Elastic wave device and electronic module

Abstract

The invention discloses an elastic wave device and an electronic module. The elastic wave device comprises a substrate and a plurality of interdigital transducers, the interdigital transducer is positioned above the substrate and comprises a plurality of interdigital electrodes; the interdigital electrode is positioned above the substrate and comprises a first metal layer and a second metal layer; the first metal layer is located above the second metal layer; the density of the first metal layer is greater than 16000 kg per cubic meter. By means of the surface acoustic wave filter, the problem that in the prior art, due to structural limitation of a traditional surface acoustic wave filter, the frequency band width is relatively limited is solved, and the frequency band width of the surface acoustic wave filter is widened while the surface of the interdigital transducer is not corroded.

Description

Technical Field

[0001] The present invention relates to the field of filters, and in particular to an elastic wave device and an electronic module. Background Art

[0002] An elastic wave device is a solid device that uses the characteristics of an acoustic-electric transducer to process various acoustic signals propagating on the surface of a piezoelectric material substrate and complete various functions, including surface acoustic wave filters, delay lines, oscillators and other devices. Among them, a surface acoustic wave filter (Surface Acoustic Wave, SAW) is abbreviated as a SAW filter, and mainly consists of a wafer substrate with piezoelectric characteristics and interdigital transducers (Interdigital Transducer, IDT) fabricated on the substrate. The principle of a surface acoustic wave filter mainly realizes acoustic-electric conversion by using its piezoelectric effect and the physical characteristics of surface acoustic wave propagation.

[0003] With the development of technologies in communication fields such as 5G, there are also higher requirements for the bandwidth of filters. However, due to the working principle and structural limitations of traditional surface acoustic wave filters, their bandwidth is relatively limited, and the surface of the interdigital transducers in the filter is prone to corrosion.

[0004] Regarding the problem that due to the structural limitations of traditional surface acoustic wave filters in the related art, their bandwidth is relatively limited, there is currently no effective solution. Summary of the Invention

[0005] In this embodiment, an elastic wave device and an electronic module are provided to solve the problems in the related art that due to the structural limitations of traditional surface acoustic wave filters, their bandwidth is relatively limited and the surface of the interdigital transducers is prone to corrosion.

[0006] In a first aspect, in this embodiment, an elastic wave device is provided, including a substrate and a plurality of interdigital transducers; The interdigital transducers are located above the substrate and include a plurality of interdigital electrodes; The interdigital electrodes are located above the substrate and include a first metal layer and a second metal layer; the first metal layer is located above the second metal layer; the density of the first metal layer is greater than 16,000 kilograms per cubic meter.

[0007] In some of the embodiments, the material of the first metal layer includes at least one of platinum, tungsten, rhenium, tantalum, gold, and hafnium.

[0008] In some of the embodiments, the thickness range of the first metal layer is 5% - 6% of the wavelength of the interdigital transducer.

[0009] In some of these embodiments, the thickness range of the second metal layer is 3% - 9.5% of the wavelength of the interdigital transducer.

[0010] In some of these embodiments, the interdigital electrode further includes an anti - oxidation layer, an anti - melting layer, and an adhesion layer; The anti - oxidation layer is located above the first metal layer; the anti - melting layer is located between the first metal layer and the second metal layer; the adhesion layer is located below the second metal layer.

[0011] In some of these embodiments, the material of the anti - melting layer includes at least one of titanium, nickel, gold, silver, and molybdenum.

[0012] In some of these embodiments, the elastic wave device further includes a temperature compensation layer and a frequency - modulation layer; The temperature compensation layer is located between the anti - oxidation layer and the frequency - modulation layer; the frequency - modulation layer is located above the temperature compensation layer.

[0013] In some of these embodiments, the substrate includes at least one piezoelectric material.

[0014] In some of these embodiments, the operating frequency range of the elastic wave device is 420 MHz - 550 MHz.

[0015] In a second aspect, in the present embodiment, an electronic module is provided, including a plurality of the elastic wave devices described in the first aspect above.

