed on the first metal layer 60. The second metal layer 61 can be, for example, an aluminum layer, a titanium layer, a copper layer, a palladium layer, or a gold layer. Alloys of these metals can also be used, or the above metals can be configured into a multilayer structure.

[0111] As described above, the busbar abutment portion 33a adjacent to busbars 224a and 234b has a larger width W2b at the connection side end 33b where a relatively large current flows, and a smaller width W1b at the non-connection side end 33c where almost no large current flows due to its lack of connection with other wiring. This reduces the overall resistance of the busbar abutment portion. Therefore, without increasing the area required for resonators P2 and P3, losses due to resistance can be reduced. Consequently, losses due to resistance in the entire elastic wave device 1 can also be reduced. Furthermore, from the perspective of reducing the resistance of the busbar abutment portion 33a, the width W1b is preferably less than 1 / 3 of the width W2b, and more preferably less than 1 / 4 of the width W2b.

[0112] <About Figure 13 Resonator and busbar adjacent section > like Figure 13 As shown, resonators P2 and P3 can also be tilted opposite each other and offset in the propagation direction (X direction). Figure 13 In wiring 33, the adjacent portion 33a2 of the busbar is indicated by a diagonal shading. The adjacent portion 33a2 is a region of wiring 33, adjacent to busbars 224a and 234b. For example... Figure 13 As shown, in the orthogonal direction, when the busbars 224a and 234b are misaligned in the propagation direction, the area where the busbars 224a and 234b overlap (i.e., the area in the same position in the X direction) when viewed from the orthogonal direction (Y direction) is the adjacent part 33a2 of the busbars.

[0113] The width W2c of the connecting end 33b2 of the busbar adjacent portion 33a2 in the orthogonal direction (Y direction) is greater than the width W1c of the non-connecting end 33c2. At the connecting end 33b2, the width of the busbar adjacent portion 33a2 in the orthogonal direction (i.e., the orthogonal distance between busbars 224a and 234b at the connecting end 33b2) reaches its maximum. The width of the busbar adjacent portion 33a2 in the orthogonal direction gradually increases from the non-connecting end 33c2 to the connecting end 33b2. Furthermore, from the perspective of reducing the resistance of the busbar adjacent portion 33a2, the width W1c is preferably less than 1 / 3 of the width W2c, and more preferably less than 1 / 4 of the width W2c.

[0114] As described above, the busbar abutment portion 33a2 adjacent to busbars 224a and 234b has a larger width on the connecting side end 33b2 where a relatively large current flows, and a smaller width on the non-connecting side end 33c2 where almost no large current flows due to its lack of connection with other wiring. This reduces the overall resistance of the busbar abutment portion. Therefore, while keeping the area required for resonators P2 and P3 constant, losses due to resistance can be reduced. Consequently, losses due to resistance in the entire elastic wave device 1 can also be reduced.

[0115] <About Figure 14 Resonator and busbar adjacent section > Figure 14 This is an enlarged top view of another embodiment of the resonators S3 and P1 disposed on the substrate 10 in the elastic wave device 1. Figure 14 As shown, resonator S3, which serves as the first resonator, and resonator P1, which serves as the second resonator, are not arranged parallel to each other. Therefore, they are arranged opposite each other in the orthogonal direction in a way that creates the closest and furthest portions between them. In other words, resonator S3 and resonator P1 are tilted opposite each other.

[0116] Between resonator S3 and resonator P1, busbar adjacent portion 35a and busbar adjacent portion 36a are separately disposed.

[0117] As described above, the resonator P1 includes an IDT electrode 210a and a reflector 210b. The IDT electrode 210a includes comb electrodes 212a and 212b, wherein the comb electrode 212a includes an electrode finger 213a and a bus bar 214a, and the comb electrode 212b includes an electrode finger 213b and a bus bar 214b.

[0118] The resonator S3 includes an IDT electrode 130a and a resonator 130b. The IDT electrode 130a includes comb electrodes 132a and 132b, wherein the comb electrode 132a includes an electrode finger 133a and a bus bar 134a, and the comb electrode 132b includes an electrode finger 133b and a bus bar 134b. The bus bars 134a and 134b are inclined relative to the electrode fingers 133a and 133b.

[0119] Wiring 35 and wiring 36 are provided between resonator S3 and resonator P1. Wiring 35 connects the bus bar 134b of resonator S3 to other resonators besides resonator S3 and resonator P1—namely, resonator P2 and resonator S2 (see...). Figure 1 Electrical connection. On the wiring 35, on the side opposite to the electrode finger 133b on the side of the busbar 134b, that is, on the side opposite to the electrode finger 133b in the busbar 134b, a busbar adjacent part 35a is provided as the adjacent part of the first busbar.

