WO2022065137A1 - Elastic wave device - Google Patents

Elastic wave device Download PDF

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Publication number
WO2022065137A1
WO2022065137A1 PCT/JP2021/033753 JP2021033753W WO2022065137A1 WO 2022065137 A1 WO2022065137 A1 WO 2022065137A1 JP 2021033753 W JP2021033753 W JP 2021033753W WO 2022065137 A1 WO2022065137 A1 WO 2022065137A1
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Prior art keywords
wiring
bus bar
elastic wave
idt electrode
width
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PCT/JP2021/033753
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French (fr)
Japanese (ja)
Inventor
祐也 平塚
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株式会社村田製作所
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Publication of WO2022065137A1 publication Critical patent/WO2022065137A1/en

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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
    • H03H9/02—Details
    • H03H9/125—Driving means, e.g. electrodes, coils
    • H03H9/145—Driving means, e.g. electrodes, coils for networks using surface acoustic waves

Definitions

  • the present invention relates to an elastic wave device.
  • Patent Document 1 describes an example of a surface acoustic wave filter.
  • This surface acoustic wave filter is a longitudinally coupled resonator type elastic wave filter and has a plurality of IDT (Interdigital Transducer) electrodes. Wiring is connected to one of the bus bars of the pair of bus bars of each IDT electrode. The wirings cross each other three-dimensionally via an insulating film. As a result, a three-dimensional crossing portion is formed. The frequency of the attenuation pole is adjusted by adjusting the capacitance by adjusting the width of the wiring at the flying junction.
  • IDT Interdigital Transducer
  • An object of the present invention is to provide an elastic wave device whose capacitance can be easily adjusted and whose insertion loss does not easily deteriorate.
  • the elastic wave device includes a piezoelectric substrate, an IDT electrode provided on the piezoelectric substrate and having a first bus bar and a second bus bar facing each other, and a plurality of electrode fingers.
  • the first wiring connected to the first bus bar, the insulating film laminated on the first wiring, and the insulating film laminated on the insulating film are electrically insulated from the first wiring.
  • the three-dimensional crossover portion is composed of the first wiring, the insulating film, and the second wiring, and when two or more natural numbers are n, n of the above are provided.
  • the first wiring is provided.
  • the capacitance can be easily adjusted and the insertion loss does not easily deteriorate.
  • FIG. 1 is a plan view of an elastic wave device according to a first embodiment of the present invention.
  • FIG. 2 is an enlarged view of FIG.
  • FIG. 3 is a plan view of the elastic wave device of the comparative example.
  • FIG. 4 is a diagram showing the attenuation frequency characteristics of the elastic wave device of the first embodiment of the present invention and the comparative example.
  • FIG. 5 is a schematic diagram of the first wiring and the first bus bar in the comparative example.
  • FIG. 6 is a schematic diagram of the first wiring and the first bus bar in the first embodiment of the present invention.
  • FIG. 7 is a schematic plan view of an elastic wave device according to a first modification of the first embodiment of the present invention.
  • FIG. 8 is a front sectional view showing the vicinity of a pair of electrode fingers of the first IDT electrode of the elastic wave device according to the second modification of the first embodiment of the present invention.
  • FIG. 1 is a plan view of an elastic wave device according to a first embodiment of the present invention.
  • FIG. 2 is an enlarged view of FIG.
  • the elastic wave device 1 of the present embodiment is used for a filter device, a multiplexer, and the like.
  • FIG. 1 shows a portion of the filter device in which the elastic wave device 1 is arranged.
  • the surface acoustic wave device 1 is a longitudinally coupled resonator type elastic wave filter and is an elastic surface wave device.
  • the elastic wave device according to the present invention is not limited to these.
  • the elastic wave device 1 has a piezoelectric substrate 2.
  • the piezoelectric substrate 2 is a piezoelectric substrate composed of only a piezoelectric layer.
  • the piezoelectric substrate 2 may be a laminated substrate including a piezoelectric layer.
  • the material of the piezoelectric layer for example, lithium tantalate, lithium niobate, zinc oxide, aluminum nitride, quartz, PZT (lead zirconate titanate) or the like can be used.
  • a plurality of IDT electrodes are provided on the piezoelectric substrate 2. More specifically, the plurality of IDT electrodes are a first IDT electrode 3A, a second IDT electrode 3B, a third IDT electrode 3C, a fourth IDT electrode 3D, and a fifth IDT electrode 3E. Elastic waves are excited by applying an AC voltage to each IDT electrode.
  • IDT electrodes are lined up along the elastic wave propagation direction. More specifically, in the elastic wave propagation direction, the first IDT electrode 3A among the plurality of IDT electrodes is located at the center. The second IDT electrode 3B and the third IDT electrode 3C are arranged so as to sandwich the first IDT electrode 3A. Further, a fourth IDT electrode 3D and a fifth IDT electrode 3E are arranged so as to sandwich the first IDT electrode 3A, the second IDT electrode 3B, and the third IDT electrode 3C.
  • a pair of reflectors 13A and 13Bs are provided on both sides of the plurality of IDT electrodes in the elastic wave propagation direction on the piezoelectric substrate 2.
  • the plurality of IDT electrodes and the pair of reflectors 13A and 13B may be made of a laminated metal film or may be made of a single layer metal film.
  • Each IDT electrode has a pair of bus bars and a plurality of electrode fingers.
  • a pair of busbars face each other.
  • the pair of busbars of the first IDT electrode 3A is the first busbar 4A and the second busbar 5A.
  • the plurality of electrode fingers of the first IDT electrode 3A are a plurality of first electrode fingers 6 and a plurality of second electrode fingers 7. One end of each of the plurality of first electrode fingers 6 is connected to the first bus bar 4A. One end of each of the plurality of second electrode fingers 7 is connected to the second bus bar 5A.
  • the plurality of first electrode fingers 6 and the plurality of second electrode fingers 7 are interleaved with each other.
  • the fourth IDT electrode 3D shown in FIG. 1 has a first bus bar 4D and a second bus bar 5D as a pair of bus bars.
  • the fifth IDT electrode 3E has a first bus bar 4E and a second bus bar 5E as a pair of bus bars.
  • Each first bus bar of the first IDT electrode 3A, the fourth IDT electrode 3D and the fifth IDT electrode 3E is electrically connected to the same signal potential.
  • each second bus bar of the first IDT electrode 3A, the fourth IDT electrode 3D and the fifth IDT electrode 3E is electrically connected to the ground potential.
  • the second bus bar is electrically connected to the ground potential via the second wiring 9b.
  • the pair of bus bars in the second IDT electrode 3B are the third bus bar 14B and the fourth bus bar 15B.
  • the pair of busbars in the third IDT electrode 3C are the third busbar 14C and the fourth busbar 15C.
  • one end of a part of the plurality of electrode fingers is connected to a third bus bar, respectively.
  • One end of the remaining part of the plurality of electrode fingers is connected to a fourth bus bar, respectively.
  • Each third bus bar of the second IDT electrode 3B and the third IDT electrode 3C is electrically connected to the ground potential.
  • the third bus bar is electrically connected to the ground potential via the second wiring 9a.
  • each fourth bus bar of the second IDT electrode 3B and the third IDT electrode 3C is electrically connected to the same signal potential.
  • a plurality of first wirings 8A are connected to the first bus bar 4A of the first IDT electrode 3A.
  • the first wiring is two wires.
  • n first wires may be provided.
  • the dimension along the elastic wave propagation direction of the first wiring 8A is defined as the width We of the first wiring 8A.
  • An insulating film 12 is laminated on the n first wirings 8A.
  • the insulating film 12 is made of an inorganic insulator, a resin, or the like.
  • the second wiring 9a is laminated on the insulating film 12.
  • the second wiring 9a is electrically isolated from the n first wirings 8A.
  • the n first wirings 8A and the second wirings 9a are three-dimensionally intersected with each other via the insulating film 12.
  • the three-dimensional crossing portion is composed of the n first wiring 8A, the insulating film 12, and the second wiring 9a.
  • the n first wirings 8A and the second wirings 9a face each other. Therefore, the flying junction functions as a capacitive element.
  • n first wirings 8A are provided, and n first wirings 8A form a flying junction together with the insulating film 12 and the second wiring 9a. There is something in it.
  • the width We of each of the first wirings 8A the facing areas of the first wirings 8A and the second wirings 9a at the flying junction can be easily adjusted. Therefore, the capacity can be easily adjusted.
  • the insertion loss is unlikely to deteriorate in this embodiment.
  • the comparative example differs from the present embodiment in that the first wiring 108 is only one.
  • the width of the first wiring 108 of the comparative example is the same as the total width We of the two first wirings 8A in the present embodiment.
  • FIG. 4 is a diagram showing the attenuation frequency characteristics of the elastic wave device of the first embodiment and the comparative example. In FIG. 4, it is shown that the insertion loss is smaller as the value on the vertical axis is located higher.
  • FIG. 5 is a schematic diagram of the first wiring and the first bus bar in the comparative example.
  • FIG. 6 is a schematic diagram of the first wiring and the first bus bar in the first embodiment.
  • the hatch in FIG. 5 indicates a region in the first bus bar 4A.
  • the dashed arrow E in FIGS. 5 and 6 schematically indicates the current.
  • the width of the first wiring 108 of the comparative example is 2We, which is twice the width We of the first wiring 8A of the first embodiment.
  • the distance from one end of the first bus bar 4A in the elastic wave propagation direction to the first wiring 108 is L1. Therefore, the maximum length of the current path from the first bus bar 4A to the first wiring 108 is L 1 .
  • the longer the current path the greater the electrical resistance.
  • the larger the electrical resistance the larger the insertion loss.
  • the current path from the hatched region in FIG. 5 to the first wiring 108 exceeds L 1/2 and is particularly long.
