Acoustic resonator and method for manufacturing same

Abstract

An acoustic resonator and a method for manufacturing same, which relate to the technical field of resonators. The acoustic resonator comprises: a substrate (1), a releasable layer (2), a piezoelectric layer (3), a plurality of interdigital electrodes (4), and at least one reflection grating (5), wherein the releasable layer (2) is arranged on one side surface of the substrate (1) and is configured to be released between the piezoelectric layer (3) and the substrate (1), and when the releasable layer (2) is released, the piezoelectric layer (3) is isolated from the substrate (1) to form a cavity; the piezoelectric layer (3) is arranged on the side surface of the releasable layer (2) facing away from the substrate (1); and the at least one reflection grating (5) is arranged on two sides of the plurality of interdigital electrodes (4). In this way, by means of a combination of providing the reflection grating (5) on two sides of the interdigital electrodes (4) of the acoustic resonator and releasing the releasable layer (2), the leakage of surface waves and bulk waves is reduced to the greatest extent, thereby improving the performance of the acoustic resonator.

Description

Acoustic wave resonator and manufacturing method thereof

[0001] The present invention claims priority to the Chinese patent application filed with the State Intellectual Property Office of the People's Republic of China on June 28, 2023, with application number 202310780311.3 and invention name “A Sound Wave Resonator and Its Manufacturing Method”, the entire contents of which are incorporated herein by reference. Technical Field

[0002] The present application relates to the technical field of resonators, and in particular to an acoustic wave resonator and a method for manufacturing the same. Background Art

[0003] As 5G wireless communications are rapidly developing, many countries have shifted their focus to the deployment of 6G networks and millimeter-wave communications. In the future, 6G networks are expected to support three common services: enhanced mobile broadband (eMBB), ultra-reliable low-latency communications (URLLC), and massive machine-type communications (mMTC), aiming to increase data rates, achieve ultra-low latency, achieve high reliability, and achieve large-scale connectivity. To meet these demands, cutting-edge technologies such as artificial intelligence (AI) and RF front-end design have been applied to 6G network design to optimize spectral efficiency. As a key technology in the RF front-end, RF filters, with their high frequency, wide bandwidth, and low insertion loss, are prerequisites for ensuring the rapid communication of big data in future wireless communication networks.

[0004] Acoustic wave filters are a very important part of current radio frequency filters. In order to meet the indicators of low insertion loss and high coupling, researchers have made great efforts in the design of acoustic wave resonator structures. For traditional surface acoustic wave filters (SAW), the method of adding reflection gratings on both sides of the electrode is often used to achieve maximum coupling of acoustic waves; thin film bulk acoustic wave filters (FBAR) choose to manufacture cavities to form an interface between the piezoelectric layer and the air, which can almost completely reflect all acoustic wave energy; solid-state assembled resonators (SMR) use multiple layers of high and low acoustic impedance overlapping and stacking to reflect energy multiple times, and finally achieve total reflection. However, the SMR technology is complex and the acoustic wave reflection effect is not ideal, and it is gradually being replaced by other technologies.

[0005] With the emergence of Lamb wave resonators and other resonators that couple surface waves to bulk waves, it is not just the energy leakage in a single direction that needs to be considered, but the coupling in multiple dimensions. Although current Lamb wave resonators use a method of etching holes on both sides of the electrode and then releasing them to obtain a bottom cavity to prevent the leakage of transverse and longitudinal waves in order to achieve high-performance acoustic resonators, as the size of the electrode continues to decrease, the etched holes on both sides of the electrode cannot achieve ideal reflection conditions due to problems such as overlay error and lateral etching. Instead, they may cause damage to the electrode due to process problems, which greatly affects the performance of the acoustic resonator.

[0006] In summary, how to minimize the leakage of surface waves and bulk waves, and thereby improve the performance of acoustic wave resonators, is a problem that those skilled in the art urgently need to solve.

[0007] Summary of the Invention

[0008] In view of this, the present application provides an acoustic wave resonator and a method for manufacturing the same, aiming to minimize the leakage of surface waves and bulk waves, thereby improving the performance of the acoustic wave resonator.

[0009] In a first aspect, the present application provides an acoustic wave resonator, comprising:

[0010] a substrate, a release layer, a piezoelectric layer, a plurality of interdigital electrodes, and at least one reflective grating;

[0011] The release layer is provided on one side surface of the substrate, and the release layer is used to be released between the piezoelectric layer and the substrate. When the release layer is released, the piezoelectric layer is isolated from the substrate to form a cavity;

[0012] The piezoelectric layer is arranged on a surface of the release layer facing away from the substrate;

[0013] The at least one reflection grid is arranged on both sides of the plurality of interdigital electrodes.

[0014] Optionally, the plurality of interdigital electrodes are arranged on a surface of the piezoelectric layer facing away from the release layer, and / or a surface of the piezoelectric layer facing the release layer.

[0015] Optionally, the reflective grid includes a plurality of root-shaped metals, at least one reflective grid is periodically distributed on both sides of the interdigitated electrodes, and the structure of the reflective grid is one of a short-circuited floating grid, an open-circuited floating grid, and a grounded reflective grid.

[0016] Optional,

[0017] The number of the reflective gratings is 1-200;

[0018] The number of the interdigital electrodes is 2-500.

[0019] Optional,

[0020] The material of the reflective grid is gold, silver, copper, chromium, nickel, aluminum, molybdenum, platinum, titanium gold, titanium aluminum, chromium gold, or chromium aluminum;

[0021] The material of the interdigital electrodes is gold, silver, copper, chromium, nickel, aluminum, molybdenum, platinum, titanium gold, titanium aluminum, chromium gold, or chromium aluminum.

[0022] Optional,

[0023] The distance between adjacent interdigital electrodes and the reflective grating is 0.001-50 μm;

[0024] The thickness of the interdigitated electrodes is 5-500 nm;

[0025] The thickness of the reflective grating is 5-500 nm;

[0026] The width of the interdigital electrodes is 0.001-5 μm;

[0027] The width of the reflective grating is 0.001-5 μm;

[0028] The length of the interdigital electrodes is 1-500 μm;

[0029] The length of the reflection grating is 1-500 μm.

[0030] Optionally, the piezoelectric layer on a side of the reflection grating away from the interdigital electrodes is a free boundary or a fixed boundary.

[0031] Optionally, the release layer is one layer or multiple layers, and the material of each layer is one of silicon dioxide, silicon nitride, lithium niobate and silicon.

[0032] Optionally, the piezoelectric layer is a lithium niobate layer, or a lithium tantalate layer, or a composite layer consisting of at least two layers of a lithium niobate layer, an aluminum nitride layer, a scandium-doped aluminum nitride layer, a lithium tantalate layer, and a zinc oxide layer.

[0033] Optionally, the piezoelectric layer has a thickness of 10-5000 nm.

