WO2023219134A1 - Elastic wave device - Google Patents

Abstract

An elastic wave device according to the present disclosure comprises: a package substrate; and an elastic wave element that is bonded to a main surface of the package substrate with a plurality of electrically conductive bumps interposed therebetween, the elastic wave element having one or more resonators and wiring that is electrically connected to the resonators. The plurality of electrically conductive bumps comprise one or more first bumps, and a second bump that is surrounded by at least one of at least one first bump and at least one resonator as seen in an orthogonal direction that is orthogonal to the main surface of the package substrate. On the package substrate, there is formed an electrically conductive pattern that is electrically connected to the second bump. As seen in the orthogonal direction, the electrically conductive pattern extends from the second bump, across at least one of a resonator and the wiring, from the inside of the first bump and the resonator surrounding the second bump toward the outside.

Description

elastic wave device

The present disclosure relates to an acoustic wave device having a piezoelectric layer.

For example, Patent Document 1 discloses an elastic wave device that uses plate waves. The elastic wave device described in Patent Document 1 includes a support, a piezoelectric substrate, and an IDT electrode. The support body is provided with a cavity. The piezoelectric substrate is provided on the support body so as to overlap with the cavity. The IDT electrode is provided on the piezoelectric substrate so as to overlap with the cavity. In an elastic wave device, a plate wave is excited by an IDT electrode.

Japanese Patent Application Publication No. 2012-257019

In recent years, there has been a demand for elastic wave devices that can suppress deterioration of characteristics.

An object of the present disclosure is to provide an elastic wave device that can suppress deterioration of characteristics.

An elastic wave device according to one aspect of the present disclosure includes:
a package board;
an acoustic wave element bonded to the main surface of the package substrate via a plurality of conductive bumps and having one or more resonators and wiring electrically connected to the resonators;
The plurality of conductive bumps are
one or more first bumps;
a second bump surrounded by at least one of at least one of the first bump and at least one of the resonators when viewed from an orthogonal direction perpendicular to the main surface of the package substrate;
A conductive pattern electrically connected to the second bump is formed on the package substrate,
Viewed from the orthogonal direction, the conductive pattern extends from the second bump, straddles at least one of the resonator and the wiring, and surrounds the second bump from the inside to the outside of the first bump and the resonator. It extends to

According to the present disclosure, it is possible to provide an elastic wave device that can suppress deterioration of characteristics.

A schematic perspective view showing the appearance of the elastic wave device of the first and second aspects Plan view showing the electrode structure on the piezoelectric layer A cross-sectional view of the portion along line AA in Figure 1A A schematic front sectional view for explaining Lamb waves propagating through a piezoelectric film of a conventional acoustic wave device. A schematic front sectional view for explaining waves of the elastic wave device of the present disclosure A schematic diagram showing a bulk wave when a voltage is applied between the first electrode and the second electrode such that the second electrode has a higher potential than the first electrode. A diagram showing resonance characteristics of an elastic wave device according to a first embodiment of the present disclosure A diagram showing the relationship between d/2p and the fractional band as a resonator of an elastic wave device A plan view of another elastic wave device according to the first embodiment of the present disclosure A reference diagram showing an example of resonance characteristics of an elastic wave device. A diagram showing the relationship between the fractional band when a large number of elastic wave resonators are configured and the amount of phase rotation of spurious impedance normalized by 180 degrees as the magnitude of spurious. A diagram showing the relationship between d/2p, metallization ratio MR, and fractional band A diagram showing a map of the fractional band with respect to the Euler angles (0°, θ, ψ) of LiNbO3 when d/p is brought as close to 0 as possible A partially cutaway perspective view for explaining an elastic wave device according to a first embodiment of the present disclosure Top view of multiple conventional elastic wave devices arranged in a grid pattern Graph showing power transmission loss versus frequency in a conventional elastic wave device Schematic plan view of multiple elastic wave devices arranged in a grid pattern A schematic cross-sectional view of an elastic wave device according to a second embodiment of the present disclosure cut in the thickness direction Schematic plan view of acoustic wave element Equivalent circuit diagram of the acoustic wave element in Figure 17 Schematic plan view showing a pair of comb-shaped electrodes A schematic plan view of an acoustic wave element, a first conductive pattern, and a second conductive pattern. A schematic perspective view of an acoustic wave element, a first conductive pattern, and a second conductive pattern. Graph showing power transmission loss versus frequency in an elastic wave device Graph showing power transmission loss versus frequency in an elastic wave device Graph showing the power passing loss with respect to the width of the second conductive pattern in the elastic wave device Graph showing the power passing loss with respect to the width of the second conductive pattern in the elastic wave device

Acoustic wave devices according to first, second, and third aspects of the present disclosure include a piezoelectric layer made of lithium niobate or lithium tantalate, and a first electrode and a second electrode facing each other in a direction crossing the thickness direction of the piezoelectric layer. and an electrode.

The elastic wave device of the first aspect utilizes a bulk wave in a thickness shear mode.

Further, in the acoustic wave device of the second aspect, the first electrode and the second electrode are adjacent electrodes, the thickness of the piezoelectric layer is d, and the distance between the centers of the first electrode and the second electrode is p. In this case, d/p is 0.5 or less. Thereby, in the first and second aspects, the Q value can be increased even when miniaturization is promoted.

Furthermore, in the third aspect of the elastic wave device, Lamb waves are used as plate waves. Then, resonance characteristics due to the Lamb wave described above can be obtained.

An acoustic wave device according to a fourth aspect of the present disclosure includes a piezoelectric layer made of lithium niobate or lithium tantalate, and an upper electrode and a lower electrode that face each other in the thickness direction of the piezoelectric layer with the piezoelectric layer interposed therebetween. Take advantage of.

Hereinafter, the present disclosure will be clarified by describing specific embodiments of the elastic wave devices of the first to fourth aspects with reference to the drawings.

It should be noted that each embodiment described in this specification is an illustrative example, and it is possible to partially replace or combine the configurations between different embodiments.

(First embodiment)
FIG. 1A is a schematic perspective view showing the appearance of an acoustic wave device according to a first embodiment of the first and second aspects, and FIG. 1B is a plan view showing an electrode structure on a piezoelectric layer. , FIG. 2 is a cross-sectional view of a portion taken along line AA in FIG. 1A.

The acoustic wave device 1 has a piezoelectric layer 2 made of LiNbO ₃ . The piezoelectric layer 2 may be made of LiTaO ₃ . Although the cut angle of LiNbO ₃ and LiTaO ₃ is a Z cut in this embodiment, it may be a rotational Y cut or an X cut. Preferably, the propagation directions of Y propagation and X propagation are ±30°. The thickness of the piezoelectric layer 2 is not particularly limited, but is preferably 50 nm or more and 1000 nm or less in order to effectively excite the thickness shear mode.

The piezoelectric layer 2 has first and second main surfaces 2a and 2b that face each other. An electrode 3 and an electrode 4 are provided on the first main surface 2a. Here, electrode 3 is an example of a "first electrode", and electrode 4 is an example of a "second electrode". In FIGS. 1A and 1B, the plurality of electrodes 3 are a plurality of first electrode fingers connected to the first bus bar 5. In FIGS. The plurality of electrodes 4 are a plurality of second electrode fingers connected to the second bus bar 6. The plurality of electrodes 3 and the plurality of electrodes 4 are interposed with each other.

The electrode 3 and the electrode 4 have a rectangular shape and have a length direction. The electrode 3 and the adjacent electrode 4 face each other in a direction perpendicular to this length direction. These plurality of electrodes 3 and 4, the first bus bar 5, and the second bus bar 6 constitute an IDT (Interdigital Transducer) electrode. The length direction of the electrodes 3 and 4 and the direction perpendicular to the length direction of the electrodes 3 and 4 are both directions that intersect the thickness direction of the piezoelectric layer 2. Therefore, it can be said that the electrode 3 and the adjacent electrode 4 face each other in the direction intersecting the thickness direction of the piezoelectric layer 2.

