High-frequency high-q acoustic resonator and method of making same

Abstract

This application discloses a high-frequency, high-Q acoustic resonator and its fabrication method. The acoustic resonator includes: a substrate; a release layer disposed on one side surface of the substrate; a piezoelectric layer disposed on the release layer away from the substrate surface; and a plurality of metal electrodes disposed on the piezoelectric layer away from the release layer surface. The release layer is used for release between the piezoelectric layer and the substrate. When the release layer releases, an etched trench is formed between the substrate and the piezoelectric layer to obtain a high-frequency, high-Q acoustic resonator with an S1 vibration mode at an x-cut piezoelectric film at -40 to +40 degrees. This solution excites the S1 vibration mode on the x-cut piezoelectric film by rotating the Euler angle, achieving a high-frequency, high-Q acoustic resonator with a quality factor (Q) exceeding 5000 or even tens of thousands at a specific angle (-40 to +40 degrees), thus meeting the current performance requirements of high-frequency, high-Q filters in the 5G and 6G frequency bands.

Description

Technical Field

[0001] This invention relates to the field of high-frequency acoustic resonator technology, and in particular to a high-frequency, high-Q acoustic resonator and its manufacturing method. Background Technology

[0002] As a crucial module in the RF front-end, the performance of radio frequency (RF) filters directly determines the ability of signals to stand out from noise in a communication system. With the advent of the 5G era, the number of filters in smartphones has exceeded 100, and the market demand for filters will further increase in the future. In today's booming communication market, with the 6G and 7G eras fast approaching, achieving high-performance filtering at even higher frequencies is a key market objective.

[0003] Quality factor (Q), as one of the important indicators for measuring the performance of filters and resonators, ensures good in-band insertion loss. Therefore, achieving an extremely high quality factor at high frequencies (MHz or even GHz) is key to achieving high-performance filtering. Acoustic resonators, with their advantages of small size, high quality factor, and high frequency, have naturally become an indispensable basic component in current radio frequency filters.

[0004] Currently, the main materials used in acoustic resonators include PZT (lead zirconate titanate piezoelectric ceramic), aluminum nitride (AlN), scandium-doped aluminum nitride (AlScN), lithium niobate (LN), and lithium tantalate (LT). Among these, lithium niobate and lithium tantalate, due to their large piezoelectric coefficient (e), can well meet the requirements of high quality factor and large electromechanical coupling coefficient (k) in the 5G and 6G frequency bands. 2 The demand for acoustic resonators has gradually made them popular materials for acoustic filter fabrication. Lithium niobate and lithium tantalate films have multiple tangential orientations, and the acoustic modes excited under different orientations are not entirely the same. Common tangential orientations include x-cut, y-cut, and z-cut. The piezoelectric coefficient used in these films varies depending on the excited acoustic mode; for example, the S0 mode uses ep. 11 The S1 mode uses e 13 The SH0 mode uses e 16 Wait a minute, the piezoelectric coefficient directly affects the performance of the resonator in that mode. Once the tangential direction of the piezoelectric film is determined, its piezoelectric coefficient can be changed by rotating the Euler angle in the plane, ultimately obtaining the acoustic resonator with optimal performance. In current research, most scholars change the electromechanical coupling coefficient of the acoustic resonator by rotating the Euler angle in the plane, but they have all ignored the impact of Euler angle changes on the quality factor. Moreover, the quality factor of acoustic resonators operating in the 5G and 6G frequency bands is difficult to exceed 1000, which greatly affects the filtering performance of the filters they form. Summary of the Invention

[0005] In view of this, this application provides a high-frequency, high-Q acoustic resonator and its fabrication method. By rotating the Euler angle, the S1 vibration mode can be excited at a specific angle (-40 to +40 degrees) of the piezoelectric thin film, thereby realizing a high-frequency, high-Q acoustic resonator.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A high-frequency, high-Q acoustic resonator, the acoustic resonator comprising:

[0008] Substrate;

[0009] A release layer disposed on one side surface of the substrate;

[0010] A piezoelectric layer disposed on the release layer away from the surface of the substrate;

[0011] Multiple metal electrodes are disposed on the surface of the piezoelectric layer;

[0012] The release layer is used for release between the piezoelectric layer and the substrate; when the release layer is released, an etched trench is formed between the substrate and the piezoelectric layer to obtain a high-frequency, high-Q acoustic resonator of the S1 vibration mode of the x-cut piezoelectric film at -40 to +40 degrees.

