Film bulk acoustic resonator and preparation method thereof

Abstract

The invention provides a film bulk acoustic resonator and a preparation method thereof, and relates to the technical field of semiconductors. The preparation method of the film bulk acoustic resonator comprises the following steps: providing a first substrate structure, and forming a first piezoelectric layer on the first substrate structure; forming a first temperature compensation layer on the first piezoelectric layer; sequentially forming a first electrode layer and a first bonding layer on the first temperature compensation layer; providing a second substrate structure, and forming a second bonding layer on the second substrate structure; bonding the first bonding layer and the second bonding layer; and removing the first substrate structure, and sequentially forming a second temperature compensation layer and a second electrode layer on the exposed first piezoelectric layer. According to the preparation method of the film bulk acoustic wave resonator, a bonding mode is adopted, the first temperature compensation layer and the first electrode layer are prepared on one side of the first piezoelectric layer, and then the second temperature compensation layer and the second electrode layer are prepared on the other side of the first piezoelectric layer, so that the temperature stability of the film bulk acoustic wave resonator can be improved, and the excellent performance of the film bulk acoustic wave resonator can be maintained.

Description

Technical Field

[0001] The present application relates to the field of semiconductor technology, and in particular to a thin film bulk acoustic wave resonator and a method for preparing the same. Background Art

[0002] Film bulk acoustic resonator (FBAR) is a high-performance device widely used in RF filters and wireless communications. Its core advantages are high quality factor, low insertion loss and miniaturization. However, the resonant frequency of FBAR is extremely sensitive to temperature changes. Temperature fluctuations can cause thermal expansion of the material, changes in sound velocity and mechanical stress, which can cause the resonant frequency to drift. This temperature-induced frequency instability seriously affects the performance and reliability of FBAR in high-precision applications, especially in communication equipment. Frequency offset may cause signal distortion, filter performance degradation and system failure.

[0003] In order to improve the temperature stability of FBAR in the prior art, a temperature compensation layer is deposited on the electrode layer before depositing the first piezoelectric layer. However, the introduction of the temperature compensation layer will have a negative impact on the subsequent films, especially on the quality of the first piezoelectric layer, thereby causing a significant negative impact on the performance of the FBAR. Summary of the invention

[0004] The purpose of the present application is to provide a thin film bulk acoustic wave resonator and a preparation method thereof, in view of the above-mentioned deficiencies in the prior art, which can not only improve the temperature stability of FBAR but also maintain the superior performance of FBAR.

[0005] To achieve the above purpose, the technical solution adopted in the embodiment of the present application is as follows:

[0006] According to one aspect of an embodiment of the present application, a method for preparing a thin film bulk acoustic wave resonator is provided, comprising: providing a first substrate structure, and forming a first piezoelectric layer on the first substrate structure; forming a first temperature compensation layer on the first piezoelectric layer, wherein the first temperature compensation layer covers a portion of the first piezoelectric layer; forming a first electrode layer and a first bonding layer in sequence on the first temperature compensation layer, wherein the first electrode layer covers the first temperature compensation layer and a portion of the first piezoelectric layer; providing a second substrate structure, and forming a second bonding layer on the second substrate structure; bonding the first bonding layer and the second bonding layer; removing the first substrate structure, and forming a second temperature compensation layer and a second electrode layer in sequence on the exposed first piezoelectric layer, wherein the second temperature compensation layer covers a portion of the first piezoelectric layer, the second temperature compensation layer corresponds to the position of the first temperature compensation layer, and the second electrode layer covers the temperature compensation layer and a portion of the first piezoelectric layer.

[0007] Optionally, after forming the first temperature compensation layer on the first piezoelectric layer, the method further includes: forming a second piezoelectric layer on the first piezoelectric layer and the first temperature compensation layer; and sequentially forming a first electrode layer and a first bonding layer on the first temperature compensation layer includes: sequentially forming a first electrode layer and a first bonding layer on the second piezoelectric layer.

[0008] Optionally, sequentially forming a second temperature compensating layer and a second electrode layer on the exposed first piezoelectric layer includes: forming a second temperature compensating layer on the exposed first piezoelectric layer, wherein the second temperature compensating layer covers a portion of the first piezoelectric layer; forming a third piezoelectric layer on the first piezoelectric layer and the second temperature compensating layer; forming a second electrode layer on the third piezoelectric layer, wherein the second electrode layer covers a portion of the third piezoelectric layer.

[0009] Optionally, forming a first temperature compensating layer on the first piezoelectric layer includes: forming a third electrode layer on the first piezoelectric layer, and forming a first temperature compensating layer on the third electrode layer, wherein the third electrode layer covers a portion of the first piezoelectric layer, and the first temperature compensating layer covers a portion of the third electrode layer; sequentially forming a first electrode layer and a first bonding layer on the first temperature compensating layer includes: forming a first electrode layer on the third electrode layer and the first temperature compensating layer, and forming a first bonding layer on the first electrode layer.

[0010] Optionally, sequentially forming a second temperature compensating layer and a second electrode layer on the exposed first piezoelectric layer includes: forming a fourth electrode layer on the exposed first piezoelectric layer, and forming a second temperature compensating layer on the fourth electrode layer, wherein the fourth electrode layer covers a portion of the first piezoelectric layer, and the second temperature compensating layer covers a portion of the fourth electrode layer; forming a second electrode layer on the fourth electrode layer and the second temperature compensating layer.

[0011] Optionally, after removing the first substrate structure and sequentially forming a second temperature compensation layer and a second electrode layer on the exposed first piezoelectric layer, the method further includes:

[0012] A passivation layer is formed on the second electrode layer, and an annular groove is formed on the passivation layer, wherein the annular groove is used to suppress the parasitic of the series resonance frequency of the thin film bulk acoustic resonator.