Furthermore, the length direction of the electrodes 3 and 4 may be replaced with the direction perpendicular to the length direction of the electrodes 3 and 4 shown in FIGS. 1A and 1B. That is, in FIGS. 1A and 1B, the electrodes 3 and 4 may extend in the direction in which the first bus bar 5 and the second bus bar 6 extend. In that case, the first bus bar 5 and the second bus bar 6 will extend in the direction in which the electrodes 3 and 4 extend in FIGS. 1A and 1B.

A plurality of pairs of structures in which an electrode 3 connected to one potential and an electrode 4 connected to the other potential are adjacent to each other are provided in a direction perpendicular to the length direction of the electrodes 3 and 4. There is. Here, the expression "electrode 3 and electrode 4 are adjacent" does not mean that electrode 3 and electrode 4 are arranged so as to be in direct contact with each other, but when electrode 3 and electrode 4 are arranged with a gap between them. refers to

Further, when the electrode 3 and the electrode 4 are adjacent to each other, no electrode connected to the hot electrode or the ground electrode, including the other electrodes 3 and 4, is arranged between the electrode 3 and the electrode 4. This logarithm does not need to be an integer pair, and may be 1.5 pairs, 2.5 pairs, or the like. The center-to-center distance between the electrodes 3 and 4, that is, the pitch, is preferably in the range of 1 μm or more and 10 μm or less. In addition, the center-to-center distance between the electrodes 3 and 4 refers to the center of the width dimension of the electrode 3 in the direction orthogonal to the length direction of the electrode 3, and the width dimension of the electrode 4 in the direction orthogonal to the length direction of the electrode 4. It is the distance between the center of Furthermore, when there is a plurality of at least one of the electrodes 3 and 4 ( electrodes 3 and 4 are a pair of electrode sets, and there are 1.5 or more pairs of electrode sets), the distance between the centers of the electrodes 3 and 4 is 1 It refers to the average value of the distance between the centers of adjacent electrodes 3 and 4 among 5 or more pairs of electrodes 3 and 4. Further, the width of the electrodes 3 and 4, that is, the dimension in the opposing direction of the electrodes 3 and 4, is preferably in the range of 150 nm or more and 1000 nm or less. Note that the distance between the centers of the electrodes 3 and 4 refers to the distance between the center of the dimension (width dimension) of the electrode 3 in the direction orthogonal to the length direction of the electrode 3 and the center of the dimension (width dimension) of the electrode 4 in the direction orthogonal to the length direction of the electrode 4. This is the distance between the center of the dimension (width dimension).

Furthermore, in this embodiment, since a Z-cut piezoelectric layer is used, the direction perpendicular to the length direction of the electrodes 3 and 4 is the direction perpendicular to the polarization direction of the piezoelectric layer 2. This is not the case when a piezoelectric material having a different cut angle is used as the piezoelectric layer 2. Here, "orthogonal" is not limited to strictly orthogonal, but approximately orthogonal (for example, the angle between the direction orthogonal to the length direction of the electrodes 3 and 4 and the polarization direction is 90°±10°) But that's fine.

A support member 8 is laminated on the second main surface 2b side of the piezoelectric layer 2 with an insulating layer 7 in between. The insulating layer 7 and the support member 8 have a frame-like shape, and have openings 7a and 8a, as shown in FIG. Thereby, a cavity 9 is formed. The cavity 9 is provided so as not to hinder the vibration of the excitation region C of the piezoelectric layer 2. Therefore, the support member 8 is laminated on the second main surface 2b with the insulating layer 7 in between, at a position that does not overlap with the portion where at least one pair of electrodes 3 and 4 are provided. Note that the insulating layer 7 may not be provided. Therefore, the support member 8 can be laminated directly or indirectly on the second main surface 2b of the piezoelectric layer 2.

The insulating layer 7 is made of silicon oxide. However, other than silicon oxide, an appropriate insulating material such as silicon oxynitride or alumina can be used. The support member 8 is made of Si. The plane orientation of the Si surface on the piezoelectric layer 2 side may be (100), (110), or (111). Preferably, Si has a high resistivity of 4 kΩ or more. However, the support member 8 can also be constructed using an appropriate insulating material or semiconductor material. Examples of materials for the support member 8 include aluminum oxide, lithium tantalate, lithium niobate, piezoelectric materials such as crystal, alumina, magnesia, sapphire, silicon nitride, aluminum nitride, silicon carbide, zirconia, cordierite, mullite, and star. Various ceramics such as tite and forsterite, dielectrics such as diamond and glass, semiconductors such as gallium nitride, etc. can be used.

The plurality of electrodes 3 and 4 and the first and second bus bars 5 and 6 are made of a suitable metal or alloy such as Al or AlCu alloy. In this embodiment, the electrodes 3 and 4 and the first and second bus bars 5 and 6 have a structure in which an Al film is laminated on a Ti film. Note that an adhesive layer other than the Ti film may be used.

During driving, an AC voltage is applied between the plurality of electrodes 3 and the plurality of electrodes 4. More specifically, an AC voltage is applied between the first bus bar 5 and the second bus bar 6. Thereby, it is possible to obtain resonance characteristics using the thickness shear mode bulk wave excited in the piezoelectric layer 2.

Further, in the acoustic wave device 1, when the thickness of the piezoelectric layer 2 is d, and the distance between the centers of any adjacent electrodes 3, 4 among the plurality of pairs of electrodes 3, 4 is p, d/p is 0. It is considered to be 5 or less. Therefore, the bulk wave in the thickness shear mode is effectively excited, and good resonance characteristics can be obtained. More preferably, d/p is 0.24 or less, in which case even better resonance characteristics can be obtained.

In addition, when there is a plurality of at least one of the electrodes 3 and 4 as in the present embodiment, that is, when there are one pair of electrodes 3 and 4 and 1.5 or more pairs of electrodes 3 and 4, the electrodes 3 and 4 are adjacent to each other. The distance p between the centers of the electrodes 3 and 4 is the average distance between the centers of the adjacent electrodes 3 and 4.

Since the elastic wave device 1 of this embodiment has the above configuration, even if the logarithm of the electrodes 3 and 4 is reduced in an attempt to achieve miniaturization, the Q value is unlikely to decrease. This is because the resonator does not require reflectors on both sides and has little propagation loss. Further, the reason why the reflector is not required is because the bulk wave in the thickness shear mode is used.

The difference between the Lamb waves used in conventional elastic wave devices and the thickness-shear mode bulk waves will be explained with reference to FIGS. 3A and 3B.

FIG. 3A is a schematic front sectional view for explaining Lamb waves propagating through a piezoelectric film of a conventional acoustic wave device. A conventional elastic wave device is described in, for example, Japanese Patent Publication No. 2012-257019. As shown in FIG. 3A, in the conventional acoustic wave device, waves propagate in the piezoelectric film 201 as indicated by arrows. Here, in the piezoelectric film 201, the first main surface 201a and the second main surface 201b are opposite to each other, and the thickness direction connecting the first main surface 201a and the second main surface 201b is the Z direction. It is. The X direction is the direction in which the electrode fingers of the IDT electrodes are lined up. As shown in FIG. 3A, in the Lamb wave, the wave propagates in the X direction as shown. Since it is a plate wave, the piezoelectric film 201 vibrates as a whole, but since the wave propagates in the X direction, reflectors are placed on both sides to obtain resonance characteristics. Therefore, wave propagation loss occurs, and when miniaturization is attempted, that is, when the number of logarithms of electrode fingers is reduced, the Q value decreases.

On the other hand, as shown in FIG. 3B, in the elastic wave device 1 of this embodiment, the vibration displacement is in the thickness-slip direction, so the waves are generated between the first principal surface 2a and the second principal surface of the piezoelectric layer 2. It propagates almost in the direction connecting the surface 2b, that is, in the Z direction, and resonates. That is, the X-direction component of the wave is significantly smaller than the Z-direction component. Since resonance characteristics are obtained by the propagation of waves in the Z direction, a reflector is not required. Therefore, no propagation loss occurs when propagating to the reflector. Therefore, even if the number of electrode pairs consisting of electrodes 3 and 4 is reduced in an attempt to promote miniaturization, the Q value is unlikely to decrease.