[0013] Preferably, in the above-described acoustic resonator, the metal electrode is located on the side surface of the piezoelectric layer facing away from the release layer;

[0014] And / or, the metal electrode is located on the side surface of the piezoelectric layer facing the substrate.

[0015] Preferably, in the above-mentioned acoustic resonator, the direction of the electric field formed by the metal electrode forms an Euler angle with the +y axis direction in the global coordinate system of the piezoelectric layer, and the Euler angle is -90 to +90 degrees.

[0016] The metal electrode is grown on the surface of the piezoelectric layer based on the Euler angle.

[0017] Preferably, in the above-mentioned acoustic resonator, the material of the metal electrode is gold, aluminum, molybdenum, platinum, or an alloy composed of titanium gold, titanium aluminum, chromium gold, and chromium aluminum.

[0018] Preferably, in the above-mentioned acoustic resonator, the number of metal electrodes is 2 to 400;

[0019] The distance between adjacent metal electrodes is 0.1-20 μm;

[0020] The thickness of the metal electrode is 5-5000 nm;

[0021] The width of the metal electrode is 0.1-20 μm;

[0022] The length of the metal electrode is 1-1000 μm.

[0023] Preferably, in the above-mentioned acoustic resonator, the release layer is one or more layers, and the material of each layer includes any one of silicon dioxide, silicon nitride, lithium niobate, and silicon;

[0024] The thickness of the release layer is 0.05-50 μm.

[0025] Preferably, in the above-mentioned acoustic resonator, the piezoelectric layer is a lithium niobate layer, or a lithium tantalate layer, or a composite layer of lithium niobate layer, aluminum nitride layer, scandium-doped aluminum nitride layer, lithium tantalate layer and zinc oxide layer.

[0026] The thickness of the piezoelectric layer is 10-5000 nm.

[0027] Preferably, the aforementioned acoustic resonator further includes:

[0028] Temperature compensation layer;

[0029] The temperature compensation layer is located on the side of the piezoelectric layer facing away from the substrate;

[0030] And / or, the temperature compensation layer is located on the side of the piezoelectric layer facing away from the metal electrode.

[0031] This invention also provides a method for manufacturing a high-frequency, high-Q acoustic resonator, the method comprising:

[0032] Provide a substrate;

[0033] A release layer is formed on one side surface of the substrate;

[0034] A piezoelectric layer is formed on the surface of the release layer away from the substrate surface;

[0035] Multiple metal electrodes are formed on the surface of the piezoelectric layer;

[0036] The release layer is used for release between the piezoelectric layer and the substrate; when the release layer is released, an etched trench is formed between the substrate and the piezoelectric layer to obtain a high-frequency, high-Q acoustic resonator of the S1 vibration mode of the x-cut piezoelectric film at -40 to +40 degrees.

[0037] Preferably, in the above manufacturing method, a plurality of metal electrodes are formed on the piezoelectric layer away from the surface of the release layer, including:

[0038] A mask layer is formed on the surface of the piezoelectric layer opposite to the release layer;

[0039] Based on the rotating Euler angle, multiple electrode windows at preset angles are photolithographically obtained on the mask layer, exposing part of the piezoelectric layer surface;

[0040] A metal electrode is formed on the electrode window using a coating technique;

[0041] Remove the remaining mask layer.