[0013] Optionally, the first temperature compensating layer includes a first sub-temperature compensating layer and a second sub-temperature compensating layer surrounding the first sub-temperature compensating layer and spaced apart from the first sub-temperature compensating layer, and the orthographic projection of the outer edge of the annular groove on the first sub-temperature compensating layer coincides with the outer edge of the first sub-temperature compensating layer.

[0014] Optionally, the second temperature compensating layer includes a third sub-temperature compensating layer and a fourth sub-temperature compensating layer surrounding the third sub-temperature compensating layer and spaced apart from the third sub-temperature compensating layer, the third sub-temperature compensating layer corresponds to the first sub-temperature compensating layer, and the fourth sub-temperature compensating layer corresponds to the second sub-temperature compensating layer.

[0015] Optionally, the orthographic projection of the outer edge of the third sub-temperature compensating layer on the first sub-temperature compensating layer is located within the outer edge of the first sub-temperature compensating layer; a passivation layer is formed on the second electrode layer, and an annular groove is formed on the passivation layer, the annular groove is used to suppress the parasitic of the series resonance frequency of the thin film bulk acoustic resonator, including: forming a thickening layer on the second electrode layer, wherein the thickening layer is spaced apart from the area of ​​the second electrode layer directly above the third sub-temperature compensating layer; depositing a passivation layer on the second electrode layer and the thickening layer, wherein an annular groove is formed between the area of ​​the passivation layer directly above the third sub-temperature compensating layer and the thickening layer.

[0016] Optionally, the orthographic projection of the outer edge of the second sub-temperature compensating layer on the first electrode layer is located within the outer edge of the first electrode layer, and a plurality of first through holes are arranged at intervals on the second sub-temperature compensating layer; and / or, the orthographic projection of the outer edge of the fourth sub-temperature compensating layer on the second electrode layer is located within the outer edge of the second electrode layer, and a plurality of second through holes are arranged at intervals on the fourth sub-temperature compensating layer.

[0017] Optionally, sequentially forming a first electrode layer and a first bonding layer on the first temperature compensation layer includes:

[0018] forming a first electrode layer on the first temperature compensation layer, and forming a cavity layer on the first electrode layer, wherein the cavity layer covers a portion of the first electrode layer;

[0019] forming a first bonding layer on the cavity layer;

[0020] After removing the first substrate structure and sequentially forming a second temperature compensation layer and a second electrode layer on the exposed first piezoelectric layer, the method further includes:

[0021] A release hole is etched, and the cavity layer is removed through the release hole.

[0022] Another aspect of the embodiments of the present application provides a thin film bulk acoustic wave resonator, which is prepared by using any of the above methods for preparing a thin film bulk acoustic wave resonator.

[0023] The beneficial effects of this application include:

[0024] The present application provides a method for preparing a thin film bulk acoustic wave resonator, including: providing a first substrate structure, and forming a first piezoelectric layer on the first substrate structure; forming a first temperature compensation layer on the first piezoelectric layer, wherein the first temperature compensation layer covers part of the first piezoelectric layer; forming a first electrode layer and a first bonding layer on the first temperature compensation layer in sequence, wherein the first electrode layer covers the first temperature compensation layer and part of the first piezoelectric layer; providing a second substrate structure, and forming a second bonding layer on the second substrate structure; bonding the first bonding layer and the second bonding layer; removing the first substrate structure, and forming a second temperature compensation layer and a second electrode layer on the exposed first piezoelectric layer in sequence, wherein the second temperature compensation layer covers part of the first piezoelectric layer, the second temperature compensation layer corresponds to the position of the first temperature compensation layer, and the second electrode layer covers the temperature compensation layer and part of the first piezoelectric layer. The method for preparing a thin film bulk acoustic wave resonator adopts a bonding method, first preparing a first temperature compensation layer and a first electrode layer on one side of the first piezoelectric layer, and then preparing a second temperature compensation layer and a second electrode layer on the other side of the first piezoelectric layer. Both sides of the first piezoelectric layer have temperature compensation layers, so the temperature stability of the thin film bulk acoustic wave resonator can be improved. In addition, since the first piezoelectric layer is formed on the first substrate structure instead of on the temperature compensation layer, when the temperature compensation layer is prepared on both sides of the first piezoelectric layer, a high-quality first piezoelectric layer can still be obtained, thereby avoiding the negative impact of the introduction of the temperature compensation layer on the quality of the first piezoelectric layer, thereby maintaining the superior performance of the thin film bulk acoustic wave resonator (such as piezoelectric performance, resonance performance, mechanical performance, etc.). Therefore, the thin film bulk acoustic wave resonator prepared by the above-mentioned thin film bulk acoustic wave resonator preparation method has both good temperature stability and superior performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 One of the flow charts of the method for preparing a thin film bulk acoustic wave resonator provided in an embodiment of the present application;

[0027] Figure 2 One of the schematic diagrams of the preparation process of the thin film bulk acoustic wave resonator provided in the embodiment of the present application;

[0028] Figure 3 The second schematic diagram of the preparation process of the thin film bulk acoustic wave resonator provided in the embodiment of the present application;

[0029] Figure 4 The third schematic diagram of the preparation process of the thin film bulk acoustic wave resonator provided in the embodiment of the present application;

[0030] Figure 5 A fourth schematic diagram of the preparation process of the thin film bulk acoustic wave resonator provided in an embodiment of the present application;

[0031] Figure 6 A fifth schematic diagram of the preparation process of the thin film bulk acoustic wave resonator provided in an embodiment of the present application;

[0032] Figure 7 Schematic diagram six of the preparation process of the thin film bulk acoustic wave resonator provided in the embodiment of the present application;

[0033] Figure 8 Schematic diagram of the preparation process of the thin film bulk acoustic wave resonator provided in the embodiment of the present application seven;

[0034] Fig. 9 Schematic diagram eight of the preparation process of the thin film bulk acoustic wave resonator provided in an embodiment of the present application;