[0034] In a second aspect, the present application provides a method for manufacturing an acoustic wave resonator, comprising:

[0035] providing a substrate;

[0036] Disposing a release layer on one side surface of the substrate;

[0037] Disposing a piezoelectric layer on a surface of the release layer facing away from the substrate;

[0038] At least one reflection grid is provided on both sides of the plurality of interdigital electrodes;

[0039] The release layer is released between the piezoelectric layer and the substrate. When the release layer is released, the piezoelectric layer is isolated from the substrate to form a cavity.

[0040] The present application provides an acoustic wave resonator and a method for manufacturing the same. The acoustic wave resonator comprises: a substrate, a release layer, a piezoelectric layer, a plurality of interdigital electrodes, and at least one reflective grating; wherein the release layer is disposed on one surface of the substrate, and is used to be released between the piezoelectric layer and the substrate. When the release layer is released, the piezoelectric layer is isolated from the substrate to form a cavity. The piezoelectric layer is disposed on the surface of the release layer facing away from the substrate, and at least one reflective grating is disposed on both sides of the plurality of interdigital electrodes. In this way, by combining the reflective gratings on both sides of the interdigital electrodes of the acoustic wave resonator with the release layer, the leakage of surface waves and bulk waves is minimized, thereby improving the performance of the acoustic wave resonator. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the technical solutions in this embodiment or the prior art, the following briefly introduces the drawings required for use in the embodiment or the prior art description. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0042] FIG1 is a cross-sectional view of an acoustic wave resonator provided in an embodiment of the present application;

[0043] FIG2 is a top view of a combination of a reflective grating and interdigital electrodes provided in an embodiment of the present application;

[0044] FIG3 is a top view of another combination of a reflective grating and interdigital electrodes provided in an embodiment of the present application;

[0045] FIG4 is a top view of another combination of a reflective grid and interdigital electrodes provided in an embodiment of the present application;

[0046] FIG5 is a simulation performance diagram of an acoustic wave resonator combining a short-circuited suspended reflective grating and interdigital electrodes provided in an embodiment of the present application;

[0047] FIG6 is a cross-sectional view of another acoustic wave resonator provided in an embodiment of the present application;

[0048] FIG7 is a cross-sectional view of another acoustic wave resonator provided in an embodiment of the present application;

[0049] FIG8 is a flow chart of a method for manufacturing an acoustic wave resonator provided in an embodiment of the present application;

[0050] FIG9 is a flow chart of another method for manufacturing an acoustic wave resonator provided in an embodiment of the present application;

[0051] FIG10 is a flow chart of another method for manufacturing an acoustic wave resonator provided in an embodiment of the present application;

[0052] 11 to 21 are schematic diagrams of a manufacturing process of an acoustic wave resonator provided in an embodiment of the present application;

[0053] 22 to 32 are schematic diagrams of another process for manufacturing an acoustic wave resonator according to an embodiment of the present application;

[0054] 33-47 are schematic diagrams of another manufacturing process of an acoustic wave resonator provided in an embodiment of the present application. DETAILED DESCRIPTION

[0055] The following will be combined with the accompanying drawings to clearly and completely describe the technical solutions in the embodiments of this application. This application provides an acoustic wave resonator and a method for manufacturing the same, which are used in the field of resonator technology. The above is merely an example and does not limit the application areas of the methods and devices provided in this application.

[0056] As 5G wireless communications are rapidly developing, many countries have shifted their focus to the deployment of 6G networks and millimeter-wave communications. In the future, 6G networks are expected to support three common services: enhanced mobile broadband (eMBB), ultra-reliable low-latency communications (URLLC), and massive machine-type communications (mMTC), aiming to increase data rates, achieve ultra-low latency, achieve high reliability, and achieve large-scale connectivity. To meet these demands, cutting-edge technologies such as artificial intelligence (AI) and RF front-end design have been applied to 6G network design to optimize spectral efficiency. As a key technology in the RF front-end, RF filters, with their high frequency, wide bandwidth, and low insertion loss, are prerequisites for ensuring the rapid communication of big data in future wireless communication networks.

[0057] Acoustic wave filters are a very important part of current radio frequency filters. In order to meet the indicators of low insertion loss and high coupling, researchers have made great efforts in the design of acoustic wave resonator structures. For traditional surface acoustic wave filters (SAW), the method of adding reflection gratings on both sides of the electrode is often used to achieve maximum coupling of acoustic waves; thin film bulk acoustic wave filters (FBAR) choose to manufacture cavities to form an interface between the piezoelectric layer and the air, which can almost completely reflect all acoustic wave energy; solid-state assembled resonators (SMR) use multiple layers of high and low acoustic impedance overlapping and stacking to reflect energy multiple times, and finally achieve total reflection. However, the SMR technology is complex and the acoustic wave reflection effect is not ideal, and it is gradually being replaced by other technologies.

[0058] With the emergence of Lamb wave resonators and other resonators that couple surface waves to bulk waves, it is not just the energy leakage in a single direction that needs to be considered, but the coupling in multiple dimensions. Although current Lamb wave resonators use a method of etching holes on both sides of the electrode and then releasing them to obtain a bottom cavity to prevent the leakage of transverse and longitudinal waves in order to achieve high-performance acoustic resonators, as the size of the electrode continues to decrease, the etched holes on both sides of the electrode cannot achieve ideal reflection conditions due to problems such as overlay error and lateral etching. Instead, they may cause damage to the electrode due to process problems, which greatly affects the performance of the acoustic resonator.

[0059] After research, the inventors proposed the technical solution of this application. The acoustic wave resonator includes: a substrate, a release layer, a piezoelectric layer, multiple interdigital electrodes, and at least one reflective grating. The release layer is disposed on one surface of the substrate and is used to be released between the piezoelectric layer and the substrate. When the release layer is released, the piezoelectric layer is isolated from the substrate to form a cavity. The piezoelectric layer is disposed on the side of the release layer facing away from the substrate. Multiple interdigital electrodes are disposed on the surface of the piezoelectric layer. At least one reflective grating is disposed on both sides of the multiple interdigital electrodes on the surface of the piezoelectric layer. In this way, by combining the reflective gratings on both sides of the interdigital electrodes of the acoustic wave resonator with the release layer, the leakage of surface waves and bulk waves is minimized, thereby improving the performance of the acoustic wave resonator.

[0060] In order to enable those skilled in the art to better understand the present application, the present application is further described in detail below in conjunction with the accompanying drawings and specific embodiments. Obviously, the embodiments described are only a part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of the present application. It should be noted that, for ease of description, only the parts related to the relevant invention are shown in the accompanying drawings. In the absence of conflict, the embodiments in the present application and the features in the embodiments can be combined with each other.

[0061] Referring to FIG1 , FIG1 is a cross-sectional view of an acoustic wave resonator provided in an embodiment of the present application, comprising:

[0062] A substrate 1 , a release layer 2 , a piezoelectric layer 3 , a plurality of interdigital electrodes 4 and at least one reflective grating 5 .

[0063] The substrate 1 may be a silicon substrate, a sapphire substrate (Al2O3), a gallium nitride substrate (GaN), or a silicon carbide substrate (SiC).