  • the distance from one end of the first bus bar 4A in the elastic wave propagation direction to the other first wiring 8A is L 1 /. It is 2.
  • the distance from the end portion to the first wiring 8A is the maximum distance from the first bus bar 4A to the first wiring 8A. Therefore, the maximum length of the current path from the first bus bar 4A to the first wiring 8A is L 1/2 .
  • the maximum length of the current path from the first bus bar 4A to the other first wiring 8A is also L 1/2 .
  • the maximum length of the current path in the first embodiment is shorter than the maximum length of the current path of the comparative example.
  • the path of the current from any position of the first bus bar 4A can be shortened. This makes it possible to substantially reduce the electrical resistance. Therefore, even if the width of the first wiring 8A is narrowed in order to adjust the capacitance, the insertion loss is unlikely to deteriorate.
  • the elastic wave device does not function as a filter.
  • the elastic wave device 1 is not easily damaged.
  • the first bus bar 4A has a plurality of openings 4d.
  • the plurality of openings 4d are arranged in the elastic wave propagation direction. More specifically, the first bus bar 4A has an inner bus bar portion 4a, an outer bus bar portion 4b, and a plurality of connection electrodes 4c.
  • the inner bus bar portion 4a and the outer bus bar portion 4b face each other in the direction in which the plurality of electrode fingers extend.
  • the plurality of connection electrodes 4c connect the inner bus bar portion 4a and the outer bus bar portion 4b.
  • the plurality of openings 4d are openings surrounded by an inner bus bar portion 4a, an outer bus bar portion 4b, and a plurality of connection electrodes 4c.
  • the second bus bar 5A also has an inner bus bar portion, an outer bus bar portion, a plurality of connection electrodes, and a plurality of openings.
  • the first bus bar 4A and the second bus bar 5A do not have to have a plurality of openings.
  • the dimension along the direction in which the plurality of electrode fingers of the first bus bar 4A extend is defined as the width Wb of the first bus bar 4A.
  • the width of the outer bus bar portion is defined as the width of the bus bar. It is preferable that the total width We of the n first wirings 8A at the flying junction is equal to or larger than the width Wb of the first bus bar 4A. In this case, the insertion loss is less likely to deteriorate.
  • the width We of the first wiring 8A at the flying junction is preferably Wb / n or less. In this case, the capacity can be adjusted to be even smaller. In this case as well, since the current path can be shortened as shown in FIG. 6, the insertion loss is unlikely to deteriorate. Therefore, the present invention is suitable when the width We of the first wiring 8A is narrow.
  • the width We of the first wiring 8A at the flying junction is preferably not more than the total film thickness of the electrodes, for example, 1 ⁇ m or more. As a result, the first wiring 8A is unlikely to be broken.
  • the width We of each first wiring 8A is the same. However, the width We of each of the first wirings 8A may be different from each other.
  • At least one first wiring 8A is located on one end side of the center of the first bus bar 4A in the elastic wave propagation direction, and at least one other first wiring 8A is the first. It is preferable that the bus bar 4A is located on the other end side of the center in the elastic wave propagation direction. Thereby, the current path can be suitably shortened.
  • n first wirings 8A, an insulating film 12 and a second wiring 9a are laminated in this order from the piezoelectric substrate 2 side.
  • the second wiring 9a, the insulating film 12, and n first wirings 8A may be laminated in this order from the piezoelectric substrate 2 side.
  • first wires 8A are connected to the signal potential, and the second wire 9a is connected to the ground potential.
  • the n first wirings 8A may be connected to the ground potential, and the second wiring 9a may be connected to the signal potential.
  • the third wiring 18 is connected to each of the second bus bars of the first IDT electrode 3A, the fourth IDT electrode 3D, and the fifth IDT electrode 3E. There is.
  • Each third wire 18 is connected to the second wire 9b.
  • the boundary between each bus bar and each third wiring 18 is shown by a alternate long and short dash line.
  • each second bus bar may be directly connected to the second wiring 9b.
  • the third wiring 18 is connected to each of the third bus bars of the second IDT electrode 3B and the third IDT electrode 3C.
  • Each third wire 18 is connected to the second wire 9a.
  • each third bus bar may be directly connected to the second wiring 9a.
  • n first wires are connected to bus bars connected to the signal potentials of all IDT electrodes.
  • two first wirings 8B are connected to the fourth bus bar 15B of the second IDT electrode 3B.
  • the flying junction is composed of two first wirings 8B, an insulating film 12 and a second wiring 9b.
  • the n first wires connected to the other IDT electrodes also form a flying junction together with the insulating film 12 and the second wire. Even at each flying junction, the capacitance can be easily adjusted and the insertion loss is unlikely to deteriorate.
  • it is sufficient that n first wires are connected to one bus bar of at least one IDT electrode. It suffices that the n first wirings together with the insulating film 12 and the second wiring form a three-dimensional crossing portion.
  • the width of the plurality of electrode fingers of each IDT electrode is widened near the end in the direction in which the plurality of electrode fingers extend.
  • the width of the plurality of electrode fingers may be constant.
  • the width of the electrode finger is a dimension along the elastic wave propagation direction of the electrode finger.
  • FIG. 7 is a schematic plan view of the elastic wave device according to the first modification of the first embodiment.
  • the widths of the plurality of first electrode fingers 26 and the plurality of second electrode fingers 27 of the first IDT electrode 23A are constant.
  • the first bus bar 24A and the second bus bar 25A of the first IDT electrode 23A do not have an opening. The same applies to each of the other IDT electrodes. Even in this case, the capacity can be easily adjusted and the insertion loss is unlikely to deteriorate.
  • the piezoelectric substrate 2 is composed of only a piezoelectric layer.
  • the piezoelectric substrate 2 may be a laminated substrate including a piezoelectric layer.
  • FIG. 8 is a front sectional view showing the vicinity of a pair of electrode fingers of the first IDT electrode of the elastic wave device according to the second modification of the first embodiment.
  • the piezoelectric substrate 32 has a support substrate 33, a high sound velocity film 34 as a high sound velocity material layer, a low sound velocity film 35, and a piezoelectric layer 36. More specifically, the high sound velocity film 34 is provided on the support substrate 33. A low sound velocity film 35 is provided on the high sound velocity film 34. The piezoelectric layer 36 is provided on the low sound velocity film 35.
  • the low sound velocity film 35 is a relatively low sound velocity film. More specifically, the speed of sound of the bulk wave propagating in the bass velocity film 35 is lower than the speed of sound of the bulk wave propagating in the piezoelectric layer 36.
  • the material of the low sound velocity film 35 for example, a material containing glass, silicon oxide, silicon nitride, lithium oxide, tantalum pentoxide, or a compound obtained by adding fluorine, carbon, or boron to silicon oxide as a main component is used. Can be done.
  • the high sound velocity material layer is a relatively high sound velocity layer. More specifically, the sound velocity of the bulk wave propagating in the high-pitched material layer is higher than the sound velocity of the elastic wave propagating in the piezoelectric layer 36.
  • the material of the high-pitched material layer include silicon, aluminum oxide, silicon carbide, silicon nitride, silicon oxynitride, sapphire, lithium tantalate, lithium niobate, crystal, alumina, zirconia, cordierite, mulite, steatite, and the like.
  • a medium containing the above materials as a main component such as forsterite, magnesia, a DLC (diamond-like carbon) film, or diamond, can be used.
  • Examples of the material of the support substrate 33 include piezoelectric materials such as aluminum oxide, lithium tantalate, lithium niobate, and crystal, alumina, sapphire, magnesia, silicon nitride, aluminum nitride, silicon carbide, zirconia, cordierite, mulite, and steer.
  • Various ceramics such as tight and forsterite, dielectrics such as diamond and glass, semiconductors or resins such as silicon and gallium nitride can be used.
  • the piezoelectric substrate 32 of the second modification the high sound velocity material layer, the low sound velocity film 35, and the piezoelectric layer 36 are laminated. Thereby, the energy of the elastic wave can be effectively confined on the piezoelectric layer 36 side.
  • the capacitance can be easily adjusted and the insertion loss is less likely to deteriorate.
  • the high sound velocity material layer may be a high sound velocity support substrate.
  • the piezoelectric substrate may be a laminated substrate of a high sound velocity support substrate, a low sound velocity film 35, and a piezoelectric layer 36.
  • the piezoelectric layer 36 is indirectly provided on the high sound velocity material layer.
  • the piezoelectric layer 36 may be provided directly on the high sound velocity material layer.
  • the piezoelectric substrate may be a laminated substrate having no low sound velocity film 35.
  • the piezoelectric substrate may be a laminated substrate of a high sound velocity support substrate and a piezoelectric layer 36.
  • the piezoelectric substrate may be a laminated substrate of the support substrate 33, the high sound velocity film 34, and the piezoelectric layer 36. Even in these cases, the energy of the elastic wave can be effectively confined on the piezoelectric layer 36 side. In addition, the capacity can be easily adjusted and the insertion loss is less likely to deteriorate.
  • a laminate of the piezoelectric layer 36 and the acoustic reflection film may be formed.
  • the acoustic reflection film includes at least one low acoustic impedance layer and at least one high acoustic impedance layer.
  • the low acoustic impedance layer is a layer having a relatively low acoustic impedance.
  • the high acoustic impedance layer is a layer having a relatively high acoustic impedance.
  • the low acoustic impedance layer and the high acoustic impedance layer are laminated alternately. Even in this case, the energy of the elastic wave can be effectively confined on the piezoelectric layer 36 side. Further, as in the first embodiment, the capacity can be easily adjusted and the insertion loss is less likely to deteriorate.