[0035] Fig.10 A ninth schematic diagram of the preparation process of a thin film bulk acoustic wave resonator provided in an embodiment of the present application;

[0036] Fig.11 Flow chart 2 of the method for preparing a thin film bulk acoustic wave resonator provided in an embodiment of the present application;

[0037] Fig.12 A tenth schematic diagram of the preparation process of the thin film bulk acoustic wave resonator provided in an embodiment of the present application;

[0038] Fig.13 11 is a schematic diagram of the preparation process of the thin film bulk acoustic wave resonator provided in an embodiment of the present application;

[0039] Fig.14 A twelfth schematic diagram of the preparation process of the thin film bulk acoustic wave resonator provided in an embodiment of the present application;

[0040] Fig.15 Thirteenth schematic diagram of the preparation process of the thin film bulk acoustic wave resonator provided in an embodiment of the present application;

[0041] Fig.16 Flow chart three of the method for preparing a thin film bulk acoustic wave resonator provided in an embodiment of the present application;

[0042] Fig.17 Fourteenth schematic diagram of the preparation process of the thin film bulk acoustic wave resonator provided in an embodiment of the present application;

[0043] Fig.18 The fifteenth schematic diagram of the preparation process of the thin film bulk acoustic wave resonator provided in the embodiment of the present application;

[0044] Fig.19Schematic diagram of the sixteenth process of preparing the thin film bulk acoustic wave resonator provided in the embodiment of the present application;

[0045] Fig. 20 The seventeenth schematic diagram of the preparation process of the thin film bulk acoustic wave resonator provided in the embodiment of the present application;

[0046] Fig.21 18th schematic diagram of the preparation process of the thin film bulk acoustic wave resonator provided in the embodiment of the present application;

[0047] Fig. 22 Schematic diagram of the nineteenth process of preparing the thin film bulk acoustic wave resonator provided in the embodiment of the present application;

[0048] Fig.23 20 is a schematic diagram of the preparation process of the thin film bulk acoustic wave resonator provided in an embodiment of the present application;

[0049] Fig.24 Flow chart 4 of the method for preparing a thin film bulk acoustic wave resonator provided in an embodiment of the present application;

[0050] Fig.25 Schematic diagram 21 of the preparation process of the thin film bulk acoustic wave resonator provided in the embodiment of the present application;

[0051] Fig.26 Flow chart 5 of the method for preparing a thin film bulk acoustic wave resonator provided in an embodiment of the present application;

[0052] Fig. 27 Schematic diagram twenty-two of the preparation process of the thin film bulk acoustic wave resonator provided in an embodiment of the present application.

[0053] Icons: 10-first substrate structure; 11-first substrate layer; 12-seed layer; 20-first piezoelectric layer; 30-first temperature compensation layer; 31-first sub-temperature compensation layer; 32-first air wing area; 33-first air bridge area; 40-first electrode layer; 50-first bonding layer; 60-second substrate structure; 61-second substrate layer; 62-first oxide layer; 63-first through hole; 70-second bonding layer; 80-second temperature compensation layer; 81-third sub-temperature compensation layer Temperature compensation layer; 82-second air wing area; 83-second air bridge area; 84-second through hole; 90-second electrode layer; 100-second piezoelectric layer; 110-third piezoelectric layer; 120-third electrode layer; 130-fourth electrode layer; 140-passivation layer; 141-annular groove; 150-lead-out hole; 160-protective layer; 170-cavity layer; 180-release hole; 190-buffer layer; 200-second oxide layer; 210-thickening layer. DETAILED DESCRIPTION

[0054] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations.

[0055] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for protection, but merely represents selected embodiments of the present application. It should be noted that, in the absence of conflict, the various features in the embodiments of the present application can be combined with each other, and the combined embodiments are still within the scope of protection of the present application.

[0056] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0057] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, or the positions or positional relationships in which the product of the application is usually placed when in use. They are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific position, be constructed and operated in a specific position, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0058] In the description of this application, it should also be noted that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0059] In one aspect of the embodiment of the present application, please refer to Figure 1 , a method for preparing a thin film bulk acoustic wave resonator is provided, comprising:

[0060] S100: providing a first substrate structure, and forming a first piezoelectric layer on the first substrate structure.

[0061] Please refer to Figure 2, the first piezoelectric layer 20 is formed on the surface of the first substrate structure 10. Optionally, the first piezoelectric layer 20 completely covers the surface of the first substrate structure 10.

[0062] For example, forming the first piezoelectric layer 20 on the first substrate structure 10 includes: depositing a layer of piezoelectric material on the first substrate structure 10 to form the first piezoelectric layer 20. For example, the first piezoelectric layer 20 is formed by using a MOCVD (Metal-Organic Chemical Vapor Deposition) process.

[0063] The piezoelectric material may include at least one of aluminum nitride (AlN), lithium niobate (LiNbO3), lithium tantalate (LiTaO3), lead zirconate titanate (PZT), zinc oxide (ZnO), scandium-doped aluminum nitride (ScAlN), quartz crystal, lead magnesium niobate (PMN) and lead fluoride (PbTiO3).

[0064] For example, the first substrate structure 10 includes a first substrate layer 11, and the first piezoelectric layer 20 is formed on the surface of the first substrate layer 11 and adheres to the first substrate layer 11. Alternatively, the first substrate structure 10 includes a first substrate layer 11 and a seed layer 12 disposed on the first substrate layer 11, the seed layer 12 completely covers the surface of the first substrate layer 11 and adheres to the first substrate layer 11, and the first piezoelectric layer 20 is formed on the surface of the seed layer 12 and adheres to the seed layer 12.

[0065] The provision of the seed layer 12 can provide a good growth foundation for the preparation of the first piezoelectric layer 20 , and can control the direction of crystal growth in the first piezoelectric layer 20 , thereby improving the film quality of the first piezoelectric layer 20 .