Note that, as shown in FIG. 4, the amplitude direction of the bulk wave in the thickness shear mode is reversed between the first region 451 included in the excitation region C of the piezoelectric layer 2 and the second region 452 included in the excitation region C. Become. FIG. 4 schematically shows a bulk wave when a voltage is applied between electrode 3 and electrode 4 such that electrode 4 has a higher potential than electrode 3. In FIG. The first region 451 is a region of the excitation region C between a virtual plane VP1 that is perpendicular to the thickness direction of the piezoelectric layer 2 and bisects the piezoelectric layer 2, and the first main surface 2a. The second region 452 is a region of the excitation region C between the virtual plane VP1 and the second principal surface 2b.

As mentioned above, in the elastic wave device 1, at least one pair of electrodes consisting of the electrode 3 and the electrode 4 are arranged, but since the wave is not propagated in the X direction, the elastic wave device 1 is made up of the electrodes 3 and 4. There does not necessarily have to be a plurality of pairs of electrodes. That is, it is only necessary that at least one pair of electrodes be provided.

For example, the electrode 3 is an electrode connected to a hot potential, and the electrode 4 is an electrode connected to a ground potential. However, the electrode 3 may be connected to the ground potential and the electrode 4 may be connected to the hot potential. In this embodiment, at least one pair of electrodes is an electrode connected to a hot potential or an electrode connected to a ground potential, as described above, and no floating electrode is provided.

FIG. 5 is a diagram showing the resonance characteristics of the elastic wave device according to the first embodiment of the present invention. Note that the design parameters of the elastic wave device 1 that obtained this resonance characteristic are as follows.
Piezoelectric layer 2: LiNbO ₃ with Euler angles (0°, 0°, 90°), thickness = 400 nm. When viewed in a direction perpendicular to the length direction of electrodes 3 and 4, the area where electrodes 3 and 4 overlap, that is, the length of excitation area C = 40 μm, the logarithm of electrodes consisting of electrodes 3 and 4 = 21 pairs, center distance between electrodes = 3 μm, width of electrodes 3 and 4 = 500 nm, d/p = 0.133.
Insulating layer 7: silicon oxide film with a thickness of 1 μm.
Support member 8: Si.

Note that the length of the excitation region C is a dimension along the length direction of the electrodes 3 and 4 of the excitation region C.

In this embodiment, the inter-electrode distances of the electrode pairs consisting of the electrodes 3 and 4 were all made equal in multiple pairs. That is, the electrodes 3 and 4 were arranged at equal pitches.

As is clear from FIG. 5, good resonance characteristics with a fractional band of 12.5% are obtained despite not having a reflector.

By the way, when the thickness of the piezoelectric layer 2 is d, and the center-to-center distance between the electrodes 3 and 4 is p, in this embodiment, d/p is preferably 0.5 or less, as described above. is 0.24 or less. This will be explained with reference to FIG.

A plurality of elastic wave devices were obtained in the same way as the elastic wave devices that obtained the resonance characteristics shown in FIG. 5, except that d/2p was varied. FIG. 6 is a diagram showing the relationship between d/2p and the fractional band of the resonator of the elastic wave device.

As is clear from FIG. 6, when d/2p exceeds 0.25, that is, when d/p>0.5, the fractional band is less than 5% even if d/p is adjusted. On the other hand, if d/2p≦0.25, that is, d/p≦0.5, the fractional bandwidth can be increased to 5% or more by changing d/p within that range. In other words, a resonator having a high coupling coefficient can be constructed. Further, when d/2p is 0.12 or less, that is, when d/p is 0.24 or less, the fractional band can be increased to 7% or more. In addition, by adjusting d/p within this range, it is possible to obtain a resonator with an even wider specific band, and it is possible to realize a resonator with an even higher coupling coefficient. Therefore, as in the elastic wave device of the second aspect of the present disclosure, by setting d/p to 0.5 or less, a resonator having a high coupling coefficient that utilizes the bulk wave of the thickness shear mode is configured. I know what I can do.

Note that, as described above, the at least one pair of electrodes may be one pair, and in the case of one pair of electrodes, the above p is the distance between the centers of adjacent electrodes 3 and 4. Furthermore, in the case of 1.5 or more pairs of electrodes, the average distance between the centers of adjacent electrodes 3 and 4 may be set to p.

Also, regarding the thickness d of the piezoelectric layer, if the piezoelectric layer 2 has thickness variations, a value obtained by averaging the thicknesses may be adopted.

FIG. 7 is a plan view of another elastic wave device according to the first embodiment of the present disclosure. In the acoustic wave device 31, a pair of electrodes including an electrode 3 and an electrode 4 are provided on the first main surface 2a of the piezoelectric layer 2. Note that K in FIG. 7 is the intersection width. As described above, in the acoustic wave device 31 of the present invention, the number of pairs of electrodes may be one. Even in this case, if the above-mentioned d/p is 0.5 or less, bulk waves in the thickness shear mode can be excited effectively.

In the elastic wave device 1, preferably, in the plurality of electrodes 3, 4, the above-mentioned adjacent It is desirable that the metallization ratio MR of the electrodes 3 and 4 satisfies MR≦1.75(d/p)+0.075. That is, when viewed in the direction in which adjacent first electrode fingers and second electrode fingers are facing each other, the region where the plurality of first electrode fingers and the plurality of second electrode fingers overlap is excited. region (intersection region), and when the metallization ratio of the plurality of first electrode fingers and the plurality of second electrode fingers with respect to the excitation region is MR, MR≦1.75 (d/p) + 0.075. It is preferable to meet the requirements. In that case, spurious can be effectively reduced.

This will be explained with reference to FIGS. 8 and 9. FIG. 8 is a reference diagram showing an example of the resonance characteristics of the elastic wave device 1. As shown in FIG. A spurious signal indicated by arrow B appears between the resonant frequency and the anti-resonant frequency. Note that d/p=0.08 and the Euler angles of LiNbO ₃ (0°, 0°, 90°). Further, the metallization ratio MR was set to 0.35.

The metallization ratio MR will be explained with reference to FIG. 1B. In the electrode structure of FIG. 1B, when focusing on a pair of electrodes 3 and 4, it is assumed that only this pair of electrodes 3 and 4 are provided. In this case, the area surrounded by the dashed line C becomes the excitation region. This excitation region is the region where the electrode 3 overlaps the electrode 4 when the electrode 3 and the electrode 4 are viewed in a direction perpendicular to the length direction of the electrodes 3 and 4, that is, in a direction in which they face each other. and a region between electrodes 3 and 4 where electrodes 3 and 4 overlap. Then, the area of the electrodes 3 and 4 in the excitation region C with respect to the area of this excitation region becomes the metallization ratio MR. That is, the metallization ratio MR is the ratio of the area of the metallized portion to the area of the excitation region.

Note that when multiple pairs of electrodes are provided, MR may be the ratio of the metallized portion included in all the excitation regions to the total area of the excitation regions.

FIG. 9 is a diagram showing the relationship between the fractional band and the amount of phase rotation of spurious impedance normalized by 180 degrees as the magnitude of spurious when a large number of elastic wave resonators are configured according to the present embodiment. be. Note that the specific band was adjusted by variously changing the thickness of the piezoelectric layer and the dimensions of the electrode. Further, although FIG. 9 shows the results when a Z-cut piezoelectric layer made of LiNbO ₃ is used, the same tendency is obtained when piezoelectric layers with other cut angles are used.

