Elastic wave device and module provided with same

Abstract

The invention relates to an elastic wave device which is characterized by comprising a supporting substrate, a dielectric layer, a piezoelectric substrate and a resonator, the dielectric layer is formed on the supporting substrate; the piezoelectric substrate is formed on the dielectric layer; the resonator includes an IDT electrode formed on a piezoelectric substrate; wherein the dielectric layer is provided with a stripe-shaped first acoustic impedance region, and the first acoustic impedance region is provided with a long side direction and a short side direction; and stripe-shaped second acoustic impedance regions which are alternately arranged with the first acoustic impedance regions, have a long-side direction and a short-side direction, and have an acoustic impedance different from that of the first acoustic impedance regions. According to the present application, it is possible to provide an elastic wave device which has good temperature characteristics and which further suppresses spurs, and a method for manufacturing the elastic wave device.

Description

Technical Field

[0001] The present application relates to an elastic wave device and a module using the same, and more particularly to a surface elastic wave device using SH waves, such as a filter, a duplexer, or a multiplexer. Background Art

[0002] In high-frequency communication systems of mobile communication terminals such as smartphones, devices such as high-frequency filters are used to remove unnecessary signals outside the frequency band used for communication.

[0003] High-frequency filters and the like use elastic wave devices including surface acoustic wave (SAW) elements. The SAW element is an element in which an IDT (Interdigital Transducer) having a pair of comb-shaped electrodes is formed on a piezoelectric substrate.

[0004] For example, a method for manufacturing an elastic surface wave device is as follows. First, a multilayer film substrate is prepared, which is formed by bonding a piezoelectric substrate that allows elastic waves to propagate and a supporting substrate whose thermal expansion coefficient is smaller than that of the piezoelectric substrate. Next, a plurality of IDT electrodes are formed on the multilayer film substrate using photolithography technology, and then the surface elastic wave device is formed by cutting out a predetermined size. In this manufacturing method, by using the multilayer film substrate, the change in the size of the piezoelectric substrate caused by temperature changes can be suppressed by the supporting substrate, thereby stabilizing the frequency characteristics of the elastic wave device.

[0005] For example, according to Patent Document 1 (Japanese Patent Publication No. 2009-278610), in order to improve the temperature characteristics of elastic wave devices, it is known to bond a supporting substrate such as a sapphire substrate with a high Young's modulus and a small linear expansion coefficient to a piezoelectric substrate to suppress expansion and contraction caused by temperature changes.

[0006] As disclosed in Patent Document 1, in order to improve the temperature characteristics of elastic wave devices, it is known to bond a support substrate such as a sapphire substrate having a high Young's modulus and a small linear expansion coefficient to a piezoelectric substrate to suppress expansion and contraction caused by temperature changes. However, a resonator using such a support substrate generates spurious signals, particularly on the high-frequency side, resulting in poor filter characteristics. Summary of the invention

[0007] The present application has been made to solve the above-mentioned problems and has an object to provide an elastic wave device having good temperature characteristics and further suppressing spurious emission, and a module using the elastic wave device.

[0008] In a first aspect, an elastic wave device is provided in this embodiment, characterized in that it comprises a supporting substrate, a dielectric layer, a piezoelectric substrate and a resonator;

[0009] The dielectric layer is formed on the supporting substrate;

[0010] The piezoelectric substrate is formed on the dielectric layer;

[0011] The resonator includes an IDT electrode formed on the piezoelectric substrate;

[0012] In which, the dielectric layer has a striped first acoustic impedance region, the first acoustic impedance region has a long side direction and a short side direction; and a striped second acoustic impedance region, the second acoustic impedance region is alternately arranged with the first acoustic impedance region and has a long side direction and a short side direction, and the second acoustic impedance region has an acoustic impedance different from that of the first acoustic impedance region.

[0013] In some embodiments, the length directions of the first acoustic impedance region and the second acoustic impedance region are configured to be the same as the length directions of the electrode fingers of the IDT electrode.