[0066] The material of the first base layer 11 may include at least one of sapphire (Al2O3), silicon carbide (SiC), and silicon (Si). The material of the seed layer 12 may include at least one of copper and nickel.

[0067] S200: forming a first temperature compensation layer on the first piezoelectric layer, wherein the first temperature compensation layer covers a portion of the first piezoelectric layer.

[0068] Please refer to Figure 3 The first temperature compensating layer 30 is formed on the side of the first piezoelectric layer 20 away from the first substrate structure 10, and covers part of the first piezoelectric layer 20. The material of the first temperature compensating layer 30 may include at least one of silicon dioxide (SiO2), titanium dioxide (TiO2), tantalum oxide (Ta2O5), silicon nitride (Si3N4) and aluminum oxide (Al2O3). The first temperature compensating layer 30 may also be a multi-layer composite film.

[0069] It should be noted that in the above and subsequent descriptions, a certain film layer completely covers another film layer, which means that the orthographic projection of a certain film layer on another film layer completely covers the surface of the other film layer, and it is not limited that a certain film layer must be attached to another film layer. A certain film layer covers part of another film layer, which means that the orthographic projection of a certain film layer on another film layer partially covers the surface of another film layer, and it is not limited that a certain film layer must be attached to another film layer. A certain film layer covering another film layer can be a certain film layer completely covering another film layer, or a certain film layer covering a part of another film layer.

[0070] The first temperature compensation layer 30 may only have a first sub-temperature compensation layer 31 (eg Figure 3 As shown), it may also include a second sub-temperature compensation layer surrounding the outer side of the first sub-temperature compensation layer 31 and spaced from the first sub-temperature compensation layer 31, and the second sub-temperature compensation layer is divided into a first air wing area 32 and a first air bridge area 33 (as shown in FIG. Figure 4 As shown). The first sub-temperature compensation layer 31 is used to perform temperature compensation on the thin film bulk acoustic wave resonator, and the first air wing region 32 and the first air bridge region 33 are used to form an air wing structure and an air bridge structure, respectively.

[0071] For example, forming the first temperature compensating layer 30 on the first piezoelectric layer 20 includes: depositing at least one layer of temperature compensating material on the first piezoelectric layer 20 to form a complete first temperature compensating film layer; etching the complete first temperature compensating film layer to remove part of the temperature compensating material and expose the first piezoelectric layer 20 under the temperature compensating material to form the first temperature compensating layer 30.

[0072] S300: forming a first electrode layer and a first bonding layer in sequence on the first temperature compensation layer, wherein the first electrode layer covers the first temperature compensation layer and a portion of the first piezoelectric layer.

[0073] Please refer to Figure 5 and Figure 6 , firstly, a first electrode layer 40 is formed on the side of the first temperature compensation layer 30 away from the first piezoelectric layer 20, and then a first bonding layer 50 is formed on the side of the first electrode layer 40 away from the first piezoelectric layer 20. The first electrode layer 40 covers the first temperature compensation layer 30, and at the same time covers part of the first piezoelectric layer 20. Optionally, the first bonding layer 50 completely covers the first piezoelectric layer 20. The first electrode layer 40 can be obtained by etching after deposition, and the first bonding layer 50 can be obtained by deposition.

[0074] The material of the first electrode layer 40 may include at least one of molybdenum (Mo), aluminum (Al), copper (Cu), tungsten (W), tantalum (Ta), platinum (Pt), ruthenium (Ru), rhodium (Rh), iridium (Ir), chromium (Cr), titanium (Ti), gold (Au), osmium (Os), rhenium (Re), and palladium (Pd). The material of the first bonding layer 50 may be gold (Au).

[0075] It should be noted that, in this embodiment, the first bonding layer 50 may be bonded to the first electrode layer 40 , and other film layers may also be disposed between the first bonding layer 50 and the first electrode layer 40 .

[0076] S400: providing a second substrate structure, and forming a second bonding layer on the second substrate structure.

[0077] Please refer to Figure 7 The second bonding layer 70 is formed on the surface of the second substrate structure. Optionally, the second bonding layer 70 completely covers the surface of the second substrate structure 60.

[0078] Illustratively, forming the second bonding layer 70 on the second substrate structure 60 includes: depositing a layer of bonding material on the second substrate structure 60 to form the second bonding layer 70 .

[0079] The material of the second bonding layer 70 may be gold (Au). Preferably, the material of the second bonding layer 70 is the same as that of the first bonding layer 50, so as to facilitate bonding between the two.

[0080] For example, the second substrate structure 60 includes a second substrate layer 61, and the second bonding layer 70 is formed on the surface of the second substrate layer 61 and adheres to the second substrate layer 61. Alternatively, the second substrate structure 60 includes a second substrate layer 61 and first oxide layers 62 respectively arranged on two opposite surfaces of the second substrate layer 61, the first oxide layer 62 completely covers the surface of the second substrate layer 61 and adheres to the second substrate layer 61, and the second bonding layer 70 is formed on the surface of one of the first oxide layers 62 and adheres to the first oxide layer 62.

[0081] The material of the second base layer 61 may include at least one of sapphire (Al2O3), silicon carbide (SiC), and silicon (Si). The material of the first oxide layer 62 may include SiO2.

[0082] S500: Bonding the first bonding layer and the second bonding layer.

[0083] The first bonding layer 50 and the second bonding layer 70 are aligned and bonded to obtain Figure 8 Semi-finished product shown.

[0084] S600: removing the first substrate structure, and sequentially forming a second temperature compensation layer and a second electrode layer on the exposed first piezoelectric layer, wherein the second temperature compensation layer covers a portion of the first piezoelectric layer, the second temperature compensation layer corresponds to the first temperature compensation layer, and the second electrode layer covers the temperature compensation layer and a portion of the first piezoelectric layer.