[0064] The release layer 2 is provided on one side surface of the substrate 1 and is used to be released between the piezoelectric layer 3 and the substrate 1. When the release layer 2 is released, the piezoelectric layer 3 is isolated from the substrate 1 to form a cavity 11 to prevent body wave leakage.

[0065] The piezoelectric layer 3 is disposed on a surface of the release layer 2 that is away from the substrate.

[0066] A plurality of interdigital electrodes 4 are disposed on the surface of the piezoelectric layer 3 .

[0067] At least one reflection grating 5 is disposed on both sides of the plurality of interdigital electrodes 4 on the surface of the piezoelectric layer 3 , wherein the reflection grating 5 is used to minimize the leakage of surface waves on both sides of the interdigital electrodes 4 .

[0068] The reflective grid 5 includes a plurality of root-shaped metal strips, which are periodically distributed on both sides of the interdigital electrodes 4 . The reflective grid 5 has a structure of a short-circuited floating grid, an open-circuited floating grid, and a grounded reflective grid.

[0069] As shown in Figure 2, Figure 2 is a top view of a reflection grid and an interdigital electrode provided in an embodiment of the present application. The reflection grid 5 is a short-circuited suspended reflection grid, that is, the reflection grids 5 on one side of the interdigital electrode 4 are all short-circuited together, but are not connected to any potential.

[0070] As shown in FIG3 , FIG3 is a top view of another combination of a reflective gate and an interdigital electrode provided in an embodiment of the present application. The reflective gate 5 is an open-circuit suspended reflective gate, that is, the reflective gates 5 located on one side of the interdigital electrodes 4 are not short-circuited with each other and are not connected to any potential.

[0071] As shown in FIG4 , FIG4 is a top view of another combination of a reflective grid and an interdigital electrode provided in an embodiment of the present application. The reflective grid 5 is a grounded reflective grid, that is, the reflective grids 5 on one side of the interdigital electrode 4 are all short-circuited together and have a potential of zero.

[0072] In addition, the material of the reflector 5 is gold, silver, copper, chromium, nickel, aluminum, molybdenum, platinum, titanium, titanium aluminum, chromium gold, or chromium aluminum; the material of the interdigitated electrode 4 is gold, silver, copper, chromium, nickel, aluminum, molybdenum, platinum, titanium, titanium aluminum, chromium gold, or chromium aluminum.

[0073] The number of the reflective gratings 5 ​​is 1-200, such as 10 or 20. The specific number of the reflective gratings 5 ​​depends on the specific situation.

[0074] The number of the interdigital electrodes 4 is 2-500, such as 10 or 20. The specific number of the interdigital electrodes 4 depends on actual conditions.

[0075] The distance between adjacent interdigital electrodes 4 and the reflective grating 5 is 0.001-50 μm, such as 0.1 μm, and the specific value depends on the actual situation.

[0076] The thickness of the interdigital electrode 4 is 5-500 nm, such as 50 nm or 100 nm, and the specific value depends on the actual situation.

[0077] The thickness of the reflective grating 5 is 5-500 nm, such as 50 nm or 100 nm, and the specific value depends on the actual situation.

[0078] The width of the interdigital electrodes 4 is 0.001-5 μm, such as 0.05 μm or 0.12 μm, and the specific value depends on the actual situation.

[0079] The width of the reflective grating 5 is 0.001-5 μm, such as 0.05 μm or 0.12 μm, and the specific value depends on the actual situation.

[0080] The length of the interdigital electrodes 4 is 1-500 μm, such as 18 μm, 24 μm or 32 μm, and the specific value depends on the actual situation.

[0081] The length of the reflective grating 5 is 1-500 μm, such as 18 μm, 24 μm or 32 μm, and the specific value depends on the actual situation.

[0082] The piezoelectric layer 3 on the side of the reflector 5 away from the interdigital electrode 4 is a free boundary or a fixed boundary, wherein the free boundary means that there is an etching window for releasing the release layer 2; the fixed boundary means that there is no etching window, and the release layer 2 is released from the substrate direction.

[0083] The release layer 2 is one or more layers, and the material of each layer is one of silicon dioxide, silicon nitride, lithium niobate and silicon. The thickness of the release layer 2 is 0.01-100 μm.

[0084] The piezoelectric layer 3 is a lithium niobate layer, a lithium tantalate layer, or a composite layer consisting of at least two of a lithium niobate layer, an aluminum nitride layer, a scandium-doped aluminum nitride layer, a lithium tantalate layer, and a zinc oxide layer. The thickness of the piezoelectric layer 3 is 10-5000 nm.

[0085] As shown in Figure 5, Figure 5 is a simulation performance diagram of an acoustic wave resonator combining a short-circuited suspended reflector and a release cavity provided in an embodiment of the present application. The results show that the operating frequency of the acoustic wave resonator obtained using this structure is greater than 6 GHz, and the electromechanical coupling coefficient is greater than 30%, which fully meets the large-bandwidth RF filtering performance requirements in the future 6G and 7G frequency bands.

[0086] From the above description, it can be seen that in the acoustic wave resonator provided by the technical solution of the present invention, by providing a combination of a reflection grating and a release layer on both sides of the acoustic wave resonator's interdigital electrodes, the leakage of surface waves and body waves is minimized, the acoustic wave capacity is maximized, and a high-frequency (>5GHz) and high-coupling (>30%) acoustic wave resonator is realized, which can well meet the future 6G, 7G and even millimeter wave frequency bands for the high frequency and large bandwidth performance requirements of the filter.

[0087] As shown in FIG6 , FIG6 is a cross-sectional view of another acoustic wave resonator provided in an embodiment of the present application, including:

[0088] A substrate 1 , a release layer 2 , a piezoelectric layer 3 , a plurality of interdigital electrodes 4 and at least one reflective grating 5 .

[0089] The substrate 1 may be a silicon substrate, a sapphire substrate (Al2O3), a gallium nitride substrate (GaN), or a silicon carbide substrate (SiC).

[0090] The release layer 2 is provided on one side surface of the substrate 1 and is used to be released between the piezoelectric layer 3 and the substrate 1. When the release layer 2 is released, the piezoelectric layer 3 is isolated from the substrate 1 to form a cavity 11 to prevent body wave leakage.

[0091] The piezoelectric layer 3 is disposed on a surface of the release layer 2 that is away from the substrate.

[0092] The piezoelectric layer 3 has a plurality of interdigital electrodes 4 on one side thereof facing the release layer 2 . Optionally, the plurality of interdigital electrodes 4 are embedded in the piezoelectric layer 3 , and the plurality of interdigital electrodes 4 are in contact with the release layer 2 .

[0093] At least one reflection grating 5 is disposed on both sides of the interdigital electrode 4 , wherein the reflection grating 5 is used to minimize the leakage of surface waves on both sides of the interdigital electrode 4 .

[0094] The reflective grid 5 includes a plurality of root-shaped metal strips, which are periodically distributed on both sides of the interdigital electrodes 4 . The reflective grid 5 has a structure of a short-circuited floating grid, an open-circuited floating grid, and a grounded reflective grid.

