Elastic Wave Device, Radio Frequency Front-End Module, and Preparation Method of Elastic Wave Device

Abstract

The present application is applicable to the field of radio frequency filtering technology, and discloses an elastic wave device, a radio frequency front-end module and a preparation method of the elastic wave device. Among them, the elastic wave device includes a piezoelectric substrate and at least one interdigital transducer disposed on the piezoelectric substrate, and the interdigital transducer includes at least two interdigital electrodes; wherein, at least one interdigital electrode includes a metal film and a first electrode film, the metal film is disposed on the piezoelectric substrate, and the surface of the metal film away from the piezoelectric substrate is a rough surface; the first electrode film is located on the rough surface. The elastic wave device of this embodiment can improve power tolerance.

Description

Technical Field

[0001] The present application relates to the field of radio frequency filtering technologies, and particularly to an elastic wave device, a radio frequency front-end module, and a preparation method of the elastic wave device. Background Art

[0002] Elastic wave devices, such as surface acoustic wave (SAW) devices, mainly consist of a piezoelectric material and interdigital transducers disposed on the piezoelectric material. The interdigital transducers include bus bars and interdigital electrodes disposed between the bus bars, and are widely used in communication devices such as mobile phones. With the development of technology and communication technologies, elastic wave devices are developing towards high power tolerance, high frequency, and high stability.

[0003] Currently, with the increasing requirement for the operating frequency of elastic wave devices, narrower finger widths are required in the fabrication of the interdigital electrodes of elastic wave devices. In this case, the increase in the power of the elastic wave device will not only cause more heat to be generated during its operation, but also cause stress migration and electron migration in the interdigital electrodes, thereby reducing the power tolerance of the elastic wave device. Summary of the Invention

[0004] In view of the deficiencies of the above-mentioned prior art, the purpose of the present application is to provide an elastic wave device, a radio frequency front-end module having the elastic wave device, and a preparation method of the elastic wave device, aiming to improve the power tolerance of the elastic wave device.

[0005] To solve the above technical problems, an embodiment of the present application provides an elastic wave device, which includes a piezoelectric substrate and at least one interdigital transducer disposed on the piezoelectric substrate. The interdigital transducer includes at least two interdigital electrodes; wherein, at least one of the interdigital electrodes includes:

[0006] a metal film, the metal film is disposed on the piezoelectric substrate, and the surface of the metal film away from the piezoelectric substrate is a rough surface;

[0007] a first electrode film, the first electrode film is located on the rough surface.

[0008] In some embodiments, the metal film includes a second electrode film and an amorphous layer, the amorphous layer is disposed between the first electrode film and the second electrode film, the surface of the second electrode film away from the piezoelectric substrate is surface-treated to form the amorphous layer, and the surface of the amorphous layer away from the second electrode film is a rough surface.

[0009] In some embodiments, at least one of the first electrode film and the second electrode film is a polycrystalline electrode film; and / or,

[0010] the grain size of the first electrode film is smaller than the grain size of the second electrode film.

[0011] In some embodiments, the material of the amorphous layer is any one of aluminum, aluminum alloy, aluminum nitride, and aluminum oxide; and / or,

[0012] The thickness of the amorphous layer is 1 nm to 4 nm.

[0013] In some embodiments, the materials of the first electrode film and the second electrode film are the same;

[0014] and / or,

[0015] The thickness range of the first electrode film is 50 nm to 500 nm, and the thickness range of the second electrode film is 10 nm to 30 nm.

[0016] In some embodiments, the material of at least one of the first electrode film and the second electrode film is aluminum or aluminum alloy.

[0017] In some embodiments, the aluminum alloy is a copper-aluminum alloy, and the mass percentage of metallic copper in the copper-aluminum alloy is 1.0 wt% to 2.0 wt%; or,

[0018] The aluminum alloy is a magnesium-aluminum alloy, and the mass percentage of metallic magnesium in the magnesium-aluminum alloy is 1.0 wt% to 2.0 wt%.

[0019] In some embodiments, the interdigital electrode further includes an adhesion film, the adhesion film is located on the piezoelectric substrate, and the metal film is located on a side of the adhesion film away from the piezoelectric substrate.

[0020] In some embodiments, the material of the adhesion film is mainly composed of chromium or titanium; and / or,

[0021] The thickness range of the adhesion film is 10 nm to 20 nm.

[0022] An embodiment of the present application further provides a radio frequency front-end module, which includes the above-mentioned elastic wave device.

[0023] An embodiment of the present application further provides a method for manufacturing an elastic wave device for manufacturing the above-mentioned elastic wave device, and the manufacturing method includes:

[0024] Form a metal film on the piezoelectric substrate;

[0025] Perform surface treatment on a side of the metal film away from the piezoelectric substrate so that a rough surface is formed on the side of the metal film away from the piezoelectric substrate;

[0026] Form a first electrode film on the rough surface.

[0027] In some embodiments, the metal film includes a second electrode film and an amorphous layer. The amorphous layer is disposed between the first electrode film and the second electrode film, and one side of the amorphous layer away from the second electrode film is a rough surface.

[0028] The step of surface-treating the metal film includes:

[0029] Surface-treat the side of the second electrode film away from the piezoelectric substrate through an inductively coupled plasma etching process or a plasma cleaning process, so as to form an amorphous layer with a rough surface on the side of the second electrode film away from the piezoelectric substrate.

[0030] In some embodiments, during the surface treatment of the metal film, the process gas used is an inert gas, nitrogen, or oxygen.

[0031] In some embodiments, the interdigital electrode further includes an adhesion film disposed between the piezoelectric substrate and the metal film;

[0032] The step of forming a metal film on the piezoelectric substrate includes:

[0033] Form an adhesion film on the piezoelectric substrate;

[0034] Form a metal film on the adhesion film by an electron beam evaporation process.

[0035] In some embodiments, during the formation of the metal film, the deposition rate of electron beam evaporation is

[0036] The elastic wave device provided by the present application has the following beneficial effects:

[0037] In the elastic wave device of this embodiment, the side of the metal film away from the piezoelectric substrate is a rough surface, and the first electrode film is located on the rough surface. In this way, the grain size and grain arrangement of the first electrode film can be made different from those of the metal film. Moreover, on the one hand, compared with setting the first electrode film on the smooth surface of the metal film, it is beneficial for the grains of the first electrode film to form more grain orientations of Al(111), which is beneficial for reducing the grain size of the first electrode film, reducing the voids between the grains in the first electrode film, increasing the difficulty of grain migration in the first electrode film, and improving the mechanical properties of the first electrode film. In this way, in the interdigital electrode where the first electrode film plays a dominant role, it is possible to increase the difficulty of stress migration, electron migration, and atomic migration in the interdigital electrode, thereby improving the power tolerance of the elastic wave device.