[0042] As described above, the high-frequency, high-Q acoustic resonator and its fabrication method provided by the present invention, by rotating the Euler angle, depositing metal electrodes at different angles on the piezoelectric layer, releasing the release layer, and periodically exciting the S1 vibration mode of the piezoelectric layer under x-cut, a high-frequency acoustic resonator with a quality factor (Q) exceeding 5000 or even tens of thousands is obtained. This can well meet the current performance requirements of high-frequency and high-Q filters in the 5G and 6G frequency bands. Furthermore, by rotating the Euler angle, while ensuring the frequency and electromechanical coupling coefficient (k) are maintained, the high-frequency, high-Q resonator can achieve high-frequency, high-Q performance. 2 With the basic parameters remaining unchanged, the quality factor of the acoustic resonator can be effectively adjusted, ultimately resulting in a high-frequency, high-Q acoustic resonator with a Q value exceeding 5000 or even tens of thousands in the S1 vibration mode within the range of -40 to +40 degrees. Attached Figure Description

[0043] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0044] The structures, proportions, sizes, etc., shown in the accompanying drawings are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed in the specification, and are not intended to limit the implementation conditions of this application. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size should still fall within the scope of the technical content disclosed in this application, provided that they do not affect the effects and purposes that this application can produce.

[0045] Figure 1 A cross-sectional view of a high-frequency, high-Q acoustic resonator provided in an embodiment of the present invention;

[0046] Figure 2 A cross-sectional view of another high-frequency, high-Q acoustic resonator provided in an embodiment of the present invention;

[0047] Figure 3 A cross-sectional view of another high-frequency, high-Q acoustic resonator provided in an embodiment of the present invention;

[0048] Figure 4 A cross-sectional view of another high-frequency, high-Q acoustic resonator provided in an embodiment of the present invention;

[0049] Figure 5 A cross-sectional view of another high-frequency, high-Q acoustic resonator provided in an embodiment of the present invention;

[0050] Figure 6 A cross-sectional view of another high-frequency, high-Q acoustic resonator provided in an embodiment of the present invention;

[0051] Figure 7 A cross-sectional view of another high-frequency, high-Q acoustic resonator provided in an embodiment of the present invention;

[0052] Figure 8 A cross-sectional view of another high-frequency, high-Q acoustic resonator provided in an embodiment of the present invention;

[0053] Figure 9 A cross-sectional view of another high-frequency, high-Q acoustic resonator provided in an embodiment of the present invention;

[0054] Figure 10 A cross-sectional view of another high-frequency, high-Q acoustic resonator provided in an embodiment of the present invention;

[0055] Figure 11 A cross-sectional view of another high-frequency, high-Q acoustic resonator provided in an embodiment of the present invention;

[0056] Figure 12 A cross-sectional view of another high-frequency, high-Q acoustic resonator provided in an embodiment of the present invention;

[0057] Figure 13 This is a schematic diagram of a high-frequency, high-Q acoustic resonator that achieves Euler angle rotation, provided by an embodiment of the present invention.

[0058] Figure 14 This is a top view of an acoustic resonator that achieves high frequency and high Q value based on rotating Euler angles, provided in an embodiment of the present invention.

[0059] Figure 15 A vibration mode diagram of a high-frequency, high-Q acoustic resonator S1 provided in an embodiment of the present invention;

[0060] Figure 16 The test performance diagram of a high-frequency, high-Q acoustic resonator provided in an embodiment of the present invention in the angle range of -40 to +40 degrees;

[0061] Figures 17-27 A process flow diagram of a method for manufacturing a high-frequency, high-Q acoustic resonator provided in an embodiment of the present invention. Detailed Implementation

[0062] The embodiments of this application will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0063] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0064] In view of this, in order to obtain a high-frequency (>3GHz) acoustic resonator with a quality factor (Q), this invention provides a method for manufacturing a high-frequency acoustic resonator with a quality factor exceeding 5000 or even tens of thousands by exciting the S1 vibration mode at a specific angle (-40 to +40 degrees) of a piezoelectric thin film based on rotating Euler angles.

