Elastic wave device

Abstract

To provide an elastic wave device having improved heat dissipation property.SOLUTION: An elastic wave device includes: a package substrate 2; a device chip 1 flip-chip mounted on the package substrate; an electrode pad formed on the package substrate; metal 5 for heat dissipation provided on a main surface opposite to the package substrate of the device chip so as to partially face each other; and a sealing part 3 composed of a sealing resin for hermetically sealing the device chip. The metal for heat dissipation includes: a device chip side joint part 5a which has a ribbon shape, and is joined to the main surface on the side opposite to the package substrate of the device chip; and an electrode pad side joint part 5b which is joined to the side part 1c of the device chip and the electrode pad 10.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to acoustic wave devices. [Background technology]

[0002] For example, a known acoustic wave device used in a duplexer is one in which a device chip equipped with a SAW (Surface Acoustic Wave) resonator is flip-chip mounted on a package substrate. The device chip may be a transmitting filter, a receiving filter, a duplexer, or the like. The SAW resonator has an IDT (Interdigital Transducer) electrode provided on the main surface of a piezoelectric substrate.

[0003] Patent Document 1 discloses an acoustic wave device that includes an acoustic wave device chip flip-chip mounted on a first wiring substrate, a metal sealing portion that seals the acoustic wave device chip, a second wiring substrate on which the first wiring substrate is mounted, and a wire that electrically connects the metal sealing portion to a ground wiring provided on the second wiring substrate, thereby enabling heat from the metal sealing portion to be transferred to the ground wiring via the wire, thereby improving heat dissipation. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-041680 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the acoustic wave device of Patent Document 1, the wires used to improve heat dissipation are thin and have a small cross-sectional area, so in order to efficiently improve heat dissipation, it is necessary to use a large number of wires to transfer heat, which poses the problem of increasing the number of parts.

[0006] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide an acoustic wave device with excellent heat dissipation properties. [Means for solving the problem]

[0007] One aspect of the acoustic wave device of the present invention is a device including: a package substrate; a device chip having at least one SAW resonator and flip-chip mounted on the package substrate; an electrode pad formed on the package substrate; a heat dissipation metal provided on a main surface of the device chip opposite to the package substrate so as to face the main surface; a sealing portion made of a sealing resin that hermetically seals the device chip; The heat dissipation metal is ribbon-shaped and includes a device chip side bonding portion facing the main surface of the device chip opposite the package substrate, a side portion located on the side of the device chip, and an electrode pad side bonding portion bonding to the electrode pad. In this way, by providing a heat dissipation metal bonded to the device chip and electrode pads, heat from the device chip can be dissipated to the electrode pads via the heat dissipation metal. The heat transferred to the electrode pads is then transferred from the electrode pads to the external connection terminals via the internal conductors. This improves the heat dissipation of the acoustic wave device. By improving the heat dissipation of the acoustic wave device, the power durability of the IDT electrodes of the SAW resonator is improved, thereby improving the reliability of the acoustic wave device.

[0008] As a specific embodiment of the above-described aspect, the acoustic wave device of the present invention includes: the side portion of the heat dissipation metal is provided opposite to and spaced from the side surface of the device chip; When viewed from the side of the heat dissipation metal of the device chip in the direction from the side to the device chip, the average distance between the part of the heat dissipation metal facing the side of the device chip and the side of the device chip is 30 μm or less. In this way, by bringing the side portions of the heat dissipation metal closer to the side surfaces of the device chip, heat is transferred from the side surfaces of the device chip to the heat dissipation metal, thereby improving the heat dissipation performance of the acoustic wave device.

[0009] As a specific embodiment of the above-described aspect, the acoustic wave device of the present invention includes: The sealing resin is disposed in at least a part of the space between the side surface of the device chip and the heat dissipation metal. In this way, by disposing the sealing resin in at least a portion of the space between the side surface of the device chip and the heat dissipation metal, heat is more easily conducted from the side surface of the device chip to the heat dissipation metal because the sealing resin has a higher thermal conductivity than gas, thereby improving the heat dissipation performance of the acoustic wave device.

[0010] As a specific embodiment of the above-described aspect, the acoustic wave device of the present invention includes: The plurality of SAW resonators include three or more series resonators and a plurality of parallel resonators, and the ladder-type filter is provided.