[0085] Please refer to Fig. 9, the first substrate structure 10 in the finished product is removed, so that the surface of the first piezoelectric layer 20 away from the first temperature compensation layer 30 is exposed. Fig.10 , firstly, a second temperature compensation layer 80 is formed on the side of the first piezoelectric layer 20 away from the first temperature compensation layer 30, and then a second electrode layer 90 is formed on the side of the second temperature compensation layer 80 away from the first piezoelectric layer 20, so that a sandwich structure of the film bulk acoustic wave resonator (first electrode layer 40-first piezoelectric layer 20-second electrode layer 90) is obtained, and both sides of the first piezoelectric layer 20 have temperature compensation layers. As for the process steps for preparing other structures of the film bulk acoustic wave resonator, they can be interspersed in the above steps or can be performed after the above steps.

[0086] The second temperature compensating layer 80 and the second electrode layer 90 can both be obtained by etching after deposition. The material of the second temperature compensating layer 80 may include at least one of silicon dioxide (SiO2), titanium dioxide (TiO2), tantalum oxide (Ta2O5), silicon nitride (Si3N4) and aluminum oxide (Al2O3). The second temperature compensating layer 80 can also be a multi-layer composite film. The material of the second electrode layer 90 may include at least one of molybdenum (Mo), aluminum (Al), copper (Cu), tungsten (W), tantalum (Ta), platinum (Pt), ruthenium (Ru), rhodium (Rh), iridium (Ir), chromium (Cr), titanium (Ti), gold (Au), osmium (Os), rhenium (Re) and palladium (Pd). Preferably, the structure of the second temperature compensating layer 80 is the same as that of the first temperature compensating layer 30, and the material is also the same; the material of the second electrode layer 90 is the same as that of the first electrode layer 40.

[0087] For example, forming a second temperature compensating layer 80 and a second electrode layer 90 in sequence on the exposed first piezoelectric layer 20 includes: depositing a layer of temperature compensating material on the surface of the exposed first piezoelectric layer 20 to form a complete second temperature compensating film layer; etching the complete second temperature compensating film layer to remove part of the temperature compensating material and expose the first piezoelectric layer 20 under the temperature compensating material to form a second temperature compensating layer 80; depositing a layer of electrode material on the second temperature compensating layer 80 and the first piezoelectric layer 20 exposed by the second temperature compensating layer 80 to form a complete second electrode film layer; etching the complete second electrode film layer to remove part of the electrode material and expose the first piezoelectric layer 20 under the electrode material to form a second electrode layer 90; and planarizing the surface of the second electrode layer 90 facing away from the first piezoelectric layer 20.

[0088] The second temperature compensating layer 80 may only include the third sub-temperature compensating layer 81, or may further include a fourth sub-temperature compensating layer surrounding the outside of the third sub-temperature compensating layer 81 and spaced apart from the third sub-temperature compensating layer 81, and the fourth sub-temperature compensating layer is divided into a second air wing area 82 and a second air bridge area 83 (such as Figure 4The third sub-temperature compensation layer 81 is used to perform temperature compensation on the thin film bulk acoustic wave resonator, and the second air wing region 82 and the second air bridge region 83 are used to form an air wing structure and an air bridge structure, respectively.

[0089] The method for preparing the above-mentioned film bulk acoustic wave resonator adopts a bonding method to first prepare a first temperature compensation layer 30 and a first electrode layer 40 on one side of the first piezoelectric layer 20, and then prepare a second temperature compensation layer 80 and a second electrode layer 90 on the other side of the first piezoelectric layer 20. Both sides of the first piezoelectric layer 20 have temperature compensation layers, so the temperature stability of the film bulk acoustic wave resonator can be improved. In addition, since the first piezoelectric layer 20 is formed on the first substrate structure 10 instead of on the temperature compensation layer, when the temperature compensation layer is prepared on both sides of the first piezoelectric layer 20, a high-quality first piezoelectric layer 20 can still be obtained, avoiding the negative impact of the introduction of the temperature compensation layer on the quality of the first piezoelectric layer 20, thereby maintaining the superior performance of the film bulk acoustic wave resonator (such as piezoelectric performance, resonance performance, mechanical performance, etc.). Therefore, the film bulk acoustic wave resonator prepared by the above-mentioned method for preparing the film bulk acoustic wave resonator has both good temperature stability and superior performance.

[0090] Optionally, see Fig.11 After forming the first temperature compensation layer on the first piezoelectric layer, the method further includes:

[0091] S700: forming a second piezoelectric layer on the first piezoelectric layer and the first temperature compensation layer.

[0092] Please refer to Fig.12 , the first temperature compensating layer 30 is formed on the side of the first piezoelectric layer 20 away from the first substrate structure 10, and covers part of the first piezoelectric layer 20. After obtaining the first temperature compensating layer 30, a second piezoelectric layer 100 is formed on the side of the first temperature compensating layer 30 away from the first piezoelectric layer 20, and the second piezoelectric layer 100 completely covers the first temperature compensating layer 30, and also covers the first piezoelectric layer 20 exposed by the first temperature compensating layer 30. The second piezoelectric layer 100 can be obtained by deposition, and the material of the second piezoelectric layer 100 is preferably the same as that of the first piezoelectric layer 20.

[0093] For example, the thickness of the second piezoelectric layer 100 is greater than the thickness of the first temperature compensation layer 30 , and the ratio of the thickness of the second piezoelectric layer 100 to the thickness of the first piezoelectric layer 20 is 0.08-0.12.

[0094] Sequentially forming a first electrode layer and a first bonding layer on the first temperature compensation layer includes:

[0095] S310: sequentially forming a first electrode layer and a first bonding layer on the second piezoelectric layer.

[0096] Please refer to Fig.13First, the first electrode layer 40 is formed on the side of the second piezoelectric layer 100 away from the first piezoelectric layer 20 , and then the first bonding layer 50 is formed on the side of the first electrode layer 40 away from the first piezoelectric layer 20 .