[0120] like Figure 14 As shown, the busbar adjoining portion 35a on the resonator S3 side is indicated by a shading line. The busbar adjoining portion 35a is a part of the wiring 35, adjacent to the busbar 134b of the resonator S3, and extends from the busbar 134b in a direction perpendicular to the propagation direction (…). Figure 11 (Extending in the Y direction). The busbar adjoining portion 35a is a region within the wiring 35, which, when viewed from the orthogonal direction, has an area where the opposing busbars 214a and 134b overlap. Wiring 36 connects busbar 214a to resonators other than resonator S3 and resonator P1. Figure 1 As shown, S1 and S2 are electrically connected.

[0121] In wiring 36, a busbar adjacency portion 36a is provided, which is located on the side opposite to the electrode finger 213b connected to the busbar 214b, and on the side opposite to the electrode finger 233b in the busbar 134b.

[0122] exist Figure 14 In the diagram, the busbar adjoining portion 36a on the resonator P1 side is indicated by a slash. Busbar adjoining portion 36a is a part of the wiring 36, adjacent to busbar 214a, and extending from busbar 214a in a perpendicular direction (…). Figure 11 (In the Y direction) it extends. The adjacent part 36a of the busbar is located in the wiring 36, in the area that overlaps with the opposite busbars 214a and 134b in the orthogonal direction.

[0123] The busbar adjacent portion 35a of the wiring 35 on the S3 side of the resonator and the busbar adjacent portion 36a of the wiring 36 on the P1 side of the resonator are separated from each other and are arranged adjacent to each other at a distance D.

[0124] Busbar adjacent portions 35a and 36a have connecting side ends 35b and 36b and non-connecting side ends 35c and 36c respectively in the propagation direction. Connecting side ends 35b and 36b are electrically close to resonator S1 or resonator S2, which are other resonators (see...). Figure 1 The non-connection end 35c and 36c are the ends located on the opposite side of the connection end 35b and 36b in the propagation direction (X direction), that is, the ends that are electrically far away from other wiring, other resonators or pads and other components, that is, the ends that are not directly connected to other wiring.

[0125] The distance between resonators, i.e., the distance between busbar 134b on the resonator S3 side and busbar 214a on the resonator P1 side, is greater than the distance W2d in the orthogonal direction (Y direction) between busbar 134b and busbar 214a at the positions corresponding to the connecting ends 35b and 36b on the non-connecting ends 36c and 36c at the positions corresponding to the non-connecting ends 36c and 36c in the orthogonal direction. The distance in the orthogonal direction between the opposing busbars 134b and 214a, i.e., the total width in the orthogonal direction including the busbar connecting ends 35a, the gap D, and the busbar connecting ends 36a, is configured to gradually widen from the non-connecting ends 36c and 36c toward the connecting ends 35b and 36b (propagation direction).

[0126] Thus, the busbar abutment portions 35a and 36a adjacent to busbars 134b and 214a have a larger width at the connection-side ends 35b and 36b where a larger current flows, and a smaller width at the non-connection-side ends 35c and 36c where a larger current does not flow because they are not connected to other wiring. This reduces the overall resistance of the busbar abutment portions. Therefore, without increasing the area required for resonators P2 and P3, losses due to resistance are effectively reduced. Consequently, losses due to resistance throughout the entire elastic wave device 1 can be reduced.

[0127] At the non-connected end portions 35c and 36c in the propagation direction, the distance between busbar 134b and busbar 214a in the orthogonal direction (Y direction), i.e., the width W1d, is preferably one-third, more preferably one-quarter, of the distance W2d between busbar 134b and busbar 214a at the connected end portions 35b and 36b in the propagation direction (X direction). This is because a larger proportion of these widths can further reduce losses due to resistance.

[0128] <About Figure 15 Resonator and busbar adjacent section > Figure 15 This is a top view showing another example of a resonator and busbar adjacent portion disposed on a substrate 10 in an elastic wave device 1. Figure 15 The resonators S3A and P1A in the middle are Figure 14 A variation where the resonators are arranged differently due to their different positions in the propagation direction (X direction). For example... Figure 15As shown, resonator S3A, serving as the first resonator, and resonator P1A, serving as the second resonator, are arranged obliquely opposite each other in the orthogonal direction. Furthermore, resonators S3A and P1A are arranged in a staggered manner in the propagation direction (X direction). Figure 15 In the example of the resonator and busbar adjacent section shown, for the resonator and busbar adjacent section shown, for the example of ... Figure 14 Examples of resonators and busbar adjacent parts in the diagram have components with the same name and function, use the same reference numerals, and detailed descriptions are omitted.

[0129] Wiring 35 and wiring 36 are provided between resonator S3A and resonator P1A. Busbar adjacent portion 35a2 and busbar adjacent portion 36a2 are separately provided between resonator S3A and resonator P1A. Busbar adjacent portion 35a2 is a region in wiring 35, which is the area where opposing busbars 214a and 134b overlap in the orthogonal direction. Busbar adjacent portion 36a2 is a region in wiring 36, which is the area where opposing busbars 214a and 134b overlap in the orthogonal direction.