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  • Physics & Mathematics (AREA)
  • Acoustics & Sound (AREA)
  • Surface Acoustic Wave Elements And Circuit Networks Thereof (AREA)

Abstract

Provided is an elastic wave device which can easily adjust the capacity thereof and has an insertion loss that is not easily degraded.　This elastic wave device 1 comprises: a piezoelectric substrate 2; a first busbar 4A and a second bus bar which are provided on the piezoelectric substrate 2 and face each other; a first IDT electrode 3A having a plurality of first and second electrode fingers 6, 7; first wiring 8A connected to the first busbar 4A; an insulating film 12 laminated on the first wiring 8A; and second wiring 9a which is laminated on the insulating film 12 and electrically insulated from the first wiring 8A. A three-dimensional crossing section is constituted by the first wiring 8A, the insulating film 12, and the second wiring 9a. When n is a natural number no less than 2, n pieces of first wiring 8A are provided.

Description

弾性波装置Elastic wave device
　本発明は、弾性波装置に関する。 The present invention relates to an elastic wave device.
　従来、弾性波装置は携帯電話機のフィルタなどに広く用いられている。下記の特許文献１には、弾性表面波フィルタの一例が記載されている。この弾性表面波フィルタは縦結合共振子型弾性波フィルタであり、複数のＩＤＴ（Ｉｎｔｅｒｄｉｇｉｔａｌ　Ｔｒａｎｓｄｕｃｅｒ）電極を有する。各ＩＤＴ電極の１対のバスバーのうち一方のバスバーには、それぞれ配線が接続されている。上記配線同士は絶縁膜を介して立体的に交叉している。これにより、立体交叉部が構成されている。立体交叉部における配線の幅の調整によって容量の調整を行うことにより、減衰極の周波数の調整が図られている。 Conventionally, elastic wave devices have been widely used for filters of mobile phones and the like. The following Patent Document 1 describes an example of a surface acoustic wave filter. This surface acoustic wave filter is a longitudinally coupled resonator type elastic wave filter and has a plurality of IDT (Interdigital Transducer) electrodes. Wiring is connected to one of the bus bars of the pair of bus bars of each IDT electrode. The wirings cross each other three-dimensionally via an insulating film. As a result, a three-dimensional crossing portion is formed. The frequency of the attenuation pole is adjusted by adjusting the capacitance by adjusting the width of the wiring at the flying junction.
特開２０１９－１０６６２２号公報Japanese Unexamined Patent Publication No. 2019-106622
　特許文献１の弾性表面波フィルタにおいて、容量を小さくする場合には、立体交叉部における配線の幅を狭くする必要がある。しかしながら、この場合には、配線抵抗が大きくなり挿入損失が大きくなるおそれがある。 In the surface acoustic wave filter of Patent Document 1, when the capacitance is to be reduced, it is necessary to narrow the width of the wiring at the flying junction. However, in this case, the wiring resistance may increase and the insertion loss may increase.
　本発明の目的は、容量を容易に調整することができ、かつ挿入損失が劣化し難い、弾性波装置を提供することにある。 An object of the present invention is to provide an elastic wave device whose capacitance can be easily adjusted and whose insertion loss does not easily deteriorate.
　本発明に係る弾性波装置は、圧電性基板と、前記圧電性基板上に設けられており、対向し合う第１のバスバー及び第２のバスバーと、複数の電極指とを有するＩＤＴ電極と、前記第１のバスバーに接続されている第１の配線と、前記第１の配線に積層されている絶縁膜と、前記絶縁膜に積層されており、前記第１の配線と電気的に絶縁されている第２の配線とを備え、前記第１の配線、前記絶縁膜及び前記第２の配線により立体交叉部が構成されており、２以上の自然数をｎとしたときに、ｎ本の前記第１の配線が設けられている。 The elastic wave device according to the present invention includes a piezoelectric substrate, an IDT electrode provided on the piezoelectric substrate and having a first bus bar and a second bus bar facing each other, and a plurality of electrode fingers. The first wiring connected to the first bus bar, the insulating film laminated on the first wiring, and the insulating film laminated on the insulating film are electrically insulated from the first wiring. The three-dimensional crossover portion is composed of the first wiring, the insulating film, and the second wiring, and when two or more natural numbers are n, n of the above are provided. The first wiring is provided.
　本発明に係る弾性波装置によれば、容量を容易に調整することができ、かつ挿入損失が劣化し難い。 According to the elastic wave device according to the present invention, the capacitance can be easily adjusted and the insertion loss does not easily deteriorate.
図１は、本発明の第１の実施形態に係る弾性波装置の平面図である。FIG. 1 is a plan view of an elastic wave device according to a first embodiment of the present invention. 図２は、図１を拡大した図である。FIG. 2 is an enlarged view of FIG. 図３は、比較例の弾性波装置の平面図である。FIG. 3 is a plan view of the elastic wave device of the comparative example. 図４は、本発明の第１の実施形態及び比較例の弾性波装置の減衰量周波数特性を示す図である。FIG. 4 is a diagram showing the attenuation frequency characteristics of the elastic wave device of the first embodiment of the present invention and the comparative example. 図５は、比較例における第１の配線及び第１のバスバーの模式図である。FIG. 5 is a schematic diagram of the first wiring and the first bus bar in the comparative example. 図６は、本発明の第１の実施形態における第１の配線及び第１のバスバーの模式図である。FIG. 6 is a schematic diagram of the first wiring and the first bus bar in the first embodiment of the present invention. 図７は、本発明の第１の実施形態の第１の変形例に係る弾性波装置の模式的平面図である。FIG. 7 is a schematic plan view of an elastic wave device according to a first modification of the first embodiment of the present invention. 図８は、本発明の第１の実施形態の第２の変形例に係る弾性波装置の第１のＩＤＴ電極の１対の電極指付近を示す正面断面図である。FIG. 8 is a front sectional view showing the vicinity of a pair of electrode fingers of the first IDT electrode of the elastic wave device according to the second modification of the first embodiment of the present invention.
　以下、図面を参照しつつ、本発明の具体的な実施形態を説明することにより、本発明を明らかにする。 Hereinafter, the present invention will be clarified by explaining a specific embodiment of the present invention with reference to the drawings.
　なお、本明細書に記載の各実施形態は、例示的なものであり、異なる実施形態間において、構成の部分的な置換または組み合わせが可能であることを指摘しておく。 It should be noted that each of the embodiments described herein is exemplary and that partial substitutions or combinations of configurations are possible between different embodiments.
　図１は、本発明の第１の実施形態に係る弾性波装置の平面図である。図２は、図１を拡大した図である。 FIG. 1 is a plan view of an elastic wave device according to a first embodiment of the present invention. FIG. 2 is an enlarged view of FIG.
　本実施形態の弾性波装置１は、フィルタ装置やマルチプレクサなどに用いられる。図１は、フィルタ装置における弾性波装置１が配置されている部分を示す。弾性波装置１は縦結合共振子型弾性波フィルタであり、かつ弾性表面波装置である。もっとも、本発明に係る弾性波装置はこれらに限定されるものではない。 The elastic wave device 1 of the present embodiment is used for a filter device, a multiplexer, and the like. FIG. 1 shows a portion of the filter device in which the elastic wave device 1 is arranged. The surface acoustic wave device 1 is a longitudinally coupled resonator type elastic wave filter and is an elastic surface wave device. However, the elastic wave device according to the present invention is not limited to these.
　弾性波装置１は圧電性基板２を有する。本実施形態においては、圧電性基板２は圧電体層のみからなる圧電基板である。もっとも、圧電性基板２は、圧電体層を含む積層基板であってもよい。圧電体層の材料としては、例えば、タンタル酸リチウム、ニオブ酸リチウム、酸化亜鉛、窒化アルミニウム、水晶、またはＰＺＴ（チタン酸ジルコン酸鉛）などを用いることができる。 The elastic wave device 1 has a piezoelectric substrate 2. In the present embodiment, the piezoelectric substrate 2 is a piezoelectric substrate composed of only a piezoelectric layer. However, the piezoelectric substrate 2 may be a laminated substrate including a piezoelectric layer. As the material of the piezoelectric layer, for example, lithium tantalate, lithium niobate, zinc oxide, aluminum nitride, quartz, PZT (lead zirconate titanate) or the like can be used.