[0097] The first temperature compensation layer 30 may only have a first sub-temperature compensation layer 31 (eg Fig.12 As shown), there may also be a second sub-temperature compensation layer located on the side of the first sub-temperature compensation layer 31 and spaced from the first sub-temperature compensation layer 31, and the second sub-temperature compensation layer is divided into a first air wing area 32 and a first air bridge area 33 (as shown Fig.14 If the first temperature compensating layer 30 also has a first air wing region 32 and a first air bridge region 33, after forming the second piezoelectric layer 100, the first air wing region 32 and the first air bridge region 33 of the first temperature compensating layer 30 need to be formed on the second piezoelectric layer 100, and then the first electrode layer 40 and the first bonding layer 50 are formed.

[0098] The first piezoelectric layer 20 and the second piezoelectric layer 100 constitute a first composite piezoelectric layer, and the first temperature compensation layer 30 is located in the first composite piezoelectric layer, which can improve the temperature compensation effect and further improve the temperature stability of the thin film bulk acoustic wave resonator. During preparation, the thickness of the second piezoelectric layer 100 can be significantly smaller than the thickness of the first piezoelectric layer 20, so that the negative impact of the first temperature compensation layer 30 on the quality of the second piezoelectric layer 100 will not have a significant impact on the performance of the thin film bulk acoustic wave resonator.

[0099] Optionally, please refer again to Fig.11 , sequentially forming a second temperature compensation layer and a second electrode layer on the exposed first piezoelectric layer comprises:

[0100] S610: forming a second temperature compensation layer on the exposed first piezoelectric layer, wherein the second temperature compensation layer covers a portion of the first piezoelectric layer.

[0101] Please refer to Fig.15 The second temperature compensation layer 80 is formed on a side of the first piezoelectric layer 20 away from the second substrate structure 60 , and covers a portion of the second piezoelectric layer 100 .

[0102] S620: forming a third piezoelectric layer on the first piezoelectric layer and the second temperature compensation layer.

[0103] After the second temperature compensating layer 80 is obtained, a third piezoelectric layer 110 is formed on the side of the second temperature compensating layer 80 away from the first piezoelectric layer 20, and the third piezoelectric layer 110 completely covers the second temperature compensating layer 80, and also covers the first piezoelectric layer 20 exposed by the second temperature compensating layer 80. The third piezoelectric layer 110 can be obtained by deposition, and the material of the third piezoelectric layer 110 is preferably the same as that of the first piezoelectric layer 20.

[0104] For example, the thickness of the third piezoelectric layer 110 is greater than the thickness of the second temperature compensation layer 80 , and the ratio of the thickness of the third piezoelectric layer 110 to the thickness of the first piezoelectric layer 20 is 0.08-0.12.

[0105] S630: forming a second electrode layer on the third piezoelectric layer, wherein the second electrode layer covers a portion of the third piezoelectric layer.

[0106] The second temperature compensating layer 80 may only have the third sub-temperature compensating layer 81, or may further have a fourth sub-temperature compensating layer surrounding the outside of the third sub-temperature compensating layer 81 and spaced apart from the third sub-temperature compensating layer 81, and the fourth sub-temperature compensating layer is divided into a second air wing area 82 and a second air bridge area 83. If the second temperature compensating layer 80 also has the second air wing area 82 and the second air bridge area 83, then after forming the third piezoelectric layer 110, the second air wing area 82 and the second air bridge area 83 of the fourth temperature compensating layer need to be formed on the third piezoelectric layer 110 before forming the second electrode layer 90.

[0107] The first piezoelectric layer 20 and the third piezoelectric layer 110 constitute a second composite piezoelectric layer, and the second temperature compensation layer 80 is located in the second composite piezoelectric layer, which can improve the temperature compensation effect and further improve the temperature stability of the thin film bulk acoustic wave resonator. During preparation, the thickness of the third piezoelectric layer 110 can be significantly smaller than the thickness of the first piezoelectric layer 20, so that the negative impact of the second temperature compensation layer 80 on the quality of the third piezoelectric layer 110 will not have a significant impact on the performance of the thin film bulk acoustic wave resonator.

[0108] Optionally, see Fig.16 , forming a first temperature compensation layer on the first piezoelectric layer comprises:

[0109] S210: forming a third electrode layer on the first piezoelectric layer, and forming a first temperature compensation layer on the third electrode layer, wherein the third electrode layer covers a portion of the first piezoelectric layer, and the first temperature compensation layer covers a portion of the third electrode layer.

[0110] Please refer to Fig.17 First, a third electrode layer 120 is formed on the side of the first piezoelectric layer 20 away from the first substrate structure 10, and then a first temperature compensation layer 30 is formed on the side of the third electrode layer 120 away from the first substrate structure 10. Both the third electrode layer 120 and the first temperature compensation layer 30 can be obtained by deposition and then etching.

[0111] Sequentially forming a first electrode layer and a first bonding layer on the first temperature compensation layer includes:

[0112] S320: forming a first electrode layer on the third electrode layer and the first temperature compensation layer, and forming a first bonding layer on the first electrode layer.

[0113] Please refer to Fig.18After the first temperature compensating layer 30 is obtained, a first electrode layer 40 is first formed on the side of the first temperature compensating layer 30 away from the first piezoelectric layer 20, and the first electrode layer 40 simultaneously covers the first temperature compensating layer 30 and the third electrode layer 120 exposed by the first temperature compensating layer 30. Then, a first bonding layer 50 is formed on the side of the first electrode layer 40 away from the first piezoelectric layer 20.

[0114] The first temperature compensation layer 30 may only have a first sub-temperature compensation layer 31 (eg Fig.18 As shown), there may also be a second sub-temperature compensation layer located on the side of the first sub-temperature compensation layer 31 and spaced from the first sub-temperature compensation layer 31, and the second sub-temperature compensation layer is divided into a first air wing area 32 and a first air bridge area 33 (as shown Fig.19 If the first temperature compensating layer 30 also has a first air wing region 32 and a first air bridge region 33, after forming the third electrode layer 120, a first etching hole for forming the first air wing region 32 and the first air bridge region 33 may be etched on the third electrode layer 120, and then a temperature compensating material is deposited, and part of the temperature compensating material is etched away to simultaneously form a first sub-temperature compensating layer 31 and a second sub-temperature compensating layer.