[0130] Wiring 35 and wiring 36 have connecting side ends 35b2 and 36b2, and non-connecting side ends 35c2 and 36c2, respectively, in the propagation direction. Connecting side ends 35b2 and 36b2 refer to the ends electrically close to other resonators or pads besides resonator S3A or resonator P1A. Non-connecting side ends 35c2 and 36c2 refer to the ends electrically far from other wirings, other resonators, or other components such as pads; that is, ends not directly connected to other wirings.

[0131] The distance between resonators, i.e., the distance between busbar 134b and busbar 214a, is wider than the distance W2e in the orthogonal direction (Y direction) at the propagation direction (X direction) positions of the connecting ends 35b2 and 36b2 of the adjacent busbar portions 35a2 and 36a2, which is greater than the distance W1e in the orthogonal direction at the propagation direction positions of the non-connecting ends 35c2 and 36c2. The orthogonal distance between busbar 134b and busbar 214a, i.e., the total width in the orthogonal direction including the adjacent busbar portion 35a2, the gap D, and the adjacent busbar portion 36a2, gradually (slowly) widens from the non-connecting ends 35b2 and 36b2 in the propagation direction toward the connecting ends 35c2 and 36c2.

[0132] Thus, in the busbar abutment portions 35a2 and 36a2 adjacent to busbars 134b and 214a, the width is increased at the connection-side ends 35b2 and 36b2 where relatively large current flows, and decreased at the non-connection-side ends 35c2 and 36c2 where almost no current flows due to lack of connection with other wiring. This reduces the overall resistance of the busbar abutment portions 35a2 and 36a2. Consequently, without increasing the substrate area required for resonators S3A and P1A, losses due to resistance can be reduced. Therefore, losses caused by electrical resistance throughout the entire elastic wave device 1 can be reduced.

[0133] At a position in the propagation direction, the distance, i.e., the width W1e, between busbar 134b and busbar 214a in the orthogonal direction (Y direction) between the non-connected ends 35c2 and 36c2 is preferably 1 / 3, more preferably 1 / 4, of the distance W2e between busbar 134b and busbar 214a in the orthogonal direction at the position of the connected ends 35b2 and 36b2 of the adjacent portions 35a2 and 36a2 in the propagation direction (X direction). This is because a larger ratio between the two can further reduce losses caused by resistance. Therefore, losses caused by electrical resistance throughout the entire elastic wave device 1 can be reduced.

[0134] <About Figure 16 The resonator and busbar adjacent section shown > Figure 16 This is a schematic plan view showing an example of a resonator with a stepped busbar and an adjacent portion of the busbar, disposed in an elastic wave device 1. Figure 16 As shown, the resonator 300 includes an IDT electrode 300a and a reflector 300b, and is connected to wiring 308 and wiring 309. The IDT electrode 300a has electrode fingers 307a and 307b in its comb-shaped electrode.

[0135] The IDT electrode 300a has stepped busbars 301a and 301b with steps in the orthogonal direction (Y direction). The stepped busbar 301a includes a first step 302a, a second step 303a, and a third step 304a. The stepped busbar 301b includes a first step 302b, a second step 303b, and a third step 304b. In this embodiment, the busbars 301a and 301b have a three-order structure, but the order can also be four or more, or a two-order structure.

[0136] In the region extending along the Y direction from the busbars 301a and 301b, wiring 308 and 309 are provided with busbar abutment portions 308a and 309a adjacent to these busbars 301a and 301b.

[0137] In the portions of busbars 308a and 309a adjacent to the first-order 302a and 302b, the second-order 303a and 303b, and the third-order 304a and 304b of busbars 301a and 301b, the widths in the orthogonal direction are W1f, W2f, and W3f, respectively, increasing in a step-like manner. Furthermore, the width of the connection-side ends 308b and 309b near other resonators or pads is W3f, which is greater than the width W1f of the non-connection-side ends 308c and 309c located on the opposite side to other resonators or pads.

[0138] In this way, the busbar adjacent portions 308a and 309a, which are adjacent to busbars 301a and 301b, have a larger width at the connection-side ends 308b and 309b where the current flows relatively large, and a smaller width at the non-connection-side ends 308c and 309c where the current is relatively small due to the absence of other wiring. This reduces the overall resistance of the busbar adjacent portions 308a and 309a. As a result, losses caused by resistance can be reduced without increasing the area required for the resonator 300 on the substrate.

[0139] In addition, in the adjacent portions 308a and 309a of the busbar, the width of one of them can be set to W1f, W2f and W3f respectively, and gradually increased in a stepped manner, while the other part can be designed with a different shape.