[0014] In some embodiments, a distance between the first acoustic impedance region and the second acoustic impedance region is different from an electrode distance between the IDT electrodes.

[0015] In some of the embodiments, when the wavelength of the elastic wave determined by the electrode interval of the IDT electrodes is set to λ, the thickness of the piezoelectric substrate is greater than or equal to 0.4λ and less than or equal to 1.0λ.

[0016] In some of the embodiments, when the wavelength of the elastic wave determined by the electrode spacing of the IDT electrodes is set to λ, the thickness of the dielectric layer is greater than or equal to 0.1λ and less than or equal to 0.5λ.

[0017] In some of the embodiments, in a cross-sectional view of the first acoustic impedance region and the second acoustic impedance region in the short side direction, within a range where four electrode fingers of the IDT electrode are configured, the first acoustic impedance region and the second acoustic impedance region are configured as three periods.

[0018] In some of the embodiments, in a cross-sectional view of the first acoustic impedance region and the second acoustic impedance region in the short side direction, within a range where eight electrode fingers of the IDT electrode are configured, the first acoustic impedance region and the second acoustic impedance region are configured as five to six periods.

[0019] In some of the embodiments, the first acoustic impedance region is made of silicon dioxide.

[0020] In some embodiments, the second acoustic impedance region is made of a material including aluminum oxide, aluminum nitride, silicon nitride, silicon oxynitride, silicon, or silicon carbide.

[0021] In some of the embodiments, the supporting substrate is made of sapphire, silicon, alumina, spinel, quartz or glass.

[0022] According to a second aspect, a module is provided in this embodiment, comprising the elastic wave device according to the first aspect.

[0023] According to the present application, it is possible to provide an elastic wave device having good temperature characteristics and further suppressing spurious emission, and a method for manufacturing the same.

[0024] Details of one or more embodiments of the present application are set forth in the following drawings and description to make other features, objects, and advantages of the present application more readily apparent. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The drawings described herein are used to provide further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute improper limitations on the present application.

[0026] Figure 1 It is a cross-sectional view showing the elastic wave device 1 according to the first embodiment.

[0027] Figure 2 1 is a cross-sectional view showing a device chip 5 of the elastic wave device 1 according to the first embodiment.

[0028] Figure 3 1 is a plan view of functional element 50 of elastic wave device 1 according to Embodiment 1.

[0029] Figure 4 It is a diagram showing the resonance characteristics of the elastic wave device 1 according to the first embodiment and a resonator of a comparative example.

[0030] Figure 5 This is a diagram showing the resonance characteristics of the elastic wave device 1 according to the first embodiment and a resonator of a comparative example (part 2).

[0031] Figure 6 1 is a diagram showing the resonance characteristics of the resonator of the elastic wave device 1 according to the first embodiment (eg, there are five periods within the range of eight electrode fingers).

[0032] Figure 7 1 is a diagram showing the resonance characteristics of the resonator of the elastic wave device 1 according to the first embodiment (eg, there are six periods within the range of eight electrode fingers).

[0033] Figure 82 is a cross-sectional view showing a structure in which five second acoustic impedance regions 12B are arranged within the range of eight electrode fingers 51 b .

[0034] Fig. 9 1 is a plan view of functional element 50 of elastic wave device 1 according to the second embodiment.

[0035] Fig.10 It is a diagram for explaining a method of manufacturing the elastic wave device 1 .

[0036] Fig.11 These are diagrams for explaining a method for manufacturing the elastic wave device 1 according to the second embodiment.

[0037] Fig.12 It is a longitudinal cross-sectional view of a module to which the elastic wave device 1 according to the first to third embodiments is applied.

[0038] In the figure: 1, elastic wave device; 3, wiring substrate; 5, device chip; 11, piezoelectric substrate; 12, dielectric layer; 12A, first acoustic impedance region; 12B, second acoustic impedance region; 13, supporting substrate; 17, sealing part; 100, module; 111, inductor; 117, sealing part; 130, wiring substrate. DETAILED DESCRIPTION

[0039] In order to more clearly understand the purpose, technical solutions and advantages of the present application, the present application is described and illustrated below in conjunction with the accompanying drawings and embodiments.