[0115] The third electrode layer 120 and the first electrode layer 40 constitute a first composite electrode layer, and the first temperature compensation layer 30 is located in the first composite electrode layer.

[0116] Optionally, please refer again to Fig.16 , sequentially forming a second temperature compensation layer and a second electrode layer on the exposed first piezoelectric layer comprises:

[0117] S640: forming a fourth electrode layer on the exposed first piezoelectric layer, and forming a second temperature compensation layer on the fourth electrode layer, wherein the fourth electrode layer covers a portion of the first piezoelectric layer, and the second temperature compensation layer covers a portion of the fourth electrode layer.

[0118] Please refer to Fig. 20 The fourth electrode layer 130 is formed on the side of the first piezoelectric layer 20 away from the second substrate structure 60, and covers a portion of the first piezoelectric layer 20. The second temperature compensation layer 80 is formed on the side of the fourth electrode layer 130 away from the second substrate structure 60, and covers a portion of the fourth electrode layer 130. The fourth electrode layer 130 can be formed by deposition and then etching.

[0119] S650: forming a second electrode layer on the fourth electrode layer and the second temperature compensation layer.

[0120] After the second temperature compensating layer 80 is obtained, a second electrode layer 90 is formed on the side of the second temperature compensating layer 80 away from the first piezoelectric layer 20 . The second electrode layer 90 covers the second temperature compensating layer 80 and the fourth electrode layer 130 exposed by the second temperature compensating layer 80 .

[0121] The second temperature compensation layer 80 may only have a third sub-temperature compensation layer 81 (eg Fig. 20 As shown), it may also include a fourth sub-temperature compensation layer surrounding the outer side of the third sub-temperature compensation layer 81 and spaced apart from the third sub-temperature compensation layer 81, and the fourth sub-temperature compensation layer is divided into a second air wing area 82 and a second air bridge area 83 (as shown Fig.21 If the second temperature compensating layer 80 also has a second air wing region 82 and a second air bridge region 83, a second etching hole for forming the second air wing region 82 and the second air bridge region 83 may be first etched on the fourth electrode layer 130, and then a temperature compensating material is deposited, and part of the temperature compensating material is etched away to simultaneously form a third sub-temperature compensating layer 81 and a fourth sub-temperature compensating layer.

[0122] The fourth electrode layer 130 and the second electrode layer 90 constitute a second composite electrode layer, and the second temperature compensation layer 80 is located in the second composite electrode layer.

[0123] In summary, the first temperature compensating layer 30 can be arranged between the first piezoelectric layer 20 and the first electrode layer 40, or in the first composite piezoelectric layer, or in the first composite electrode layer. The second temperature compensating layer 80 can be arranged between the first piezoelectric layer 20 and the second electrode layer 90, or in the second composite piezoelectric layer, or in the second composite electrode layer.

[0124] Optionally, after removing the first substrate structure and sequentially forming a second temperature compensation layer and a second electrode layer on the exposed first piezoelectric layer, the method further includes:

[0125] S800: forming a passivation layer on the second electrode layer, and forming an annular groove on the passivation layer, wherein the annular groove is used to suppress parasitics of the series resonance frequency of the thin film bulk acoustic resonator.

[0126] Please refer to Fig. 22 The passivation layer 140 is formed on the side of the second electrode layer 90 away from the second substrate structure 60. The passivation layer 140 is used to protect the second electrode layer 90 and prevent the second electrode layer 90 from being oxidized. The passivation layer 140 can be formed by etching after deposition. The material of the passivation layer 140 may include at least one of SiO2, Si3N4, AlN and Al2O3. An annular groove 141 is formed on the surface of the passivation layer 140 away from the second electrode layer 90. The annular groove 141 can be formed by etching the passivation layer 140, or it can be naturally formed on the passivation layer 140 when the passivation layer 140 is deposited.

[0127] Optionally, the first temperature compensating layer 30 includes a first sub-temperature compensating layer 31 and a second sub-temperature compensating layer surrounding the first sub-temperature compensating layer 31 and spaced apart from the first sub-temperature compensating layer 31 , and the orthographic projection of the outer edge of the annular groove 141 on the first sub-temperature compensating layer 31 coincides with the outer edge of the first sub-temperature compensating layer 31 .

[0128] Optionally, the second temperature compensating layer 80 includes a third sub-temperature compensating layer 81 and a fourth sub-temperature compensating layer surrounding the third sub-temperature compensating layer 81 and spaced apart from the third sub-temperature compensating layer 81, the third sub-temperature compensating layer 81 corresponds to the first sub-temperature compensating layer 31, and the fourth sub-temperature compensating layer corresponds to the second sub-temperature compensating layer.

[0129] The second sub-temperature compensating layer and the fourth sub-temperature compensating layer are both ring-shaped. For example, the fourth sub-temperature compensating layer and the second sub-temperature compensating layer are rotationally symmetrical structures, that is, the fourth sub-temperature compensating layer can be obtained by rotating the second sub-temperature compensating layer by 180°.

[0130] Optionally, see Fig.23 and Fig.24 The outer edge of the third sub-temperature compensation layer 81 forms a passivation layer on the first sub-temperature compensation layer 31 and the second electrode layer, and forms an annular groove on the passivation layer, and the annular groove is used to suppress the parasitic of the series resonance frequency of the thin film bulk acoustic wave resonator, including:

[0131] S810: forming a thickening layer on the second electrode layer, wherein the thickening layer is spaced apart from a region of the second electrode layer directly above the third sub-temperature compensation layer.