[0011] As a specific embodiment of the above-described aspect, the acoustic wave device of the present invention includes: The device chip side joint portion of the heat dissipation metal on the main surface of the device chip is arranged in a position overlapping with one of the series resonators that are not the first or last stage of the ladder-type filter or between those resonators in a plan view. In this way, by arranging the device chip-side bonding portion of the heat dissipation metal near the series resonators that are not the first or last stage of the ladder filter, the device chip-side bonding portion of the heat dissipation metal can be provided in a portion of the main surface of the device chip that becomes relatively hot. This is because the first and last stage resonators of the ladder filter are close to the electrode pads and therefore easily dissipate heat through the electrode pads, while the resonators that are not the first or last stage of the ladder filter are far from the electrode pads and therefore do not easily dissipate heat through the electrode pads. This improves the heat dissipation performance of the acoustic wave device.

[0012] As a specific embodiment of the above-described aspect, the acoustic wave device of the present invention includes: The thickness of the heat dissipation metal is 10 μm or more and 30 μm or less.

[0013] As a specific embodiment of the above-described aspect, the acoustic wave device of the present invention includes: The width of the ribbon-shaped heat dissipation metal is 100 μm or more and 300 μm or less. [Effects of the Invention]

[0014] According to the acoustic wave device of the present invention, heat dissipation metal is provided that is bonded to the device chip and the electrode pads on the package substrate, so that heat from the device chip can be dissipated to the electrode pads via the heat dissipation metal. This heat is transferred from the electrode pads to the external connection terminals through the internal conductors. This improves the heat dissipation of the acoustic wave device. By improving the heat dissipation of the acoustic wave device, it becomes possible to improve the reliability of the IDT electrodes, such as their power durability. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a cross-sectional view illustrating an embodiment of an acoustic wave device according to the present invention. [Figure 2] 1 is a plan view of an acoustic wave device according to a first embodiment of the present invention, with a sealing portion omitted. [Figure 3]FIG. 3(a) is a side view of the heat dissipation metal, and FIG. 3(b) is a plan view of the heat dissipation metal. [Figure 4] 1 is a diagram showing the positional relationship in a plan view of a receiver and a resonator of a device chip, electrode pads, and heat dissipation metal in an acoustic wave device according to the present invention. [Figure 5] FIG. 2 is a diagram illustrating a transmitting section and a receiving section of a duplexer according to the first embodiment. [Figure 6] FIG. 10 is a cross-sectional view illustrating an acoustic wave device according to a second embodiment. [Figure 7] FIG. 10 is a diagram showing a temperature simulation of an acoustic wave device according to the present invention. [Figure 8] FIG. 10 is a diagram showing a temperature simulation of a conventional example. DETAILED DESCRIPTION OF THE INVENTION

[0016] First Embodiment Fig. 1 is a cross-sectional view showing a first embodiment of an acoustic wave device according to the present invention. Fig. 2 is a plan view of the acoustic wave device, omitting a sealing portion 3 and pads 21. This acoustic wave device 100 includes a device chip 1, a package substrate 2 on which the device chip 1 is flip-chip mounted, a heat dissipation metal 5, a sealing portion 3 that hermetically seals the device chip 1 and the heat dissipation metal with resin, and electrode pads 10, 11, 12, 13, 14, and 15.

[0017] In this embodiment, the device chip 1 is a device chip of a duplexer equipped with a SAW resonator. The device chip may be another device chip such as a transmission filter, as long as it is a device chip equipped with at least one SAW resonator. The device chip 1 is flip-chip mounted on the package substrate 2 via bumps 8. Pads 21 formed on the main surface 1a of the device chip 1 are bonded to electrode pads 10 to 15 formed on the main surface 2a of the package substrate 2 by the bumps 8.

[0018] Gold, solder, etc. can be used as the material for the bumps 8. The pads 21 are formed of an appropriate metal such as aluminum, gold, copper, silver, titanium, chromium, or nickel, or an alloy containing these metals, and may be formed by laminating multiple layers of these metals.

[0019] The electrode pads 10 to 15 are formed from an appropriate metal such as aluminum, gold, copper, silver, titanium, chromium, or nickel, or an alloy thereof, and may be formed by laminating a plurality of layers of these metals.