　圧電性基板２上には複数のＩＤＴ電極が設けられている。より具体的には、上記複数のＩＤＴ電極は、第１のＩＤＴ電極３Ａ、第２のＩＤＴ電極３Ｂ、第３のＩＤＴ電極３Ｃ、第４のＩＤＴ電極３Ｄ及び第５のＩＤＴ電極３Ｅである。各ＩＤＴ電極に交流電圧を印加することにより、弾性波が励振される。 A plurality of IDT electrodes are provided on the piezoelectric substrate 2. More specifically, the plurality of IDT electrodes are a first IDT electrode 3A, a second IDT electrode 3B, a third IDT electrode 3C, a fourth IDT electrode 3D, and a fifth IDT electrode 3E. Elastic waves are excited by applying an AC voltage to each IDT electrode.
　複数のＩＤＴ電極は弾性波伝搬方向に沿って並んでいる。より具体的には、弾性波伝搬方向において、複数のＩＤＴ電極のうち第１のＩＤＴ電極３Ａが中央に位置する。第１のＩＤＴ電極３Ａを挟むように、第２のＩＤＴ電極３Ｂ及び第３のＩＤＴ電極３Ｃが配置されている。さらに、第１のＩＤＴ電極３Ａ、第２のＩＤＴ電極３Ｂ及び第３のＩＤＴ電極３Ｃを挟むように、第４のＩＤＴ電極３Ｄ及び第５のＩＤＴ電極３Ｅが配置されている。圧電性基板２上における、複数のＩＤＴ電極の弾性波伝搬方向両側には、１対の反射器１３Ａ及び反射器１３Ｂが設けられている。複数のＩＤＴ電極及び１対の反射器１３Ａ及び反射器１３Ｂは、積層金属膜からなっていてもよく、単層の金属膜からなっていてもよい。 Multiple IDT electrodes are lined up along the elastic wave propagation direction. More specifically, in the elastic wave propagation direction, the first IDT electrode 3A among the plurality of IDT electrodes is located at the center. The second IDT electrode 3B and the third IDT electrode 3C are arranged so as to sandwich the first IDT electrode 3A. Further, a fourth IDT electrode 3D and a fifth IDT electrode 3E are arranged so as to sandwich the first IDT electrode 3A, the second IDT electrode 3B, and the third IDT electrode 3C. A pair of reflectors 13A and 13Bs are provided on both sides of the plurality of IDT electrodes in the elastic wave propagation direction on the piezoelectric substrate 2. The plurality of IDT electrodes and the pair of reflectors 13A and 13B may be made of a laminated metal film or may be made of a single layer metal film.
　各ＩＤＴ電極は、１対のバスバーと、複数の電極指とを有する。１対のバスバーは対向し合っている。第１のＩＤＴ電極３Ａの１対のバスバーは、第１のバスバー４Ａ及び第２のバスバー５Ａである。第１のＩＤＴ電極３Ａの複数の電極指は、図２に示すように、複数の第１の電極指６及び複数の第２の電極指７である。複数の第１の電極指６の一端は、それぞれ第１のバスバー４Ａに接続されている。複数の第２の電極指７の一端は、それぞれ第２のバスバー５Ａに接続されている。複数の第１の電極指６及び複数の第２の電極指７は互いに間挿し合っている。 Each IDT electrode has a pair of bus bars and a plurality of electrode fingers. A pair of busbars face each other. The pair of busbars of the first IDT electrode 3A is the first busbar 4A and the second busbar 5A. As shown in FIG. 2, the plurality of electrode fingers of the first IDT electrode 3A are a plurality of first electrode fingers 6 and a plurality of second electrode fingers 7. One end of each of the plurality of first electrode fingers 6 is connected to the first bus bar 4A. One end of each of the plurality of second electrode fingers 7 is connected to the second bus bar 5A. The plurality of first electrode fingers 6 and the plurality of second electrode fingers 7 are interleaved with each other.
　同様に、図１に示す第４のＩＤＴ電極３Ｄは、１対のバスバーとしての第１のバスバー４Ｄ及び第２のバスバー５Ｄを有する。第５のＩＤＴ電極３Ｅは、１対のバスバーとしての第１のバスバー４Ｅ及び第２のバスバー５Ｅを有する。第１のＩＤＴ電極３Ａ、第４のＩＤＴ電極３Ｄ及び第５のＩＤＴ電極３Ｅの各第１のバスバーは同じ信号電位に電気的に接続される。他方、第１のＩＤＴ電極３Ａ、第４のＩＤＴ電極３Ｄ及び第５のＩＤＴ電極３Ｅの各第２のバスバーはグラウンド電位に電気的に接続される。なお、上記各第２のバスバーは、第２の配線９ｂを介して、グラウンド電位に電気的に接続される。 Similarly, the fourth IDT electrode 3D shown in FIG. 1 has a first bus bar 4D and a second bus bar 5D as a pair of bus bars. The fifth IDT electrode 3E has a first bus bar 4E and a second bus bar 5E as a pair of bus bars. Each first bus bar of the first IDT electrode 3A, the fourth IDT electrode 3D and the fifth IDT electrode 3E is electrically connected to the same signal potential. On the other hand, each second bus bar of the first IDT electrode 3A, the fourth IDT electrode 3D and the fifth IDT electrode 3E is electrically connected to the ground potential. The second bus bar is electrically connected to the ground potential via the second wiring 9b.
　図１に示すように、第２のＩＤＴ電極３Ｂにおける１対のバスバーは第３のバスバー１４Ｂ及び第４のバスバー１５Ｂである。第３のＩＤＴ電極３Ｃにおける１対のバスバーは第３のバスバー１４Ｃ及び第４のバスバー１５Ｃである。各ＩＤＴ電極において、複数の電極指のうち一部の一端は、それぞれ第３のバスバーに接続されている。複数の電極指のうち残りの一部の一端は、それぞれ第４のバスバーに接続されている。第２のＩＤＴ電極３Ｂ及び第３のＩＤＴ電極３Ｃの各第３のバスバーはグラウンド電位に電気的に接続される。なお、上記各第３のバスバーは、第２の配線９ａを介して、グラウンド電位に電気的に接続される。他方、第２のＩＤＴ電極３Ｂ及び第３のＩＤＴ電極３Ｃの各第４のバスバーは同じ信号電位に電気的に接続される。 As shown in FIG. 1, the pair of bus bars in the second IDT electrode 3B are the third bus bar 14B and the fourth bus bar 15B. The pair of busbars in the third IDT electrode 3C are the third busbar 14C and the fourth busbar 15C. In each IDT electrode, one end of a part of the plurality of electrode fingers is connected to a third bus bar, respectively. One end of the remaining part of the plurality of electrode fingers is connected to a fourth bus bar, respectively. Each third bus bar of the second IDT electrode 3B and the third IDT electrode 3C is electrically connected to the ground potential. The third bus bar is electrically connected to the ground potential via the second wiring 9a. On the other hand, each fourth bus bar of the second IDT electrode 3B and the third IDT electrode 3C is electrically connected to the same signal potential.
　第１のＩＤＴ電極３Ａの第１のバスバー４Ａには、複数本の第１の配線８Ａが接続されている。本実施形態においては、第１の配線は２本である。もっとも、２以上の自然数をｎとしたときに、ｎ本の第１の配線が設けられていればよい。なお、図２に示すように、第１の配線８Ａの弾性波伝搬方向に沿う寸法を、第１の配線８Ａの幅Ｗｅとする。ｎ本の第１の配線８Ａには、絶縁膜１２が積層されている。絶縁膜１２は、無機の絶縁体または樹脂などからなる。 A plurality of first wirings 8A are connected to the first bus bar 4A of the first IDT electrode 3A. In this embodiment, the first wiring is two wires. However, when n is a natural number of 2 or more, n first wires may be provided. As shown in FIG. 2, the dimension along the elastic wave propagation direction of the first wiring 8A is defined as the width We of the first wiring 8A. An insulating film 12 is laminated on the n first wirings 8A. The insulating film 12 is made of an inorganic insulator, a resin, or the like.
　絶縁膜１２には、上記第２の配線９ａが積層されている。第２の配線９ａは、ｎ本の第１の配線８Ａと電気的に絶縁されている。ｎ本の第１の配線８Ａと、第２の配線９ａとは、絶縁膜１２を介して立体的に交叉している。これにより、ｎ本の第１の配線８Ａ、絶縁膜１２及び第２の配線９ａによって、立体交叉部が構成されている。立体交叉部においては、ｎ本の第１の配線８Ａと、第２の配線９ａとが対向し合っている。よって、立体交叉部は容量素子として機能する。 The second wiring 9a is laminated on the insulating film 12. The second wiring 9a is electrically isolated from the n first wirings 8A. The n first wirings 8A and the second wirings 9a are three-dimensionally intersected with each other via the insulating film 12. As a result, the three-dimensional crossing portion is composed of the n first wiring 8A, the insulating film 12, and the second wiring 9a. At the flying junction, the n first wirings 8A and the second wirings 9a face each other. Therefore, the flying junction functions as a capacitive element.