[0065] Since the piezoelectric coefficient, dielectric constant, and elastic modulus of piezoelectric materials change with the rotation of the Euler angle, they affect the electromechanical coupling coefficient and quality factor of their acoustic resonators. Furthermore, different arrangements of metal electrodes at specific Euler angles and wavelengths can excite different acoustic vibration modes, thus obtaining acoustic resonators at specific frequencies. Therefore, rotating the Euler angle can yield acoustic resonators with high frequencies and high Q values ​​under different modes.

[0066] refer to Figures 1-4 , Figure 1 This is a cross-sectional view of a high-frequency, high-Q acoustic resonator provided in an embodiment of the present invention. Figure 2 This is a cross-sectional view of another high-frequency, high-Q acoustic resonator provided in an embodiment of the present invention. Figure 3 A cross-sectional view of another high-frequency, high-Q acoustic resonator provided in an embodiment of the present invention. Figure 4 A cross-sectional view of another high-frequency, high-Q acoustic resonator provided in an embodiment of the present invention.

[0067] like Figure 1 As shown, the acoustic resonator includes:

[0068] Substrate 11; the substrate 11 may be a silicon substrate, a sapphire substrate (Al2O3), a gallium nitride substrate (GaN), or a silicon carbide substrate (SiC);

[0069] A release layer 12 is disposed on one side surface of the substrate 11;

[0070] A piezoelectric layer 13 is disposed on the surface of the release layer 12 opposite to the surface of the substrate 11;

[0071] A plurality of (at least two) metal electrodes 16 are disposed on the surface of the piezoelectric layer 13;

[0072] The release layer 12 can be used for release between the piezoelectric layer 13 and the substrate 11; when the release layer 12 is released, an etched trench 20 is formed between the substrate 11 and the piezoelectric layer 13 to obtain a high-frequency, high-Q acoustic resonator of the S1 vibration mode at a specific angle (-40 to +40 degrees) of the x-cut piezoelectric film.

[0073] Furthermore, such as Figures 2-4 As shown, the acoustic resonator further includes:

[0074] Temperature compensation layer 21;

[0075] like Figure 2 As shown, the temperature compensation layer 21 can be located on the side surface of the piezoelectric layer 13 facing away from the substrate 11;

[0076] Or, such as Figure 3 As shown, the temperature compensation layer 21 can be located on the side surface of the piezoelectric layer 13 facing the substrate 11;

[0077] Or, such as Figure 4 As shown, the temperature compensation layer 21 can be located simultaneously on the side surface of the piezoelectric layer 13 facing away from the substrate 11 and on the side surface of the piezoelectric layer 13 facing the substrate 11.

[0078] In this embodiment of the invention, the metal electrode 16 may be located on the surface of the piezoelectric layer 13 facing away from the release layer 12, such as... Figures 1-4 As shown;

[0079] Alternatively, the metal electrode 16 may be located on the side surface of the piezoelectric layer 13 facing the substrate 11, such as... Figures 5-8 As shown;

[0080] Alternatively, the metal electrode 16 may be located simultaneously on the surface of the piezoelectric layer 13 facing away from the release layer 12 and on the surface of the piezoelectric layer 13 facing the substrate 11, such as... Figure 9-12 As shown.

[0081] refer to Figures 5-8 , Figure 5 A cross-sectional view of another high-frequency, high-Q acoustic resonator provided in an embodiment of the present invention. Figure 6 A cross-sectional view of another high-frequency, high-Q acoustic resonator provided in an embodiment of the present invention. Figure 7 A cross-sectional view of another high-frequency, high-Q acoustic resonator provided in an embodiment of the present invention. Figure 8 A cross-sectional view of another high-frequency, high-Q acoustic resonator provided in an embodiment of the present invention.

[0082] exist Figures 5-8 In the configuration shown, the metal electrode 16 is located on the side surface of the piezoelectric layer 13 facing the substrate 11.