[0020] The package substrate 2 can be made of an insulating material, for example, a multi-layer substrate in which a metal material such as copper having conductivity and an insulating material such as resin are laminated in multiple layers.

[0021] 2, the above-mentioned electrode pads 10 to 15 are provided on a main surface 2a of the package substrate 2 on the device chip 1 side. As shown in Fig. 1, an internal conductor 22 is provided inside the package substrate 2, and an external connection terminal 23 connected to the internal conductor 22 is provided on a main surface 2b of the package substrate 2 opposite to the device chip 1.

[0022] The device chip 1 has an IDT electrode (not shown) on a piezoelectric substrate on its main surface 1a, which faces the package substrate 2. A support substrate (not shown) may be bonded to the side of the piezoelectric substrate opposite the main surface 1a. An internal space 9, free of resin, is provided on the main surface 1a of the device chip 1, which faces the package substrate 2, so as not to inhibit mechanical resonance of the surface of the piezoelectric substrate. The piezoelectric substrate may be made of, for example, lithium tantalate (LiTaO3) or lithium niobate (LiNbO3). The support substrate may be made of, for example, sapphire, silicon, alumina, spinel, quartz, or glass. The IDT electrode is made of a metal, such as an aluminum-copper alloy.

[0023] The sealing resin of the sealing portion 3 is not particularly limited to a synthetic resin, but for example, epoxy resin or polyimide can be used.

[0024] The heat dissipation metal 5 will now be described. The heat dissipation metal 5 has a ribbon-like shape and includes a device chip-side bonding portion 5a facing the main surface 1b of the device chip 1 on the side opposite the package substrate 2, a side portion 5c located on the side of the device chip 1, and an electrode pad-side bonding portion 5b in contact with the electrode pad 10.

[0025] The device chip side bonding portion 5a of the heat dissipation metal 5 is provided to face the main surface 1b of the device chip 1, which is the side opposite the package substrate 2, and is bonded to the main surface 1b of the device chip 1 via a metal plating 7 by ribbon bonding. The heat dissipation metal 5 is made of a metal such as aluminum, copper, or gold. The metal plating 7 can be made of multiple metal layers, for example, a copper plating with a thin gold plating applied thereon. The metal plating 7 may also be made of other metals. The provision of this metal plating 7 makes it easier to bond the heat dissipation metal 5 to the device chip 1 by ribbon bonding.

[0026] The electrode pad side bonding portion 5b of the heat dissipation metal 5 is bonded to the electrode pad 10 by ribbon bonding. As shown in FIG. 2, the electrode pad 10 has an extension portion 10a extending from the position of the bump 8, and the electrode pad side bonding portion 5b is bonded to the extension portion 10a. The electrode pad 10 is connected to the internal conductor 22 via the The external connection terminal 23a is connected to the ground (GND).

[0027] The side portion 5c of the heat dissipation metal 5 faces the side portion 1c of the device chip 1, and a space 30 is provided at a distance D from the side portion 1c of the device chip 1. By configuring the side portion 5c of the heat dissipation metal 5 close to the side portion 1c of the device chip 1 in this way, heat is transferred from the side portion 1c of the device chip 1 to the side portion 5c of the heat dissipation metal 5, thereby improving the heat dissipation effect of the heat dissipation metal 5. The average distance between the side portion 5c of the heat dissipation metal 5 and the surface facing the side portion 1c of the device chip 1 (meaning the portion E of the side portion 5c of the heat dissipation metal 5 that overlaps with the side portion 1c of the device chip 1 when viewed from the side from arrow A in Figure 1) is preferably 30 μm or less, for example. This is because the closer the side portion 1c of the device chip 1 and the side portion 5c of the heat dissipation metal 5 are, the higher the heat dissipation effect.

[0028] Fig. 3(a) is a side view of the heat dissipation metal 5, and Fig. 3(b) is a plan view of the heat dissipation metal 5. The thickness T of the heat dissipation metal 5 in Fig. 3(a) is preferably 10 μm or more and 30 μm or less, and can be, for example, 25 μm. If the thickness T of the heat dissipation metal 5 is too thick, the force applied to the device chip 1 when the heat dissipation metal 5 is joined by ribbon bonding may be too great, which may lead to damage to the component.