[0038] On the other hand, reducing the grain size of the first electrode film and the voids between the grains in the first electrode film helps to improve the arrangement stability of each grain, enhance the structural stability of the first electrode film, thereby improving the adhesion of the first electrode film, enabling it to adhere more firmly to the rough surface, and also improving the power tolerance of the elastic wave device from the side. Description of the Drawings

[0039] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on the structures shown in these drawings.

[0040] Figure 1 is a schematic structural diagram of an elastic wave device provided by an embodiment of the present application;

[0041] Figure 2 is a schematic structural diagram of the elastic wave device in Embodiment 1 provided by an embodiment of the present application;

[0042] Figure 3 is Figure 2 a schematic structural diagram of the interdigital electrode in

[0043] Figure 4 is Figure 3 a schematic structural diagram of the amorphous layer in

[0044] Figure 5 is a schematic structural diagram of an interdigital transducer in the elastic wave device provided by an embodiment of the present application;

[0045] Figure 6 is a schematic structural diagram of a comparative example provided by an embodiment of the present application;

[0046] Figure 7 is a comparison chart of the percentage of the full width at half maximum between Embodiment 1 and the comparative example provided by an embodiment of the present application.

[0047] Explanation of the Reference Numerals in the Drawings:

[0048] 10. Elastic wave device; 1. Piezoelectric substrate; 2. Interdigital transducer; 21. Interdigital electrode; 211. Metal film; 2111. Rough surface; 2112. Second electrode film; 2113. Amorphous layer; 212. First electrode film; 213. Adhesion film; 22. Bus bar. Detailed Embodiments

[0049] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without making creative efforts belong to the scope of protection of the present application.

[0050] It should be noted that all directional indications (such as up, down, left, right, front, back...) in the embodiments of the present application are only used to explain the relative positional relationship and movement conditions between components in a specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0051] It should also be noted that when an element is referred to as "fixed to" or "disposed on" another element, it can be directly on the other element or there may be an intermediate element at the same time. When an element is referred to as "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element through an intermediate element.

[0052] In addition, the descriptions involving "first", "second", etc. in the present application are only for descriptive purposes, and cannot be understood as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In addition, the technical solutions between various embodiments can be combined with each other, but it must be based on the ability of those of ordinary skill in the art to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present application.

[0053] In the related art, elastic wave devices such as surface acoustic wave filters are mainly composed of a piezoelectric material and interdigital transducers disposed on the piezoelectric material. The interdigital transducers include bus bars and interdigital electrodes disposed between the bus bars, and are widely used in the communication field. In elastic wave devices such as surface acoustic wave filters, with the increasing requirement for their operating frequency, narrower finger widths will be required in the manufacturing process of the elastic wave devices. In this case, the increase in the power of the elastic wave device is likely to cause serious heating during its working state, generating more heat. Seriously, it will cause stress migration and electron migration in the interdigital electrodes, thereby reducing the power tolerance of the elastic wave device.

[0054] At the same time, when a high power is applied to the elastic wave device, there are dangling bonds in the grain boundaries of the main electrode mainly or only made of aluminum in the interdigital electrodes. Therefore, only a very small amount of energy can cause atomic migration in the main electrode, resulting in the formation of hills and cracks in the main electrode, ultimately damaging the interdigital electrodes, and further reducing the power tolerance of the elastic wave device.

[0055] It can be understood that currently, there are methods of filling metal in the grain boundaries of the main electrode to suppress electrode damage caused by atomic migration. There are also methods of eliminating grain boundaries through single crystallization of the aluminum electrode, so that almost no atomic migration occurs in the main electrode, thereby enhancing the power handling ability of the device. However, for increasingly high power requirements, methods to improve the power tolerance of surface acoustic wave filters are still needed to meet the requirements in the communication field, such as those currently applied in 5G (the technical specifications of the fifth-generation mobile communication technology).

[0056] In view of this, referring to Figure 1 , the present application provides an elastic wave device 10, which reduces the grain size of the first electrode film 212 and obtains a better grain orientation by setting the surface of the metal film 211 facing away from the piezoelectric substrate 1 in at least one interdigital electrode 21 as a rough surface 2111 and setting the first electrode film 212 on the rough surface 2111, thereby improving the power tolerance of the elastic wave device 10.

[0057] The following will Figures 1 to 5 , in conjunction with the accompanying drawings, make a detailed description of some embodiments of the present application. Without conflict, the following embodiments and the features in the embodiments can be combined with each other.

[0058] It should be noted that in the drawings, Figures 1 to 5 are only exemplary. Among them, for the convenience of illustration, as in Figure 2 , not all the reference numerals of all the structures in the elastic wave device 10 are marked. Obviously, the structures without marked reference numerals in Figure 2 can be shown in other drawings, such as Figure 3 . The various drawings can be used together to illustrate without conflict. Among them, Figure 1 exemplarily shows a structure of the elastic wave device 10 in the embodiment, Figure 2 exemplarily shows another structure of the elastic wave device 10 in the embodiment, Figure 3 exemplarily shows the grain size and grain arrangement of the interdigital electrode 21 in the first embodiment, Figure 4 is an enlarged schematic view of the amorphous layer 2113 in the first embodiment, Figure 5 exemplarily shows the structure of the interdigital transducer 2 in the embodiment, Figure 6 exemplarily shows the grain size and grain arrangement of the interdigital electrode 21 in the comparative example, Figures 2 to 4 and Figure 6For the convenience of only showing the differences in grain size and grain arrangement between Example 1 and the comparative example, it does not limit the grain size and grain arrangement of the interdigital electrode 21 in this embodiment. When there is no conflict, the various drawings can jointly illustrate, and these are not limitations on the specific structure of the interdigital electrode 21 in the elastic wave device 10.

[0059] Referring to Figure 1 , Figure 2 and Figure 5 , the elastic wave device 10 of the embodiment of the present application includes a piezoelectric substrate 1 and at least one interdigital transducer 2 provided on the piezoelectric substrate 1. The interdigital transducer 2 includes at least two interdigital electrodes 21. Among them, at least one interdigital electrode 21 includes a metal film 211 and a first electrode film 212. The metal film 211 is provided on the piezoelectric substrate 1, and the surface of the metal film 211 away from the piezoelectric substrate 1 is a rough surface 2111. The first electrode film 212 is located on the rough surface 2111.