[0083] In this method, the acoustic resonator further includes: a temperature compensation layer 21;

[0084] like Figure 6 As shown, the temperature compensation layer 21 can be located on the side surface of the piezoelectric layer 13 facing away from the substrate 11;

[0085] Or, such as Figure 7 As shown, the temperature compensation layer 21 can be located on the side surface of the piezoelectric layer 13 facing the substrate 11;

[0086] Or, such as Figure 8 As shown, the temperature compensation layer 21 can be located simultaneously on the side surface of the piezoelectric layer 13 facing away from the substrate 11 and on the side surface of the piezoelectric layer 13 facing the substrate 11.

[0087] refer to Figures 9-12 , Figure 9 A cross-sectional view of another high-frequency, high-Q acoustic resonator provided in an embodiment of the present invention. Figure 10 A cross-sectional view of another high-frequency, high-Q acoustic resonator provided in an embodiment of the present invention. Figure 11 A cross-sectional view of another high-frequency, high-Q acoustic resonator provided in an embodiment of the present invention. Figure 12 A cross-sectional view of another high-frequency, high-Q acoustic resonator provided in an embodiment of the present invention.

[0088] exist Figures 9-12 In the configuration shown, the metal electrode 16 is located simultaneously on the side surface of the piezoelectric layer 13 facing away from the release layer 12 and on the side surface of the piezoelectric layer 13 facing the substrate 11.

[0089] In this method, the acoustic resonator further includes: a temperature compensation layer 21;

[0090] like Figure 9 As shown, the temperature compensation layer 21 can be located on the side surface of the piezoelectric layer 13 facing away from the substrate 11;

[0091] Or, such as Figure 10 As shown, the temperature compensation layer 21 can be located on the side surface of the piezoelectric layer 13 facing the substrate 11;

[0092] Or, such as Figure 11As shown, the temperature compensation layer 21 can be located simultaneously on the side surface of the piezoelectric layer 13 facing away from the substrate 11 and on the side surface of the piezoelectric layer 13 facing the substrate 11.

[0093] In this embodiment of the invention, the electric field direction formed by the metal electrode 16 (i.e., the sound wave propagation direction +y') forms an Euler angle α with the +y axis direction in the global coordinate system of the piezoelectric layer 13. The Euler angle α ranges from -90 to +90 degrees (or 0 to +90, +270 to +360 degrees. +90 to +270 degrees is a symmetrical angle and will not be repeated). The metal electrode 16 is grown on the surface of the piezoelectric layer 13 based on the Euler angle α. Figure 13 As shown, Figure 13 This is a schematic diagram of a high-frequency, high-Q acoustic resonator that achieves Euler angle rotation, provided as an embodiment of the present invention.

[0094] In this embodiment of the invention, the material of the metal electrode 16 can be gold, aluminum, molybdenum, platinum, or an alloy composed of titanium gold, titanium aluminum, chromium gold, and chromium aluminum;

[0095] The thickness of the metal electrode 16 can be 5-5000 nm, such as 50 nm or 200 nm.

[0096] The number of metal electrodes 16 can be 2 to 400, such as 8 or 16.

[0097] The distance between adjacent metal electrodes 16 can be 0.1-20 μm, such as 2 μm;

[0098] The width of the metal electrode 16 is 0.1-20 μm, such as 4 μm or 5 μm;

[0099] The length of the metal electrode 16 is 1-1000um, such as 120um, 200um or 240um.

[0100] In this embodiment of the invention, the release layer 12 can be one or more layers, and the material of each layer includes any one of silicon dioxide, silicon nitride, lithium niobate and silicon; the thickness of the release layer 12 can be 0.05-50um, such as 10um or 25um.

[0101] In this embodiment of the invention, the piezoelectric layer 13 may be a lithium niobate layer (LN), a lithium tantalate layer (LT), or a composite layer 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 13 may be 10-5000 nm, such as 200 nm or 600 nm.

[0102] like Figure 14 As shown, Figure 14This invention provides a top view of a high-frequency, high-Q acoustic resonator based on rotating Euler angles. In this method, y represents the propagation direction, x represents the thickness direction, and z represents the length direction. Ten angles—0 degrees, ±5 degrees, ±10 degrees, ±30 degrees, ±60 degrees, and +90 degrees—can be selected to design the acoustic resonator, ultimately resulting in a high-frequency acoustic resonator with a quality factor exceeding 5000 or even tens of thousands in the S1 mode within the vibration range of -40 to +40 degrees.