[0029] The width W of the heat dissipation metal 5 is preferably 100 μm or more and 300 μm or less, and can be, for example, 250 μm. Since one side of the planar surface of the device chip of an acoustic wave device is often small, for example, 2 mm or less, the width W of the heat dissipation metal 5 must be configured accordingly. More specifically, in this embodiment, the device chip 1 is rectangular in plan view, with one side being 2 mm and the other being 1 mm. The thickness of the device chip 1 is, for example, 200 μm. The thickness of the package substrate 2 of the acoustic wave device is, for example, approximately 150 μm. The height of the bumps 8 is, for example, 10 μm to 50 μm. The diameter of the bumps 8 is, for example, 70 μm to 120 μm. If the width W of the heat dissipation metal 5 is too wide, the force applied to the device chip 1 when the heat dissipation metal 5 is bonded by ribbon bonding may be large, which may lead to damage to the components of the acoustic wave device.

[0030] In this way, since the metal of the heat dissipation metal 5 has a higher thermal conductivity than the synthetic resin of the sealing portion 3, the heat dissipation metal 5 is configured to join the main surface 1b of the device chip 1 with the electrode pad 10 connected to the ground, so that the heat generated in the device chip 1 is transferred to the ground through the electrode pad 10 and dissipated. This makes it possible to improve the heat dissipation of the acoustic wave device. By improving the heat dissipation of the acoustic wave device, it becomes possible to improve reliability by improving the power resistance of the IDT electrodes, for example.

[0031] Furthermore, by bringing the side portion 5c of the heat dissipation metal 5 close to the side surface 1c of the device chip, heat is transferred from the side surface of the device chip to the heat dissipation metal, which further improves the heat dissipation performance of the acoustic wave device and improves the reliability of the acoustic wave device.

[0032] Furthermore, since the heat dissipation metal 5 is ribbon-shaped and has a larger cross-sectional area than a wire, it is possible to reduce the number of components compared to wires used in wire bonding, and it is possible to create a heat dissipation structure that is less susceptible to the effects of the skin effect and proximity effect caused by the high frequencies that occur when the acoustic wave device is operating.

[0033] Fig. 4 is a diagram showing the positional relationship in a plan view of a receiver 42, a resonator, electrode pads 10 to 15, and a heat dissipation metal 5 arranged on the main surface 1a of the device chip 1. Fig. 5 is a diagram showing the circuit of a transmitter 41 and a receiver 42 of a duplexer 40 of the device chip 1. Note that the pads 21 are omitted in Fig. 4.

[0034] 5, the duplexer 40 includes a transmitter 41 and a receiver 42. The transmitter 41, which functions as a transmission filter, is connected between the antenna terminal ANT and the transmission input terminal TX-IN. The receiver 42, which functions as a reception filter, is connected between the antenna terminal ANT and the reception output terminal RX-OUT.

[0035] The transmitter 41, which serves as a transmit filter, has a ladder-type filter. Specifically, it has series resonators S1, S2, S3, and S4, each of which is a SAW resonator, and parallel resonators P1, P2, and P3. The series resonators S1 to S4 are connected in series with each other, and the parallel resonators P1, P2, and P3 are connected in parallel to the series resonators S1 to S4 and are also connected to ground. Note that, although the ladder-type filter of this embodiment has four stages of series resonators, it may have three or more stages, e.g., five stages.

[0036] The transmitter 41, which serves as a transmit filter, is connected in this order from a transmit input terminal TX-IN to series resonators S1, S2, S3, and S4, and to an antenna terminal ANT. Of the series resonators, the first stage is series resonator S1, the last stage is series resonator S4, and the only ones that are neither the first nor the last stage are series resonators S2 and S3.

[0037] The receiving section 42 and the resonator are located on the main surface 1a of the device chip 1 (see FIG. 1), and are therefore hidden by the device chip 1 in a plan view, but are shown by solid lines in FIG. 4 for ease of viewing. The heat dissipation metal 5 and metal plating 7 are shown by dashed lines.

[0038] The area 31 that is prone to high temperatures in the plan view of FIG. 4 will be described. The transmit filter (transmitter 41) consumes more power than the receive filter (receiver 42), and therefore tends to become hotter during operation. More specifically, the series resonator S1, which is the first stage of the transmitter 41, is located close to the transmit input terminal TX-IN, and therefore consumes the most power and tends to become hotter. The series resonator S4, which is the final stage, is located close to the antenna terminal, and is therefore thought to dissipate heat via the antenna terminal ANT. The series resonators S2 and S3, which are neither the first nor the final stage, are not close to any terminals. Considering these factors, the area 31 around the series resonators S1, S2, and S3 is a region that is prone to becoming hot.