　本実施形態の特徴は、ｎ本の第１の配線８Ａが設けられており、かつｎ本の第１の配線８Ａが、絶縁膜１２及び第２の配線９ａと共に立体交叉部を構成していることにある。各第１の配線８Ａの幅Ｗｅを調整することにより、立体交叉部における各第１の配線８Ａ及び第２の配線９ａの対向面積を容易に調整することができる。よって、容量を容易に調整することができる。 The feature of this embodiment is that n first wirings 8A are provided, and n first wirings 8A form a flying junction together with the insulating film 12 and the second wiring 9a. There is something in it. By adjusting the width We of each of the first wirings 8A, the facing areas of the first wirings 8A and the second wirings 9a at the flying junction can be easily adjusted. Therefore, the capacity can be easily adjusted.
　加えて、本実施形態においては挿入損失が劣化し難い。この詳細を、本実施形態と比較例とを比較することにより示す。図３に示すように、比較例は、第１の配線１０８が１本のみである点において本実施形態と異なる。比較例の第１の配線１０８の幅は、本実施形態における２本の第１の配線８Ａの幅Ｗｅの合計と同じである。 In addition, the insertion loss is unlikely to deteriorate in this embodiment. This detail will be shown by comparing this embodiment with a comparative example. As shown in FIG. 3, the comparative example differs from the present embodiment in that the first wiring 108 is only one. The width of the first wiring 108 of the comparative example is the same as the total width We of the two first wirings 8A in the present embodiment.
　図４は、第１の実施形態及び比較例の弾性波装置の減衰量周波数特性を示す図である。図４においては、縦軸の値が上方に位置するほど挿入損失が小さいことを示す。 FIG. 4 is a diagram showing the attenuation frequency characteristics of the elastic wave device of the first embodiment and the comparative example. In FIG. 4, it is shown that the insertion loss is smaller as the value on the vertical axis is located higher.
　図４に示すように、第１の実施形態においては、比較例よりも挿入損失が小さいことがわかる。この理由を図５及び図６を参照して説明する。 As shown in FIG. 4, it can be seen that in the first embodiment, the insertion loss is smaller than that in the comparative example. The reason for this will be described with reference to FIGS. 5 and 6.
　図５は、比較例における第１の配線及び第１のバスバーの模式図である。図６は、第１の実施形態における第１の配線及び第１のバスバーの模式図である。図５中のハッチングは、第１のバスバー４Ａ中の領域を示す。図５及び図６中の破線の矢印Ｅは電流を模式的に示す。 FIG. 5 is a schematic diagram of the first wiring and the first bus bar in the comparative example. FIG. 6 is a schematic diagram of the first wiring and the first bus bar in the first embodiment. The hatch in FIG. 5 indicates a region in the first bus bar 4A. The dashed arrow E in FIGS. 5 and 6 schematically indicates the current.
　図５に示すように、比較例の第１の配線１０８の幅は、第１の実施形態の第１の配線８Ａの幅Ｗｅの２倍である２Ｗｅである。第１のバスバー４Ａの弾性波伝搬方向における一方端部から第１の配線１０８までの距離は、Ｌ１である。よって、第１のバスバー４Ａから第１の配線１０８までの、電流の経路の最大の長さはＬ１である。電流の経路が長い分、電気抵抗は大きくなる。そして、電気抵抗が大きいほど、挿入損失は大きくなる。例えば、図５中のハッチングで示す領域から第１の配線１０８までの電流の経路は、Ｌ１／２を超えており、特に長い。 As shown in FIG. 5, the width of the first wiring 108 of the comparative example is 2We, which is twice the width We of the first wiring 8A of the first embodiment. The distance from one end of the first bus bar 4A in the elastic wave propagation direction to the first wiring 108 is L1. Therefore, the maximum length of the current path from the first bus bar 4A to the first wiring 108 is L 1 . The longer the current path, the greater the electrical resistance. The larger the electrical resistance, the larger the insertion loss. For example, the current path from the hatched region in FIG. 5 to the first wiring 108 exceeds L 1/2 and is particularly long.
　これに対して、図６に示すように、第１の実施形態においては、第１のバスバー４Ａの弾性波伝搬方向における一方端部から、一方の第１の配線８Ａまで距離は、Ｌ１／２である。なお、第１の実施形態では、上記端部から上記第１の配線８Ａまでの距離が、第１のバスバー４Ａから上記第１の配線８Ａまでの最大の距離である。そのため、第１のバスバー４Ａから上記第１の配線８Ａまでの、電流の経路の最大の長さはＬ１／２である。同様にして、第１のバスバー４Ａから他方の第１の配線８Ａまでの、電流の経路の最大の長さもＬ１／２である。このように、第１の実施形態における電流の経路の最大の長さは、比較例の電流の経路の最大の長さよりも短い。よって、第１のバスバー４Ａのいずれの位置からの電流の経路も短くすることができる。これにより、電気抵抗を実質的に低くすることができる。よって、容量を調整するために、第１の配線８Ａの幅を狭くしたとしても、挿入損失が劣化し難い。 On the other hand, as shown in FIG. 6, in the first embodiment, the distance from one end of the first bus bar 4A in the elastic wave propagation direction to the other first wiring 8A is L 1 /. It is 2. In the first embodiment, the distance from the end portion to the first wiring 8A is the maximum distance from the first bus bar 4A to the first wiring 8A. Therefore, the maximum length of the current path from the first bus bar 4A to the first wiring 8A is L 1/2 . Similarly, the maximum length of the current path from the first bus bar 4A to the other first wiring 8A is also L 1/2 . Thus, the maximum length of the current path in the first embodiment is shorter than the maximum length of the current path of the comparative example. Therefore, the path of the current from any position of the first bus bar 4A can be shortened. This makes it possible to substantially reduce the electrical resistance. Therefore, even if the width of the first wiring 8A is narrowed in order to adjust the capacitance, the insertion loss is unlikely to deteriorate.
　さらに、比較例においては、第１の配線１０８が断線すると、弾性波装置がフィルタとして機能しなくなる。これに対して、第１の実施形態においては、ｎ本の第１の配線８Ａのうち１本の第１の配線８Ａが断線したとしても、他の第１の配線８Ａにより信号を流すことができる。よって、弾性波装置１が破損し難い。 Further, in the comparative example, if the first wiring 108 is broken, the elastic wave device does not function as a filter. On the other hand, in the first embodiment, even if one of the n first wirings 8A is disconnected, a signal can be passed through the other first wiring 8A. can. Therefore, the elastic wave device 1 is not easily damaged.
　ところで、図２に示すように、本実施形態においては、第１のバスバー４Ａは、複数の開口部４ｄを有する。複数の開口部４ｄは弾性波伝搬方向に並んでいる。より具体的には、第１のバスバー４Ａは、内側バスバー部４ａ、外側バスバー部４ｂ及び複数の接続電極４ｃを有する。内側バスバー部４ａ及び外側バスバー部４ｂは、複数の電極指が延びる方向において対向し合っている。複数の接続電極４ｃは、内側バスバー部４ａ及び外側バスバー部４ｂを接続している。複数の開口部４ｄは、内側バスバー部４ａ、外側バスバー部４ｂ及び複数の接続電極４ｃにより囲まれた開口部である。第２のバスバー５Ａも同様に、内側バスバー部、外側バスバー部、複数の接続電極及び複数の開口部を有する。なお、第１のバスバー４Ａ及び第２のバスバー５Ａは、複数の開口部を有していなくともよい。 By the way, as shown in FIG. 2, in the present embodiment, the first bus bar 4A has a plurality of openings 4d. The plurality of openings 4d are arranged in the elastic wave propagation direction. More specifically, the first bus bar 4A has an inner bus bar portion 4a, an outer bus bar portion 4b, and a plurality of connection electrodes 4c. The inner bus bar portion 4a and the outer bus bar portion 4b face each other in the direction in which the plurality of electrode fingers extend. The plurality of connection electrodes 4c connect the inner bus bar portion 4a and the outer bus bar portion 4b. The plurality of openings 4d are openings surrounded by an inner bus bar portion 4a, an outer bus bar portion 4b, and a plurality of connection electrodes 4c. The second bus bar 5A also has an inner bus bar portion, an outer bus bar portion, a plurality of connection electrodes, and a plurality of openings. The first bus bar 4A and the second bus bar 5A do not have to have a plurality of openings.
　ここで、第１のバスバー４Ａの複数の電極指が延びる方向に沿う寸法を第１のバスバー４Ａの幅Ｗｂとする。なお、本明細書においては、バスバーが上記のように複数の開口部を有する場合には、外側バスバー部の幅をバスバーの幅とする。立体交叉部におけるｎ本の第１の配線８Ａの幅Ｗｅの合計が第１のバスバー４Ａの幅Ｗｂ以上であることが好ましい。この場合には、挿入損失がより一層劣化し難い。 Here, the dimension along the direction in which the plurality of electrode fingers of the first bus bar 4A extend is defined as the width Wb of the first bus bar 4A. In the present specification, when the bus bar has a plurality of openings as described above, the width of the outer bus bar portion is defined as the width of the bus bar. It is preferable that the total width We of the n first wirings 8A at the flying junction is equal to or larger than the width Wb of the first bus bar 4A. In this case, the insertion loss is less likely to deteriorate.