[0060] In this embodiment, the elastic wave device 10 includes a piezoelectric substrate 1 and at least one interdigital transducer 2 provided on the piezoelectric substrate 1. The interdigital transducer 2 is used to realize acoustic-electric conversion. The interdigital transducer 2 includes at least two interdigital electrodes 21. Among them, at least one interdigital electrode 21 includes a first electrode film 212 and a metal film 211 provided on the piezoelectric substrate 1.

[0061] In this embodiment, the surface of the metal film 211 away from the piezoelectric substrate 1 is a rough surface 2111, and the first electrode film 212 is located on the rough surface 2111. In this way, the grain size and grain arrangement of the first electrode film 212 can be different from those of the metal film 211. Moreover, on the one hand, compared with setting the first electrode film 212 on the smooth surface of the metal film 211, it is beneficial for the grains of the first electrode film 212 to form more grain orientations of Al(111), which is beneficial to reducing the grain size of the first electrode film 212, reducing the voids between the grains in the first electrode film 212, increasing the difficulty of grain migration in the first electrode film 212, and improving the mechanical properties of the first electrode film 212. In this way, in the interdigital electrode 21 where the first electrode film 212 plays a dominant role, the difficulty of stress migration, electron migration, and atomic migration in the interdigital electrode 21 can be increased, thereby improving the power tolerance of the elastic wave device 10.

[0062] On the other hand, reducing the grain size of the first electrode film 212 and the voids between the grains in the first electrode film 212 helps to improve the arrangement stability of the grains, improve the structural stability of the first electrode film 212, thereby improving the adhesion of the first electrode film 212 to more firmly adhere to the rough surface 2111, and can also improve the power tolerance of the elastic wave device 10 from the side.

[0063] In this embodiment, the elastic wave device 10 may be a surface acoustic wave resonator having an interdigital transducer 2, or may be a device such as a filter having one or more interdigital transducers 2. Among the at least two interdigital electrodes 21 included in the interdigital transducer 2, at least one interdigital electrode 21 having the above structure can improve the power tolerance of the elastic wave device 10. Obviously, it is also possible that multiple or all of the interdigital electrodes 21 of the interdigital transducer 2 have the above structure, and this embodiment does not specifically limit it.

[0064] Combined Figure 5 , in this embodiment, the interdigital transducer 2 includes two bus bars 22 arranged in parallel, and at least two interdigital electrodes 21 are arranged between the two bus bars 22. Specifically, it may be two or more. Generally, the number of interdigital electrodes 21 is greater than two. A part of the interdigital electrodes 21 is connected to one bus bar 22, and another part of the interdigital electrodes 21 is connected to the other bus bar 22. The interdigital electrodes 21 connected to different bus bars 22 are alternately and spaced apart.

[0065] Combined Figure 1 and Figure 3 , in this embodiment, the surface of the metal film 211 away from the piezoelectric substrate 1 is a rough surface 2111. It should be understood that the rough surface 2111 may be directly formed on the surface of the metal film 211 away from the piezoelectric substrate 1 as the boundary between the metal film 211 and the first electrode film 212; the rough surface 2111 may also be indirectly formed on the surface of the metal film 211 away from the piezoelectric substrate 1. For example, an amorphous layer 2113 having a rough surface 2111 is formed on the surface of the metal film 211 away from the piezoelectric substrate 1. The amorphous layer 2113 is a part of the metal film 211, and the rough surface 2111 is the boundary between the amorphous layer 2113 and the first electrode film 212. The rough surface 2111 formed by the above two methods can make the grain size and grain arrangement of the first electrode film 212 different from those of the metal film 211.

[0066] Referring to Figure 2 and Figure 3 , in some embodiments, the metal film 211 includes a second electrode film 2112 and an amorphous layer 2113. The amorphous layer 2113 is disposed between the first electrode film 212 and the second electrode film 2112. The surface of the second electrode film 2112 away from the piezoelectric substrate 1 is surface-treated to form the amorphous layer 2113, and the surface of the amorphous layer 2113 away from the second electrode film 2112 is the rough surface 2111.

[0067] In this embodiment, the metal film 211 includes a second electrode film 2112 and an amorphous layer 2113. The amorphous layer 2113 is disposed between the first electrode film 212 and the second electrode film 2112. The amorphous layer 2113 can separate the first electrode film 212 and the second electrode film 2112. On the side of the second electrode film 2112 away from the piezoelectric substrate 1, the amorphous layer 2113 with a rough surface 2111 is formed through surface treatment. The grain size of the amorphous layer 2113 is different from that of the second electrode film 2112, and the grain arrangement also changes. The grain arrangement of the amorphous layer 2113 is different from that of the second electrode film 2112. The amorphous layer 2113 can, to a certain extent, prevent the grains of the first electrode film 212 from migrating into the second electrode film 2112, improving the grain stability of the first electrode film 212.

[0068] In this embodiment, the process of surface treatment on the side of the second electrode film 2112 away from the piezoelectric substrate 1 includes, but is not limited to, processes such as inductively coupled plasma etching and plasma cleaning.

[0069] Combined with Figure 4 , in this embodiment, the rough surface 2111 can be understood as an uneven surface with multiple protrusions and multiple depressions in the thickness direction of the amorphous layer 2113. The multiple protrusions and multiple depressions of the rough surface 2111 can be evenly arranged or arranged irregularly, which is not specifically limited in this embodiment. Of course, the uniform arrangement of the multiple protrusions and multiple depressions of the rough surface 2111 can help improve the quality of the first electrode film 212 formed on the rough surface 2111.

[0070] Combined with Figure 2 and Figure 3 , in some embodiments, at least one of the first electrode film 212 and the second electrode film 2112 is a polycrystalline electrode film.

[0071] It can be understood that in this embodiment, as an implementation manner, the first electrode film 212 is a polycrystalline electrode film. As another implementation manner, the second electrode film 2112 is a polycrystalline electrode film. As yet another implementation manner, both the first electrode film 212 and the second electrode film 2112 are polycrystalline electrode films.