In the area surrounded by the ellipse J in FIG. 9, the spurious is as large as 1.0. As is clear from FIG. 9, when the fractional band exceeds 0.17, that is, exceeds 17%, a large spurious with a spurious level of 1 or more will affect the pass band even if the parameters that make up the fractional band are changed. Appear within. That is, as in the resonance characteristics shown in FIG. 8, a large spurious signal indicated by arrow B appears within the band. Therefore, it is preferable that the fractional band is 17% or less. In this case, by adjusting the thickness of the piezoelectric layer 2, the dimensions of the electrodes 3 and 4, etc., the spurious can be reduced.

FIG. 10 is a diagram showing the relationship between d/2p, metallization ratio MR, and fractional band. Among the above elastic wave devices, various elastic wave devices having different d/2p and MR were constructed and the fractional bands were measured. The hatched area on the right side of the broken line D in FIG. 10 is a region where the fractional band is 17% or less. The boundary between the hatched area and the unhatched area is expressed as MR=3.5(d/2p)+0.075. That is, MR=1.75(d/p)+0.075. Therefore, preferably MR≦1.75 (d/p)+0.075. In that case, it is easy to set the fractional band to 17% or less. More preferably, it is the region to the right of MR=3.5(d/2p)+0.05 indicated by the dashed line D1 in FIG. That is, if MR≦1.75(d/p)+0.05, the fractional band can be reliably set to 17% or less.

FIG. 11 is a diagram showing a map of the fractional band with respect to Euler angles (0°, θ, ψ) of LiNbO ₃ when d/p is brought as close to 0 as possible. The hatched areas in FIG. 11 are areas where a fractional band of at least 5% can be obtained, and the range of the area can be approximated by the following equations (1), (2), and (3). ).

(0°±10°, 0° to 20°, arbitrary ψ)...Formula (1)

(0°±10°, 20° to 80°, 0° to 60° (1-(θ-50) ² /900) ^1/2 ) or (0°±10°, 20° to 80°, [180 °-60° (1-(θ-50) ² /900) ^1/2 ] ~ 180°) ...Formula (2)

(0°±10°, [180°-30° (1-(ψ-90) ² /8100) ^1/2 ] ~ 180°, arbitrary ψ) ...Formula (3)

Therefore, in the case of the Euler angle range of the above formula (1), formula (2), or formula (3), the fractional band can be made sufficiently wide, which is preferable.

FIG. 12 is a partially cutaway perspective view for explaining the elastic wave device according to the first embodiment of the present disclosure. The elastic wave device 81 has a support substrate 82 . The support substrate 82 is provided with an open recess on the upper surface. A piezoelectric layer 83 is laminated on the support substrate 82 . Thereby, a cavity 9 is formed. An IDT electrode 84 is provided on the piezoelectric layer 83 above the cavity 9 . Reflectors 85 and 86 are provided on both sides of the IDT electrode 84 in the elastic wave propagation direction. In FIG. 12, the outer periphery of the cavity 9 is indicated by a broken line. Here, the IDT electrode 84 includes first and second bus bars 84a and 84b, an electrode 84c as a plurality of first electrode fingers, and an electrode 84d as a plurality of second electrode fingers. The plurality of electrodes 84c are connected to the first bus bar 84a. The plurality of electrodes 84d are connected to the second bus bar 84b. The plurality of electrodes 84c and the plurality of electrodes 84d are interposed with each other.

In the elastic wave device 81, by applying an alternating current electric field to the IDT electrode 84 on the cavity 9, a Lamb wave as a plate wave is excited. Since the reflectors 85 and 86 are provided on both sides, the resonance characteristic due to the Lamb wave described above can be obtained.

In this way, the elastic wave device of the present disclosure may utilize plate waves.

(Second embodiment)
An elastic wave device according to a second embodiment will be described. In the second embodiment, descriptions of contents that overlap with those in the first embodiment will be omitted as appropriate. In the second embodiment, the contents described in the first embodiment can be applied.

Problems with conventional elastic wave devices will be explained. FIG. 13 is a plan view of a plurality of conventional elastic wave devices arranged in a grid. That is, FIG. 13 is a plan view of a plurality of conventional elastic wave devices arranged in a grid pattern. Here, "planar view" means viewed from the stacking direction D11, which will be described later.

The elastic wave device 600 shown in FIG. 13 has a CSP (Chip Size Package) structure, and includes a package substrate and an acoustic wave element having one or more resonators. FIG. 13 shows the package substrate of the acoustic wave device 600, and the acoustic wave element is not shown because it is provided below the package substrate (on the back side of the page). The acoustic wave element and the package substrate are bonded to each other via conductive bumps (not shown). Thereby, the acoustic wave element and the package substrate are electrically connected to each other.

During manufacturing, etc., the acoustic wave devices 600 are arranged in a grid pattern when viewed from above, and are finally cut into individual pieces. FIG. 13 depicts nine elastic wave devices 600 arranged in a grid. Among the nine elastic wave devices 600, the elastic wave device 600A located in the center is depicted in its entirety. Among the nine elastic wave devices 600, eight elastic wave devices 600 located around the elastic wave device 600A are partially illustrated.

Each of the nine elastic wave devices 600 has a conductive pattern 610. Pattern 610 is provided on the package substrate. A plurality of bumps are provided between the package substrate and the acoustic wave element. Each pattern 610 is electrically connected to an acoustic wave element via a corresponding bump. Hereinafter, details will be explained using the elastic wave device 600A among the nine elastic wave devices 600 depicted in FIG. 13 as an example.

The elastic wave device 600A has three patterns 611, 612, and 613 as the pattern 610. Each pattern 611, 612, 613 is electrically connected to an acoustic wave element via a corresponding bump. In the configuration shown in FIG. 13, the elastic wave device 600A includes at least three bumps (a bump that connects the pattern 611 and the acoustic wave element, a bump that connects the pattern 612 and the acoustic wave element, and a bump that connects the pattern 613 and the acoustic wave element). (bumps connecting).

The elastic wave device 600 configured as described above has the following two problems.

The first problem is that there is room for further improvement in terms of improving the strength of the elastic wave device 600.

Typically, the bump is provided at a position that overlaps the outer edge of the elastic wave device 600 in plan view. Therefore, the strength of the elastic wave device 600 may be weakened at positions other than the outer edge of the elastic wave device 600 (positions where no bumps are provided) in a plan view.

The second problem is that the characteristics of the acoustic wave element may deteriorate. The details are explained below.

As described above, each of the plurality of patterns 610 provided on the package substrate is electrically connected to the acoustic wave element via the corresponding bump. In this case, the potential of each bump may be different. When a voltage is applied between two bumps having different potentials, an excessive current may flow through the resonator between the two bumps, causing damage to the resonator (for example, electrostatic damage). In order to prevent damage to the resonator as described above, as shown in FIG. 13, patterns of adjacent acoustic wave devices 600 are electrically connected to each other by conductive patterns 620 (hereinafter also referred to as tie bars 620). This is done to make the potential the same.

In the case of the elastic wave device 600A, the pattern 611 is electrically connected to the adjacent elastic wave device 600B via tie bars 621. The pattern 612 is electrically connected to the adjacent acoustic wave device 600B via a tie bar 622. The pattern 613 is electrically connected to the adjacent elastic wave device 600C via a tie bar 623.

Depending on the position where the tie bar 620 is provided in the acoustic wave device 600 or the position where the resonator is provided in the acoustic wave element, the tie bar 620 and the resonator may overlap in plan view, or the tie bar 620 and the resonator may overlap in plan view. and may be located close to each other. In these cases, there is a risk of charge coupling between the tie bar 620 and the resonator. When the tie bar 620 and the resonator are charge-coupled, parasitic capacitance is generated, which may cause deterioration of the characteristics of the acoustic wave device as described below.

FIG. 14 is a graph showing power passing loss (Attenuation) with respect to frequency (Frequency) in a conventional elastic wave device. As shown in FIG. 14, the passband of the characteristic L41 in the configuration in which the tie bar 620 is provided is worse than the passband in the characteristic L42 in the configuration in which the tie bar 620 is not provided. In other words, the power passing loss of the characteristic L41 in the configuration in which the tie bar 620 is provided is greater than the power passing loss in the characteristic L42 in the configuration in which the tie bar 620 is not provided. Furthermore, the bandwidth of the characteristic L43 in the configuration in which the tie bar 620 is provided is narrower than the bandwidth in the characteristic L44 in the configuration in which the tie bar 620 is not provided.