[0140] < Figure 17 The resonator and busbar adjacent section shown > Figure 17 This is a top view showing the resonator and the adjacent portion of the busbar in another example of an elastic wave device 1. (Example:) Figure 17 As shown, two resonators 400 and 500, each with a stepped busbar, are arranged opposite each other. Figure 17 As shown, the resonator 400 includes an IDT electrode 400a and a reflector 400b, and is connected to wiring 408 and wiring 600.

[0141] The IDT electrode 400a in the comb electrode includes electrode fingers 407 and busbars 401a and 401b. The IDT electrode 400a of the resonator 400 has busbars 401a and 401b with stepped steps in the orthogonal direction (Y direction). The stepped busbar 401a includes a first step 402a, a second step 403a, and a third step 404a. The stepped busbar 401b includes a first step 402b, a second step 403b, and a third step 404b.

[0142] The resonator 500 includes an IDT electrode 500a and a reflector 500b, and is connected to wiring 508 and wiring 600. The IDT electrode 500a includes electrode fingers 507 and busbars 501a and 501b in the comb electrode.

[0143] The IDT electrode 500a of the resonator 500 includes stepped busbars 501a and 501b with stepped steps in the orthogonal direction (Y direction). The stepped busbar 501a includes a first step 502a, a second step 503a, and a third step 504a. The stepped busbar 501b includes a first step 502b, a second step 503b, and a third step 504b.

[0144] In the region extending along the Y direction from busbars 401b and 501a, wiring 600 has a busbar abutment portion 600a adjacent to these busbars 401b and 501a.

[0145] In the portions of the busbar adjacent to the first 402b, 502a, the second 403b, 503a, and the third 404b, 504a of the busbars 401b and 501a, the width in the orthogonal direction increases in a stepped manner along the propagation direction (X direction) with W1g, W2g, and W3g respectively. Furthermore, the width of the connection side end 600b electrically close to other resonators or pads in the wiring path is W3g, while the width W1g of the non-connection side end 600c located on the side opposite to other resonators or pads is smaller than its width. Preferably, W1g is less than 1 / 3 of W3g, more preferably less than 1 / 4 of W3g. This is because the larger the ratio of W1g to W3g, the more significant the reduction in losses caused by electrical resistance.

[0146] The busbar adjoining portion 600a, which is configured in this way and adjacent to busbars 401b and 501a, has a larger width at the connection side end 600b, which carries a relatively large current, and a smaller width at the non-connection side end 600c, which is not connected to other wiring and therefore carries a smaller current. This reduces the electrical resistance of the entire busbar adjoining portion 600a. Therefore, in the elastic wave device equipped with resonators 400 and 500, losses due to electrical resistance can be reduced without increasing the area required for resonators 400 and 500.

[0147] <About Figure 18 The resonator and busbar adjacent part in the middle > As Figure 17 The example shown illustrates a variation in the positional relationship between resonators 400 and 500 in the propagation direction (X direction). Figure 18 A top view is shown of another example of the two resonators constituting the elastic wave device 1 and the adjacent portion of the busbar. Figure 18 In the example shown, resonators 400, 500 and busbar adjacent portion 601a, with Figure 17The resonators 400, 500 and the adjacent part of the busbar 600a that have the same name and function use the same symbol and their descriptions are omitted.

[0148] exist Figure 18 In this configuration, resonators 400 and 500 are arranged opposite each other in a perpendicular direction. The positions of resonators 400 and 500 in the propagation direction (X direction) are different from each other. A wiring 601 is provided between resonators 400 and 500.

[0149] In wiring 601, a busbar adjacency portion 601a is provided, which is located at the position where busbars 401b and 501a overlap (i.e., are in the same position in the X direction) when viewed from the orthogonal direction (Y direction), and extends in the region from busbar 401b toward busbar 501a in the orthogonal direction (Y direction). This busbar adjacency portion 601a is adjacent to busbars 401b and 501a.

[0150] The busbar adjacent portion 601a has a connecting side end 601b and a non-connecting side end 601c in the propagation direction. The connecting side end 601b is the end that is electrically closer to other resonators (i.e., resonators other than resonators 400 and 500) or pads in the wiring connection. The connecting side end 601b and the end 501d of the busbar 501a are located in the same position in the propagation direction (X direction).

[0151] The non-connection end 601c is the end located on the opposite side of the connection end 601b in the propagation direction (X direction). It is an end that is electrically far away from other wiring, other resonators, or other components such as pads; that is, the non-connection end 601c is an end that is not directly connected to other wiring. The non-connection end 601c is in the same position as the end 401c of the busbar 401b in the propagation direction (X direction).

[0152] In the portion of the busbar adjacent to the first step 402b, 502a, the second step 403b, 503a and the third step 404b, 504a of the busbars 401b and 501a, the width of the portion in the orthogonal direction gradually increases in a step-like manner along the propagation direction (X direction), namely W1h, W2h and W3h.