[0072] It can be learned that, compared with single-crystal thin film materials, polycrystalline thin film materials have less dependence on the substrate and are easier to grow. If the first electrode film 212 is a polycrystalline electrode film, the formation difficulty of the first electrode film 212 can be reduced; if the second electrode film 2112 is a polycrystalline electrode film, the formation difficulty of the second electrode film 2112 can be reduced; if both the first electrode film 212 and the second electrode film 2112 are polycrystalline electrode films, the formation difficulty of both the first electrode film 212 and the second electrode film 2112 can be reduced, thereby reducing the difficulty of fabricating the interdigital electrode 21.

[0073] Combined with Figure 2 and Figure 3 , in some embodiments, the grain size of the first electrode film 212 is smaller than the grain size of the second electrode film 2112.

[0074] In this embodiment, by forming an amorphous layer 2113 with a rough surface on the second electrode film 2112, and forming the first electrode film 2112 on the rough surface 2111, the grain size of the first electrode film 212 is made smaller than the grain size of the second electrode film 2112. Furthermore, the voids between the grains in the first electrode film 212 are smaller than the voids between the grains in the second electrode film 2112. To a certain extent, this increases the difficulty of grain migration of the first electrode film 212 to the second electrode film 2112, effectively avoiding the occurrence of electron migration in the interdigital electrode 21, effectively preventing damage to the electrodes, and improving the power tolerance of the elastic wave device 10.

[0075] It should be noted that combined with 3 and Figure 4 , in the amorphous layer 2113, the grain size is different from that of the second electrode film 2112, and the arrangement of the grains in the amorphous layer 2113 is disorderly, which can achieve different grain sizes and different grain arrangements between the first electrode film 212 and the second electrode film 2112.

[0076] Combined with Figure 2 and Figure 3 , in some embodiments, the material of the amorphous layer 2113 is any one of metallic aluminum, aluminum alloy, aluminum nitride, and aluminum oxide.

[0077] In this embodiment, the amorphous layer 2113 is formed by surface treatment on the side of the second electrode film 2112 away from the piezoelectric substrate 1. According to the specific surface treatment process, the material of the amorphous layer 2113 can be the same as or different from the material of the second electrode film 2112.

[0078] In one embodiment, inductively coupled plasma etching is performed on the upper surface of the second electrode film 2112 using an inert gas. The inert gas does not chemically react with the second electrode film 2112, and only serves to grow the amorphous layer 2113 on the upper surface of the second electrode film 2112 and make the side of the amorphous layer 2113 away from the second electrode film 2112 rough. In this case, the material of the amorphous layer 2113 is the same as the material of the second electrode film 2112. Exemplarily, the inert gas is argon (Ar).

[0079] In one embodiment, nitrogen (N 2 ) or oxygen (O 2 ) is used as the process gas for inductively coupled plasma etching. N 2 or O 2It can chemically react with the upper surface of the second electrode film 2112, not only forming an amorphous layer 2113 made of aluminum nitride or aluminum oxide on the upper surface of the second electrode film 2112, but also making the side of the amorphous layer 2113 away from the second electrode film 2112 rough. In this case, the material of the amorphous layer 2113 is different from that of the second electrode film 2112.

[0080] Combined with Figure 2 and Figure 3 , in some embodiments, the thickness of the amorphous layer 2113 is 1 nm to 4 nm.

[0081] In this embodiment, the thickness of the amorphous layer 2113 is designed as above, which will neither have an adverse effect on the formation of the first electrode film 212 nor affect the dominant role of the first electrode film 212. Moreover, the first electrode film 212 is formed on the rough surface 2111 of the amorphous layer 2113 with a thickness of 1 nm to 4 nm, which helps to improve the power tolerance of the interdigital transducer 2, thereby improving the power tolerance of the elastic wave device 10.

[0082] Combined with Figure 2 and Figure 3 , in some embodiments, the materials of the first electrode film 212 and the second electrode film 2112 are the same. In this embodiment, only when the materials of the first electrode film 212 and the second electrode film 2112 are the same, on the basis of the first electrode film 2112 being formed on the rough surface 2111, is it more conducive to changing the grain size and grain arrangement of the first electrode film 212 to achieve the effect of improving the power tolerance of the elastic wave device 10. It should be noted that if the materials of the first electrode film 212 and the second electrode film 2112 are different, it will increase the difficulty of changing the grain size and grain arrangement of the first electrode film 212, making it difficult to achieve the effect of improving the power tolerance of the elastic wave device 10. Therefore, preferably, in this embodiment, the first electrode film 212 and the second electrode film 2112 are made of the same material.

[0083] Combined with Figure 2 and Figure 3 , in some embodiments, the thickness range of the first electrode film 212 is 50 nm to 500 nm, and the thickness range of the second electrode film 2112 is 10 nm to 30 nm.

[0084] In this embodiment, the thickness range of the first electrode film 212 can be selected according to the actual product requirements, and the thickness of the second electrode film 2112 cannot be too thick or too thin. Being too thick will affect the dominant role of the first electrode film 212, and being too thin will result in a poor effect of the formed amorphous layer 2113. Therefore, the thickness of the second electrode film 2112 needs to be designed as above to effectively ensure the effect of the formed amorphous layer 2113 and not affect the dominant role of the first electrode film 212.

[0085] In this embodiment, the thickness of the second electrode film 2112 is limited within the range of 10 nm to 30 nm. With a proper thickness, it can effectively ensure the formation of the amorphous layer 2113 and the effect of the formed amorphous layer 2113. Moreover, from this numerical range, no matter which specific thickness value within this range is selected for the second electrode film 2112, it is less than the thickness of the first electrode film 212, thus not affecting the dominant role of the first electrode film 212.

[0086] Combined with Figure 2 and Figure 3 , in some embodiments, the material of at least one of the first electrode film 212 and the second electrode film 2112 is metallic aluminum or aluminum alloy.

[0087] In this embodiment, the first electrode film 212 is mainly made of aluminum or only made of aluminum, which helps the formation of the first electrode film 212. The second electrode film 2112 is mainly made of aluminum or only made of aluminum, which helps the formation of the second electrode film 2112. It can be understood that the materials of the first electrode film 212 and the second electrode film 2112 can be the same or different. Preferably, the materials of both are the same, which is more conducive to changing the grain size and grain arrangement of the first electrode film 212 to achieve the effect of improving the power tolerance of the elastic wave device 10.

[0088] Combined with Figure 2 and Figure 3 , in some embodiments, the aluminum alloy is a copper-aluminum alloy, and the mass percentage of metallic copper in the copper-aluminum alloy is 1.0 wt% to 2.0 wt%.