In the elastic wave device of the second embodiment of the present disclosure, the strength can be improved. Furthermore, in the elastic wave device according to the second embodiment of the present disclosure, deterioration of the characteristics of the acoustic wave element can be reduced.

Hereinafter, the configuration of the elastic wave device 100 of the second embodiment will be explained.

FIG. 15 is a schematic plan view of a plurality of elastic wave devices arranged in a grid.

In the second embodiment, the elastic wave device 100 has a CSP (Chip Size Package) structure. In the second embodiment, as shown in FIG. 15, a plurality of elastic wave devices 100 are arranged in a grid pattern. Although nine elastic wave devices 100 (100A to 100I) are shown in FIG. 15, the number of elastic wave devices 100 is not limited to nine. In FIG. 15, internal electrodes 330 that are not visible from the outside of the package substrate 300 are depicted for convenience.

Each of the plurality of elastic wave devices 100A to 100I has the same configuration. Therefore, in the following explanation, the configuration of the elastic wave device 100A will be explained, and the explanation of the elastic wave devices 100 (100B to 100I) other than the elastic wave device 100A will be omitted. Elastic wave devices 100 (100B to 100I) other than elastic wave device 100A will be mentioned as necessary. g

FIG. 16 is a schematic cross-sectional view of the elastic wave device according to the second embodiment of the present disclosure, cut in the thickness direction. Note that since FIG. 16 is a schematic diagram, the position, size, number, etc. of each component (for example, the comb-shaped electrode 240) in FIG. 16 do not correspond one-to-one with other diagrams such as FIG. 15. .

As shown in FIG. 16, the elastic wave device 100A includes an acoustic wave element 200 and a package substrate 300. The acoustic wave element 200 is bonded to the package substrate 300 via a plurality of conductive bumps 400 at a portion, and directly bonded to the package substrate 300 at another portion.

The acoustic wave element 200 includes a support member consisting of a support substrate 210 and an intermediate (bonding) layer 220, a piezoelectric body 230, a pair of comb-shaped electrodes 240, wiring 250, an electrode 260, a dielectric film 270, and a sealing resin 280. The support substrate 210, the bonding layer 220, the piezoelectric body 230, the pair of comb-shaped electrodes 240, the wiring 250, the electrodes 260, the dielectric film 270, and the sealing resin 280 are laminated in the lamination direction D11. has been done. The stacking direction D11 is the thickness direction of the elastic wave device 100A. Note that the support member may include only the support substrate 210.

The bonding layer 220 is provided on the support substrate 210. The piezoelectric body 230 is provided on the bonding layer 220. The pair of comb-shaped electrodes 240 and the wiring 250 are provided on the piezoelectric body 230. Electrode 260 is provided on wiring 250. The dielectric film 270 is provided on the piezoelectric body 230 and the wiring 250 so as to cover the pair of comb-shaped electrodes 240 .

The sealing resin 280 is made of a resin such as polyimide or epoxy. The sealing resin 280 includes the support substrate 210, the bonding layer 220, the piezoelectric body 230, the pair of comb-shaped electrodes 240, the wiring 250, and the electrode 260, except for the side to which the package substrate 300 is bonded. , and the dielectric film 270. The sealing resin 280 is bonded to one main surface 300A of the package substrate 300. On the other hand, the main surface 300A is an example of the main surface of the package substrate 300.

In the second embodiment, the support substrate 210 is made of silicon (Si), the bonding layer 220 is made of silicon oxide (SiOx), and the piezoelectric body 230 is made of lithium niobate (LN, LiNbOx). has been done. Note that the materials constituting each of the support substrate 210, the bonding layer 220, and the piezoelectric body 230 are not limited to the above-mentioned materials. For example, the piezoelectric body 230 may be made of lithium tantalate (LiTaOx).

The bonding layer 220 has a recess 221. The recessed portion 221 is recessed from the main surface 220A of the bonding layer 220 in the stacking direction D11. The space defined by the recess 221 and the piezoelectric body 230 is the cavity 220B. In the second embodiment, the recess 221 is provided in the bonding layer 220, but the recess 221 may be provided across the bonding layer 220 and the support substrate 210.

The piezoelectric body 230 has a membrane 231. The membrane 231 is a portion of the piezoelectric body 230 that overlaps the cavity 220B when viewed from the stacking direction D11 (in other words, when viewed from above in the stacking direction D11). In other words, the membrane 231 is a portion of the piezoelectric body 230 that is not in contact with the main surface 220A of the bonding layer 220 when viewed from above in the stacking direction D11. The cavity 220B is a space defined by the recess 221 and the membrane 231.

The shape of the membrane 231 when viewed in plan in the stacking direction D11 depends on the shape of the cavity 220B. In the second embodiment, the membrane 231 has a rectangular shape when viewed in plan in the stacking direction D11, but may have a shape other than a rectangle.

The pair of comb-shaped electrodes 240, the wiring 250, and the electrode 260 are made of a conductive material (for example, copper). In the second embodiment, dielectric film 270 is made of silicon oxide (SiO2).

A pair of comb-shaped electrodes 240, wiring 250, and electrodes 260 are laminated on the opposite side of the piezoelectric body 230 to the bonding layer 220. In the second embodiment, the pair of comb-shaped electrodes 240 are IDT (Interdigital Transdecer) electrodes. The configuration of the pair of comb-shaped electrodes 240 will be explained in detail later.

FIG. 17 is a schematic plan view of the acoustic wave element.

As shown in FIG. 17, the elastic wave element 200 includes one or more resonators 290. In the second embodiment, the acoustic wave element 200 includes 22 resonators 290. Each of the plurality of resonators 290 includes a pair of comb-shaped electrodes 240, a piezoelectric body 230, and a portion of a dielectric film 270. Note that each of the plurality of resonators 290 may further include a part of a support member. The piezoelectric body 230, the dielectric film 270, and a part of the support member are located in a region of the piezoelectric body 230 and the dielectric film 270 that overlaps with the pair of comb-shaped electrodes 240 when viewed in plan in the stacking direction D11, and in the region thereof. This is a portion located in the surrounding neighborhood area.

As shown in FIGS. 16 and 17, the wiring 250 is electrically connected to the resonator 290 and the electrode 260. Thereby, the wiring 250 electrically connects the plurality of resonators 290 to each other, and electrically connects the resonators 290 and the electrodes 260 to each other. Note that in the second embodiment, the wiring 250 is a patterned wiring formed on the piezoelectric body 230, but is not limited thereto. For example, the wiring 250 may be a wire or the like.

The electrode 260 is electrically connected to an external electrode 340 provided on one main surface 300A of the package substrate 300 via a bump 400.

FIG. 18 is an equivalent circuit diagram of the acoustic wave element of FIG. 17.

In the second embodiment, 22 resonators 290 are connected as shown in the equivalent circuit diagram shown in FIG. Eight of the 22 resonators 290 are arranged in series on a signal path 251 of the wiring 250 that connects the input terminal In and the output terminal Out. Fourteen of the twenty-two resonators 290 are arranged on a ground path 252 of the wiring 250 that connects the node 251A on the signal path 251 and the ground GND.

Hereinafter, the configuration of the pair of comb-shaped electrodes 240 will be explained. FIG. 19 is a schematic plan view showing a pair of comb-shaped electrodes.