[0016] Compared with the related art, in an elastic wave device and an electronic module provided in the present embodiment, the elastic wave device includes a substrate and a plurality of interdigital transducers; the interdigital transducers are located above the substrate and include a plurality of interdigital electrodes; the interdigital electrodes are located above the substrate and include a first metal layer and a second metal layer; the first metal layer is located above the second metal layer; the density of the first metal layer is greater than 16000 kg / m³. Through this device, the problem in the prior art that due to the structural limitations of traditional surface acoustic wave filters, their bandwidth is relatively limited is solved, and while the surface of the interdigital transducer is not corroded, the bandwidth of the surface acoustic wave filter is broadened. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings described herein are used to provide a further understanding of the present application and form a part of the present application. The schematic embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation to the present application. In the drawings: Figure 1 is a schematic structural diagram of an elastic wave device of an embodiment; Figure 2 is a schematic structural diagram of an elastic wave device of an embodiment; Figure 3 Schematic structural diagram of an elastic wave device according to an embodiment; Figure 4 Schematic structural diagram of the elastic wave device of this preferred embodiment; Figure 5 Surface of the interdigital transducer of this preferred embodiment; Figure 6 Filtering characteristic diagram of the elastic wave device of this preferred embodiment; Figure 7 Schematic structural diagram of the elastic wave device of Embodiment 1; Figure 8 Filtering characteristic diagram of the elastic wave device of Embodiment 1; Figure 9 Schematic structural diagram of the elastic wave device of Embodiment 2; Figure 10 Surface of the interdigital transducer of Embodiment 2; Figure 11 Schematic structural diagram of the elastic wave device of Embodiment 3; Figure 12 Surface of the interdigital transducer of Embodiment 3; Figure 13 Filtering characteristic diagram of the elastic wave device of Embodiment 3.

[0018] In the figure: 1. Interdigital transducer; 2. Substrate; 3. Sealing part; 4. Device chip; 5. Wiring substrate; 6. External connection terminal; 7. Cavity; 8. Reflector; 10. Interdigital electrode; 11. Bump; 12. Electrode pad; 101. First metal layer; 102. Second metal layer; 103. Antioxidant layer; 104. Anti-melting layer; 105. Adhesion layer; 201. Lithium tantalate piezoelectric layer; 202. Silicon oxide piezoelectric layer; 203. Spinel piezoelectric layer. Detailed implementation manners

[0019] To more clearly understand the purpose, technical solution and advantages of this application, the following describes and explains this application in combination with the accompanying drawings and embodiments.

[0020] Unless otherwise defined, technical terms or scientific terms involved in this application shall have the ordinary meanings understood by those with ordinary skills in the technical field to which this application belongs. In this application, words such as "a", "an", "one kind", "the", "these", etc. do not indicate a limitation in quantity, and they can be singular or plural. Terms such as "include", "comprise", "have" and any variations thereof involved in this application are intended to cover non-exclusive inclusion; for example, a process, method, system, product or device that includes 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 in these processes, methods, products or devices. Terms such as "connect", "be connected", "couple" and other similar words involved in this application are not limited to physical or mechanical connections, but may include electrical connections, whether directly connected or indirectly connected. The term "plurality" involved in this application means 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 simultaneously, and B exists alone. Usually, the character " / " indicates that the objects associated before and after are in an "or" relationship. Terms such as "first", "second", "third", etc. involved in this application only distinguish similar objects and do not represent a specific sorting for the objects.

[0021] Figure 1 and Figure 2 is a schematic structural diagram of a surface acoustic wave device according to an embodiment. Figure 2 is Figure 1 a top view of the surface acoustic wave device in Figure 1 and Figure 2 As shown, the surface acoustic wave device of this embodiment includes a substrate 2 and a plurality of interdigital transducers 1.