[0089] In this embodiment, metallic copper can fill the dangling bonds existing in the grain boundaries of the first electrode film 212 made of aluminum, and can also fill the dangling bonds existing in the grain boundaries of the second electrode film 2112 made of aluminum. Therefore, the materials of both the first electrode film 212 and / or the second electrode film 2112 can be selected as the copper-aluminum alloy, and the mass percentage of metallic copper in the copper-aluminum alloy is 1.0 wt% to 2.0 wt%.

[0090] Combined with Figure 2 and Figure 3 , in some embodiments, the aluminum alloy is a magnesium-aluminum alloy, and the mass percentage of metallic magnesium in the magnesium-aluminum alloy is 1.0 wt% to 2.0 wt%.

[0091] In this embodiment, metallic magnesium can fill the dangling bonds existing in the grain boundaries of the first electrode film 212 made of aluminum, and can also fill the dangling bonds existing in the grain boundaries of the second electrode film 2112 made of aluminum. Therefore, the materials of both the first electrode film 212 and / or the second electrode film 2112 can be selected as the magnesium-aluminum alloy, and the mass percentage of metallic magnesium in the magnesium-aluminum alloy is 1.0 wt% to 2.0 wt%.

[0092] In one embodiment, when the second electrode film 2112 is made of aluminum, copper aluminum alloy or magnesium aluminum alloy, the thickness of the second electrode film 2112 is 15 nm, which can improve the effect of the amorphous layer 2113 formed by surface treatment of the second electrode film 2112.

[0093] Combined with Figure 1 , in one embodiment, the rough surface 2111 can be directly formed on the side of the metal film 211 away from the piezoelectric substrate 1, serving as the junction between the metal film 211 and the first electrode film 212. That is to say, the surface of the metal film 211 can be directly roughened so that multiple protrusions and multiple depressions are formed on the surface of the metal film 211. In this case, the metal film 211 and the first electrode film 212 are preferably made of the same material, such as both made of metal aluminum or aluminum alloy, which is beneficial to changing the grain size and grain arrangement of the first electrode film 212 formed on the rough surface 2111 to achieve the effect of improving the power tolerance of the elastic wave device 10.

[0094] Combined with Figure 2 and Figure 3 , in one embodiment, the rough surface 2111 can be indirectly formed on the side of the metal film 211 away from the piezoelectric substrate 1. For example, the surface of the metal film 211 away from the piezoelectric substrate 1 is surface-treated so that an amorphous layer 2113 with a rough surface 2111 is formed on the upper surface of the metal film. The amorphous layer 2113 is part of the metal film 211, and the rough surface 2111 serves as the junction between the amorphous layer 2113 and the first electrode film 212. That is to say, multiple protrusions and multiple depressions are formed on the side of the amorphous layer 2113 away from the piezoelectric substrate. In this case, the metal 211 and the first electrode film 212 are also preferably made of the same material, such as both made of metal aluminum or aluminum alloy, which is beneficial to changing the grain size and grain arrangement of the first electrode film 212 formed on the rough surface to achieve the effect of improving the power tolerance of the elastic wave device 10.

[0095] Referring to Figure 1 、 Figure 2 and Figure 3 , in some embodiments, the interdigital electrode 21 further includes an adhesion film 213. The adhesion film 213 is located on the piezoelectric substrate 1, and the metal film 211 is located on the side of the adhesion film 213 away from the piezoelectric substrate 1.

[0096] In this embodiment, by providing the adhesion film 213 between the piezoelectric substrate 1 and the metal film 211, the adhesion between the metal film 211 and the piezoelectric substrate 1 can be enhanced. Combined with Figure 2 , it should be understood that in the embodiment where the metal film 211 includes the second electrode film 2112 and the amorphous layer 2113, by providing the adhesion film 213 between the piezoelectric substrate 1 and the metal film 211, the adhesion between the second electrode film 2112 and the piezoelectric substrate 1 can be enhanced.

[0097] In an embodiment where the amorphous layer 2113 is not formed on the metal film 211, an adhesion film 213 is provided between the piezoelectric substrate 1 and the metal film 211, and the effect of enhancing the adhesion between the metal film 211 and the piezoelectric substrate 1 can also be achieved.

[0098] Combined Figure 1 and Figure 2 , in some embodiments, the material of the adhesion film 213 mainly comprises chromium or titanium.

[0099] In this embodiment, the adhesion film 213 mainly made of chromium or titanium on the piezoelectric substrate 1 can further enhance the adhesion between the metal film 211 and the piezoelectric substrate 1. In this embodiment, the material of the adhesion film 213 can be metallic titanium or metallic chromium, and the material of the adhesion film 213 can also be an alloy mainly comprising chromium or titanium.

[0100] Combined Figure 1 , in some embodiments, the thickness range of the adhesion film 213 is 10 nm to 20 nm.

[0101] It can be understood that if the thickness of the adhesion film 213 is too thick, it is easy to cause too large a load, too high a resistance and insufficient strength, and if it is too thin, it will cause poor growth effects of the metal film 211 and the first electrode film 212, which will have an adverse impact on the performance of the finally manufactured elastic wave device 10. Therefore, in this embodiment, the thickness of the adhesion film 213 is designed within the above range. In one embodiment, the thickness of the adhesion film 213 is set to 12 nm, which can make the adhesion film 213 have appropriate strength, and will not cause too large a load and too high a resistance, and can improve the growth effects of the metal film 211 and the first electrode film 212, and improve the performance of the elastic wave device 10.

[0102] Combined Figure 1 and Figure 2 , in some embodiments, the material of the piezoelectric substrate 1 mainly comprises any one or a combination of lithium niobate and lithium tantalate. The piezoelectric substrate 1 is a piezoelectric material with piezoelectric effect. The piezoelectric substrate 1 can mainly be made of lithium niobate (LiNbO 3 ), or can mainly be made of lithium tantalate (LiTaO 3 ), or can also mainly be made of lithium niobate (LiNbO 3 ) and lithium tantalate (LiTaO 3 ). This embodiment does not make specific limitations on this.

[0103] Combined Figure 1 and Figure 2 , in one embodiment, the piezoelectric substrate 1 is a 42° YX lithium tantalate substrate.