[0039] The device chip-side joint 5a of the heat dissipation metal on the main surface of the device chip is arranged in a position overlapping one of the series resonators S2 and S3 that are not the first or last stage of the transmitter 41 serving as a ladder filter, or between these resonators, in a plan view. By providing the device chip-side joint 5a near the series resonators S2 and S3 that are not the first or last stage in this way, heat from the periphery of the series resonators S2 and S3 that are not near any terminals can be dissipated, thereby more efficiently improving the heat dissipation of the acoustic wave device 100.

[0040] The receiving unit 42 as a receiving filter can employ, for example, a multimode filter (DMS filter).

[0041] Second Embodiment FIG. 6 is a cross-sectional view showing a second embodiment of an acoustic wave device. Portions with the same names and functions as those in the first embodiment are denoted by the same reference numerals, and a description thereof will be omitted. In an acoustic wave device 200, a sealing resin 3a is provided in a part of a space 30 between a side surface 1c of a device chip 1 and a side portion 5c of a heat dissipation metal 5. By providing the sealing resin 3a in the space 30 in this manner, the sealing resin 3a has a higher thermal conductivity than gas, and therefore the heat dissipation efficiency of the heat dissipation metal 5 is improved. This improves the heat dissipation performance of the acoustic wave device 200, thereby improving reliability.

[0042] In the acoustic wave device 200, the electrode pad 10b bonded to the bump 8 and the electrode pad 10c bonded to the heat dissipation metal 5 are provided separately. The electrode pad 10b is connected to the internal conductor 22b of the package substrate 2, and the electrode pad 10c is connected to the internal conductor 22c of the package substrate 2 and is connected to ground through the external connection terminal 23a. In this way, even if the electrode pad 10b bonded to the bump 8 and the electrode pad 10c bonded to the heat dissipation metal 5 are provided separately, heat can be dissipated by the heat dissipation metal 5 as in the first embodiment.

[0043] <About the effects> The effects of the acoustic wave device configured as described above will be described. To verify the effects of the acoustic wave device of this embodiment, temperature simulations were performed on acoustic wave devices (SAW resonators of the conventional example and the example). FIG. 7 shows an acoustic wave device of sample 301 as Example 1. In the acoustic wave device of sample 301, the average distance between the side portion 5c of the heat dissipation metal 5 and the surface facing the side surface 1c of the device chip 1 was set to 30 μm. In FIGS. 7 and 8, the sealing portion 3 made of sealing resin is indicated by a dashed line. Although not shown, temperature simulations were also performed on Example 2, in which the average distance between the side portion 5c of the heat dissipation metal 5 and the surface facing the side surface 1c of the device chip 1 was set to 20 μm, and on Example 3, in which the average distance between the side portion 5c of the heat dissipation metal 5 and the surface facing the side surface 1c of the device chip 1 was set to 10 μm. In Examples 1 to 3, no sealing resin was provided in the space 30 (see FIG. 1). 8 shows a conventional example in which a temperature simulation was performed on an acoustic wave device of sample 300 that does not have a heat dissipation metal. Note that parts with the same names and functions as those in the above-described embodiment are denoted by the same reference numerals and will not be described again.

[0044] The conditions common to the conventional example and Examples 1 to 3 are shown below. All conditions are common except for the heat dissipation metal 5.

[0045] Heat dissipation metal requirements Width: 250 μm Thickness: 20 μm Thermal conductivity: 155 W / m·K (aluminum) Wavelength λ: 4.1μm Piezoelectric substrate material: Lithium tantalate substrate Package substrate material: Multi-layered substrate made of epoxy resin and copper plates

[0046] In Examples 1 to 3 and the conventional example, the highest temperatures were observed at portions U1 (FIG. 7) and U2 (FIG. 8) corresponding to the series resonators S1 and S2 provided on the main surface 1a of the device chip 1 on the package substrate 2 side. The results are shown in the table below. [Table 1]