[0040] Unless otherwise defined, the technical terms or scientific terms involved in this application shall have the general meaning understood by people with ordinary skills in the technical field to which this application belongs. The words "one", "a", "a", "the", "these" and the like in this application do not represent quantitative restrictions, and they can be singular or plural. The terms "include", "comprise", "have" and any variants thereof involved in this application are intended to cover non-exclusive inclusions; for example, a process, method and system, product or device comprising a series of steps or modules (units) is not limited to the listed steps or modules (units), but may include unlisted steps or modules (units), or may include other steps or modules (units) inherent to these processes, methods, products or devices. The words "connect", "connected", "coupled" and the like involved in this application are not limited to physical or mechanical connections, but may include electrical connections, whether directly or indirectly. The "multiple" involved in this application refers to two or more. "And / or" describes the association relationship of associated objects, indicating that there can be three relationships. For example, "A and / or B" can mean: A exists alone, A and B exist at the same time, and B exists alone. Usually, the character " / " indicates that the objects associated with each other are in an "or" relationship. The terms "first", "second", "third", etc. involved in this application are only used to distinguish similar objects and do not represent a specific ordering of the objects.

[0041] Implementation Method 1

[0042] Figure 1 It is a cross-sectional view showing the elastic wave device 1 according to the first embodiment.

[0043] like Figure 1 As shown, elastic wave device 1 includes wiring substrate 3 , external connection terminals 31 , device chip 5 , electrode pads 9 , bumps 15 , and sealing portion 17 .

[0044] For example, the wiring substrate 3 is a multilayer substrate made of resin. For example, the wiring substrate 3 is a low temperature co-fired ceramics (LTCC) multilayer substrate made of a plurality of dielectric layers.

[0045] A plurality of external connection terminals 31 are formed on the lower surface of the wiring substrate 3 .

[0046] A plurality of electrode pads 9 are formed on the main surface of the wiring substrate 3. For example, the electrode pads 9 are formed of copper or an alloy containing copper. For example, the thickness of the electrode pads 9 is 10 μm to 20 μm.

[0047] A bump 15 is formed on the upper surface of each electrode pad 9. For example, the bump 15 is a gold bump. For example, the height of the bump 15 is 10 μm to 50 μm.

[0048] A gap 16 is formed between the wiring substrate 3 and the device chip 5 .

[0049] The device chip 5 is mounted on the wiring substrate 3 by flip chip bonding via the bumps 15. The device chip 5 is electrically connected to the plurality of electrode pads 9 via the plurality of bumps 15.

[0050] The device chip 5 is a substrate on which the elastic wave elements 50 are formed. For example, a transmission filter and a reception filter are formed on the main surface of the device chip 5, and the transmission filter includes a plurality of elastic wave elements 50 mainly serving as resonators.

[0051] The transmission filter is a ladder-type filter composed of a plurality of series resonators and a plurality of parallel resonators, and is used to transmit a passband signal of the transmission filter.

[0052] The reception filter is a ladder-type filter for transmitting a passband signal of the reception filter.

[0053] The sealing portion 17 is made of an insulator such as synthetic resin or a metal material and is used to cover the device chip 5 .

[0054] When the sealing part 17 is formed of a synthetic resin, the synthetic resin may be epoxy resin, polyimide, etc. Preferably, the sealing part 17 is made of epoxy resin and is formed of the epoxy resin by a low temperature curing process.

[0055] Figure 2 1 is a cross-sectional view showing a device chip 5 of the elastic wave device 1 according to the first embodiment.

[0056] like Figure 2 As shown, the device chip 5 includes a piezoelectric substrate 11, a dielectric layer 12, and a support substrate 13. On the piezoelectric substrate 11, an elastic wave element 50 is formed.

[0057] The piezoelectric substrate 11 is, for example, a substrate formed of a piezoelectric single crystal such as lithium tantalate, lithium niobate, or crystal. In another embodiment, the piezoelectric substrate 11 is a substrate formed of piezoelectric ceramics.