　あるいは、上記に限らず、立体交叉部における第１の配線８Ａの幅Ｗｅは、Ｗｂ／ｎ以下であることが好ましい。この場合には、容量をより一層小さくするように調整することができる。なお、この場合にも、図６に示したように電流の経路を短くすることができるため、挿入損失が劣化し難い。よって、第１の配線８Ａの幅Ｗｅが狭い場合には、本発明が好適である。他方、立体交叉部における第１の配線８Ａの幅Ｗｅは、電極の総膜厚以上、例えば１μｍ以上であることが好ましい。それによって、第１の配線８Ａが断線し難い。 Alternatively, not limited to the above, the width We of the first wiring 8A at the flying junction is preferably Wb / n or less. In this case, the capacity can be adjusted to be even smaller. In this case as well, since the current path can be shortened as shown in FIG. 6, the insertion loss is unlikely to deteriorate. Therefore, the present invention is suitable when the width We of the first wiring 8A is narrow. On the other hand, the width We of the first wiring 8A at the flying junction is preferably not more than the total film thickness of the electrodes, for example, 1 μm or more. As a result, the first wiring 8A is unlikely to be broken.
　本実施形態においては、各第１の配線８Ａの幅Ｗｅは同じである。もっとも、各第１の配線８Ａの幅Ｗｅは互いに異なっていてもよい。 In this embodiment, the width We of each first wiring 8A is the same. However, the width We of each of the first wirings 8A may be different from each other.
　少なくとも１本の第１の配線８Ａが、第１のバスバー４Ａの弾性波伝搬方向における中央よりも一方端部側に位置し、かつ他の少なくとも１本の第１の配線８Ａが、第１のバスバー４Ａの弾性波伝搬方向における中央よりも他方端部側に位置していることが好ましい。それによって、電流の経路を好適に短くすることができる。 At least one first wiring 8A is located on one end side of the center of the first bus bar 4A in the elastic wave propagation direction, and at least one other first wiring 8A is the first. It is preferable that the bus bar 4A is located on the other end side of the center in the elastic wave propagation direction. Thereby, the current path can be suitably shortened.
　本実施形態では、圧電性基板２側から、ｎ本の第１の配線８Ａ、絶縁膜１２及び第２の配線９ａの順序において積層されている。もっとも、圧電性基板２側から、第２の配線９ａ、絶縁膜１２及びｎ本の第１の配線８Ａの順序において積層されていてもよい。 In this embodiment, n first wirings 8A, an insulating film 12 and a second wiring 9a are laminated in this order from the piezoelectric substrate 2 side. However, the second wiring 9a, the insulating film 12, and n first wirings 8A may be laminated in this order from the piezoelectric substrate 2 side.
　ｎ本の第１の配線８Ａは信号電位に接続され、第２の配線９ａはグラウンド電位に接続される。なお、ｎ本の第１の配線８Ａがグラウンド電位に接続され、第２の配線９ａが信号電位に接続されてもよい。 The n first wires 8A are connected to the signal potential, and the second wire 9a is connected to the ground potential. The n first wirings 8A may be connected to the ground potential, and the second wiring 9a may be connected to the signal potential.
　図１に示すように、本実施形態では、第１のＩＤＴ電極３Ａ、第４のＩＤＴ電極３Ｄ及び第５のＩＤＴ電極３Ｅの各第２のバスバーに、それぞれ第３の配線１８が接続されている。各第３の配線１８が第２の配線９ｂに接続されている。図１においては、各バスバーと各第３の配線１８の境界を一点鎖線により示す。もっとも、各第２のバスバーは、第２の配線９ｂに直接的に接続されていてもよい。 As shown in FIG. 1, in the present embodiment, the third wiring 18 is connected to each of the second bus bars of the first IDT electrode 3A, the fourth IDT electrode 3D, and the fifth IDT electrode 3E. There is. Each third wire 18 is connected to the second wire 9b. In FIG. 1, the boundary between each bus bar and each third wiring 18 is shown by a alternate long and short dash line. However, each second bus bar may be directly connected to the second wiring 9b.
　同様に、第２のＩＤＴ電極３Ｂ及び第３のＩＤＴ電極３Ｃの各第３のバスバーに、それぞれ第３の配線１８が接続されている。各第３の配線１８が第２の配線９ａに接続されている。もっとも、各第３のバスバーは、第２の配線９ａに直接的に接続されていてもよい。 Similarly, the third wiring 18 is connected to each of the third bus bars of the second IDT electrode 3B and the third IDT electrode 3C. Each third wire 18 is connected to the second wire 9a. However, each third bus bar may be directly connected to the second wiring 9a.
　ところで、図１に示すように、弾性波装置１においては、全てのＩＤＴ電極の信号電位に接続されるバスバーに、それぞれｎ本の第１の配線が接続されている。例えば、第２のＩＤＴ電極３Ｂの第４のバスバー１５Ｂには、２本の第１の配線８Ｂが接続されている。２本の第１の配線８Ｂ、絶縁膜１２及び第２の配線９ｂにより立体交叉部が構成されている。他の各ＩＤＴ電極に接続されたｎ本の第１の配線も、絶縁膜１２及び第２の配線と共に、立体交叉部を構成している。各立体交叉部においても、容量を容易に調整することができ、かつ挿入損失が劣化し難い。もっとも、少なくとも１個のＩＤＴ電極の一方のバスバーに、ｎ本の第１の配線が接続されていればよい。該ｎ本の第１の配線が、絶縁膜１２及び第２の配線と共に立体交叉部を構成していればよい。 By the way, as shown in FIG. 1, in the elastic wave device 1, n first wires are connected to bus bars connected to the signal potentials of all IDT electrodes. For example, two first wirings 8B are connected to the fourth bus bar 15B of the second IDT electrode 3B. The flying junction is composed of two first wirings 8B, an insulating film 12 and a second wiring 9b. The n first wires connected to the other IDT electrodes also form a flying junction together with the insulating film 12 and the second wire. Even at each flying junction, the capacitance can be easily adjusted and the insertion loss is unlikely to deteriorate. However, it is sufficient that n first wires are connected to one bus bar of at least one IDT electrode. It suffices that the n first wirings together with the insulating film 12 and the second wiring form a three-dimensional crossing portion.
　第１の実施形態においては、各ＩＤＴ電極の複数の電極指の幅は、複数の電極指が延びる方向の端部付近において広くなっている。もっとも、複数の電極指の幅は一定であってもよい。なお、電極指の幅は、電極指の弾性波伝搬方向に沿う寸法である。 In the first embodiment, the width of the plurality of electrode fingers of each IDT electrode is widened near the end in the direction in which the plurality of electrode fingers extend. However, the width of the plurality of electrode fingers may be constant. The width of the electrode finger is a dimension along the elastic wave propagation direction of the electrode finger.
　図７は、第１の実施形態の第１の変形例に係る弾性波装置の模式的平面図である。 FIG. 7 is a schematic plan view of the elastic wave device according to the first modification of the first embodiment.
　第１の実施形態の第１の変形例では、第１のＩＤＴ電極２３Ａの複数の第１の電極指２６及び複数の第２の電極指２７の幅は一定である。第１のＩＤＴ電極２３Ａの第１のバスバー２４Ａ及び第２のバスバー２５Ａは開口部を有しない。他の各ＩＤＴ電極においても同様である。この場合においても、容量を容易に調整することができ、かつ挿入損失が劣化し難い。 In the first modification of the first embodiment, the widths of the plurality of first electrode fingers 26 and the plurality of second electrode fingers 27 of the first IDT electrode 23A are constant. The first bus bar 24A and the second bus bar 25A of the first IDT electrode 23A do not have an opening. The same applies to each of the other IDT electrodes. Even in this case, the capacity can be easily adjusted and the insertion loss is unlikely to deteriorate.
　図１に示す第１の実施形態においては、圧電性基板２は圧電体層のみからなる。もっとも、上述したように、圧電性基板２は、圧電体層を含む積層基板であってもよい。 In the first embodiment shown in FIG. 1, the piezoelectric substrate 2 is composed of only a piezoelectric layer. However, as described above, the piezoelectric substrate 2 may be a laminated substrate including a piezoelectric layer.
　図８は、第１の実施形態の第２の変形例に係る弾性波装置の第１のＩＤＴ電極の１対の電極指付近を示す正面断面図である。 FIG. 8 is a front sectional view showing the vicinity of a pair of electrode fingers of the first IDT electrode of the elastic wave device according to the second modification of the first embodiment.