[0103] like Figure 15 As shown, Figure 15 The S1 vibration mode diagram of a high-frequency, high-Q acoustic resonator provided in this embodiment of the invention. The S1 mode is a symmetrical compression body wave of a piezoelectric thin film vibration in the thickness direction.

[0104] like Figure 16 As shown, Figure 16 The test performance diagram of a high-frequency, high-Q acoustic resonator provided in this embodiment of the invention is shown in the angle range of -40 to +40 degrees. The results show that the acoustic resonator achieves the desired performance at the anti-resonance frequency f within this angle range. p The quality factor at 6.642GHz can exceed 5,000 or even tens of thousands, fully meeting the performance requirements of filters in the current 5G and 6G frequency bands.

[0105] As described above, the high-frequency, high-Q acoustic resonator provided by this invention, by rotating the Euler angle, deposits metal electrodes at different angles on the piezoelectric layer, releases the release layer, and periodically excites the S1 vibration mode of the piezoelectric layer under the x-cut, resulting in a high-frequency acoustic resonator with a quality factor (Q) exceeding 5000 or even tens of thousands. This effectively meets the current performance requirements of high-frequency, high-Q filters in the 5G and 6G frequency bands. Furthermore, by rotating the Euler angle, while ensuring the frequency and electromechanical coupling coefficient (k... 2 With the basic parameters remaining unchanged, the quality factor of the acoustic resonator can be effectively adjusted, ultimately resulting in a high-frequency, high-Q acoustic resonator with a Q value exceeding 5000 or even tens of thousands in the S1 vibration mode within the range of -40 to +40 degrees.

[0106] Based on the above embodiments, another embodiment of the present invention also provides a method for manufacturing a high-frequency, high-Q acoustic resonator, so as to... Figures 1-4 The following explanation uses an acoustic resonator as an example. Figures 17-27 As shown, Figures 17-27 A process flow diagram of a method for manufacturing a high-frequency, high-Q acoustic resonator provided in an embodiment of the present invention is shown. The manufacturing method includes:

[0107] Step S11: As Figure 17 As shown, a substrate 11 is provided;

[0108] The substrate 11 may be a silicon substrate, a sapphire substrate (Al2O3), a gallium nitride substrate (GaN), or a silicon carbide substrate (SiC).

[0109] Step S12: As Figure 18 As shown, a release layer 12 is formed on one side surface of the substrate 11;

[0110] The release layer 12 can be one or more layers; the material of each layer includes any one of silicon dioxide, silicon nitride, lithium niobate, and silicon.

[0111] The thickness of the release layer 12 can be 0.05-50 μm, such as 10 μm or 30 μm. The release layer 11 can be used for release between the piezoelectric layer 13 and the substrate 11.

[0112] Step S13: As Figure 19 As shown, a piezoelectric layer 13 is formed on the surface of the release layer 12 opposite to the substrate 11;

[0113] The piezoelectric layer 13 can be a lithium niobate layer, a lithium tantalate layer, or a composite layer 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 13 can be 10-5000 nm, such as 200 nm or 500 nm.

[0114] Step S14: As Figures 20-27 As shown, a plurality of metal electrodes 16 are formed on the surface of the piezoelectric layer 13 opposite to the release layer 12;

[0115] The release layer 12 can be used for release between the piezoelectric layer 13 and the substrate 11; when the release layer 12 is released, an etched trench 20 is formed between the substrate 11 and the piezoelectric layer 13 to obtain a high-frequency, high-Q acoustic resonator of the S1 vibration mode at a specific angle (-40 to +40 degrees) of the x-cut piezoelectric film.