[0095] As shown in Figure 2, Figure 2 is a top view of a reflection grid and an interdigital electrode provided in an embodiment of the present application. The reflection grid 5 is a short-circuited suspended reflection grid, that is, the reflection grids 5 on one side of the interdigital electrode 4 are all short-circuited together, but are not connected to any potential.

[0096] As shown in FIG3 , FIG3 is a top view of another combination of a reflective gate and an interdigital electrode provided in an embodiment of the present application. The reflective gate 5 is an open-circuit suspended reflective gate, that is, the reflective gates 5 located on one side of the interdigital electrodes 4 are not short-circuited with each other and are not connected to any potential.

[0097] As shown in FIG4 , FIG4 is a top view of another combination of a reflective grid and an interdigital electrode provided in an embodiment of the present application. The reflective grid 5 is a grounded reflective grid, that is, the reflective grids 5 on one side of the interdigital electrode 4 are all short-circuited together and have a potential of zero.

[0098] In addition, the material of the reflector 5 is gold, silver, copper, chromium, nickel, aluminum, molybdenum, platinum, titanium, titanium aluminum, chromium gold, or chromium aluminum; the material of the interdigitated electrode 4 is gold, silver, copper, chromium, nickel, aluminum, molybdenum, platinum, titanium, titanium aluminum, chromium gold, or chromium aluminum.

[0099] The number of the reflective gratings 5 ​​is 1-200, such as 10 or 20. The specific number of the reflective gratings 5 ​​depends on the specific situation.

[0100] The number of the interdigital electrodes 4 is 2-500, such as 10 or 20. The specific number of the interdigital electrodes 4 depends on actual conditions.

[0101] The distance between adjacent interdigital electrodes 4 and the reflective grating 5 is 0.001-50 μm, such as 0.1 μm, and the specific value depends on the actual situation.

[0102] The thickness of the interdigital electrode 4 is 5-500 nm, such as 50 nm or 100 nm, and the specific value depends on the actual situation.

[0103] The thickness of the reflective grating 5 is 5-500 nm, such as 50 nm or 100 nm, and the specific value depends on the actual situation.

[0104] The width of the interdigital electrodes 4 is 0.001-5 μm, such as 0.05 μm or 0.12 μm, and the specific value depends on the actual situation.

[0105] The width of the reflective grating 5 is 0.001-5 μm, such as 0.05 μm or 0.12 μm, and the specific value depends on the actual situation.

[0106] The length of the interdigital electrodes 4 is 1-500 μm, such as 18 μm, 24 μm or 32 μm, and the specific value depends on the actual situation.

[0107] The length of the reflective grating 5 is 1-500 μm, such as 18 μm, 24 μm or 32 μm, and the specific value depends on the actual situation.

[0108] The piezoelectric layer 3 on the side of the reflector 5 away from the interdigital electrode 4 is a free boundary or a fixed boundary, wherein the free boundary means that there is an etching window for releasing the release layer 2; the fixed boundary means that there is no etching window, and the release layer 2 is released from the substrate direction.

[0109] The release layer 2 is one or more layers, and the material of each layer is one of silicon dioxide, silicon nitride, lithium niobate and silicon. The thickness of the release layer 2 is 0.01-100 μm.

[0110] The piezoelectric layer 3 is a lithium niobate layer, a lithium tantalate layer, or a composite layer consisting of at least two of a lithium niobate layer, an aluminum nitride layer, a scandium-doped aluminum nitride layer, a lithium tantalate layer, and a zinc oxide layer. The thickness of the piezoelectric layer 3 is 10-5000 nm.

[0111] As shown in FIG7 , FIG7 is a cross-sectional view of another acoustic wave resonator provided in an embodiment of the present application, including:

[0112] A substrate 1 , a release layer 2 , a piezoelectric layer 3 , a plurality of interdigital electrodes 4 and at least one reflective grating 5 .

[0113] The substrate 1 may be a silicon substrate, a sapphire substrate (Al2O3), a gallium nitride substrate (GaN), or a silicon carbide substrate (SiC).

[0114] The release layer 2 is provided on one side surface of the substrate 1 and is used to be released between the piezoelectric layer 3 and the substrate 1. When the release layer is released, the piezoelectric layer 3 is isolated from the substrate 1 to form a cavity 11 to prevent body wave leakage.

[0115] The piezoelectric layer 3 is disposed on a surface of the release layer 2 that is away from the substrate.

[0116] Multiple interdigitated electrodes 4 are arranged on the side surface of the piezoelectric layer 3 facing away from the release layer 2 and the side surface of the piezoelectric layer 3 facing the release layer 2. Optionally, multiple interdigitated electrodes 4 are embedded in the piezoelectric layer 3, and multiple interdigitated electrodes 4 are in contact with the release layer 2, and multiple interdigitated electrodes 4 are arranged on the surface of the piezoelectric layer 3.

[0117] At least one reflection grating 5 is disposed on both sides of the interdigital electrode 4 , wherein the reflection grating 5 is used to minimize the leakage of surface waves on both sides of the interdigital electrode 4 .

[0118] The reflective grid 5 includes a plurality of root-shaped metal strips, which are periodically distributed on both sides of the interdigital electrodes 4 . The reflective grid 5 has a structure of a short-circuited floating grid, an open-circuited floating grid, and a grounded reflective grid.

[0119] As shown in Figure 2, Figure 2 is a top view of a reflection grid and an interdigital electrode provided in an embodiment of the present application. The reflection grid 5 is a short-circuited suspended reflection grid, that is, the reflection grids 5 on one side of the interdigital electrode 4 are all short-circuited together, but are not connected to any potential.

[0120] As shown in FIG3 , FIG3 is a top view of another combination of a reflective gate and an interdigital electrode provided in an embodiment of the present application. The reflective gate 5 is an open-circuit suspended reflective gate, that is, the reflective gates 5 located on one side of the interdigital electrodes 4 are not short-circuited with each other and are not connected to any potential.

[0121] As shown in FIG4 , FIG4 is a top view of another combination of a reflective grid and an interdigital electrode provided in an embodiment of the present application. The reflective grid 5 is a grounded reflective grid, that is, the reflective grids 5 on one side of the interdigital electrode 4 are all short-circuited together and have a potential of zero.

[0122] In addition, the material of the reflector 5 is gold, silver, copper, chromium, nickel, aluminum, molybdenum, platinum, titanium, titanium aluminum, chromium gold, or chromium aluminum; the material of the interdigitated electrode 4 is gold, silver, copper, chromium, nickel, aluminum, molybdenum, platinum, titanium, titanium aluminum, chromium gold, or chromium aluminum.

[0123] The number of the reflective gratings 5 ​​is 1-200, such as 10 or 20. The specific number of the reflective gratings 5 ​​depends on the specific situation.

[0124] The number of the interdigital electrodes 4 is 2-500, such as 10 or 20. The specific number of the interdigital electrodes 4 depends on actual conditions.