　第１の実施形態の第２の変形例では、圧電性基板３２は、支持基板３３と、高音速材料層としての高音速膜３４と、低音速膜３５と、圧電体層３６とを有する。より具体的には、支持基板３３上に高音速膜３４が設けられている。高音速膜３４上に低音速膜３５が設けられている。低音速膜３５上に圧電体層３６が設けられている。 In the second modification of the first embodiment, the piezoelectric substrate 32 has a support substrate 33, a high sound velocity film 34 as a high sound velocity material layer, a low sound velocity film 35, and a piezoelectric layer 36. More specifically, the high sound velocity film 34 is provided on the support substrate 33. A low sound velocity film 35 is provided on the high sound velocity film 34. The piezoelectric layer 36 is provided on the low sound velocity film 35.
　低音速膜３５は相対的に低音速な膜である。より具体的には、低音速膜３５を伝搬するバルク波の音速は、圧電体層３６を伝搬するバルク波の音速よりも低い。低音速膜３５の材料としては、例えば、ガラス、酸化ケイ素、酸窒化ケイ素、酸化リチウム、五酸化タンタル、または、酸化ケイ素にフッ素、炭素やホウ素を加えた化合物を主成分とする材料を用いることができる。 The low sound velocity film 35 is a relatively low sound velocity film. More specifically, the speed of sound of the bulk wave propagating in the bass velocity film 35 is lower than the speed of sound of the bulk wave propagating in the piezoelectric layer 36. As the material of the low sound velocity film 35, for example, a material containing glass, silicon oxide, silicon nitride, lithium oxide, tantalum pentoxide, or a compound obtained by adding fluorine, carbon, or boron to silicon oxide as a main component is used. Can be done.
　高音速材料層は、相対的に高音速な層である。より具体的には、高音速材料層を伝搬するバルク波の音速は、圧電体層３６を伝搬する弾性波の音速よりも高い。高音速材料層の材料としては、例えば、シリコン、酸化アルミニウム、炭化ケイ素、窒化ケイ素、酸窒化ケイ素、サファイア、タンタル酸リチウム、ニオブ酸リチウム、水晶、アルミナ、ジルコニア、コージライト、ムライト、ステアタイト、フォルステライト、マグネシア、ＤＬＣ（ダイヤモンドライクカーボン）膜またはダイヤモンドなど、上記材料を主成分とする媒質を用いることができる。 The high sound velocity material layer is a relatively high sound velocity layer. More specifically, the sound velocity of the bulk wave propagating in the high-pitched material layer is higher than the sound velocity of the elastic wave propagating in the piezoelectric layer 36. Examples of the material of the high-pitched material layer include silicon, aluminum oxide, silicon carbide, silicon nitride, silicon oxynitride, sapphire, lithium tantalate, lithium niobate, crystal, alumina, zirconia, cordierite, mulite, steatite, and the like. A medium containing the above materials as a main component, such as forsterite, magnesia, a DLC (diamond-like carbon) film, or diamond, can be used.
　支持基板３３の材料としては、例えば、酸化アルミニウム、タンタル酸リチウム、ニオブ酸リチウム、水晶などの圧電体、アルミナ、サファイア、マグネシア、窒化ケイ素、窒化アルミニウム、炭化ケイ素、ジルコニア、コージライト、ムライト、ステアタイト、フォルステライトなどの各種セラミック、ダイヤモンド、ガラスなどの誘電体、シリコン、窒化ガリウムなどの半導体または樹脂などを用いることができる。 Examples of the material of the support substrate 33 include piezoelectric materials such as aluminum oxide, lithium tantalate, lithium niobate, and crystal, alumina, sapphire, magnesia, silicon nitride, aluminum nitride, silicon carbide, zirconia, cordierite, mulite, and steer. Various ceramics such as tight and forsterite, dielectrics such as diamond and glass, semiconductors or resins such as silicon and gallium nitride can be used.
　第２の変形例の圧電性基板３２においては、高音速材料層と、低音速膜３５と、圧電体層３６とが積層されている。それによって、弾性波のエネルギーを圧電体層３６側に効果的に閉じ込めることができる。加えて、第１の実施形態と同様に、容量を容易に調整することができ、かつ挿入損失が劣化し難い。 In the piezoelectric substrate 32 of the second modification, the high sound velocity material layer, the low sound velocity film 35, and the piezoelectric layer 36 are laminated. Thereby, the energy of the elastic wave can be effectively confined on the piezoelectric layer 36 side. In addition, as in the first embodiment, the capacitance can be easily adjusted and the insertion loss is less likely to deteriorate.
　なお、高音速材料層は高音速支持基板であってもよい。この場合には、圧電性基板は、高音速支持基板と、低音速膜３５と、圧電体層３６との積層基板であってもよい。ここで、第２の変形例においては、圧電体層３６は、高音速材料層上に間接的に設けられている。もっとも、圧電体層３６は、高音速材料層上に直接的に設けられていてもよい。圧電性基板は低音速膜３５を有しない積層基板であってもよい。この場合には、圧電性基板は、高音速支持基板と圧電体層３６との積層基板であってもよい。あるいは、圧電性基板は、支持基板３３と、高音速膜３４と、圧電体層３６との積層基板であってもよい。これらの場合においても、弾性波のエネルギーを圧電体層３６側に効果的に閉じ込めることができる。加えて、容量を容易に調整することができ、かつ挿入損失が劣化し難い。 The high sound velocity material layer may be a high sound velocity support substrate. In this case, the piezoelectric substrate may be a laminated substrate of a high sound velocity support substrate, a low sound velocity film 35, and a piezoelectric layer 36. Here, in the second modification, the piezoelectric layer 36 is indirectly provided on the high sound velocity material layer. However, the piezoelectric layer 36 may be provided directly on the high sound velocity material layer. The piezoelectric substrate may be a laminated substrate having no low sound velocity film 35. In this case, the piezoelectric substrate may be a laminated substrate of a high sound velocity support substrate and a piezoelectric layer 36. Alternatively, the piezoelectric substrate may be a laminated substrate of the support substrate 33, the high sound velocity film 34, and the piezoelectric layer 36. Even in these cases, the energy of the elastic wave can be effectively confined on the piezoelectric layer 36 side. In addition, the capacity can be easily adjusted and the insertion loss is less likely to deteriorate.
　なお、圧電体層３６と音響反射膜との積層体が構成されていてもよい。音響反射膜は、少なくとも１層の低音響インピーダンス層及び少なくとも１層の高音響インピーダンス層を含む。低音響インピーダンス層は、相対的に音響インピーダンスが低い層である。高音響インピーダンス層は、相対的に音響インピーダンスが高い層である。低音響インピーダンス層及び高音響インピーダンス層は交互に積層されている。この場合においても、弾性波のエネルギーを圧電体層３６側に効果的に閉じ込めることができる。さらに、第１の実施形態と同様に、容量を容易に調整することができ、かつ挿入損失が劣化し難い。 A laminate of the piezoelectric layer 36 and the acoustic reflection film may be formed. The acoustic reflection film includes at least one low acoustic impedance layer and at least one high acoustic impedance layer. The low acoustic impedance layer is a layer having a relatively low acoustic impedance. The high acoustic impedance layer is a layer having a relatively high acoustic impedance. The low acoustic impedance layer and the high acoustic impedance layer are laminated alternately. Even in this case, the energy of the elastic wave can be effectively confined on the piezoelectric layer 36 side. Further, as in the first embodiment, the capacity can be easily adjusted and the insertion loss is less likely to deteriorate.
１…弾性波装置
２…圧電性基板
３Ａ～３Ｅ…第１～第５のＩＤＴ電極
４Ａ，４Ｄ，４Ｅ…第１のバスバー
４ａ…内側バスバー部
４ｂ…外側バスバー部
４ｃ…接続電極
４ｄ…開口部
５Ａ，５Ｄ，５Ｅ…第２のバスバー
６，７…第１，第２の電極指
８Ａ，８Ｂ…第１の配線
９ａ，９ｂ…第２の配線
１２…絶縁膜
１３Ａ，１３Ｂ…反射器
１４Ｂ，１４Ｃ…第３のバスバー
１５Ｂ，１５Ｃ…第４のバスバー
１８…第３の配線
２３Ａ…第１のＩＤＴ電極
２４Ａ，２５Ａ…第１，第２のバスバー
２６，２７…第１，第２の電極指
３２…圧電性基板
３３…支持基板
３４…高音速膜
３５…低音速膜
３６…圧電体層
１０８…第１の配線 1 ... Elastic wave device 2 ... Conductive substrates 3A to 3E ... First to fifth IDT electrodes 4A, 4D, 4E ... First bus bar 4a ... Inner bus bar portion 4b ... Outer bus bar portion 4c ... Connection electrode 4d ... Opening 5A, 5D, 5E ... 2nd bus bar 6,7 ... 1st, 2nd electrode fingers 8A, 8B ... 1st wiring 9a, 9b ... 2nd wiring 12 ... Insulating film 13A, 13B ... Reflector 14B, 14C ... 3rd bus bar 15B, 15C ... 4th bus bar 18 ... 3rd wiring 23A ... 1st IDT electrode 24A, 25A ... 1st, 2nd bus bar 26, 27 ... 1st, 2nd electrode finger 32 ... piezoelectric substrate 33 ... support substrate 34 ... high-pitched speed film 35 ... low-pitched speed film 36 ... piezoelectric layer 108 ... first wiring