[0058] The thickness of the piezoelectric substrate 11 can be set to 0.3 μm to 5 μm.

[0059] The dielectric layer 12 includes a first acoustic impedance region 12A and a second acoustic impedance region 12B. The constituent material of the first acoustic impedance region 12A includes silicon nitride, silicon oxynitride, silicon, aluminum oxide, silicon dioxide or silicon carbide. The constituent material of the second acoustic impedance region 12B includes aluminum oxide, aluminum nitride, silicon nitride, silicon oxynitride, silicon or silicon carbide, and is different from the material used in the first acoustic impedance region 12A.

[0060] The thickness of the dielectric layer 12 may be 0.5 μm to 2 μm.

[0061] exist Figure 2 In the example shown, the first acoustic impedance region 12A and the second acoustic impedance region 12B are arranged in three periods with respect to the four electrode fingers 51b on the piezoelectric substrate 11. In other words, three second acoustic impedance regions 12B are arranged within the range of the four electrode fingers 51b. Further, the pitch arrangement of the first acoustic impedance region 12A and the second acoustic impedance region 12B is different from the pitch of the electrode fingers 51b.

[0062] like Figure 2 As shown, the second acoustic impedance region 12B may also be formed to penetrate the first acoustic impedance region 12A. That is, the dielectric layer 12 may also be formed on the piezoelectric substrate 11 side or the support substrate 13 side so that the second acoustic impedance region 12B is exposed. The thickness of the second acoustic impedance region 12B may also be more than half of the thickness of the dielectric layer 12.

[0063] According to another embodiment, the dielectric layer 12 may also be formed such that the second acoustic impedance region 12B is not exposed toward the piezoelectric substrate 11 side.

[0064] According to another embodiment, the dielectric layer 12 may also be formed such that the second acoustic impedance region 12B is not exposed toward the support substrate 13 side.

[0065] The constituent materials of the support substrate 13 include sapphire, silicon, alumina, spinel, silicon nitride, aluminum nitride, silicon carbide, silicon oxynitride, diamond, quartz, glass, etc. The smaller the thermal expansion coefficient of the support substrate 13 and the higher the Young's modulus, the better. The temperature characteristics of the elastic wave device 1 are improved by the above-mentioned support substrate 13. A representative support substrate 13 that meets such conditions is a sapphire substrate, which has a high hardness and is chemically stable, so it is more difficult to process a surface with a concave-convex shape or a serrated shape, resulting in a decrease in the yield. Therefore, the support substrate 13 is preferably a flat rectangular parallelepiped with a flat surface.

[0066] The thickness of the support substrate 13 is 50 μm to 200 μm.

[0067] Figure 3 is a top view of a functional element 50 of the elastic wave device 1 according to the first embodiment. Figure 3 , an example of an elastic wave element 50 formed on a piezoelectric substrate 11 is described.

[0068] For ease of explanation, Figure 3 The piezoelectric substrate 11 is not shown, but an elastic wave element 50 is formed on the main surface of the piezoelectric substrate 11 (see Figure 2 ), which includes an IDT (Interdigital Transducer) electrode 51 and a pair of reflectors 52. The IDT electrode 51 and the pair of reflectors 52 are provided so as to be able to excite elastic waves (mainly SH waves).

[0069] For example, the IDT electrode 51 and the pair of reflectors 52 are formed of an alloy of aluminum and copper. For example, the IDT electrode 51 and the pair of reflectors 52 are formed of an appropriate metal such as aluminum, molybdenum, iridium, tungsten, cobalt, nickel, ruthenium, chromium, strontium, titanium, palladium, silver, or an alloy of these metals.

[0070] For example, the IDT electrode 51 and the pair of reflectors 52 are formed of a laminated metal film in which a plurality of metal layers are laminated. For example, the thickness of the IDT electrode 51 and the pair of reflectors 52 is 150 nm to 450 nm.