[0022] Specifically, the substrate 2 includes at least one piezoelectric material. When an external force is applied to the substrate 2, the substrate 2 will generate a small deformation and generate an electrical signal; one side of the interdigital transducer 1 converts the electrical signal into a sound wave, and the other side of the interdigital transducer 1 converts the received sound wave back into an electrical signal, thereby realizing functions such as signal frequency modulation and signal filtering of the surface acoustic wave device.

[0023] The interdigital transducer 1 is located above the substrate 2 and includes a plurality of interdigital electrodes 10.

[0024] Specifically, the interdigital transducer 1 is located above the substrate 2 and is used to realize the conversion from a surface acoustic wave to an electrical signal. The above-mentioned interdigital transducer 1 includes a number of interdigital electrodes 10 arranged in a cross pattern. By adjusting parameters such as the spacing between the cross-arranged interdigital electrodes 10, the wavelength and operating frequency of the interdigital transducer can be adjusted.

[0025] The interdigital electrode 10 is located above the substrate, and includes a first metal layer 101 and a second metal layer 102; the first metal layer 101 is located above the second metal layer 102; the density of the first metal layer 101 is greater than 16,000 kilograms per cubic meter.

[0026] Specifically, the interdigital electrode 10 is located above the substrate 2. The first metal layer 101 on the interdigital electrode 10 is located above the second metal layer 102, and the density of the first metal layer 101 is greater than that of the second metal layer 102. The density range of the first metal layer 101 is greater than 16,000 kilograms per cubic meter. In this embodiment, by adding the first metal layer 101 to the interdigital electrode 10, the mass of the interdigital electrode 10 is increased, thereby reducing the wave velocity of the surface acoustic wave of the interdigital transducer 1, which helps to broaden the bandwidth of the surface acoustic wave filter including the elastic wave device; by arranging the first metal layer 101 with a larger density and higher stability above the second metal layer 102, the surface of the interdigital transducer including the elastic wave device is prevented from being corroded; by adding the first metal layer 101 to the interdigital electrode 10, while increasing the mass of the interdigital electrode 10, the size of the interdigital electrode 10 is reduced, and further the device size of the surface acoustic wave filter including the elastic wave device is reduced.

[0027] It should be noted that in this embodiment, the conductivity of the second metal layer 102 is greater than that of the first metal layer 101, and the quality factor (Q value) of the interdigital transducer 1 can be improved through the second metal layer 102; as Figure 2 shown, the left and right sides of the interdigital transducer 1 are respectively adjacent to the reflectors 8, and both the interdigital electrode 10 and the reflectors 8 are formed by a stacked metal film formed by stacking several metal layers. For example, the thickness of the interdigital electrode 10 and the reflectors 8 is 150 nm to 450 nm.

[0028] In summary, the above elastic wave device broadens the bandwidth of the surface acoustic wave filter including the elastic wave device by adding the first metal layer 101 to the interdigital electrode 10, thereby increasing the mass of the interdigital electrode 10; by arranging the first metal layer 101 with a larger density and chemical stability above the second metal layer 102, the surface of the surface acoustic wave filter including the elastic wave device is prevented from being corroded; by adding the first metal layer 101 with a density greater than 16,000 kilograms per cubic meter to the interdigital electrode 10, the device size of the surface acoustic wave filter is reduced; by adding the second metal layer 102 with a larger conductivity, the Q value of the surface acoustic wave filter is improved, solving the problem in the prior art that due to the structural limitation of the traditional surface acoustic wave filter, its bandwidth is relatively limited, and realizing that while the surface of the surface acoustic wave filter is not corroded, the bandwidth of the surface acoustic wave filter is broadened.

[0029] In some of these embodiments, the material of the first metal layer includes at least one of platinum, tungsten, rhenium, tantalum, gold, and hafnium.

[0030] Specifically, in this embodiment, the material of the first metal layer includes at least one of platinum, tungsten, rhenium, tantalum, gold, and hafnium, so that the density of the first metal layer is greater than 16,000 kilograms per cubic meter. By increasing the mass of the interdigital electrodes in the elastic wave device, the bandwidth of the elastic wave device is thus broadened.