[0125] The distance between adjacent interdigital electrodes 4 and the reflective grating 5 is 0.001-50 μm, such as 0.1 μm, and the specific value depends on the actual situation.

[0126] The thickness of the interdigital electrode 4 is 5-500 nm, such as 50 nm or 100 nm, and the specific value depends on the actual situation.

[0127] The thickness of the reflective grating 5 is 5-500 nm, such as 50 nm or 100 nm, and the specific value depends on the actual situation.

[0128] The width of the interdigital electrodes 4 is 0.001-5 μm, such as 0.05 μm or 0.12 μm, and the specific value depends on the actual situation.

[0129] The width of the reflective grating 5 is 0.001-5 μm, such as 0.05 μm or 0.12 μm, and the specific value depends on the actual situation.

[0130] The length of the interdigital electrodes 4 is 1-500 μm, such as 18 μm, 24 μm or 32 μm, and the specific value depends on the actual situation.

[0131] The length of the reflective grating 5 is 1-500 μm, such as 18 μm, 24 μm or 32 μm, and the specific value depends on the actual situation.

[0132] The piezoelectric layer 3 on the side of the reflector 5 away from the interdigital electrode 4 is a free boundary or a fixed boundary, wherein the free boundary means that there is an etching window for releasing the release layer 2; the fixed boundary means that there is no etching window, and the release layer 2 is released from the substrate direction.

[0133] The release layer 2 is one or more layers, and the material of each layer is one of silicon dioxide, silicon nitride, lithium niobate and silicon. The thickness of the release layer 2 is 0.01-100 μm.

[0134] The piezoelectric layer 3 is a lithium niobate layer, a lithium tantalate layer, or a composite layer consisting of at least two of a lithium niobate layer, an aluminum nitride layer, a scandium-doped aluminum nitride layer, a lithium tantalate layer, and a zinc oxide layer. The thickness of the piezoelectric layer 3 is 10-5000 nm.

[0135] In the above embodiment of the present application, the acoustic wave resonator includes: a substrate, a release layer, a piezoelectric layer, a plurality of interdigital electrodes and at least one reflection grating; wherein the release layer is arranged on one side surface of the substrate, and the release layer is used to be released between the piezoelectric layer and the substrate. When the release layer is released, the piezoelectric layer is isolated from the substrate to form a cavity. The piezoelectric layer is arranged on the side surface of the release layer facing away from the substrate, and at least one reflection grating is arranged on both sides of the plurality of interdigital electrodes. In this way, by combining the arrangement of reflection gratings on both sides of the interdigital electrodes of the acoustic wave resonator and the release layer, the leakage of surface waves and body waves is minimized, thereby improving the performance of the acoustic wave resonator. Referring to Figure 8, Figure 8 is a flow chart of a method for manufacturing an acoustic wave resonator provided in an embodiment of the present application, comprising:

[0136] S801: providing a substrate.

[0137] As shown in FIG11 , a substrate 1 is provided, wherein the substrate 1 may be a silicon substrate, a sapphire substrate (Al 2 O 3 ), a gallium nitride substrate (GaN), or a silicon carbide substrate (SiC).

[0138] S802: Disposing a release layer on one surface of the substrate.

[0139] As shown in Figure 12, a release layer 2 is provided on one side of the substrate 1. The release layer 2 comprises one or more layers, each layer being made of one of silicon dioxide, silicon nitride, lithium niobate, and silicon. The thickness of the release layer 2 is 0.01-100 μm. The release layer 2 can be released between the piezoelectric layer 3 and the substrate 1.

[0140] S803: Disposing a piezoelectric layer on a surface of the release layer facing away from the substrate.

[0141] As shown in FIG13 , a piezoelectric layer 3 is provided on the surface of the release layer 2 facing away from the substrate.

[0142] The piezoelectric layer 3 is a lithium niobate layer, a lithium tantalate layer, or a composite layer consisting of at least two of a lithium niobate layer, an aluminum nitride layer, a scandium-doped aluminum nitride layer, a lithium tantalate layer, and a zinc oxide layer. The thickness of the piezoelectric layer 3 is 10-5000 nm.

[0143] S804: Disposing a plurality of interdigital electrodes on the surface of the piezoelectric layer.

[0144] S805: Disposing at least one reflection grating on both sides of the plurality of interdigital electrodes on the surface of the piezoelectric layer.

[0145] In this embodiment, the implementation of step S804 and the implementation of step S805 can be performed simultaneously, as follows:

[0146] As shown in FIG14 , a first mask layer 6 is formed on the surface of the piezoelectric layer 3 facing away from the release layer 2 . The first mask layer 6 can be any one of photoresist, silicon oxide, silicon nitride, or a combination of the two.

[0147] As shown in FIG15 , after photolithography on the first mask layer 6 , stripping or reactive ion etching is used to obtain the first electrode and the reflective grid window 7 , and partially expose the surface of the piezoelectric layer 3 ; wherein the photolithography technology can be either ultraviolet lithography or electron beam lithography or a combination of the two.

[0148] As shown in FIG16 , interdigitated electrodes 4 and reflective grating 5 are formed on the first electrode and reflective grating window 7 by coating technology, wherein the coating technology can be one of thermal evaporation, electron beam evaporation or magnetron sputtering or a combination of the two.

[0149] Finally, as shown in FIG17 , the remaining first mask layer 6 is removed.

[0150] The reflective grid 5 includes a plurality of root-shaped metal strips, which are periodically distributed on both sides of the interdigital electrodes 4 . The reflective grid 5 has a structure of a short-circuited floating grid, an open-circuited floating grid, and a grounded reflective grid.

[0151] As shown in Figure 2, Figure 2 is a top view of a reflection grid and an interdigital electrode provided in an embodiment of the present application. The reflection grid 5 is a short-circuited suspended reflection grid, that is, the reflection grids 5 on one side of the interdigital electrode 4 are all short-circuited together, but are not connected to any potential.

[0152] As shown in FIG3 , FIG3 is a top view of another combination of a reflective gate and an interdigital electrode provided in an embodiment of the present application. The reflective gate 5 is an open-circuit suspended reflective gate, that is, the reflective gates 5 located on one side of the interdigital electrodes 4 are not short-circuited with each other and are not connected to any potential.

[0153] As shown in FIG4 , FIG4 is a top view of another combination of a reflective grid and an interdigital electrode provided in an embodiment of the present application. The reflective grid 5 is a grounded reflective grid, that is, the reflective grids 5 on one side of the interdigital electrode 4 are all short-circuited together and have a potential of zero.

[0154] In addition, the material of the reflector 5 is gold, silver, copper, chromium, nickel, aluminum, molybdenum, platinum, titanium, titanium aluminum, chromium gold, or chromium aluminum; the material of the interdigitated electrode 4 is gold, silver, copper, chromium, nickel, aluminum, molybdenum, platinum, titanium, titanium aluminum, chromium gold, or chromium aluminum.