[0071] The IDT electrode 51 includes a pair of comb-shaped electrodes 51 a. The pair of comb-shaped electrodes 51 a face each other. The comb-shaped electrode 51 a includes a plurality of electrode fingers 51 b and a bus bar 51 c.

[0072] The bus bar 51c connects the plurality of electrode fingers 51b. The plurality of electrode fingers 51b are arranged so that their length directions are aligned.

[0073] One of the pair of reflectors 52 is adjacent to one side of the IDT electrode 51 . The other of the pair of reflectors 52 is adjacent to the other side of the IDT electrode 51 .

[0074] The piezoelectric substrate 11 and the supporting substrate 13 ( Figure 3 A dielectric layer 12 is formed between the two (not shown). Figure 3 As shown in FIG. 1 , the first acoustic impedance region 12A and the second acoustic impedance region 12B are respectively formed as stripe-shaped regions having a long side direction and a short side direction. Figure 3 As shown, the first acoustic impedance regions 12A and the second acoustic impedance regions 12B are alternately arranged in the short-side direction.

[0075] like Figure 3 As shown, the long side direction of the first acoustic impedance region 12A and the second acoustic impedance region 12B is the same as the long side direction of the electrode finger 51 b .

[0076] Figure 4This is a diagram showing the resonance characteristics of the elastic wave device 1 according to Embodiment 1 and the resonator of the comparative example. Lithium tantalate is used for the piezoelectric substrate 11. The thickness of the piezoelectric substrate 11 is set to 0.4λ, 0.5λ, 0.6λ, 0.7λ, and 0.8λ when the wavelength of the elastic wave determined by the pitch of the electrode fingers is λ, and calculation is performed.

[0077] The thickness of the dielectric layer 12 is 0.25λ. In addition, the widths of the first acoustic impedance region 12A and the second acoustic impedance region 12B in the short side direction are set to be the same width, that is, the duty ratio is set to 50%. The first acoustic impedance region 12A is made of silicon dioxide. The second acoustic impedance region 12B is made of aluminum oxide. The support substrate 13 is a sapphire substrate.

[0078] In the comparative example, lithium tantalate is formed to a thickness of 0.4λ on a sapphire substrate, and dielectric layer 12 is not included. Except for this, the resonator of the comparative example is the same as that of elastic wave device 1 according to the first embodiment.

[0079] exist Figure 4 In the figure, the peaks and valleys observed from 950MHz to 1050MHz are caused by the original resonant mode. In contrast, the peaks and valleys that appear at higher frequencies, that is, from 1100MHz to 1700MHz, are based on non-original resonant modes and are called spurious. If there are strong spurious signals, the filtering characteristics will be significantly deteriorated when constructing a resonator to construct a filter, etc. Therefore, the smaller the height of the spurious peaks and the depth of the valleys, the better the characteristics of the resonator. Figure 4 As shown, it can be seen that the resonator of the elastic wave device involved in embodiment 1 has significantly improved spurious performance in any resonance characteristic when the thickness of the piezoelectric substrate 11 is in the range of 0.4λ to 0.8λ, compared with the resonance characteristic LT0.4λ / SA of the piezoelectric substrate in the comparative example, where the SA is a sapphire substrate.

[0080] Figure 5 Graph (part 2) showing the resonance characteristics of elastic wave device 1 according to embodiment 1 and a resonator of a comparative example. The thickness of piezoelectric substrate 11 is 0.6λ. The thickness of dielectric layer 12 is set to 0.05λ, 0.1λ, 0.25λ, and 0.5λ, and calculations are performed. Other aspects are similar to Figure 4 The comparative example is the same as the description in . In the comparative example, lithium tantalate is formed with a thickness of 0.6λ on a sapphire substrate, and does not include dielectric layer 12 . The other aspects of the comparative example are the same as the resonator of elastic wave device 1 according to the first embodiment.