[0116] In this embodiment of the invention, the method for forming a plurality of metal electrodes 16 on the surface of the piezoelectric layer 13 includes:

[0117] First, such as Figure 20 As shown, a mask layer 14 is formed on the surface of the piezoelectric layer 13 opposite to the release layer 12; the mask layer 14 can be any one of photoresist, silicon oxide, silicon nitride, or a combination of both;

[0118] Then, as Figure 21As shown, based on the rotation Euler angle α, after photolithography on the mask layer 14, multiple electrode windows 15 at preset angles (-90 to +90 degrees) are obtained by lift-off or reactive ion etching, exposing part of the surface of the piezoelectric layer 13; wherein, the photolithography technology can be any one of ultraviolet lithography or electron beam lithography or a combination of both;

[0119] Then, as Figure 22 As shown, a metal electrode 16 is formed on the electrode window 15 by a coating technique; wherein, the coating technique can be one of electron beam evaporation or magnetron sputtering or a combination of both;

[0120] Finally, as Figure 23 As shown, the remaining mask layer 14 is removed.

[0121] In this embodiment of the invention, the material of the metal electrode 16 can be gold, aluminum, molybdenum, platinum, or an alloy composed of titanium gold, titanium aluminum, chromium gold, and chromium aluminum.

[0122] The thickness of the metal electrode 16 can be 5-5000 nm, such as 50 nm or 200 nm.

[0123] The number of metal electrodes 16 can be 2 to 400, such as 8 or 16.

[0124] The distance between adjacent metal electrodes 16 can be 0.1-20 μm, such as 2 μm;

[0125] The width of the metal electrode 16 is 0.1-20 μm, such as 4 μm or 5 μm.

[0126] The length of the metal electrode 16 is 1-1000um, such as 120um, 200um or 240um.

[0127] In this embodiment of the invention, the method for forming an etching trench 20 between the substrate 11 and the piezoelectric layer 13 includes:

[0128] First, such as Figure 24 As shown, a hard mask layer 17 is formed on the entire surface of the device;

[0129] Then, as Figure 25 As shown, reactive ion etching is performed on the hard mask layer 17 to form a first etching window 18 on both sides of the metal electrode 16, exposing part of the surface of the piezoelectric layer 13.

[0130] Then, as Figure 26As shown, based on the first etching window 18, under the protection of the hard mask 17, the piezoelectric layer 13 is etched by inductively coupled plasma etching to form the second etching window 19 and expose the release layer 12.

[0131] Then, as Figure 27 As shown, an oxide etching solution (acid or alkali) is injected into the second etching window 19 to release the release layer 12;

[0132] Finally, as Figure 1 As shown, by removing the remaining hard mask layer 17, a high-frequency, high-Q acoustic resonator with the S1 vibration mode at a specific angle (-40 to +40 degrees) of the x-cut piezoelectric thin film is finally obtained.

[0133] Other methods can also be used Figures 5-8 or Figures 9-12 The acoustic resonator shown is used as an example for illustration, and will not be elaborated further here.

[0134] As described above, the method for fabricating a high-frequency, high-Q acoustic resonator provided by the present invention involves rotating the Euler angle, depositing metal electrodes at different angles on a piezoelectric layer, releasing the release layer, and periodically exciting the S1 vibration mode of the piezoelectric layer under the x-cut by periodic electric field excitation. This yields a high-frequency acoustic resonator with a quality factor (Q) exceeding 5000 or even tens of thousands, which can well meet the current performance requirements of high-frequency and high-Q filters in the 5G and 6G frequency bands. Furthermore, by rotating the Euler angle, the frequency and electromechanical coupling coefficient (k) are maintained. 2 With the basic parameters remaining unchanged, the quality factor of the acoustic resonator can be effectively adjusted, ultimately resulting in a high-frequency, high-Q acoustic resonator with a Q value exceeding 5000 or even tens of thousands in the S1 vibration mode within the range of -40 to +40 degrees.

[0135] It should be noted that this application only shows Euler angles in the range of -90 to +90 degrees; the remaining angles are also within the scope of protection of this invention.