As shown in FIG. 19, the pair of comb-shaped electrodes 240 include a first busbar electrode 241 and a second busbar electrode 242 facing each other, and a plurality of first electrode fingers 243 connected to the first busbar electrode 241. It has a plurality of second electrode fingers 244 connected to the second bus bar electrode 242. One of the pair of comb-shaped electrodes 240 includes a first busbar electrode 241 and a first electrode finger 243. The other of the pair of comb-shaped electrodes 240 includes a second busbar electrode 242 and a second electrode finger 244. The plurality of first electrode fingers 243 and the plurality of second electrode fingers 244 are inserted into each other. That is, the plurality of first electrode fingers 243 and the plurality of second electrode fingers 244 are arranged alternately. Adjacent first electrode fingers 243 and second electrode fingers 244 constitute a pair of electrode sets.

The first busbar electrode 241 corresponds to the electrode 5 of the first embodiment. The second busbar electrode 242 corresponds to the electrode 6 of the first embodiment. The first electrode finger 243 corresponds to the electrode 3 of the first embodiment. The second electrode finger 244 corresponds to the electrode 4 of the first embodiment.

When viewed in plan in the stacking direction D11, at least a portion of the pair of comb-shaped electrodes 240 is provided on the membrane 231. That is, the cavity 220B overlaps at least a portion of the pair of comb-shaped electrodes 240 in a plan view. In the second embodiment, when viewed in plan in the stacking direction D11, among the pair of comb-shaped electrodes 240, a part of the first busbar electrode 241, a part of the second busbar electrode 242, a part of the first electrode finger 243, and a second electrode finger 244 are provided on the membrane 231 (see FIG. 16).

As shown in FIG. 16, the package substrate 300 includes three layers of base materials 311, 312, and 313, an interlayer connection conductor 320, an internal electrode 330, and an external electrode 340.

The package substrate 300 has a rectangular parallelepiped shape as a whole. In the second embodiment, the package substrate 300 is formed by integrating base materials 311, 312, and 313 stacked in the stacking direction D11. That is, in the second embodiment, the package substrate 300 is an integrated structure of three base materials. The stacking direction D11 is a direction perpendicular to one main surface 300A of the package substrate 300, and is an example of a perpendicular direction. The number of base materials that constitute the package substrate 300 is not limited to three. Each of the base materials 311, 312, and 313 is insulating and has a plate shape. In the second embodiment, the base materials 311, 312, and 313 are made of, for example, resin such as polyimide or epoxy, ceramic, or the like.

The three layers of base materials 311, 312, and 313 are stacked in the stacking direction D11. The base material 311 is provided on the acoustic wave element 200. The base material 312 is provided on the base material 311. The base material 313 is provided on the base material 312.

The interlayer connection conductor 320 is formed inside the package substrate 300. Interlayer connection conductor 320 may be formed on at least one of base materials 311, 312, and 313. In FIG. 16, three interlayer connection conductors 320 are formed on a base material 311, two interlayer connection conductors 320 are formed on a base material 312, and two interlayer connection conductors 320 are formed on a base material 313.

The interlayer connection conductor 320 is formed by filling conductive paste into through holes that penetrate the base materials 311, 312, and 313 in the stacking direction D11. The conductive paste contains conductive powder, such as copper. The conductive powder contained in the conductive paste is not limited to copper, and may be, for example, silver. In the second embodiment, since the through hole has a truncated conical shape, the interlayer connection conductor 320 has a truncated conical shape. The shape of the through hole is not limited to a truncated cone shape, but may be, for example, a cylinder or a square prism.

The internal electrode 330 is formed inside the package substrate 300. Internal electrodes 330 may be formed on the surfaces of base materials 311, 312, and 313. Internal electrodes 330 are formed by printing conductive paste on the surfaces of base materials 311, 312, and 313. The conductive paste is made of copper or silver, for example. The internal electrode 330 is electrically connected to other internal electrodes 330 and external electrodes 340 via the interlayer connection conductor 320. In the second embodiment, part of the internal electrode 330 is a first conductive pattern 331 (tie bar 331) and a second conductive pattern 332 (tie bar 332), which will be described later.

The external electrode 340 is formed outside the package substrate 300. That is, the external electrode 340 is exposed to the outside of the package substrate 300. In the second embodiment, the external electrodes 340 are formed on one main surface 300A and the other main surface 300B of the package substrate 300.

The external electrode 340 is configured in the same manner as the internal electrode 330. That is, in the second embodiment, the external electrodes 340 are formed by printing conductive paste on one main surface 300A and the other main surface 300B of the package substrate 300.

As described above, the external electrode 340 is electrically connected to the internal electrode 330 via the interlayer connection conductor 320. Further, the external electrode 340 formed on one main surface 300A is electrically connected to the electrode 260 of the acoustic wave element 200 via the bump 400.

Note that in the second embodiment, the external electrodes 340 are formed by printing conductive paste on the package substrate 300, but the present invention is not limited thereto. For example, the external electrode 340 may be a wire or the like. Furthermore, although the first conductive pattern 331 and the second conductive pattern 332, which will be described later, are part of the internal electrode 330 in the second embodiment, they are not limited thereto. For example, a first conductive pattern 331 and a second conductive pattern 332, which will be described later, may be part of the external electrode 340.

The plurality of bumps 400 are made of a conductive material such as solder. The bump 400 electrically connects the electrode 260 of the acoustic wave element 200 and the external electrode 340 of the package substrate 300. That is, the bump 400 is electrically connected to the wiring 250 of the acoustic wave element 200 via the electrode 260.

The elastic wave device 100A includes a plurality of bumps 400. The plurality of bumps 400 include one or more first bumps 410 and one or more second bumps 420.

As shown in FIG. 17, in the second embodiment, the elastic wave device 100A includes eight first bumps 410 (411 to 418) and one second bump 420. That is, in the second embodiment, the elastic wave device 100A includes nine bumps 400.

In the second embodiment, the six first bumps 412, 413, 414, 416, 417, and 418 are connected to GND (reference potential). Further, the two first bumps 411 and 415 are connected to HOT (positive phase signal). Further, the second bump 420 is connected to FLOAT (independent potential). However, the connection of each bump 400 is not limited to the above. For example, the second bump 420 may be connected to GND.

When viewed in plan in the stacking direction D11, the second bump 420 is surrounded by a plurality of first bumps 410 (411 to 418). In the second embodiment, the second bump 420 is located at the center of the acoustic wave element 200 when viewed from above in the stacking direction D11, and the eight first bumps 411 to 418 are located at the center when viewed from above in the stacking direction D11. It is located at the outer edge of the acoustic wave element 200.

The second bump 420 is surrounded by a plurality of resonators 290 when viewed in plan in the stacking direction D11.

In other words, when viewed in plan in the stacking direction D11, the second bump 420 is surrounded by the plurality of first bumps 410 (411 to 418) and is surrounded by the plurality of resonators 290.

Note that the second bump 420 only needs to be surrounded by at least one of the first bump 410 and the resonator 290 when viewed in plan in the stacking direction D11. For example, while the plurality of first bumps 410 surround the second bumps 420 when viewed in plan in the stacking direction D11, the resonator 290 may not surround the second bumps 420. Contrary to the above, the plurality of resonators 290 may surround the second bumps 420 while the first bumps 410 may not surround the second bumps 420 when viewed in plan in the stacking direction D11.

When viewed in plan in the stacking direction D11, one or more first bumps 410 and one or more resonators 290 may cooperate to surround the second bumps 420. For example, when viewed in plan in the stacking direction D11, the plurality of first bumps 410 are arranged on the right side of the second bumps 420, and the plurality of resonators 290 are arranged on the left side of the second bumps 420. The first bump 410 and the plurality of resonators 290 may cooperate to surround the second bump 420.

As described above, part of the internal electrode 330 (see FIG. 16) included in the package substrate 300 is the first conductive pattern 331 and the second conductive pattern 332. The second conductive pattern 332 is an example of a conductive pattern. In the second embodiment, each of the elastic wave devices 100 includes seven first conductive patterns 331 (331A to 331G) and one second conductive pattern 332. Note that the number of first conductive patterns 331 is not limited to seven, and the number of second conductive patterns 332 is not limited to one.