[0104] In some embodiments, the piezoelectric substrate 1 may include a substrate and a piezoelectric layer. Specifically, the material of the piezoelectric layer is mainly composed of any one of lithium niobate and lithium tantalate or a combination thereof. The material of the piezoelectric layer uses a piezoelectric material with piezoelectric effect. For example, the piezoelectric layer may be mainly made of lithium niobate (LiNbO 3 ), or may be mainly made of lithium tantalate (LiTaO 3 ), or may be mainly made of lithium niobate (LiNbO 3 ) and lithium tantalate (LiTaO 3 ). The substrate may be made of materials such as silicon, quartz, sapphire, silicon carbide, etc. This embodiment does not make specific limitations on this.

[0105] It can be understood that the elastic wave device 10 provided in the embodiments of the present application may be a surface acoustic wave resonator, a temperature-compensated surface acoustic wave resonator, a piezoelectric thin film type surface acoustic wave resonator with a multilayer structure of the piezoelectric substrate, or a longitudinal coupling resonator with multiple interdigital transducers, or a filter composed of the above multiple resonators, etc. The embodiments of the present application do not make specific limitations.

[0106] Combined with Figure 1 and Figure 2 , the embodiments of the present application further provide a radio frequency front-end module, which includes the above-mentioned elastic wave device 10.

[0107] In this embodiment, the radio frequency front-end module has the above-mentioned elastic wave device 10. It can be understood that in the radio frequency front-end module of the embodiments of the present application, since the above-mentioned elastic wave device 10 is used and the surface of the metal film 211 away from the piezoelectric substrate 1 is set as the rough surface 2111, and the first electrode film 212 is located on the rough surface 2111, thus, the grain size and grain arrangement of the first electrode film 212 can be different from those of the metal film 211. Moreover, compared with setting the first electrode film 212 on the smooth surface of the metal film 211, reducing the grain size of the first electrode film 212 and reducing the voids between the grains in the first electrode film 212 can increase the difficulty of stress migration and electron migration in the interdigital electrode 21, and increase the difficulty of atomic migration, thereby improving the power tolerance of the elastic wave device 10.

[0108] On the other hand, reducing the grain size of the first electrode film 212 and reducing the voids between the grains in the first electrode film 212 helps to improve the arrangement stability of each grain, improve the structural stability of the first electrode film 212, thereby improving the adhesion of the first electrode film 212, so as to more firmly adhere to the rough surface 2111, and can also improve the power tolerance of the elastic wave device 10 from the side.

[0109] Combined with Figure 1, The embodiment of the present application further provides a method for manufacturing an elastic wave device 10, which is used to manufacture the above-mentioned elastic wave device 10. Wherein, the method for manufacturing the elastic wave device 10 includes:

[0110] Form a metal film 211 on the piezoelectric substrate 1;

[0111] Perform surface treatment on the side of the metal film 211 away from the piezoelectric substrate 1, so that a rough surface 2111 is formed on the side of the metal film 211 away from the piezoelectric substrate 1;

[0112] Form a first electrode film 212 on the rough surface 2111.

[0113] In this embodiment, first form a metal film 211 on the piezoelectric substrate 1, then perform surface treatment on the side of the metal film 211 away from the piezoelectric substrate 1, so that a rough surface 2111 is formed on the side of the metal film 211 away from the piezoelectric substrate 1, and then form a first electrode film 212 on the rough surface 2111. Compared with directly forming the first electrode film 212 on the metal film 211 without forming a rough surface 2111 on the side of the metal film 211 away from the piezoelectric substrate 1, in the fabricated interdigital electrode 21, the grain size and grain arrangement of the first electrode film 212 are different from those of the metal film 211.

[0114] Moreover, on the one hand, it is beneficial for the grains of the first electrode film 212 to form more grain orientations of Al(111), which is beneficial for reducing the grain size of the first electrode film 212, reducing the voids between the grains in the first electrode film 212, increasing the difficulty of grain migration in the first electrode film 212, and improving the mechanical properties of the first electrode film 212. In this way, in the interdigital electrode 21 where the first electrode film 212 plays a dominant role, it is possible to increase the difficulty of stress migration, electron migration, and atomic migration in the interdigital electrode 21, thereby improving the power tolerance of the fabricated elastic wave device 10.

[0115] On the other hand, reducing the grain size of the first electrode film 212 and the voids between the grains in the first electrode film 212 helps to improve the arrangement stability of the grains, improve the structural stability of the first electrode film 212, thereby improving the adhesion of the first electrode film 212, so as to adhere more firmly to the rough surface 2111, and can also improve the power tolerance of the fabricated elastic wave device 10 from the side.

[0116] Combined Figure 2 and Figure 3 , In some embodiments, the metal film 211 includes a second electrode film 2112 and an amorphous layer 2113. The amorphous layer 2113 is disposed between the first electrode film 212 and the second electrode film 2112, and the side of the amorphous layer 2113 away from the second electrode film 2112 is the rough surface 2111;

[0117] The steps for surface treatment of the metal film 211 include:

[0118] The surface of the second electrode film 2112 away from the piezoelectric substrate 1 is surface-treated by an inductively coupled plasma etching process or a plasma cleaning process, so as to form an amorphous layer 2113 with a rough surface 2111 on the surface of the second electrode film 2112 away from the piezoelectric substrate 1.

[0119] In this embodiment, surface-treating the surface of the second electrode film 2112 away from the piezoelectric substrate 1 by an inductively coupled plasma etching process or a plasma cleaning process can effectively avoid damaging the first electrode film 212, and can form an amorphous layer 2113 with a certain thickness on the surface of the first electrode film 212 away from the piezoelectric substrate 1. Combining with the above elastic wave device 10, it can be known that the thickness of the amorphous layer 2113 should be designed within the range of 1 nm to 4 nm.

[0120] Combined with Figure 2 and Figure 3 , in some embodiments, during the process of surface-treating the metal film 211, the process gas used is an inert gas, nitrogen or oxygen.

[0121] In this embodiment, compared with directly forming the first electrode film 212 on the metal film 211 without forming a rough surface 2111 on the surface of the metal film 211 away from the piezoelectric substrate 1, bombarding the surface of the metal film 211 away from the piezoelectric substrate 1 with an inert gas, nitrogen or oxygen can form a very thin amorphous layer 2113, so that the first electrode film 212 formed on the metal film 211 has a smaller grain size, thereby improving the power tolerance of the elastic wave device 10. Among them, the inert gas can be argon (Ar) or other inert gases.