[0153] Furthermore, the width of the connection-side end 601b near other resonators or pads is W3h, while the width W1h of the non-connection-side end 601c located opposite to other resonators or pads is smaller than this width. W1h is preferably less than 1 / 3 of W3h, and more preferably less than 1 / 4 of W3h. This is because a larger ratio of W1h to W3h results in a more significant reduction in resistance-induced losses.

[0154] In this way, the overall resistance of the busbar adjacent portion 601a, which is adjacent to busbars 401b and 501a, can be reduced by making the width of the connection side end 601b, which carries a larger current, and the width of the non-connection side end 601c, which carries almost no current because it is not connected to other wiring, smaller. Therefore, in the elastic wave device equipped with resonators 400 and 500, the loss caused by resistance can be reduced without increasing the footprint required for resonators 400 and 500.

[0155] < Figure 19 The resonator and busbar adjacent section shown > Figure 19 A top view is shown of another embodiment of two resonators, with their busbars arranged in a stepped configuration, and the adjacent portion of the busbars, disposed in an elastic wave device. For... Figure 17 The parts with the same name and function as the resonator and busbar adjacent parts will be referred to by the same symbols below, and their descriptions will be omitted.

[0156] exist Figure 19 In this configuration, resonators 40 and 500 are arranged opposite each other along a perpendicular direction and are positioned identically in the propagation direction (X direction). Wiring 602 and wiring 603 are provided between resonators 400 and 500. Wiring 602 and wiring 603 are adjacent to each other, spaced apart by a distance D, and are not electrically directly connected.

[0157] Wiring 602 is electrically connected to busbar 401b and other resonators (i.e., resonators other than resonators 400 and 500) or pads not shown. Wiring 603 is electrically connected to busbar 501a and other resonators or pads not shown.

[0158] like Figure 19 As shown, busbar adjacent portions 602a and 603a are indicated by diagonal shading. In wiring 602, a first busbar adjacent portion 602a is provided in the region extending from busbar 401b in the Y direction, adjacent to busbar 401b.

[0159] In wiring 603, in the region extending from busbar 501a in the Y direction, there is a second busbar abutment portion 603a adjacent to busbar 501a.

[0160] The extent of the adjacent portions 602a and 603a of the busbars in the propagation direction (X direction) is the extent of the overlap between the busbars 401b and 501a when viewed from the orthogonal direction (Y direction) (i.e., the extent of the busbars in the same position in the X direction).

[0161] In this embodiment, the end 401c of busbar 401b and the end 501c of busbar 501a are at the same position in the propagation direction; in addition, the end 401d of busbar 401b and the end 501d of busbar 501a are also at the same position in the propagation direction.

[0162] The busbar adjoint portion 602a has a connecting end 602b and a non-connecting end 602c in the propagation direction (X direction). The connecting end 602b is the end electrically close to other resonators or pads besides the aforementioned resonators 400 and 500. The connecting end 602b is located in the same position as end 401d of the busbar 401b in the propagation direction. The non-connecting end 602c is the end located on the opposite side of the connecting end 602b in the propagation direction, that is, the end electrically farthest from other wiring, other resonators, or other components such as pads; in other words, it is the end not directly connected to other wiring. The non-connecting end 602c is located in the same position as end 401c of the busbar 401b in the propagation direction.

[0163] The busbar abutment portion 602a, which is adjacent to the first busbar, has a width that gradually increases in a stepped manner along the orthogonal direction in the regions of the first step 402b, the second step 403b, and the third step 404b of the busbar 401b, extending in the propagation direction (X direction). Furthermore, the connection side end 602b, located electrically closer to other resonators or pads, has a width in the orthogonal direction (Y direction) greater than that of the non-connection side end 602c, located on the opposite side to other resonators or pads.

[0164] As the adjacent part of the second busbar, the width of the busbar adjacent part 603a in the region of the first step 502a, the second step 503a and the third step 504a of the adjacent busbar 501a gradually increases in a step-like manner as the propagation direction (X direction) extends.

[0165] Furthermore, the width of the connection side end 603b, located on the side electrically closer to other resonators or pads, is greater than the width of the non-connection side end 603c, located on the opposite side to other resonators or pads.

[0166] exist Figure 19 In the middle, the width in the orthogonal direction between the adjacent parts 602a and 603a of the busbars, including the interval D between them, that is, the distance between the busbars 401b and 501a in the orthogonal direction (Y direction), gradually increases in a step-like manner from the first segment 402b, 502a to the second segment 403b, 503a and the third segment 404b, 504a along the propagation direction (X direction) as W1i, W2i and W3i respectively.

[0167] Furthermore, the total width of the busbar adjacent portions 602a and 603a, and their spacing D in the orthogonal direction (Y direction) is W3i at the connection-side end (i.e., the end located at the same position as end 401d of busbar 401a in the propagation direction) near other resonators or pads, and larger W1i at the non-connection-side end (i.e., the end located at the same position as end 401c of busbar 401a in the propagation direction) opposite other resonators or pads. Preferably, W1i is less than 1 / 3 of W3i, more preferably less than 1 / 4 of W3i. This is because the larger the ratio between W1i and W3i, the more significant the reduction in losses due to resistance.