[0155] The number of the reflective gratings 5 ​​is 1-200, such as 10 or 20. The specific number of the reflective gratings 5 ​​depends on the specific situation.

[0156] The number of the interdigital electrodes 4 is 2-500, such as 10 or 20. The specific number of the interdigital electrodes 4 depends on actual conditions.

[0157] The distance between adjacent interdigital electrodes 4 and the reflective grating 5 is 0.001-50 μm, such as 0.1 μm, and the specific value depends on the actual situation.

[0158] The thickness of the interdigital electrode 4 is 5-500 nm, such as 50 nm or 100 nm, and the specific value depends on the actual situation.

[0159] The thickness of the reflective grating 5 is 5-500 nm, such as 50 nm or 100 nm, and the specific value depends on the actual situation.

[0160] The width of the interdigital electrodes 4 is 0.001-5 μm, such as 0.05 μm or 0.12 μm, and the specific value depends on the actual situation.

[0161] The width of the reflective grating 5 is 0.001-5 μm, such as 0.05 μm or 0.12 μm, and the specific value depends on the actual situation.

[0162] The length of the interdigital electrodes 4 is 1-500 μm, such as 18 μm, 24 μm or 32 μm, and the specific value depends on the actual situation.

[0163] The length of the reflective grating 5 is 1-500 μm, such as 18 μm, 24 μm or 32 μm, and the specific value depends on the actual situation.

[0164] S806: releasing the release layer between the piezoelectric layer and the substrate.

[0165] First, as shown in FIG18 , a second mask layer 8 is formed on the entire device surface. The second mask layer 8 can be any one of photoresist, silicon oxide, silicon nitride, or a combination of the two.

[0166] Then, as shown in FIG19 , reactive ion etching is performed on the second mask layer 8 to form first etching windows 9 on both sides of the reflective grid 5 and expose a portion of the surface of the piezoelectric layer 3 .

[0167] Then, as shown in FIG20 , based on the first etching window 9 , under the protection of the second mask layer 8 , the piezoelectric layer 3 is etched using inductively coupled plasma etching to form a second etching window 10 and expose the release layer 2 .

[0168] As shown in Figure 21, an oxide etching solution or dry gas etching is injected into the second etching window 10 to release the release layer 2 to obtain a cavity 11. Finally, the remaining second mask layer 8 is removed to finally obtain an acoustic wave resonator.

[0169] As shown in FIG9 , FIG9 is a flow chart of another method for manufacturing an acoustic wave resonator provided in an embodiment of the present application, including:

[0170] S901: providing a substrate.

[0171] As shown in FIG22 , a substrate 1 is provided, wherein the substrate 1 may be a silicon substrate, a sapphire substrate (Al 2 O 3 ), a gallium nitride substrate (GaN), or a silicon carbide substrate (SiC).

[0172] S902: Disposing a release layer on one surface of the substrate.

[0173] As shown in Figure 23, a release layer 2 is provided on one side of the substrate 1. The release layer 2 comprises one or more layers, each layer being made of one of silicon dioxide, silicon nitride, lithium niobate, and silicon. The thickness of the release layer 2 is 0.01-100 μm. The release layer 2 can be released between the piezoelectric layer 3 and the substrate 1.

[0174] S903: Disposing a plurality of interdigital electrodes on a surface of the release layer facing away from the substrate.

[0175] S904: Disposing at least one reflective grating on both sides of the plurality of interdigital electrodes on the surface of the release layer.

[0176] In this embodiment, the implementation of step S903 and the implementation of step S904 can be performed simultaneously, as follows:

[0177] As shown in FIG24 , a third mask layer 12 is formed on the surface of the release layer 2 facing away from the substrate 1 . The third mask layer 12 can be any one of photoresist, silicon oxide, silicon nitride, or a combination of the two.

[0178] As shown in FIG25 , after photolithography on the third mask layer 12 , stripping or reactive ion etching is used to obtain the second electrode and the reflective grid window 13 , and partially expose the surface of the release layer 2 ; wherein the photolithography technology can be either ultraviolet lithography or electron beam lithography or a combination of the two.

[0179] As shown in FIG26 , interdigitated electrodes 4 and reflective grating 5 are formed on the second electrode and reflective grating window 13 by coating technology, wherein the coating technology may be thermal evaporation, electron beam evaporation or magnetron sputtering or a combination of the two.

[0180] Finally, as shown in FIG. 27 , the remaining third mask layer 12 is removed.

[0181] The reflective grid 5 includes a plurality of root-shaped metal strips, which are periodically distributed on both sides of the interdigital electrodes 4 . The reflective grid 5 has a structure of a short-circuited floating grid, an open-circuited floating grid, and a grounded reflective grid.

[0182] As shown in Figure 2, Figure 2 is a top view of a reflection grid and an interdigital electrode provided in an embodiment of the present application. The reflection grid 5 is a short-circuited suspended reflection grid, that is, the reflection grids 5 on one side of the interdigital electrode 4 are all short-circuited together, but are not connected to any potential.

[0183] As shown in FIG3 , FIG3 is a top view of another combination of a reflective gate and an interdigital electrode provided in an embodiment of the present application. The reflective gate 5 is an open-circuit suspended reflective gate, that is, the reflective gates 5 located on one side of the interdigital electrodes 4 are not short-circuited with each other and are not connected to any potential.

[0184] As shown in FIG4 , FIG4 is a top view of another combination of a reflective grid and an interdigital electrode provided in an embodiment of the present application. The reflective grid 5 is a grounded reflective grid, that is, the reflective grids 5 on one side of the interdigital electrode 4 are all short-circuited together and have a potential of zero.

[0185] In addition, the material of the reflector 5 is gold, silver, copper, chromium, nickel, aluminum, molybdenum, platinum, titanium, titanium aluminum, chromium gold, or chromium aluminum; the material of the interdigitated electrode 4 is gold, silver, copper, chromium, nickel, aluminum, molybdenum, platinum, titanium, titanium aluminum, chromium gold, or chromium aluminum.

[0186] The number of the reflective gratings 5 ​​is 1-200, such as 10 or 20. The specific number of the reflective gratings 5 ​​depends on the specific situation.

[0187] The number of the interdigital electrodes 4 is 2-500, such as 10 or 20. The specific number of the interdigital electrodes 4 depends on actual conditions.

[0188] The distance between adjacent interdigital electrodes 4 and the reflective grating 5 is 0.001-50 μm, such as 0.1 μm, and the specific value depends on the actual situation.

[0189] The thickness of the interdigital electrode 4 is 5-500 nm, such as 50 nm or 100 nm, and the specific value depends on the actual situation.

[0190] The thickness of the reflective grating 5 is 5-500 nm, such as 50 nm or 100 nm, and the specific value depends on the actual situation.

[0191] The width of the interdigital electrodes 4 is 0.001-5 μm, such as 0.05 μm or 0.12 μm, and the specific value depends on the actual situation.

[0192] The width of the reflective grating 5 is 0.001-5 μm, such as 0.05 μm or 0.12 μm, and the specific value depends on the actual situation.