[0047] As can be seen from Table 1, the maximum temperature of the device chip main surface 1a in Examples 1 to 3 is 2.3°C or more higher than that of the conventional example, indicating that the provision of the heat dissipation metal 5 provides a heat dissipation effect. Furthermore, the main surface 1b of the conventional example has a region where the temperature in the center exceeds 82.4°C, which indicates that it is higher than the main surface 1b of Example 1. This indicates that the provision of the heat dissipation metal 5 provides a heat dissipation effect. Furthermore, comparing Examples 1 to 3, the maximum temperature of the main surface 1a of the device chip 1 decreases as the average distance [μm] between the side surface 1c of the device chip 1 and the surface of the side portion 5c of the heat dissipation metal 5 facing the side surface of the device chip decreases from 30 μm to 20 μm to 10 μm. Therefore, it can be said that the shorter these distances are, the higher the heat dissipation effect. This indicates that heat is transferred from the side surface 1c of the device chip 1 to the side portion 5c of the heat dissipation metal 5 and dissipated.

[0048] In the above-described embodiment, the device chip 1 includes a duplexer 40. However, the device chip may include other filters or resonators as long as it includes at least one SAW resonator. For example, the present invention is applicable to acoustic wave devices including device chips of other multiplexers or transmit filters. In the above-described embodiment, the acoustic wave device includes a ladder-type filter. However, the present invention is applicable to other filters or resonators as long as it includes a SAW resonator. Multiple device chips and multiple heat dissipation metals may be provided on one package substrate 2. The cross-sectional shape of the heat dissipation metal 5 is not limited to those shown in FIGS. 1 and 6 , and may have a shape in which the upper portion 5d of FIG. 6 protrudes further upward.

[0049] It should be noted that the drawings used in the above explanation are schematic, and the dimensions and ratios on the drawings do not necessarily correspond to those of the actual product.

[0050] The present invention has been described above, but when specifically implementing the present invention as an acoustic wave device, it is not limited to the above-described embodiments, and various modifications and additions are possible within the scope of the gist of the present invention. [Explanation of symbols]

[0051] 1. Device chip 2 Package substrate 3 Sealing part 5 Heat dissipation metal 5a Device chip side joint 5b Electrode pad side joint 10, 10b, 10c, 11, 12, 13, 14 Electrode pads 22, 22b, 22c Inner conductor 23, 23a External connection terminal 30 space 31 areas 40 Duplexer 41 Transmitter (transmitting filter) 42 Receiver (receive filter) 100 Acoustic Wave Devices S1,S2,S3,S4 series resonator P1,P2,P3 parallel resonator

Claims

1. A package substrate; a device chip having at least one SAW resonator and being flip-chip mounted on the package substrate; an electrode pad formed on the package substrate; a heat dissipation metal provided on a main surface of the device chip opposite to the package substrate so as to face the main surface; a sealing portion made of a sealing resin that hermetically seals the device chip; Equipped with The heat dissipation metal has a ribbon-like shape and includes a device chip-side bonding portion facing the main surface of the device chip opposite the package substrate, a side portion located on the side of the device chip, and an electrode pad-side bonding portion bonded to the electrode pad. Acoustic wave devices.

2. the side portion of the heat dissipation metal is provided opposite to and spaced from the side surface of the device chip; When viewed from the side of the heat dissipation metal of the device chip in a direction from the side of the device chip to the device chip, the average distance between the portion of the heat dissipation metal facing the side of the device chip and the side of the device chip is 30 μm or less. The acoustic wave device according to claim 1 .

3. The acoustic wave device according to claim 2 , wherein the sealing resin is disposed in at least a part of the space between the side surface of the device chip and the heat dissipation metal.

4. The acoustic wave device is The plurality of SAW resonators include three or more series resonators and a plurality of parallel resonators. The acoustic wave device according to claim 1 .

5. The device chip side bonding portion of the heat dissipation metal on the main surface of the device chip is arranged in a position overlapping with one of the series resonators other than the first stage and the last stage of the ladder filter or between the resonators in the series resonators in the first stage and the last stage of the ladder filter in a plan view. The acoustic wave device according to claim 4 .

6. The thickness of the heat dissipation metal is 10 μm or more and 30 μm or less. The acoustic wave device according to claim 1 .

7. The width of the ribbon-shaped heat dissipation metal is 100 μm or more and 300 μm or less. The acoustic wave device according to claim 1 .

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