[0168] As described above, the busbar abutment portions 602a and 603a adjacent to busbars 401b and 501a have their overall resistance reduced by making the width of the connection-side ends 602b and 603b, which carry relatively large currents, larger, and the width of the non-connection-side ends 602c and 603c, which carry smaller currents because they are not connected to other wiring. Therefore, in the elastic wave device equipped with resonators 400 and 500, losses due to resistance can be reduced without increasing the area occupied by resonators 400 and 500 on the substrate.

[0169] <About Figure 20 The resonator and busbar adjacent section shown > Figure 20 The diagram shown is a plan view of another example of a step-shaped busbar forming two resonators constituting an elastic wave device and the adjacent portion of the busbar. Figure 20 The example shown is of two resonators and the adjacent part of the busbar. Figure 19 A modified example where the positional relationship between the two resonators in the propagation direction is altered. Figure 20 In China, for the sake of Figure 19 Examples of resonators and busbar junctions shown have parts with the same name and function, which are referred to by the same reference numerals and their descriptions are omitted.

[0170] exist Figure 20 In this design, resonator 400, serving as the first resonator, and resonator 500, serving as the second resonator, are arranged opposite each other in a perpendicular direction. The positions of resonators 400 and 500 in the propagation direction (X-direction) are different from each other. Wiring 604 and wiring 605 are provided between resonators 400 and 500. Although wiring 604 and wiring 605 are arranged adjacent to each other, they are separated by a distance D and are not directly connected electrically.

[0171] Wiring 604 is electrically connected to bus 401 and other resonators (i.e., resonators other than resonators 400 and 500) or pads not shown. Wiring 605 is electrically connected to bus 501a and other resonators (i.e., resonators other than resonators 400 and 500) or pads not shown.

[0172] like Figure 20 As shown, busbar adjacent portion 604a and busbar adjacent portion 605a are indicated by diagonal shading. In wiring 604, in a region extending from busbar 401b in the Y direction, a busbar adjacent portion 604a is provided as a first busbar adjacent portion, which is adjacent to busbar 401b.

[0173] In wiring 605, in a region extending from busbar 501a in the Y direction, there is a busbar abutment portion 600a that serves as an abutment portion of the second busbar, and this portion is adjacent to busbar 501a.

[0174] The extent of the busbar adjacent portion 604a, which is adjacent to the first busbar, and the busbar adjacent portion 605a, which is adjacent to the second busbar, in the propagation direction (X direction) is the area where the busbars 401b and 501a overlap when viewed from the orthogonal direction (Y direction) (i.e., the part where the two are in the same position in the propagation direction).

[0175] In this example, busbar 401b has ends 401c and 401d in the propagation direction. Busbar 501a has ends 501c and 501d in the propagation direction.

[0176] Busbar adjoining portion 604a, serving as the adjoining portion of the first busbar, has a connecting side end 604b and a non-connecting side end 604c along the propagation direction. The connecting side end 604b is the end on the wiring path that is electrically close to the resonator or pad other than the aforementioned resonators 400 and 500, which are other resonators. The connecting side end 604b is located at the same position as the end 401d of busbar 401b in the propagation direction.

[0177] The non-connection end 604c of the busbar adjacent portion 604a is the end located on the opposite side of the connection end 604b in the propagation direction (X direction), and is electrically separated from other wiring, other resonators, or pads and other components. In other words, the non-connection end 604c is the end that is not directly connected to other wiring. This non-connection end 604c is located in the same position as the end 501c of the busbar 501a in the propagation direction.

[0178] The busbar adjacency portion 604a, which is adjacent to the first busbar, has a width in the orthogonal direction that gradually widens in a stepped manner along the propagation direction (X direction) at the portions adjacent to the first step 402b, second step 403b, and third step 404b of the busbar 401b. Furthermore, the connection side end 604b, which is electrically close to other resonators or pads in the wiring path, has a width in the orthogonal direction (Y direction) that is greater than the width of the non-connection side end 604c located on the opposite side.

[0179] Busbar adjoining portion 605a, serving as the adjoining portion of the second busbar, has a connecting side end 605b and a non-connecting side end 605c in the propagation direction. The connecting side end 605b is the end on the wiring path that is electrically close to the resonator or pad other than the aforementioned resonator 400 and resonator 500, which is another resonator. This connecting side end 605b is located at the same position as the end 401d of busbar 401b in the propagation direction.

[0180] The non-connection end 605c of the busbar adjacent portion 605a is the end located on the opposite side of the connection end 605b in the propagation direction, that is, the end that is electrically far away from other wiring, other resonators, or other components such as pads. In other words, the non-connection end 605c is the end that is not directly connected to other wiring. This non-connection end 605c is located at the same position as the end 501c of the busbar 501a in the propagation direction (X direction).