[0193] The length of the interdigital electrodes 4 is 1-500 μm, such as 18 μm, 24 μm or 32 μm, and the specific value depends on the actual situation.

[0194] The length of the reflective grating 5 is 1-500 μm, such as 18 μm, 24 μm or 32 μm, and the specific value depends on the actual situation.

[0195] S905: Disposing a piezoelectric layer on a surface of the release layer facing away from the substrate, such that a plurality of interdigital electrodes are embedded in the piezoelectric layer and in contact with the release layer.

[0196] As shown in FIG28 , a piezoelectric layer 3 is provided on the surface of the release layer 2 facing away from the substrate, so that a plurality of interdigital electrodes 4 are embedded in the piezoelectric layer 3 and a plurality of interdigital electrodes 5 are in contact with the release layer 2 .

[0197] The piezoelectric layer 3 is a lithium niobate layer, a lithium tantalate layer, or a composite layer consisting of at least two of a lithium niobate layer, an aluminum nitride layer, a scandium-doped aluminum nitride layer, a lithium tantalate layer, and a zinc oxide layer. The thickness of the piezoelectric layer 3 is 10-5000 nm.

[0198] S906: releasing the release layer between the piezoelectric layer and the substrate.

[0199] First, as shown in FIG29 , a second mask layer 8 is formed on the entire device surface. The second mask layer 8 can be any one of photoresist, silicon oxide, silicon nitride, or a combination of the two.

[0200] Then, as shown in FIG30 , reactive ion etching is performed on the second mask layer 8 to form a first etching window 9 and expose a portion of the surface of the piezoelectric layer 3 .

[0201] Then, as shown in Figure 31, based on the first etching window 9, under the protection of the second mask layer 8, the piezoelectric layer 3 is etched using inductively coupled plasma etching to form a second etching window 10 and expose the release layer 2. The second etching window 10 is located on both sides of the reflective grid 5.

[0202] As shown in FIG32 , an oxide etching solution or dry gas etching is injected into the second etching window 10 to release the release layer 2 to obtain a cavity 11 . Finally, the remaining second mask layer 8 is removed to finally obtain an acoustic wave resonator.

[0203] As shown in FIG10 , FIG10 is a flow chart of another method for manufacturing an acoustic wave resonator provided in an embodiment of the present application, including:

[0204] S1001: Provide a substrate.

[0205] As shown in FIG33 , a substrate 1 is provided, wherein the substrate 1 may be a silicon substrate, a sapphire substrate (Al 2 O 3 ), a gallium nitride substrate (GaN), or a silicon carbide substrate (SiC).

[0206] S1002: a release layer is provided on one surface of the substrate.

[0207] As shown in Figure 34 , a release layer 2 is provided on one side of substrate 1. Release layer 2 comprises one or more layers, each layer being made of one of silicon dioxide, silicon nitride, lithium niobate, and silicon. The thickness of release layer 2 is 0.01-100 μm. Release layer 2 can be released between piezoelectric layer 3 and substrate 1.

[0208] S1003: a plurality of interdigital electrodes are provided on a surface of the release layer facing away from the substrate.

[0209] S1004: Disposing at least one reflective grating on both sides of the plurality of interdigital electrodes on the surface of the release layer.

[0210] In this embodiment, the implementation of step S1003 and the implementation of step S1004 can be performed simultaneously, as follows:

[0211] As shown in FIG35 , a third mask layer 12 is formed on the surface of the release layer 2 facing away from the substrate 1 . The third mask layer 12 can be any one of photoresist, silicon oxide, silicon nitride, or a combination of the two.

[0212] As shown in FIG36 , after photolithography on the third mask layer 12 , stripping or reactive ion etching is used to obtain the second electrode and the reflective grid window 13 , and partially expose the surface of the release layer 2 ; wherein the photolithography technology can be either ultraviolet lithography or electron beam lithography or a combination of the two.

[0213] As shown in FIG37 , the interdigitated electrodes 4 and the reflective grating 5 are formed on the second electrode and the reflective grating window 13 by coating technology, wherein the coating technology can be one of thermal evaporation, electron beam evaporation or magnetron sputtering or a combination of the two.

[0214] Finally, as shown in FIG38 , the remaining third mask layer 12 is removed.

[0215] The reflective grid 5 includes a plurality of root-shaped metal strips, which are periodically distributed on both sides of the interdigital electrodes 4 . The reflective grid 5 has a structure of a short-circuited floating grid, an open-circuited floating grid, and a grounded reflective grid.

[0216] As shown in Figure 2, Figure 2 is a top view of a reflection grid and an interdigital electrode provided in an embodiment of the present application. The reflection grid 5 is a short-circuited suspended reflection grid, that is, the reflection grids 5 on one side of the interdigital electrode 4 are all short-circuited together, but are not connected to any potential.

[0217] As shown in FIG3 , FIG3 is a top view of another combination of a reflective gate and an interdigital electrode provided in an embodiment of the present application. The reflective gate 5 is an open-circuit suspended reflective gate, that is, the reflective gates 5 located on one side of the interdigital electrodes 4 are not short-circuited with each other and are not connected to any potential.

[0218] As shown in FIG4 , FIG4 is a top view of another combination of a reflective grid and an interdigital electrode provided in an embodiment of the present application. The reflective grid 5 is a grounded reflective grid, that is, the reflective grids 5 on one side of the interdigital electrode 4 are all short-circuited together and have a potential of zero.

[0219] In addition, the material of the reflector 5 is gold, silver, copper, chromium, nickel, aluminum, molybdenum, platinum, titanium, titanium aluminum, chromium gold, or chromium aluminum; the material of the interdigitated electrode 4 is gold, silver, copper, chromium, nickel, aluminum, molybdenum, platinum, titanium, titanium aluminum, chromium gold, or chromium aluminum.

[0220] The number of the reflective gratings 5 ​​is 1-200, such as 10 or 20. The specific number of the reflective gratings 5 ​​depends on the specific situation.

[0221] The number of the interdigital electrodes 4 is 2-500, such as 10 or 20. The specific number of the interdigital electrodes 4 depends on actual conditions.

[0222] The distance between adjacent interdigital electrodes 4 and the reflective grating 5 is 0.001-50 μm, such as 0.1 μm, and the specific value depends on the actual situation.

[0223] The thickness of the interdigital electrode 4 is 5-500 nm, such as 50 nm or 100 nm, and the specific value depends on the actual situation.

[0224] The thickness of the reflective grating 5 is 5-500 nm, such as 50 nm or 100 nm, and the specific value depends on the actual situation.

[0225] The width of the interdigital electrodes 4 is 0.001-5 μm, such as 0.05 μm or 0.12 μm, and the specific value depends on the actual situation.

[0226] The width of the reflective grating 5 is 0.001-5 μm, such as 0.05 μm or 0.12 μm, and the specific value depends on the actual situation.

[0227] The length of the interdigital electrodes 4 is 1-500 μm, such as 18 μm, 24 μm or 32 μm, and the specific value depends on the actual situation.