FIG. 20 is a schematic plan view of the acoustic wave element, the first conductive pattern, and the second conductive pattern. FIG. 21 is a schematic perspective view of an acoustic wave element, a first conductive pattern, and a second conductive pattern.

As shown in FIGS. 20 and 21, the first conductive pattern 331A is electrically connected to the first bump 411. The first conductive pattern 331B is electrically connected to the first bump 412. The first conductive patterns 331C and 331D are electrically connected to the first bump 413. The first conductive pattern 331E is electrically connected to the first bump 415. The first conductive pattern 331F is electrically connected to the first bump 416. The first conductive pattern 331G is electrically connected to the first bump 417. The second conductive pattern 332 is electrically connected to the second bump 420. Note that the combination of electrical connection between each of the first conductive pattern 331 and the second conductive pattern 332 and the bump 400 is not limited to the above-mentioned combination.

As shown in FIG. 15, the first conductive pattern 331 and the second conductive pattern 332 electrically connect two adjacent elastic wave devices 100 in the plurality of elastic wave devices 100 arranged in a grid.

Hereinafter, the electrical connection of the first conductive pattern 331 and the second conductive pattern 332 between the elastic wave device 100A and the elastic wave devices 100B, 100D, 100F, and 100H adjacent to the elastic wave device 100A will be explained.

The first conductive pattern 331A of the elastic wave device 100A is electrically connected to the first conductive pattern 331F of the elastic wave device 100B. The first conductive pattern 331B of the elastic wave device 100A is electrically connected to the first conductive pattern 331E of the elastic wave device 100B. The first conductive pattern 331C of the elastic wave device 100A is electrically connected to the second conductive pattern 332 of the elastic wave device 100D. The first conductive pattern 331D of the elastic wave device 100A is electrically connected to the first conductive pattern 331G of the elastic wave device 100D. The first conductive pattern 331E of the elastic wave device 100A is electrically connected to the first conductive pattern 331B of the elastic wave device 100F. The first conductive pattern 331F of the elastic wave device 100A is electrically connected to the first conductive pattern 331A of the elastic wave device 100F. The first conductive pattern 331G of the elastic wave device 100A is electrically connected to the first conductive pattern 331D of the elastic wave device 100H. The second conductive pattern 332 of the elastic wave device 100A is electrically connected to the first conductive pattern 331C of the elastic wave device 100H. Note that the combination of electrical connections between the first conductive pattern 331 and the second conductive pattern 332 is not limited to the above-mentioned combination.

As shown in FIGS. 20 and 21, in the second embodiment, the second conductive pattern 332 includes a first portion 332A and a second portion 332B.

The first portion 332A is electrically connected to the second bump 420. In the second embodiment, the first portion 332A extends from the second bump 420 toward the first bump 411. The first portion 332A does not overlap the resonator 290 when viewed in plan in the stacking direction D11.

The second portion 332B is continuous with the first portion 332A. The second portion 332B straddles the resonator 290 and the wiring 250. Thereby, the second portion 332B extends from the inside of the first bump 410 and the resonator 290 surrounding the second bump 420 to the outside of the first bump 410 and the resonator 290 surrounding the second bump 420. That is, when viewed in plan in the stacking direction D11, a portion of the second portion 332B overlaps with the resonator 290 and the wiring 250.

Although the second embodiment describes a configuration in which the second portion 332B straddles the resonator 290 and the wiring 250, the present invention is not limited to this. For example, the second portion 332B may straddle the resonator 290 but not the wiring 250. That is, when viewed in plan in the stacking direction D11, the second portion 332B may overlap the resonator 290 but not the wiring 250. Further, for example, contrary to the above, the second portion 332B may straddle the wiring 250 but not straddle the resonator 290. As described above, the second portion 332B extends from the inside of the first bump 410 surrounding the second bump 420 and the resonator 290 to the outside, straddling at least one of the resonator 290 and the wiring 250.

In the second embodiment, a configuration in which the second conductive pattern 332 includes the first portion 332A and the second portion 332B has been described, but the present invention is not limited to this. For example, the second conductive pattern 332 may include the second portion 332B but may not include the first portion 332A. In this case, the second conductive pattern 332 composed of only the second portion 332B extends, for example, from the second bump 420 to the first bump 413 side (left side in the paper of FIG. 20) and straddles the resonator 290 and the wiring 250. Further, in FIG. 20, the width of the first portion 332A is drawn to be the same as the width of the second portion 332B, and in FIG. 21, the width W of the second portion 332B is drawn larger than the width of the first portion 332A. Yes, but not limited to this. For example, the width W of the second portion 332B may be smaller than the first portion 332A.

When viewed in plan in the stacking direction D11, the larger the width W (see FIG. 21) of the second conductive pattern 332, the larger the area where the second portion 332B of the second conductive pattern 332 overlaps with the resonator 290 and the wiring 250.

Below, with reference to FIGS. 22 to 25, the power passing loss when the width W of the second portion 332B of the second conductive pattern 332 is varied will be explained. “S21” in FIGS. 22 and 23 indicates that the power passing loss is the power passing loss from the input terminal In to the output terminal Out in the equivalent circuit diagram of FIG. Note that in FIGS. 22 to 25, the width W of the second portion 332B is changed while the width of the first portion 332A is constant; however, when the widths of both the second portion 332B and the first portion 332A are changed, Even if there is, a measurement result with the same tendency as the measurement result described below can be obtained.

FIG. 22 is a graph showing power passing loss (Attenuation) with respect to frequency (Frequency) in an elastic wave device. FIG. 23 is a graph showing power passing loss versus frequency in an elastic wave device.

In FIGS. 22 and 23, each of L11, L21, and L31 shows the characteristics when the width W of the second portion 332B is 30 μm. Each of L12, L22, and L32 shows the characteristics when the width W of the second portion 332B is 50 μm. Each of L13, L23, and L33 shows the characteristics when the width W of the second portion 332B is 150 μm. Each of L14, L24, and L34 shows the characteristics when the width W of the second portion 332B is 250 μm.

As shown in FIGS. 22 and 23, the larger the width W of the second portion 332B, the larger the power passing loss and the narrower the bandwidth.

FIG. 24 is a graph showing the power passing loss with respect to the width of the second conductive pattern in the elastic wave device. The measurements in Figure 24 are performed at a frequency of 4650 MHz. As shown in FIG. 24, the larger the width W of the second portion 332B, the larger the power passing loss. Note that in FIG. 24, when the widths W are the same or substantially the same, there are variations in the plurality of measurement results, but this is because the position of the second portion 332B in each measurement result is different.

FIG. 25 is a graph showing the power passing loss with respect to the width of the second conductive pattern in the elastic wave device. The measurements in Figure 25 are performed at a frequency of 4650 MHz.

As shown in FIG. 25, when the width W of the second portion 332B of the second conductive pattern 332 is 50 μm, the power passing loss is −3.152 dB (see the broken line in FIG. 25). In order to suppress the deterioration from the standard to 0.5 dB or less based on the power passing loss of −3.152 dB, the width W may be set to 150 μm or less, for example (see the dashed-dotted line in FIG. 25).

Based on the above measurement results, in the second embodiment, the width W of the second portion 332B of the second conductive pattern 332 is set to be 150 μm or less when viewed in plan in the stacking direction D11. Of course, the width W of the first portion 332A in addition to the second portion 332B may also be 150 μm or less. Note that the width W is not limited to 150 μm or less. For example, the width W is the width W that can suppress the deterioration from the above-mentioned standard to 0.5 dB or less in FIG. 25 (in other words, the width W when the power passing loss is -3.6 dB in FIG. 25). It may be less than a certain 190 μm.

According to the second embodiment, the elastic wave device 100 includes, in addition to the first bump 410 located at the outer edge of the acoustic wave element 200 when viewed from above in the stacking direction D11, an elastic wave device 410 when viewed from above in the stacking direction D11. A second bump 420 is provided at the center of the wave element 200. That is, in the acoustic wave device 100, the acoustic wave element 200 and the package substrate 300 are connected by the bumps 400 not only at the outer edge but also at the center when viewed in plan in the stacking direction D11. Thereby, the elastic wave device 100 can have improved strength compared to an elastic wave device that does not include the second bump 420 located at the center.