[0031] In some of these embodiments, the thickness range of the first metal layer is 5% - 6% of the wavelength of the interdigital transducer.

[0032] Specifically, the wavelength of the above-mentioned interdigital transducer is the wavelength defined by the pitch between the cross-arranged interdigital electrodes, denoted as λ. By adjusting the thickness range of the first metal layer to 5% - 6% of the wavelength λ of the interdigital transducer, it helps to improve the accuracy of the working frequency adjustment of the elastic wave device.

[0033] In some of these embodiments, the thickness range of the second metal layer is 3% - 9.5% of the wavelength of the interdigital transducer.

[0034] Specifically, by adjusting the thickness range of the second metal layer to 3% - 9.5% of the wavelength λ of the above-mentioned interdigital transducer, it helps to improve the accuracy of the working frequency adjustment of the elastic wave device.

[0035] In some of these embodiments, the interdigital electrodes further include an anti-oxidation layer, an anti-fusion layer, and an adhesion layer.

[0036] The anti-oxidation layer is located above the first metal layer; the anti-fusion layer is located between the first metal layer and the second metal layer; the adhesion layer is located below the second metal layer.

[0037] Specifically, in this embodiment, the material of the anti-oxidation layer is titanium, which is used to prevent the surface of the interdigital electrodes from being oxidized; it should be noted that in other embodiments, the anti-oxidation layer can also be other anti-oxidation materials; in this embodiment, the anti-fusion layer is titanium, which is used to prevent the melting and diffusion phenomena between the first metal layer and the second metal layer; in this embodiment, the adhesion layer is titanium, and the adhesion layer is used to enhance the bonding force between the interdigital electrodes and the substrate. By providing the anti-oxidation layer, anti-fusion layer, and adhesion layer on the interdigital electrodes, the stability of the frequency modulation performance of the elastic wave device is ensured, and the service life of the elastic wave device is extended. It should be noted that in other embodiments, the anti-oxidation layer can also be other materials with anti-oxidation functions; the anti-fusion layer can also be other high-melting-point and high-conductivity metal materials with the function of preventing metal melting; the adhesion layer can also be other materials with the function of enhancing the bonding force between the interdigital electrodes and the substrate.

[0038] In some of these embodiments, the material of the anti-melting layer includes at least one of titanium, nickel, gold, silver, and molybdenum.

[0039] Specifically, the anti-melting layer in this embodiment is used to prevent the melting and diffusion phenomena between the first metal layer and the second metal layer, ensuring the stability of the frequency modulation performance of the elastic wave device and extending the service life of the elastic wave device.

[0040] In some of these embodiments, the elastic wave device further includes a temperature compensation layer and a frequency modulation layer.

[0041] The temperature compensation layer is located between the anti-oxidation layer and the frequency modulation layer; the frequency modulation layer is located above the temperature compensation layer.

[0042] Specifically, the material of the temperature compensation layer in this embodiment includes at least one of silicon dioxide and silicon oxyfluoride, and the thickness range of the temperature compensation layer is 20% - 70% of the wavelength λ of the above-mentioned interdigital transducer; the material of the frequency modulation layer includes at least one of silicon nitride, aluminum nitride, aluminum oxynitride, aluminum oxide, and silicon carbide. Through the above temperature compensation layer and frequency modulation layer, the stability and accuracy of the frequency modulation function of the elastic wave device are ensured.

[0043] In some of these embodiments, the substrate includes at least one piezoelectric material.

[0044] Specifically, the piezoelectric materials include lithium tantalate, silicon oxide, spinel, and lithium niobate. The crystal cut angle is adjusted correspondingly according to the piezoelectric material to reduce the coupling of the shear horizontal wave (SH) on the interdigital electrode, thereby improving the filtering performance of the elastic wave device.

[0045] In some of these embodiments, the operating frequency range of the elastic wave device is 420 MHz - 550 MHz.