[0081] like Figure 5As shown, it can be seen that the resonator of the elastic wave device according to the first embodiment has improved spurious emission compared to the comparative example at any thickness of the dielectric layer 12. In particular, when the thickness of the dielectric layer 12 is 0.1λ or more, the spurious emission is significantly improved compared to the comparative example. Furthermore, when the thickness of the dielectric layer 12 is 0.25λ and 0.5λ, the spurious emission is improved more significantly.

[0082] Figure 6 1 is a diagram showing the resonance characteristics of the resonator of the elastic wave device 1 according to the first embodiment (eg, there are five periods within the range of eight electrode fingers).

[0083] The resonance characteristic 4λ / 4 is a resonance characteristic when the first acoustic impedance region 12A and the second acoustic impedance region 12B are arranged in four cycles within the range of 4λ electrode fingers, that is, eight electrode fingers 51b. In other words, four second acoustic impedance regions 12B are arranged within the range of eight electrode fingers 51b.

[0084] The resonance characteristic 4λ / 5 is a resonance characteristic when the first acoustic impedance region 12A and the second acoustic impedance region 12B are arranged in five cycles within the range of 4λ electrode fingers, that is, eight electrode fingers 51b. In other words, five second acoustic impedance regions 12B are arranged within the range of eight electrode fingers 51b. Figure 8 2 is a cross-sectional view showing a structure in which five second acoustic impedance regions 12B are arranged within the range of eight electrode fingers 51 b .

[0085] The resonance characteristic 4λ / 7 is a resonance characteristic when the first acoustic impedance region 12A and the second acoustic impedance region 12B are arranged in seven cycles with respect to 4λ electrode fingers, that is, eight electrode fingers 51b. In other words, seven second acoustic impedance regions 12B are arranged within the range of eight electrode fingers 51b.

[0086] Figure 7 1 is a diagram showing the resonance characteristics of the resonator of the elastic wave device 1 according to the first embodiment (eg, there are six periods within the range of eight electrode fingers).

[0087] The resonance characteristic 4λ / 6 is a resonance characteristic when the first acoustic impedance region 12A and the second acoustic impedance region 12B are arranged in six cycles within the range of eight electrode fingers 51b, which are arranged with 4λ. In other words, six second acoustic impedance regions 12B are arranged within the range of eight electrode fingers 51b. In other words, three second acoustic impedance regions 12B are arranged within the range of four electrode fingers 51b. The resonance characteristic 4λ / 4 and the resonance characteristic 4λ / 7 are similar to Figure 6 Same as described in .

[0088] like Figure 6 and Figure 7As shown, it can be seen that the resonator of the elastic wave device according to Embodiment 1 significantly improves spurious emission when first acoustic impedance regions 12A and second acoustic impedance regions 12B are arranged in five or six cycles with respect to eight electrode fingers 51 b.

[0089] Here, the results of the first acoustic impedance region 12A and the second acoustic impedance region 12B under four cycles, five cycles, six cycles, seven cycles and discrete conditions are shown for eight electrode fingers. The results show that the results of five cycles and six cycles are relatively good. However, considering that the improvement effect is small when the ratio of the number of electrode fingers 51b to the number of second acoustic impedance 12B is close to 2 times or 1 times, it is reasonable to expect that good characteristics can also be obtained in the case of a cycle between five cycles and six cycles, such as 5.5 cycles (for sixteen electrode fingers, the number of second acoustic impedance 12B is 11). That is, the good region has a certain width.

[0090] According to the first embodiment described above, it is possible to provide an elastic wave device that has better temperature characteristics and further suppresses spurious emission.

[0091] Implementation Method 2

[0092] Fig. 9 FIG. 4 is a top view of a functional element 50 of the elastic wave device 1 according to the second embodiment. Fig. 9 As shown, the long side direction of the first acoustic impedance region 12A and the second acoustic impedance region 12B is different from the long side direction of the electrode finger 51b. With this configuration, the acoustic impedance difference of the lateral mode waves is generated, thereby reducing the lateral mode spurious.

[0093] The other structures are the same as those in Implementation 1, and thus the description thereof will be omitted.

[0094] According to the second embodiment described above, it is possible to provide an elastic wave device in which high-frequency spurious emission is suppressed and transverse-mode spurious emission is reduced.