[0122] Combined with Figure 2 and Figure 3 , in one embodiment, the surface of the second electrode film 2112 away from the piezoelectric substrate 1 is bombarded with an inert gas, nitrogen or oxygen to form an amorphous layer 2113 on the upper surface of the second electrode film 2112. It can be understood that when using Ar, N2 or O2 as the process gas for inductively coupled plasma etching, not only can excessive damage to the second electrode film 2112 be effectively avoided at a lower radio frequency power and a shorter time, but also a thin amorphous layer 2113 with a rough surface 2111 can be formed on the upper surface of the second electrode film 2112, which is beneficial to the formation of the first electrode film 212. And compared with directly forming the first electrode film 212 on the smooth surface of the metal film 211, the first electrode film 212 has a better grain orientation, a smaller grain size and a stronger adhesion, and thus the fabricated elastic wave device 10 has a higher power tolerance.

[0123] Combined with Figure 2 and Figure 3 In a specific embodiment, during the surface treatment of the second electrode film 2112, the pressure is 0.133 Pa to 133 Pa and maintained in a vacuum environment, which is beneficial to the formation of the amorphous layer 2113 having the rough surface 2111.

[0124] Combined with Figure 1 In some embodiments, the interdigital electrode 21 further includes an adhesion film 213 disposed between the piezoelectric substrate 1 and the metal film 211;

[0125] The step of forming the metal film 211 on the piezoelectric substrate 1 includes:

[0126] Forming an adhesion film 213 on the piezoelectric substrate 1;

[0127] Forming the metal film 211 on the adhesion film 213 by electron beam evaporation.

[0128] In this embodiment, first forming the adhesion film 213 on the piezoelectric substrate 1 and then forming the metal film 211 on the adhesion film 213 by electron beam evaporation can effectively improve the adhesion of the metal film 211 to the piezoelectric substrate 1, thereby improving the performance of the fabricated elastic wave device 10.

[0129] Combined with Figure 2 and Figure 3 In some embodiments, during the formation of the metal film 211, the deposition rate of electron beam evaporation is

[0130] In this embodiment, during the process of forming the metal film 211 on the adhesion film 213 by electron beam evaporation, the deposition rate used is It can reduce the control difficulty, can control the uniformity of the formed metal film 211 to a certain extent, improve the quality of the fabricated metal film 211, and contribute to the subsequent formation of the amorphous layer 2113. At the same time, if the deposition rate exceeds Even if the subsequent surface treatment of the metal film 211 is carried out, the amorphous layer 2113 cannot be formed.

[0131] Combined with Figure 2 and Figure 3 In a specific embodiment, the step of forming the metal film 211 on the piezoelectric substrate 1 includes:

[0132] S1. Forming an adhesion film 213 on the piezoelectric substrate 1 by electron beam evaporation, and the deposition rate of electron beam evaporation is

[0133] S2. Form a second electrode film 2112 on the adhesion film 213 by electron beam evaporation, and the deposition rate of the electron beam evaporation is

[0134] S3. Bombard the side of the second electrode film 2112 away from the piezoelectric substrate 1 with argon, nitrogen or oxygen to form an amorphous layer 2113 with a rough surface 2111 on the upper surface of the second electrode film 2112.

[0135] By forming the adhesion film 213 first, then forming the second electrode film 2112, and then performing surface treatment on the upper surface of the second electrode film 2112 in the above manner, the control difficulty can be reduced, and the uniformity of the formed adhesion film 213 and second electrode film 2112 can be ensured to a certain extent, improving the quality of the formed adhesion film 213 and second electrode film 2112. It can also ensure to a certain extent that the second electrode film 2112 forms an amorphous layer 2113 with a rough surface 2111 after surface treatment, thereby improving the performance of the formed first electrode film 212. When the metal film 211 and the first electrode film 212 are used as the main electrodes of the interdigital electrode 21, the power tolerance of the elastic wave device 10 is comprehensively improved.

[0136] Combined with Figure 2 and Figure 3 , in some embodiments, the step of forming the first electrode film 212 on the rough surface 2111 includes: forming the first electrode film 212 on the rough surface 2111 by electron beam evaporation, and the deposition rate of the electron beam evaporation is

[0137] In the process of forming the first electrode film 212 in the above manner in this embodiment, the control difficulty can be reduced, and the uniformity of the formed first electrode film 212 can be ensured to a certain extent, improving the quality of the formed first electrode film 212.

[0138] Combined with Figure 1 , in some embodiments, before the step of forming the metal film 211 on the piezoelectric substrate 1, a photolithographic pattern layer with a hollow pattern is formed on the piezoelectric substrate 1; after the first electrode film 212 is formed on the rough surface 2111, the photolithographic pattern layer is peeled off to form an electrode pattern with a thickness on the piezoelectric substrate 1. In this embodiment, the metal lift-off process is used to obtain the electrode pattern structure. The peeling process can effectively avoid physical and chemical damage to each film layer in the interdigital electrode 21 and effectively avoid contamination of the interdigital electrode 21, thereby improving the quality of the prepared interdigital electrode 21.

[0139] Combined with Figure 2, in some embodiments, after the first electrode film 212 is formed on the rough surface 2111, an etching process can be used to form the electrode pattern, or a photolithography pattern layer with a hollow pattern can be formed again on the rough surface 2111, and the first electrode film 212 can be prepared by a lift-off process. The embodiments of the present application do not make specific limitations.

[0140] Referring to Figures 1 to 7 , based on the elastic wave device 10 and the preparation method of the elastic wave device 10 provided by the embodiments of the present application, the embodiments of the present application compare the provided Example 1 with the comparative example to make the effects of the embodiments of the present application more intuitive. Among them, in Example 1, the interdigital electrode 21 includes an adhesion film 213, a first electrode film 212, a second electrode film 2112, and an amorphous layer 2113 with a rough surface 2111. The second electrode film 2112 and the amorphous layer 2113 are located between the adhesion film 213 and the first electrode film 212, the amorphous layer 2113 is located between the first electrode film 212 and the second electrode film 2112, and the first electrode film 212 is provided on the rough surface 2111. In the comparative example, it includes an adhesion film 213 and a first electrode film 212, and the first electrode film 212 is located on the adhesion film 213.

[0141] Figure 2 FIG. 9 is a schematic structural diagram of the elastic wave device 10 in Example 1, and exemplarily shows the grain size and grain arrangement of the interdigital electrode 21 in the interdigital transducer 2 of the elastic wave device 10. Figure 6 FIG. 10 is a schematic structural diagram of the comparative example, and exemplarily shows the grain size and grain arrangement of the interdigital electrode 21.