[0046] Specifically, the elastic wave device in this embodiment is a surface acoustic wave filter. The above operating frequency range represents the center frequency range when the surface acoustic wave filter is in the operating state. The operating frequency range of the traditional surface acoustic wave filter is 820 MHz - 2300 MHz. In this embodiment, by adding a first metal layer with a density greater than 16000 kg / m³ to the interdigital electrode, the mass of the interdigital electrode is increased, and the surface acoustic wave velocity of the interdigital electrode is reduced, thereby reducing the operating frequency range of the surface acoustic wave filter including the interdigital electrode to 420 MHz - 550 MHz.

[0047] In some of these embodiments, the elastic wave device includes a wiring substrate, an external connection terminal, a device chip, a sealing portion, a bump, and an electrode pad.

[0048] Specifically, Figure 3Schematic structural diagram of a surface acoustic wave device according to an embodiment, as Figure 3 shown. The surface acoustic wave device includes a wiring substrate 5, an external connection terminal 6, a device chip 4, a sealing portion 3, bumps 11, and electrode pads 12. Among them, the wiring substrate 5 is a multilayer substrate formed of resin; the external connection terminal 6 is located below the wiring substrate 5; the electrode pads 12 are located on the main surface of the wiring substrate 23, and the constituent material of the electrode pads 12 is copper or an alloy containing copper, with a thickness of 10 μm to 20 μm; the bumps 11 are located on the upper surface of the electrode pads 12, and the constituent material of the bumps 11 is gold, with a height of 10 μm to 50 μm; the device chip 4 includes a substrate and interdigital transducers; a cavity 7 is formed between the device chip 4 and the wiring substrate 5.

[0049] By adding a first metal layer with a density greater than 16,000 kg / m³ to the interdigital electrodes of the device chip 4 in the above surface acoustic wave device, the mass of the interdigital electrodes is increased, the surface acoustic wave velocity of the interdigital electrodes is reduced, and thus the bandwidth of the surface acoustic wave device is broadened.

[0050] In this embodiment, an electronic module is also provided, which includes a plurality of the above surface acoustic wave devices.

[0051] Specifically, the electronic module in this embodiment includes a plurality of the above surface acoustic wave devices. By adding a first metal layer with a density greater than 16,000 kg / m³ to the interdigital electrodes of the surface acoustic wave device, the surface acoustic wave velocity of the surface acoustic wave device is reduced, the bandwidth of the surface acoustic wave device in the low-frequency band is increased, and thus the bandwidth of the electronic module in the low-frequency band is increased. Among them, the frequency range of the above low-frequency band is 200 MHz - 800 MHz.

[0052] The following describes and illustrates this embodiment through preferred embodiments.

[0053] Figure 4 Schematic structural diagram of the surface acoustic wave device according to this preferred embodiment. As Figure 4 shown, the surface acoustic wave device according to this preferred embodiment includes interdigital transducers 1 and a substrate 2, and the above interdigital transducers 1 are located above the substrate 2.

[0054] Among them, the interdigital transducer 1 includes a plurality of interdigital electrodes 10. The interdigital electrodes 10 are located above the substrate 2. The interdigital electrodes 10 include a first metal layer 101, a second metal layer 102, an anti-oxidation layer 103, an anti-melting layer 104, and an adhesion layer 105. Among them, the anti-oxidation layer 103 is located above the first metal layer 101; the first metal layer 101 is located above the anti-melting layer 104; the anti-melting layer 104 is located above the second metal layer 102; the second metal layer 102 is located above the adhesion layer 105, and the adhesion layer 105 is located above the substrate 2. Among them, the material of the first metal layer 101 in this preferred embodiment is platinum (with a density of 21460 kg / m³), and the thickness range is 5% - 6% of the wavelength of the interdigital transducer 1; the material of the second metal layer 102 is aluminum, and the thickness range is 3% - 9.5% of the wavelength of the interdigital transducer 1; the materials of the anti-oxidation layer 103, the anti-melting layer 104, and the adhesion layer 105 are titanium, and the thickness is 15 nm.