Claims (4)

  1. 　圧電性基板と、
    　前記圧電性基板上に設けられており、対向し合う第１のバスバー及び第２のバスバーと、複数の電極指と、を有するＩＤＴ電極と、
    　前記第１のバスバーに接続されている第１の配線と、
    　前記第１の配線に積層されている絶縁膜と、
    　前記絶縁膜に積層されており、前記第１の配線と電気的に絶縁されている第２の配線と、
    を備え、
    　前記第１の配線、前記絶縁膜及び前記第２の配線により立体交叉部が構成されており、
    　２以上の自然数をｎとしたときに、ｎ本の前記第１の配線が設けられている、弾性波装置。     Piezoelectric board and
    An IDT electrode provided on the piezoelectric substrate and having a first bus bar and a second bus bar facing each other, and a plurality of electrode fingers.
    The first wiring connected to the first bus bar and
    The insulating film laminated on the first wiring and
    A second wiring laminated on the insulating film and electrically insulated from the first wiring,
    Equipped with
    The three-dimensional crossing portion is composed of the first wiring, the insulating film, and the second wiring.
    An elastic wave device provided with n lines of the first wiring, where n is a natural number of 2 or more.
  2. 　前記第１の配線の弾性波伝搬方向に沿う寸法を前記第１の配線の幅Ｗｅとし、前記第１のバスバーの前記複数の電極指が延びる方向に沿う寸法を前記第１のバスバーの幅Ｗｂとしたときに、前記立体交叉部におけるｎ本の前記第１の配線の幅Ｗｅの合計が、前記第１のバスバーの幅Ｗｂ以上である、請求項１に記載の弾性波装置。 The dimension along the elastic wave propagation direction of the first wiring is defined as the width We of the first wiring, and the dimension along the direction in which the plurality of electrode fingers of the first bus bar extends is the width Wb of the first bus bar. The elastic wave device according to claim 1, wherein the total width We of n wires at the three-dimensional crossing portion is equal to or larger than the width Wb of the first bus bar.
  3. 　前記第１の配線の弾性波伝搬方向に沿う寸法を前記第１の配線の幅Ｗｅとし、前記第１のバスバーの前記複数の電極指が延びる方向に沿う寸法を前記第１のバスバーの幅Ｗｂとしたときに、前記立体交叉部における各前記第１の配線の幅Ｗｅが、Ｗｂ／ｎ以下である、請求項１に記載の弾性波装置。 The dimension along the elastic wave propagation direction of the first wiring is defined as the width We of the first wiring, and the dimension along the direction in which the plurality of electrode fingers of the first bus bar extends is the width Wb of the first bus bar. The elastic wave device according to claim 1, wherein the width We of each of the first wirings in the three-dimensional crossing portion is Wb / n or less.
  4. 　縦結合共振子型弾性波フィルタであり、
    　前記ＩＤＴ電極が第１のＩＤＴ電極であり、
    　前記圧電性基板上に設けられており、対向し合う第３のバスバー及び第４のバスバーと、複数の電極指と、を有する第２のＩＤＴ電極をさらに備え、
    　前記第２の配線が前記第３のバスバーに電気的に接続されている、請求項１～３のいずれか１項に記載の弾性波装置。     It is a longitudinally coupled resonator type elastic wave filter.
    The IDT electrode is the first IDT electrode, and the IDT electrode is the first IDT electrode.
    A second IDT electrode provided on the piezoelectric substrate and having a third bus bar and a fourth bus bar facing each other and a plurality of electrode fingers is further provided.
    The elastic wave device according to any one of claims 1 to 3, wherein the second wiring is electrically connected to the third bus bar.
PCT/JP2021/033753 2020-09-28 2021-09-14 Elastic wave device WO2022065137A1 (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2024098786A1 (en) * 2022-11-09 2024-05-16 华为技术有限公司 Surface acoustic wave resonator, filter, and electronic device

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JP2007259023A (en) * 2006-03-23 2007-10-04 Matsushita Electric Ind Co Ltd Surface acoustic wave filter and communication instrument using the same
WO2010150882A1 (en) * 2009-06-26 2010-12-29 京セラ株式会社 Surface acoustic wave filter and branching filter using same
WO2019123811A1 (en) * 2017-12-19 2019-06-27 株式会社村田製作所 Elastic wave device

Patent Citations (3)

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Publication number Priority date Publication date Assignee Title
JP2007259023A (en) * 2006-03-23 2007-10-04 Matsushita Electric Ind Co Ltd Surface acoustic wave filter and communication instrument using the same
WO2010150882A1 (en) * 2009-06-26 2010-12-29 京セラ株式会社 Surface acoustic wave filter and branching filter using same
WO2019123811A1 (en) * 2017-12-19 2019-06-27 株式会社村田製作所 Elastic wave device

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2024098786A1 (en) * 2022-11-09 2024-05-16 华为技术有限公司 Surface acoustic wave resonator, filter, and electronic device

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