[0181] As the adjacent portion of the second busbar, the busbar adjacent portion 605a, in the portions adjacent to the first step 502a, the second step 503a, and the third step 504a of the busbar 501a, gradually widens in a stepped manner along the propagation direction (X direction). Furthermore, the width of the connection side end 605b near other resonators or pads is greater than the width of the non-connection side end 605c located on its opposite side.

[0182] exist Figure 20 In the diagram, the adjacent portions 604a and 605a of the busbars are separated by a distance D. The total width in the orthogonal direction formed by the adjacent portions 604a and 605a of the busbars and the distance D between them (i.e., the spacing between busbars 401b and 501a in the orthogonal direction) gradually increases in a stepped manner along the propagation direction (X direction), starting from the first steps 402b and 502a, and proceeding sequentially to the second steps 403b and 503a and the third steps 404b and 504a, respectively, as W1j, W2j, and W3j. It should be noted that the "distance between opposing busbars 401b and 501a in the orthogonal direction" refers to the "width between the ends of the adjacent portions 604a and 605a in the orthogonal direction".

[0183] Furthermore, including the interval D, the total width of the busbar adjacent portions 604a and 605a is W3j at the connecting end 604b and connecting end 605b (i.e., at the same position as end 401d of busbar 401a in the propagation direction), while the width W1j at the non-connecting end 604c and non-connecting end 605c (i.e., at the same position as end 401c of busbar 401a in the propagation direction) is less than W3j. Moreover, the width W1j is preferably less than 1 / 3 of W3j, more preferably less than 1 / 4 of W3j. This is because the larger the ratio of W1j to W3j, the more significant the reduction in resistance-induced loss.

[0184] As described above, the busbar abutment portions 604a and 605a adjacent to busbars 401b and 501a have their width increased at the connection-side ends 604b and 605b where a relatively large current flows, and their width reduced at the non-connection-side ends 604c and 605c where a smaller current flows due to their lack of connection with other wiring. This reduces the overall resistance of the busbar abutment portions 604a and 605a. Therefore, in the elastic wave device equipped with resonators 400 and 500, losses due to resistance can be reduced without increasing the area occupied by resonators 400 and 500 on the substrate.

[0185] While the embodiments described above use an elastic wave device with a stepped filter as an example, they can also be applied to other types of filters. For example, they can also be applied to a receiving filter with a DMS.

[0186] Furthermore, the illustrations used in the above description are schematic diagrams, and the dimensions, proportions, etc. shown in the diagrams may not necessarily be consistent with the actual product.

[0187] As described above, although the present invention has been explained, the present invention as an elastic wave device is not limited to the above embodiments in specific implementation. Various changes and additions can be made without departing from the spirit and scope of the present invention.

Claims

1. An elastic wave device characterized by, An elastic wave 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 between the pad and the plurality of resonators, wherein each of the plurality of resonators includes an IDT electrode having a pair of comb electrodes facing each other, the comb electrode includes a plurality of electrode fingers provided on the comb electrode, and a bus bar electrically connected to the plurality of electrode fingers; in a plan view, the bus bar abutment portion is provided on a side of the bus bar opposite to a side on which the electrode fingers are provided and adjacent to the side, and is located in a region extending in an orthogonal direction orthogonal to a direction of elastic wave propagation of the IDT electrode from the bus bar; the bus bar abutment portion has, in the direction of elastic wave propagation, a connection-side end portion toward the pad or another resonator and closer on the wiring, and a non-connection-side end portion opposite to the pad or another resonator; an orthogonal direction width of the bus bar abutment portion at the connection-side end portion is greater than an orthogonal direction width at the non-connection-side end portion; an orthogonal direction width of the bus bar abutment portion of the wiring in the direction of elastic wave propagation gradually increases or stepwise increases from the non-connection-side end portion toward the connection-side end portion.

2. The elastic wave device according to claim 1, wherein: in the plurality of resonators, one of the resonators is provided with two bus bars electrically connected to electrode fingers of the resonator and facing each other; the bus bar abutment portions abut the two bus bars, respectively; the two bus bar abutment portions each have: in the direction of elastic wave propagation, a connection-side end portion closer to a wiring connected to the pad or another resonator, and a non-connection-side end portion opposite to the pad and the other resonator; an orthogonal direction width at the connection-side end portion is greater than an orthogonal direction width at the non-connection-side end portion of the bus bar abutment portion; the two bus bar abutment portions each gradually increase or stepwise increase in the orthogonal direction width from the non-connection-side end portion toward the connection-side end portion of the bus bar.