[0055] The substrate 2 includes a lithium tantalate piezoelectric layer 201, a silicon oxide piezoelectric layer 202, and a spinel piezoelectric layer 203. Among them, the lithium tantalate piezoelectric layer 201 is located above the silicon oxide piezoelectric layer 202; above the silicon oxide piezoelectric layer 202 is located the spinel piezoelectric layer 203.

[0056] Figure 5 is the surface of the interdigital transducer of this preferred embodiment, as Figure 5 shown, the surface of the interdigital transducer 1 of the elastic wave device of this preferred embodiment will not be corroded; due to the presence of the anti-melting layer 104 between the first metal layer 101 and the second metal layer 102, there is no melting phenomenon between the first metal layer 101 and the second metal layer 102; Figure 6 is the filtering characteristic diagram of the elastic wave device of this preferred embodiment, Figure 6 the coordinate diagram in represents the insertion loss (dB) corresponding to the frequency (MHz) when the elastic wave device works. In this preferred embodiment, taking the insertion loss of 10 dB as the standard, the corresponding low cut-off frequency is 444 MHz, and the high cut-off frequency is 462 MHz. Therefore, the working frequency of the elastic wave device of this preferred embodiment is (444 + 462) / 2 = 453 MHz.

[0057] Next, through Example 1, Example 2, and Example 3, they are respectively compared and analyzed with the above-mentioned preferred embodiment. The specific analysis process is as follows: Example 1

[0058] Figure 7 is the structural schematic diagram of the elastic wave device of Example 1, as Figure 7 shown, the elastic wave device of this Example 1 includes an interdigital transducer 1 and a substrate 2, and the above-mentioned interdigital transducer 1 is located above the substrate 2.

[0059] Among them, the interdigital transducer 1 includes a plurality of interdigital electrodes 10. The interdigital electrodes 10 are located above the substrate 2. The interdigital electrodes 10 include a second metal layer 102, an anti-oxidation layer 103, and an adhesion layer 105. Among them, the anti-oxidation layer 103 is located above the second metal layer 102; the second metal layer 102 is located above the adhesion layer 105; the adhesion layer 105 is located above the substrate 2. Among them, the material of the second metal layer 102 is aluminum, and the thickness range is 3% - 9.5% of the wavelength of the interdigital transducer 1; the materials of the anti-oxidation layer 103 and the adhesion layer 105 are titanium, and the thickness is 15 nanometers. The substrate 2 of the first embodiment has the same structure as the substrate of the elastic wave device in the above-mentioned preferred embodiment, and includes a lithium tantalate piezoelectric layer 201, a silicon oxide piezoelectric layer 202, and a spinel piezoelectric layer 203.

[0060] Figure 8 It is a filtering characteristic diagram of the elastic wave device in the first embodiment, as Figure 8 shown. The operating frequency of the elastic wave device in the first embodiment is 902.5 MHz, while the operating frequency of the elastic wave device in the above-mentioned preferred embodiment is 453 MHz. It can be seen that by adding the first metal layer 101 to the interdigital electrode in the above-mentioned preferred embodiment of the elastic wave device, the mass of the interdigital electrode is increased, the wave velocity of the surface acoustic wave on the interdigital electrode is reduced, and thus the bandwidth of the surface acoustic wave filter including the elastic wave device is broadened. Embodiment 2

[0061] Figure 9 It is a schematic structural diagram of the elastic wave device in the second embodiment, as Figure 9 shown. The elastic wave device in the first embodiment includes an interdigital transducer 1 and a substrate 2. The above-mentioned interdigital transducer 1 is located above the substrate 2.