The second conductive pattern 332 extending from the second bump 420 located at the center passes over the resonator 290 and wiring 250 more easily than the first conductive pattern 331 extending from the bump provided at the outer edge. Therefore, the characteristics of the acoustic wave element 200 described above are likely to deteriorate. Therefore, in the second embodiment, the width W of the second portion 332B of the second conductive pattern 332 is set to be 150 μm or less based on the measurement results described above. Thereby, deterioration of the characteristics of the acoustic wave element 200 can be reduced.

(Summary of embodiment)
(1) The elastic wave device of the present disclosure includes:
a package board;
an acoustic wave element bonded to the main surface of the package substrate via a plurality of conductive bumps and having one or more resonators and wiring electrically connected to the resonators;
The plurality of conductive bumps are
one or more first bumps;
a second bump surrounded by at least one of at least one of the first bump and at least one of the resonators when viewed from an orthogonal direction perpendicular to the main surface of the package substrate;
A conductive pattern electrically connected to the second bump is formed on the package substrate,
Viewed from the orthogonal direction, the conductive pattern extends from the second bump, straddles at least one of the resonator and the wiring, and surrounds the second bump from the inside to the outside of the first bump and the resonator. It extends to

(2) In the elastic wave device of (1),
When viewed from the orthogonal direction, the width of the conductive pattern may be 150 (μm) or less at a position overlapping with the resonator.

(3) In the elastic wave device of (1) or (2),
The resonator is
A piezoelectric body,
A pair of comb-shaped electrodes provided on the piezoelectric body may be provided.

(4) In the elastic wave device of (3),
The resonator may further include a support member laminated with the piezoelectric body,
The support member may have a cavity on the piezoelectric body side, and the cavity may overlap at least a portion of the pair of comb-shaped electrodes in a plan view.

(5) In the elastic wave device of (3) or (4),
The pair of comb-shaped electrodes may be IDT (Interdigital Transducer) electrodes,
The IDT electrode may include a plurality of first electrode fingers included in one of the pair of comb-shaped electrodes, and a plurality of second electrode fingers included in the other of the pair of comb-shaped electrodes. ,
The plurality of first electrode fingers and the plurality of second electrode fingers may be arranged alternately.

(6) In the elastic wave device of (5),
When the film thickness of the piezoelectric body is d, and the center-to-center distance between the adjacent first electrode finger and the second electrode finger is p, d/p may be 0.5 or less.

(7) In the elastic wave device of (6),
The d/p may be 0.24 or less.

(8) In any one of the elastic wave devices (5) to (7),
When the film thickness of the piezoelectric body is d, and the center-to-center distance between the adjacent first electrode finger and the second electrode finger is p,
With respect to the area of the excitation region, which is the region where the first electrode fingers and the second electrode fingers overlap, when viewed along the direction in which the plurality of first electrode fingers and the plurality of second electrode fingers are arranged, When MR is a metallization ratio that is a ratio of the total area of the first electrode finger and the second electrode finger in the excitation region, MR may satisfy the following formula.
MR≦1.75×(d/p)+0.075

(9) In any one of the elastic wave devices (3) to (8),
The piezoelectric material may be lithium niobate or lithium tantalate.

(10) In the elastic wave device of (9),
The Euler angles (φ, θ, ψ) of the lithium niobate or lithium tantalate may be within the range of the following formula (1), formula (2), or formula (3).
(0°±10°, 0° to 20°, arbitrary ψ) ...Formula (1)
(0°±10°, 20° to 80°, 0° to 60° (1-(θ-50) ² /900) ^1/2 ) or (0°±10°, 20° to 80°, [180 °-60° (1-(θ-50) ² /900) ^1/2 ] ~ 180°) ...Formula (2)
(0°±10°, [180°-30° (1-(ψ-90) ² /8100) ^1/2 ] ~ 180°, arbitrary ψ) ...Formula (3)

(11) In any one of the elastic wave devices (1) to (10),
It may be configured such that a bulk wave in a thickness shear mode can be used as the main wave.

(12) In any one of the elastic wave devices (1) to (10),
It may be configured such that a plate wave can be used as the main wave.

Claims (12)

1. a package board;
   an acoustic wave element bonded to the main surface of the package substrate via a plurality of conductive bumps and having one or more resonators and wiring electrically connected to the resonators;
   The plurality of conductive bumps are
   one or more first bumps;
   a second bump surrounded by at least one of at least one of the first bump and at least one of the resonators when viewed from an orthogonal direction perpendicular to the main surface of the package substrate;
   A conductive pattern electrically connected to the second bump is formed on the package substrate,
   Viewed from the orthogonal direction, the conductive pattern extends from the second bump, straddles at least one of the resonator and the wiring, and surrounds the second bump from the inside to the outside of the first bump and the resonator. An elastic wave device extending to.
2. The elastic wave device according to claim 1, wherein the width of the conductive pattern is 150 (μm) or less at a position overlapping the resonator when viewed from the orthogonal direction.
3. The resonator is
   A piezoelectric body,
   The elastic wave device according to claim 1 or 2, further comprising a pair of comb-shaped electrodes provided on the piezoelectric body.
4. The resonator further includes a support member laminated with the piezoelectric body,
   The acoustic wave device according to claim 3, wherein the support member has a cavity on the piezoelectric body side, and the cavity overlaps at least a portion of the pair of comb-shaped electrodes in a plan view.
5. The pair of comb-shaped electrodes are IDT (Interdigital Transducer) electrodes,
   The IDT electrode includes a plurality of first electrode fingers included in one of the pair of comb-shaped electrodes, and a plurality of second electrode fingers included in the other of the pair of comb-shaped electrodes,
   The elastic wave device according to claim 3 or 4, wherein the plurality of first electrode fingers and the plurality of second electrode fingers are arranged alternately.
6. According to claim 5, where d is the film thickness of the piezoelectric body and p is the center-to-center distance between the adjacent first electrode fingers and the second electrode fingers, d/p is 0.5 or less. elastic wave device.
7. The elastic wave device according to claim 6, wherein the d/p is 0.24 or less.
8. When the film thickness of the piezoelectric body is d, and the center-to-center distance between the adjacent first electrode finger and the second electrode finger is p,
   With respect to the area of the excitation region, which is the region where the first electrode fingers and the second electrode fingers overlap, when viewed along the direction in which the plurality of first electrode fingers and the plurality of second electrode fingers are arranged, Claims 5 to 7, where MR is a metallization ratio that is a ratio of the total area of the first electrode finger and the second electrode finger in the excitation region, MR satisfies the following formula: The elastic wave device according to any one of the above.
   MR≦1.75×(d/p)+0.075
9. The acoustic wave device according to any one of claims 3 to 8, wherein the piezoelectric material is lithium niobate or lithium tantalate.
10. The elastic wave device according to claim 9, wherein the Euler angles (φ, θ, ψ) of the lithium niobate or lithium tantalate are in the range of the following formula (1), formula (2), or formula (3). .
    (0°±10°, 0° to 20°, arbitrary ψ) ...Formula (1)
    (0°±10°, 20° to 80°, 0° to 60° (1-(θ-50) ² /900) ^1/2 ) or (0°±10°, 20° to 80°, [180 °-60° (1-(θ-50) ² /900) ^1/2 ] ~ 180°) ...Formula (2)
    (0°±10°, [180°-30° (1-(ψ-90) ² /8100) ^1/2 ] ~ 180°, arbitrary ψ) ...Formula (3)
11. The elastic wave device according to any one of claims 1 to 10, wherein the elastic wave device is configured to be able to utilize a thickness-shear mode bulk wave as the main wave.
12. The elastic wave device according to any one of claims 1 to 10, configured to be able to use a plate wave as a main wave.

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