[0095] Fig.10 is a diagram for explaining a method for manufacturing the elastic wave device 1 according to the first embodiment. Fig.10 A method for manufacturing the elastic wave device 1 according to the first embodiment will be described.

[0096] like Fig.10 As shown in (a), a first acoustic impedance film is formed on a supporting substrate 13. Next, the first acoustic impedance film is patterned. In the patterning step, a process such as a lift-off method or an etching method can be appropriately selected according to the material of the first acoustic impedance film.

[0097] like Fig.10As shown in (b), the area where the first acoustic impedance film is removed by the patterning process is filled with the second acoustic impedance material. The filling method of the second acoustic impedance material can be appropriately selected according to the material, such as the scraper method, the evaporation method, the sputtering method and the like.

[0098] like Fig.10 As shown in (c), the second acoustic impedance material is polished until the first acoustic impedance film is exposed. In the polishing process, a chemical polishing process or a mechanical polishing process can be appropriately selected according to the material.

[0099] like Fig.10 As shown in (d), after the polishing step, it is bonded to piezoelectric substrate 11. Acoustic wave element 50 is formed so as to obtain desired device characteristics on piezoelectric substrate 11, and a packaging step is performed to obtain acoustic wave device 1 according to the first embodiment.

[0100] Fig.11 is a diagram for explaining a second method for manufacturing the elastic wave device 1. Fig.11 A second method for manufacturing the elastic wave device 1 will be described.

[0101] like Fig.11 As shown in (a), a second acoustic impedance film is formed on a supporting substrate 13. Next, the second acoustic impedance film is patterned. In the patterning step, a process such as a lift-off method or an etching method can be appropriately selected according to the material of the second acoustic impedance film.

[0102] like Fig.11 As shown in (b), the first acoustic impedance material is filled in the area where the second acoustic impedance film is removed by the patterning process. The filling method of the first acoustic impedance material can be appropriately selected according to the material, such as a scraper method, a vapor deposition method, a sputtering method, a press-in method, and the like.

[0103] like Fig.11 As shown in (c), the first acoustic impedance material is polished. The polishing may be performed until the first acoustic impedance film is exposed, or the first acoustic impedance film may not be exposed. In the polishing process, a chemical polishing process or a mechanical polishing process may be appropriately selected according to the material.

[0104] like Fig.11 As shown in (d), after the polishing step, it is bonded to piezoelectric substrate 11. Acoustic wave element 50 is configured to obtain desired device characteristics, and a packaging step is performed to obtain acoustic wave device 1.

[0105] Fig.12 It is a longitudinal sectional view of a module according to the elastic wave device 1 applied to Embodiments 1 to 3. The same reference numerals are used to denote the same or corresponding parts as those in Embodiments 1 to 3, and the description of such parts is omitted.

[0106] exist Fig.12 Module 100 includes wiring substrate 130 , a plurality of external connection terminals 131 , integrated circuit component IC, elastic wave device 1 , inductor 111 , and sealing portion 117 .

[0107] A plurality of external connection terminals 31 are formed on the lower surface of the wiring substrate 130. The plurality of external connection terminals 131 are mounted on a motherboard of a predetermined mobile communication terminal.

[0108] For example, an integrated circuit component IC is mounted inside the wiring substrate 130. The integrated circuit component IC includes a switch circuit and a low noise amplifier.

[0109] Acoustic wave device 1 is mounted on the main surface of wiring substrate 130 .

[0110] The inductor 111 is an integrated passive device (IPD) and is mounted on the main surface of the wiring substrate 130 for impedance matching.

[0111] Sealing portion 117 seals a plurality of electronic components including elastic wave device 1 .

[0112] Module 100 described above includes elastic wave device 1. Therefore, it is possible to provide an elastic wave device module having good temperature characteristics and further suppressing spurious emission.

[0113] Although some aspects of at least one embodiment have been described above, it should be understood that various changes, modifications and improvements can be easily conceived by those skilled in the art. The changes, modifications and improvements involved are intended to become part of this application and are intended to be within the scope of this application.