[0062] Among them, the interdigital transducer 1 includes a plurality of interdigital electrodes 10. The interdigital electrodes 10 are located above the substrate 2. The interdigital electrodes 10 include a first metal layer 101, a second metal layer 102, an anti-oxidation layer 103, and an adhesion layer 105. Among them, the anti-oxidation layer 103 is located above the first metal layer 101; the first metal layer 101 is located above the second metal layer 102; the second metal layer 102 is located above the adhesion layer 105, and the adhesion layer 105 is located above the substrate 2. Among them, the material of the first metal layer 101 in this preferred embodiment is platinum, and the thickness range is 5% - 6% of the wavelength of the interdigital transducer 1; the material of the second metal layer 102 is aluminum, and the thickness range is 3% - 9.5% of the wavelength of the interdigital transducer 1; the materials of the anti-oxidation layer 103 and the adhesion layer 105 are titanium, and the thickness is 15 nanometers. The substrate 2 of the second embodiment has the same structure as the substrate of the elastic wave device in the above-mentioned preferred embodiment, and includes a lithium tantalate piezoelectric layer 201, a silicon oxide piezoelectric layer 202, and a spinel piezoelectric layer 203.

[0063] Figure 10 The surface of the interdigital transducer of Example 2 is shown as Figure 10 shown. Due to the melting and diffusion phenomena occurring between the first metal layer 101 and the second metal layer 102, black spots appear on the surface of the interdigital transducer including the elastic wave device. Thus, it can be seen that the elastic wave device of the above preferred embodiment adds an anti-melting layer 104 in the interdigital electrode to prevent the melting and diffusion phenomena occurring between the first metal layer 101 and the second metal layer 102, thereby extending the service life of the elastic wave device. Example 3

[0064] Figure 11 The structural schematic diagram of the elastic wave device of Example 3 is shown as Figure 11 shown. The elastic wave device of this Example 1 includes an interdigital transducer 1 and a substrate 2, and the above interdigital transducer 1 is located above the substrate 2. Among them, the interdigital transducer 1 includes a plurality of interdigital electrodes 10. The interdigital electrodes 10 are located above the substrate 2. The interdigital electrodes 10 include a first metal layer 101, a second metal layer 102, an anti-oxidation layer 103, an anti-melting layer 104, and an adhesion layer 105. Among them, the anti-oxidation layer 103 is located above the second metal layer 102; the second metal layer 102 is located above the anti-melting layer 104; the anti-melting layer 104 is located above the first metal layer 101; the first metal layer 101 is located above the adhesion layer 105, and the adhesion layer 105 is located above the substrate 2. Among them, the material of the first metal layer 101 in this preferred embodiment is platinum, and the thickness range is 5% - 6% of the wavelength of the interdigital transducer 1; the material of the second metal layer 102 is aluminum, and the thickness range is 3% - 9.5% of the wavelength of the interdigital transducer 1; the materials of the anti-oxidation layer 103, the anti-melting layer 104, and the adhesion layer 105 are titanium, and the thickness is 15 nanometers. The substrate 2 of this Example 2 has the same structure as the substrate of the elastic wave device of the above preferred embodiment, and includes a lithium tantalate piezoelectric layer 201, a silicon oxide piezoelectric layer 202, and a spinel piezoelectric layer 203.

[0065] Figure 12 The surface of the interdigital transducer of Example 3 is shown as Figure 12 shown. Since in Example 3, the second metal layer 102 with a smaller density and chemically active properties is set above the first metal layer 101, the surface of the interdigital transducer is corroded; Figure 13 The filtering characteristic diagram of the elastic wave device of Example 3 is shown as Figure 13As shown, the operating frequency of the elastic wave device in Embodiment 3 is 527.5 MHz. It can be seen therefrom that the elastic wave device of the above preferred embodiment prevents the surface of the surface acoustic wave filter including the elastic wave device from being corroded by disposing the first metal layer 101 with a relatively large density and high chemical stability above the second metal layer 102, thereby extending the service life of the elastic wave device; and the operating frequency of the elastic wave device of the above preferred embodiment is 527.5 MHz, which is lower than the operating frequency of the elastic wave device in Embodiment 3. Therefore, the surface acoustic wave filter including the elastic wave device of the above preferred embodiment has a lower passband frequency and a wider frequency band.