[0228] The length of the reflective grating 5 is 1-500 μm, such as 18 μm, 24 μm or 32 μm, and the specific value depends on the actual situation.

[0229] S1005: Disposing a piezoelectric layer on a surface of the release layer facing away from the substrate, such that a plurality of interdigital electrodes are embedded in the piezoelectric layer and in contact with the release layer.

[0230] As shown in FIG39 , a piezoelectric layer 3 is provided on the surface of the release layer 2 facing away from the substrate, so that a plurality of interdigital electrodes 4 are embedded in the piezoelectric layer 3 and a plurality of interdigital electrodes 5 are in contact with the release layer 2 .

[0231] The piezoelectric layer 3 is a lithium niobate layer, a lithium tantalate layer, or a composite layer consisting of at least two of a lithium niobate layer, an aluminum nitride layer, a scandium-doped aluminum nitride layer, a lithium tantalate layer, and a zinc oxide layer. The thickness of the piezoelectric layer 3 is 10-5000 nm.

[0232] S1006: Disposing a plurality of interdigital electrodes on the surface of the piezoelectric layer.

[0233] S1007: Disposing at least one reflection grating on both sides of the plurality of interdigital electrodes on the surface of the piezoelectric layer.

[0234] In this embodiment, the implementation of step S1006 and the implementation of step S1007 can be performed simultaneously, as follows:

[0235] As shown in FIG40 , a first mask layer 6 is formed on the surface of the piezoelectric layer 3 facing away from the release layer 2 . The first mask layer 6 can be any one of photoresist, silicon oxide, silicon nitride, or a combination of the two.

[0236] As shown in FIG41 , after photolithography on the first mask layer 6 , stripping or reactive ion etching is used to obtain the first electrode and the reflective grid window 7 , and partially expose the surface of the piezoelectric layer 3 ; wherein the photolithography technology can be either ultraviolet lithography or electron beam lithography or a combination of the two.

[0237] As shown in FIG42 , the interdigitated electrodes 4 and the reflective grating 5 are formed on the first electrode and the reflective grating window 7 by coating technology, wherein the coating technology can be one of thermal evaporation, electron beam evaporation or magnetron sputtering or a combination of the two.

[0238] Finally, as shown in FIG43 , the remaining first mask layer 6 is removed.

[0239] S1008: releasing the release layer between the piezoelectric layer and the substrate.

[0240] First, as shown in FIG44 , a second mask layer 8 is formed on the entire device surface. The second mask layer 8 can be any one of photoresist, silicon oxide, silicon nitride, or a combination of the two.

[0241] Then, as shown in FIG45 , reactive ion etching is performed on the second mask layer 8 to form first etching windows 9 on both sides of the reflective grid 5 and expose a portion of the surface of the piezoelectric layer 3 .

[0242] Then, as shown in FIG46 , based on the first etching window 9 , under the protection of the second mask layer 8 , the piezoelectric layer 3 is etched using inductively coupled plasma etching to form a second etching window 10 and expose the release layer 2 .

[0243] As shown in Figure 47, an oxide etching solution or dry gas etching is injected into the second etching window 10 to release the release layer 2 to obtain a cavity 11. Finally, the remaining second mask layer 8 is removed to obtain an acoustic wave resonator.

[0244] The various embodiments in this specification are described in a progressive, parallel, or combined manner. Each embodiment focuses on the differences from other embodiments, and reference can be made to the common and similar parts between the various embodiments. The fabrication methods disclosed in the embodiments are described briefly because they correspond to the acoustic wave resonators disclosed in the embodiments. For relevant details, refer to the description of the acoustic wave resonator.

[0245] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, so that an article or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such article or device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the article or device comprising the aforementioned elements.

[0246] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present application. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application is not limited to the embodiments shown herein, but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An acoustic wave resonator, characterized in that: include: A substrate, a release layer, a piezoelectric layer, a plurality of interdigitated electrodes, and at least one reflective grating; The release layer is disposed on one side surface of the substrate, and the release layer is used to be released between the piezoelectric layer and the substrate. When the release layer is released, the piezoelectric layer is isolated from the substrate to form a cavity; The piezoelectric layer is arranged on a surface of the release layer facing away from the substrate; The at least one reflection grid is disposed on both sides of the plurality of interdigital electrodes.

2. The acoustic wave resonator according to claim 1, characterized in that The plurality of interdigital electrodes are disposed on a surface of the piezoelectric layer facing away from the release layer, and / or a surface of the piezoelectric layer facing the release layer.

3. The acoustic wave resonator according to claim 1, characterized in that The reflective grid includes a plurality of root-shaped metals. The at least one reflective grid is periodically distributed on both sides of the interdigitated electrodes. The structure of the reflective grid is one of a short-circuited floating grid, an open-circuited floating grid and a grounded reflective grid.

4. The acoustic wave resonator according to claim 1, characterized in that The number of the reflective gratings is 1-200; The number of the interdigital electrodes is 2-500.

5. The acoustic wave resonator according to claim 1, characterized in that The material of the reflective grid is gold, silver, copper, chromium, nickel, aluminum, molybdenum, platinum, titanium gold, titanium aluminum, chromium gold, or chromium aluminum; The material of the interdigital electrodes is gold, silver, copper, chromium, nickel, aluminum, molybdenum, platinum, titanium-gold, titanium-aluminum, chromium-gold, or chromium-aluminum.

6. The acoustic wave resonator according to claim 1, characterized in that The distance between adjacent interdigital electrodes and the reflective grating is 0.001-50 μm; The thickness of the interdigitated electrode is 5-500nm; The thickness of the reflective grating is 5-500nm; The width of the interdigital electrodes is 0.001-5 μm; The width of the reflective grating is 0.001-5 μm; The length of the interdigital electrodes is 1-500 μm; The length of the reflection grating is 1-500 μm.

7. The acoustic wave resonator according to claim 1, characterized in that The piezoelectric layer on the side of the reflection grating away from the interdigital electrodes is a free boundary or a fixed boundary.

8. The acoustic wave resonator according to claim 1, characterized in that The release layer is one layer or multiple layers, and the material of each layer is one of silicon dioxide, silicon nitride, lithium niobate and silicon.

9. The acoustic wave resonator according to claim 1, characterized in that The piezoelectric layer is a lithium niobate layer, a lithium tantalate layer, or a composite layer consisting of at least two layers of a lithium niobate layer, an aluminum nitride layer, a scandium-doped aluminum nitride layer, a lithium tantalate layer, and a zinc oxide layer; The thickness of the piezoelectric layer is 10-5000nm.

10. A method for manufacturing an acoustic wave resonator, characterized in that: include: providing a substrate; Disposing a release layer on one side surface of the substrate; Disposing a piezoelectric layer on a surface of the release layer facing away from the substrate; At least one reflection grating is arranged on both sides of the plurality of interdigitated electrodes; The release layer is released between the piezoelectric layer and the substrate. When the release layer is released, the piezoelectric layer is isolated from the substrate to form a cavity.

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