[0142] From Figure 2 and Figure 6 , it can be seen that the grain size in Example 1 is significantly smaller than that in the comparative example, and it can also be clearly seen that the grain arrangement in Example 1 is better than that in the comparative example, indicating that the power tolerance of Example 1 is higher than that of Comparative Example 1. Figure 4 FIG. 20 is an enlarged structural diagram of the amorphous layer 2113 in Example 1, and exemplarily shows the grain arrangement in the amorphous layer 2113. From Figure 4 , it can be seen that the grain arrangement in the amorphous layer 2113 is disordered.

[0143] Figure 7 FIG. 26 is a comparative diagram of the percentage reduction in the full width at half maximum of Example 1 and the comparative example. The vertical coordinate is the percentage reduction in the full width at half maximum (FWHM), and the horizontal coordinate is the comparative example (BEFORE) and the example (AFTER). The full width at half maximum is an index used to measure the grain size. The lower the value of the full width at half maximum, the smaller the grain size.

[0144] From Figure 7As can be seen, compared with the comparative example, the half-width height of Example 1 decreased by a certain value in percentage. Exemplarily, the half-width height of the comparative example is 1.06, and the half-width height of Example 1 is 1.04. Compared with the comparative example, the half-width height of Example 1 decreased by 2%. It can be seen that compared with the comparative example, the half-width height of Example 1 decreased, and the half-width height of Example 1 is significantly smaller than that of the comparative example, indicating that the grain size of the interdigital electrode 21 in Example 1 is smaller than that of the interdigital electrode 21 in the comparative example, indicating that the growth effect of the interdigital electrode 21 in Example 1 is better than that of the interdigital electrode 21 in the comparative example, thereby improving the power tolerance of the surface acoustic wave device 10 of Example 1.

[0145] Combined with the above, compared with the comparative example, Example 1 provided in the embodiment of the present application has a smaller grain size. The grain arrangements of Example 1 and the comparative example are different, and the grain arrangement of Example 1 can form more Al(111) grain orientations, indicating that the power tolerance of Example 1 is significantly improved compared with the comparative example.

[0146] The above are only the preferred embodiments of the present application, and do not limit the patent scope of the present application. Any equivalent structural transformation made by using the content of the specification and drawings of the present application under the application concept of the present application, or direct / indirect application in other related technical fields are included in the patent protection scope of the present application.

Claims

1. An elastic wave device, characterized in that, it includes a piezoelectric substrate and at least one interdigital transducer disposed on the piezoelectric substrate, and the interdigital transducer includes at least two interdigital electrodes; wherein, at least one of the interdigital electrodes includes: a metal film, the metal film is disposed on the piezoelectric substrate, and the surface of the metal film away from the piezoelectric substrate is a rough surface; a first electrode film, the first electrode film is located on the rough surface; the rough surface is used to make the grain size and grain arrangement of the first electrode film different from those of the metal film.

2. The elastic wave device according to claim 1, characterized in that, the metal film includes a second electrode film and an amorphous layer, the amorphous layer is disposed between the first electrode film and the second electrode film, the surface of the second electrode film away from the piezoelectric substrate is surface-treated to form the amorphous layer, and the surface of the amorphous layer away from the second electrode film is a rough surface.

3. The elastic wave device according to claim 2, characterized in that, at least one of the first electrode film and the second electrode film is a polycrystalline electrode film; and / or, the grain size of the first electrode film is smaller than that of the second electrode film.

4. The elastic wave device according to claim 2, characterized in that, the material of the amorphous layer is any one of aluminum metal, aluminum alloy, aluminum nitride and aluminum oxide; and / or, the thickness of the amorphous layer is 1 nm to 4 nm.

5. The elastic wave device according to claim 2, characterized in that, the first electrode film and the second electrode film are made of the same material; and / or, the thickness range of the first electrode film is 50 nm to 500 nm, and the thickness range of the second electrode film is 10 nm to 30 nm.

6. The elastic wave device according to claim 2, characterized in that, at least one of the first electrode film and the second electrode film is made of aluminum metal or aluminum alloy.

7. The elastic wave device according to claim 6, characterized in that, the aluminum alloy is a copper-aluminum alloy, and the mass percentage of metallic copper in the copper-aluminum alloy is 1.0 wt% to 2.0 wt%; or, the aluminum alloy is a magnesium-aluminum alloy, and the mass percentage of metallic magnesium in the magnesium-aluminum alloy is 1.0 wt% to 2.0 wt%.

8. The elastic wave device according to any one of claims 1-7, characterized in that, the interdigital electrode further includes an adhesion film, the adhesion film is located on the piezoelectric substrate, and the metal film is located on the surface of the adhesion film away from the piezoelectric substrate.

9. The elastic wave device according to claim 8, characterized in that, the material of the adhesion film is mainly composed of chromium or titanium; and / or, the thickness range of the adhesion film is 10 nm to 20 nm.

10. A radio frequency front-end module, characterized in that, it includes the elastic wave device according to any one of claims 1-9.

11. A method for manufacturing an elastic wave device for manufacturing the elastic wave device according to any one of claims 1-9, characterized in that, the manufacturing method includes: forming a metal film on the piezoelectric substrate; The surface of the metal film away from the piezoelectric substrate is surface-treated to form a rough surface on the side of the metal film away from the piezoelectric substrate; A first electrode film is formed on the rough surface; The rough surface is used to make the grain size and grain arrangement of the first electrode film different from those of the metal film.

12. The method for manufacturing an elastic wave device according to claim 11, wherein, The metal film includes a second electrode film and an amorphous layer. The amorphous layer is disposed between the first electrode film and the second electrode film, and the side of the amorphous layer away from the second electrode film is a rough surface; The step of surface-treating the metal film includes: The surface of the second electrode film away from the piezoelectric substrate is surface-treated by an inductively coupled plasma etching process or a plasma cleaning process to form an amorphous layer with a rough surface on the side of the second electrode film away from the piezoelectric substrate.

13. The method for manufacturing an elastic wave device according to claim 11 or 12, wherein, During the process of surface-treating the metal film, the process gas used is an inert gas or oxygen.

14. The method for manufacturing an elastic wave device according to claim 11, wherein, The interdigital electrode further includes an adhesion film disposed between the piezoelectric substrate and the metal film; The step of forming a metal film on the piezoelectric substrate includes: Forming an adhesion film on the piezoelectric substrate; Forming a metal film on the adhesion film by an electron beam evaporation process.

15. The method for manufacturing an elastic wave device according to claim 14, wherein, During the process of forming the metal film, the deposition rate of electron beam evaporation is

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