[0066] In summary, the elastic wave device of the above preferred embodiment broadens the frequency band width of the surface acoustic wave filter including the elastic wave device by adding the first metal layer to the interdigital electrode, thereby increasing the mass of the interdigital electrode; prevents the surface of the surface acoustic wave filter including the elastic wave device from being corroded by disposing the first metal layer with a relatively large density and high stability above the second metal layer; reduces the device size of the surface acoustic wave filter by adding the first metal layer with a density greater than 16,000 kg / m³ to the interdigital electrode; and improves the Q value of the surface acoustic wave filter by adding the second metal layer with a relatively large conductivity, solving the problem in the prior art that due to the structural limitation of the traditional surface acoustic wave filter, its frequency band width is relatively limited, and achieving the broadening of the frequency band width of the surface acoustic wave filter while preventing the surface of the surface acoustic wave filter from being corroded.

[0067] It should be understood that the specific embodiments described herein are only used to explain the device, rather than to limit it. According to the embodiments provided in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0068] Obviously, the drawings are only some examples or embodiments of the present application. For those of ordinary skill in the art, the present application can also be applied to other similar situations according to these drawings without creative efforts. In addition, it can be understood that although the work done during the development process may be complex and time-consuming, for those of ordinary skill in the art, certain design, manufacturing or production changes based on the technical content disclosed in the present application are only conventional technical means and should not be regarded as insufficient disclosure of the present application.

[0069] As used in this application, the term "embodiment" means that the specific features, structures, or characteristics described in connection with the embodiments may be included in at least one embodiment of this application. The phrase appears in various places in the specification and does not necessarily mean the same embodiment, nor does it mean that it is independent or alternative to other embodiments and mutually exclusive. Those of ordinary skill in the art can clearly or implicitly understand that the embodiments described in this application can be combined with other embodiments without conflict.

[0070] The above-described embodiments merely represent several implementation manners of this application. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of patent protection. It should be noted that for those of ordinary skill in the art, without departing from the concept of this application, several modifications and improvements can still be made, and these all fall within the protection scope of this application. Therefore, the protection scope of this application shall be subject to the appended claims.

Claims

1. An elastic wave device, characterized in that, It includes a substrate and a plurality of interdigital transducers; The interdigital transducers are located above the substrate and include a plurality of interdigital electrodes; The interdigital electrodes are located above the substrate and include a first metal layer and a second metal layer; the first metal layer is located above the second metal layer; the density of the first metal layer is greater than 16,000 kilograms per cubic meter.

2. The elastic wave device according to claim 1, characterized in that, The material of the first metal layer includes at least one of platinum, tungsten, rhenium, tantalum, gold, and hafnium.

3. The elastic wave device according to claim 1, characterized in that, The thickness range of the first metal layer is 5% - 6% of the wavelength of the interdigital transducer.

4. The elastic wave device according to claim 1, wherein The thickness range of the second metal layer is 3% - 9.5% of the wavelength of the interdigital transducer.

5. The elastic wave device according to claim 1, characterized in that, The interdigital electrodes further include an anti-oxidation layer, an anti-melting layer, and an adhesion layer; The anti-oxidation layer is located above the first metal layer; the anti-melting layer is located between the first metal layer and the second metal layer; the adhesion layer is located below the second metal layer.

6. The elastic wave device according to claim 5, wherein The material of the anti-melting layer includes at least one of titanium, nickel, gold, silver, and molybdenum.

7. The elastic wave device according to claim 5, characterized in that, The elastic wave device further includes a temperature compensation layer and a frequency modulation layer; The temperature compensation layer is located between the anti-oxidation layer and the frequency modulation layer; the frequency modulation layer is located above the temperature compensation layer.

8. The elastic wave device according to claim 1, wherein The substrate includes at least one piezoelectric material.

9. The elastic wave device according to claim 1, wherein: The operating frequency range of the elastic wave device is 420 MHz - 550 MHz.

10. An electronic module, characterized in that, It includes a plurality of elastic wave devices as described in claims 1 to 9.

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