[0136] The various embodiments in this specification are described in a progressive, parallel, or combined manner. Each embodiment focuses on its differences from other embodiments, and similar or identical parts between embodiments can be referred to interchangeably. Regarding the manufacturing methods disclosed in the embodiments, since they correspond to the high-frequency, high-Q acoustic resonators disclosed in the embodiments, the description is relatively simple; relevant parts can be found in the acoustic resonator section.

[0137] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that an article or apparatus comprising a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such an article or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the article or apparatus that includes the aforementioned element.

[0138] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A high-frequency high-Q acoustic resonator, characterized by, The application relates to a piezoelectric film resonator, which comprises the following components: a substrate; a release layer arranged on one side surface of the substrate; a piezoelectric layer arranged on the side surface of the release layer away from the substrate; a plurality of metal electrodes arranged on the surface of the piezoelectric layer; the electric field direction formed by the metal electrodes is an Euler angle with the +y axis direction in the global coordinate system of the piezoelectric layer, and the Euler angle is -90-+90 degrees; and the metal electrodes are grown on the surface of the piezoelectric layer based on the Euler angle. The metal electrodes are located on the side surface of the piezoelectric layer away from the release layer. The metal electrodes are located on the side surface of the piezoelectric layer towards the substrate. The material of the metal electrodes is gold, aluminum, molybdenum, platinum or titanium gold, titanium aluminum, chromium gold and chromium aluminum. The number of the metal electrodes is 2-400. The distance between adjacent metal electrodes is 0.1-20 um.

2. The acoustic resonator of claim 1, wherein, The thickness of the metal electrodes is 5-5000 nm. The width of the metal electrodes is 0.1-20 um.

3. The acoustic resonator of claim 1, wherein, The length of the metal electrodes is 1-1000 um.

4. The acoustic resonator of claim 3, wherein, The release layer is one or more layers, and the material of each layer comprises any one of silicon dioxide, silicon nitride, lithium niobate and silicon. The thickness of the release layer is 0.05-50 um. The piezoelectric layer is a lithium niobate layer, a lithium tantalate layer or a composite layer 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 10-5000 nm. The application further relates to a manufacturing method of the piezoelectric film resonator.

5. The acoustic wave resonator of claim 1, wherein, The manufacturing method comprises the following steps: providing a substrate; forming a release layer on one side surface of the substrate; forming a piezoelectric layer on the side surface of the release layer away from the substrate; and forming a plurality of metal electrodes on the surface of the piezoelectric layer; the electric field direction formed by the metal electrodes is an Euler angle with the +y axis direction in the global coordinate system of the piezoelectric layer, and the Euler angle is -90-+90 degrees; and the metal electrodes are grown on the surface of the piezoelectric layer based on the Euler angle. The release layer is used for releasing the piezoelectric layer and the substrate; when the release layer is released, an etching groove is formed between the substrate and the piezoelectric layer, the piezoelectric layer above the etching groove is suspended, and pores penetrating through the piezoelectric layer and the release layer exist on both sides, so that a high-frequency high-Q acoustic wave resonator of the S1 vibration mode of the x-cut piezoelectric film at a specific angle of -40-+40 degrees is obtained, wherein the high-frequency high-Q value is more than 5000.

6. The acoustic wave resonator of claim 1, wherein, ​ ​ 7. The acoustic wave resonator of claim 1, wherein, ​ ​ ​ ​ 8. A method of fabricating a high-frequency high-Q acoustic resonator, comprising: ​ ​ ​ ​ ​ ​ 9. The method of manufacturing according to claim 8, wherein, A plurality of metal electrodes are formed on the surface of the piezoelectric layer away from the releasing layer, comprising: A mask layer is formed on the surface of the piezoelectric layer away from the releasing layer; Based on the rotation Euler angle, a plurality of electrode windows at preset angles are obtained by photoetching on the mask layer, and part of the surface of the piezoelectric layer is exposed; Metal electrodes are formed on the electrode windows by plating technology; The remaining mask layer is removed.

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