[0114] The expressions and terms used in the present invention are for illustrative purposes only and should not be considered as limiting. The use of "include", "have", "have", "include" and their variations as used herein means including the following listed items, their equivalents and additional items.

[0115] The reference to "or" means that any term described using "or" can be interpreted as indicating one, multiple, and all instances of the terms.

[0116] References to front, back, left, right, top, bottom, up, down, horizontal, vertical, inside and outside are for the convenience of description. Such references do not mean that the constituent elements of the present application are limited to any particular position or spatial orientation. Therefore, the above description and drawings are only for illustration.

[0117] The term "embodiment" in this application refers to a specific feature, structure or characteristic described in conjunction with the embodiment that can be included in at least one embodiment of the present application. The appearance of this phrase in various locations in the specification does not necessarily mean the same embodiment, nor does it mean that it is mutually exclusive with other embodiments and is independent or optional. It is clearly or implicitly understood by those of ordinary skill in the art that the embodiments described in this application can be combined with other embodiments without conflict.

[0118] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of patent protection. It should be pointed out that, for a person of ordinary skill in the art, several variations, corrections and improvements can be made without departing from the concept of the present application, and these all belong to the scope of protection of the present application. Therefore, the scope of protection of the present application shall be subject to the attached claims.

Claims

1. An elastic wave device, characterized in that: It has a supporting substrate, a dielectric layer, a piezoelectric substrate and a resonator; The dielectric layer is formed on the supporting substrate; The piezoelectric substrate is formed on the dielectric layer; The resonator includes an IDT electrode formed on the piezoelectric substrate; In which, the dielectric layer has a striped first acoustic impedance region, the first acoustic impedance region has a long side direction and a short side direction; and a striped second acoustic impedance region, the second acoustic impedance region is alternately arranged with the first acoustic impedance region and has a long side direction and a short side direction, and the second acoustic impedance region has an acoustic impedance different from that of the first acoustic impedance region.

2. The elastic wave device according to claim 1, characterized in that: The length directions of the first acoustic impedance region and the second acoustic impedance region are arranged to be the same as the length directions of the electrode fingers of the IDT electrode.

3. The elastic wave device according to claim 1, characterized in that: The distance between the first acoustic impedance region and the second acoustic impedance region is different from the electrode distance between the IDT electrodes.

4. The elastic wave device according to claim 1, characterized in that: When the wavelength of the elastic wave determined by the electrode interval of the IDT electrodes is λ, the thickness of the piezoelectric substrate is greater than or equal to 0.4λ and less than or equal to 1.0λ.

5. The elastic wave device according to claim 1, characterized in that: When the wavelength of the elastic wave determined by the electrode interval of the IDT electrodes is λ, the thickness of the dielectric layer is greater than or equal to 0.1λ and less than or equal to 0.5λ.

6. The elastic wave device according to claim 1, characterized in that: In a cross-sectional view of the first acoustic impedance region and the second acoustic impedance region in the short-side direction, the first acoustic impedance region and the second acoustic impedance region are arranged in three periods within a range where four electrode fingers of the IDT electrode are arranged.

7. The elastic wave device according to claim 1, characterized in that: In a cross-sectional view of the first acoustic impedance region and the second acoustic impedance region in the short-side direction, the first acoustic impedance region and the second acoustic impedance region are arranged in five to six periods within a range where eight electrode fingers of the IDT electrode are arranged.

8. The elastic wave device according to claim 1, characterized in that: The first acoustic impedance region is made of silicon dioxide.

9. The elastic wave device according to claim 1, characterized in that: The second acoustic impedance region is made of a material including aluminum oxide, aluminum nitride, silicon nitride, silicon oxynitride, silicon or silicon carbide.

10. The elastic wave device according to claim 1, wherein: The supporting substrate is made of sapphire, silicon, alumina, spinel, quartz or glass.

11. A module, characterized in that: An elastic wave device according to any one of claims 1 to 10.

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