3. The elastic wave device according to claim 1, wherein: in the plurality of resonators provided on the piezoelectric substrate, a first resonator and a second resonator are provided; the first resonator and the second resonator are arranged opposite to each other in an orthogonal direction so that a closest portion and a farthest portion are formed therebetween; the bus bar abutment portion is a wiring region for electrically connecting the first resonator and the second resonator; the bus bar abutment portion abuts a bus bar of the first resonator toward the second resonator and a bus bar of the second resonator toward the first resonator, and is a region in which the two bus bars overlap each other in the orthogonal direction view and a region extending in the orthogonal direction from the two bus bars. The bus bar abutment portion has: a portion that is farthest apart in an orthogonal direction between the first resonator and the second resonator, and is a connection-side end portion that is closer to the pad or other resonators than the first resonator and the second resonator provided on the piezoelectric substrate; and a portion that is closer in the orthogonal direction between the first resonator and the second resonator, and is a non-connection-side end portion that is opposite the pad or other resonators; The non-connection-side end portion of the bus bar abutment portion has a width in the orthogonal direction that is smaller than a width of the connection-side end portion in the orthogonal direction, and the width of the connection-side end portion in the orthogonal direction is greater than a width of the bus bar abutment portion in the non-connection-side end portion in the orthogonal direction, The width of the bus bar abutment portion gradually or stepwise increases from the non-connection-side end portion toward the connection-side end portion.

4. The elastic wave device according to claim 1, wherein: Among the plurality of resonators provided on the piezoelectric substrate, a first resonator and a second resonator that are opposite each other in a plan view are provided; As a bus bar abutment portion, there are provided: a first bus bar abutment portion that abuts a bus bar on the first resonator side of a bus bar that abuts the second resonator; a second bus bar abutment portion that abuts a bus bar on the second resonator side of a bus bar that abuts the first resonator; the first bus bar abutment portion and the second bus bar abutment portion are electrically insulated from each other; the first bus bar abutment portion and the second bus bar abutment portion are provided in wiring that extends from the bus bar on the second resonator side of the first resonator and the bus bar on the first resonator side of the second resonator, respectively, in regions that overlap each other in the orthogonal direction view; the first bus bar abutment portion that abuts the first resonator has a connection-side end portion and a non-connection-side end portion in the elastic wave propagation direction of the first resonator, the connection-side end portion is in a wiring region that is closer to a pad or other resonators provided on the piezoelectric substrate, and has a greater width in an orthogonal direction that is orthogonal to the propagation direction; the non-connection-side end portion is on a side opposite the pad or other resonators, and has a smaller width in the orthogonal direction; the width of the first bus bar abutment portion gradually increases or stepwise increases in the orthogonal direction from the non-connection-side end portion toward the connection-side end portion; the second bus bar abutment portion that abuts the second resonator has a connection-side end portion and a non-connection-side end portion in the elastic wave propagation direction of the second resonator; the connection-side end portion of the second bus bar abutment portion is in a wiring region that is closer to a pad or other resonators provided on the piezoelectric substrate, and has a greater width in an orthogonal direction that is orthogonal to the propagation direction; the non-connection-side end portion of the second bus bar abutment portion is on a side opposite the pad or other resonators, and has a smaller width in the orthogonal direction; The width of the second bus bar abutment portion in the orthogonal direction gradually increases or increases in steps from the non-connection side end portion toward the connection side end portion; In the propagation direction, the distance between the connection side end portion of the first bus bar abutment portion and the non-connection side end portion of the second bus bar abutment portion is closer than the distance between the connection side end portion of the first bus bar abutment portion and the connection side end portion of the second bus bar abutment portion. In the propagation direction, the distance between the non-connection side end portion of the first bus bar abutment portion and the connection side end portion of the second bus bar abutment portion is closer than the distance between the non-connection side end portion of the first bus bar abutment portion and the non-connection side end portion of the second bus bar abutment portion.

5. The elastic wave device according to any one of claims 1 to 4, wherein The bus bar is connected to the electrode fingers in a diagonal manner in a plan view.

6. The elastic wave device according to any one of claims 1 to 4, wherein The bus bar is formed in steps in a plan view.

7. The elastic wave device according to any one of claims 1 to 3, wherein The width of the bus bar abutment portion in the orthogonal direction at the non-connection side end portion is 1 / 3 or less of the width in the orthogonal direction at the connection side end portion.

8. The elastic wave device according to claim 4, wherein The first bus bar abutment portion and the second bus bar abutment portion are provided between the oppositely arranged bus bars, The total width in the orthogonal direction of the distance between the oppositely arranged bus bars, including the first bus bar abutment portion and the second bus bar abutment portion, is taken as a reference, The total width in the orthogonal direction of the first bus bar abutment portion and the second bus bar abutment portion at the non-connection side end portions is 1 / 3 or less of the total width in the orthogonal direction of the first bus bar abutment portion and the second bus bar abutment portion at the connection side end portions.

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

10. The elastic wave device according to claim 7, wherein The width of the bus bar abutment portion in the orthogonal direction at the non-connection side end portion is 1 / 4 or less of the width in the orthogonal direction at the connection side end portion.

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