[0132] S820: depositing a passivation layer on the second electrode layer and the thickening layer, wherein an annular groove is formed between the passivation layer and the thickening layer in a region directly above the third sub-temperature compensation layer.

[0133] The surface of the second electrode layer 90 is uneven, and the area of ​​the second electrode layer 90 located directly above the third sub-temperature compensation layer 81 is higher than other areas of the second electrode layer 90. A thickening layer 210 is formed on other areas of the second electrode layer 90, and a gap is formed between the thickening layer 210 and the area of ​​the second electrode layer 90 located directly above the third sub-temperature compensation layer 81. The passivation layer 140 covers the thickening layer 210 and the area of ​​the second electrode layer 90 located directly above the third sub-temperature compensation layer 81, and fills the gap. Since the passivation layer 140 is obtained in the form of deposition, the thickness of the passivation layer 140 is uniform, so an annular groove 141 is naturally formed between the area of ​​the passivation layer 140 located directly above the third sub-temperature compensation layer 81 and the thickening layer 210 when the passivation layer 140 is prepared. In this way, the etching of the passivation layer 140 can be reduced once, thereby effectively reducing the process cost.

[0134] Optionally, the orthographic projection of the outer edge of the second sub-temperature compensating layer on the first electrode layer 40 is located within the outer edge of the first electrode layer 40, and a plurality of first through holes 63 are arranged at intervals on the second sub-temperature compensating layer; and / or, the orthographic projection of the outer edge of the fourth sub-temperature compensating layer on the second electrode layer 90 is located within the outer edge of the second electrode layer 90, and a plurality of second through holes 84 are arranged at intervals on the fourth sub-temperature compensating layer.

[0135] Please refer to Fig.25 , the orthographic projection of the outer edge of the second sub-temperature compensation layer on the first electrode layer 40 is located within the outer edge of the first electrode layer 40, that is, the first electrode layer 40 is located outside the second sub-temperature compensation layer. After the second sub-temperature compensation layer is released, the area of ​​the first electrode layer 40 located outside the second sub-temperature compensation layer can play a supporting role, thereby improving the stability of the thin film bulk acoustic wave resonator. Similarly, the orthographic projection of the outer edge of the fourth sub-temperature compensation layer on the second electrode layer 90 is located within the outer edge of the second electrode layer 90, which can also improve the stability of the thin film bulk acoustic wave resonator.

[0136] A plurality of first through holes 63 are arranged at intervals on the second sub-temperature compensation layer. When the first electrode layer 40 is formed on the second sub-temperature compensation layer, the first electrode layer 40 will fill the first through hole 63. After the second sub-temperature compensation layer is released, the area of ​​the first electrode layer 40 located in the first through hole 63 can play a supporting role, thereby improving the stability of the thin film bulk acoustic wave resonator. Similarly, a plurality of second through holes 84 are arranged at intervals on the fourth sub-temperature compensation layer, which can also improve the stability of the thin film bulk acoustic wave resonator.

[0137] Optionally, after removing the first substrate structure 10 and sequentially forming a second temperature compensation layer 80 and a second electrode layer 90 on the exposed first piezoelectric layer 20, the method further includes: forming an extraction hole 150 on the area of ​​the first piezoelectric layer 20 exposed by the second electrode layer 90, the extraction hole 150 exposing the surface of the first electrode layer 40; and forming a protective layer 160 protective layer 160 in the second electrode layer 90 and the extraction hole 150, wherein the protective layer 160 is conductive.

[0138] Optionally, see Fig.26 and Figure 6 , sequentially forming a first electrode layer and a first bonding layer on the first temperature compensation layer includes:

[0139] S330: forming a first electrode layer on the first temperature compensation layer, and forming a cavity layer on the first electrode layer, wherein the cavity layer covers a portion of the first electrode layer.

[0140] S340: forming a first bonding layer on the cavity layer.

[0141] After removing the first substrate structure and sequentially forming a second temperature compensation layer and a second electrode layer on the exposed first piezoelectric layer, the method further includes:

[0142] S900: etching a release hole, and removing the cavity layer through the release hole.

[0143] Please refer to Fig.25 The cavity layer 170 can be released and removed in a subsequent process, so as to form a cavity in the area where the cavity layer 170 is located. The material of the cavity layer 170 may include at least one of Si and Si3N4.

[0144] Furthermore, the release hole 180 also passes through the second sub-temperature compensating layer and / or the fourth sub-temperature compensating layer, and releases the second sub-temperature compensating layer and / or the fourth sub-temperature compensating layer while releasing the cavity layer 170 to form an air wing structure or an air bridge structure. Of course, the second sub-temperature compensating layer and the fourth sub-temperature compensating layer may not be released.

[0145] Before forming the cavity layer 170, a buffer layer 190 can also be formed on the surface of the first electrode layer 40 away from the first piezoelectric layer 20, the buffer layer 190 completely covers the first electrode layer 40 and the first piezoelectric layer 20 exposed by the first electrode layer 40, and the cavity layer 170 is formed on the surface of the buffer layer 190 away from the first electrode layer 40, and the cavity layer 170 is located above the first temperature compensation layer 30 and covers part of the buffer layer 190.

[0146] Introducing the buffer layer 190 between the first electrode layer 40 and the cavity layer 170 can improve the interface matching between the first electrode layer 40 and the cavity layer 170 and reduce the difference in thermal expansion coefficient. The material of the buffer layer 190 may include at least one of SiO2 and Si3N4.

[0147] Before forming the first bonding layer 50, a second oxide layer 200 can also be formed on the surface of the cavity layer 170 away from the first electrode layer 40, and the second oxide layer 200 completely covers the cavity layer 170 and the buffer layer 190 exposed by the cavity layer 170. The first bonding layer 50 is formed on the surface of the second oxide layer 200 away from the first piezoelectric layer 20.

[0148] The second oxide layer 200 can play an insulating role, and can also provide support and protection for the first bonding layer 50, limit the diffusion area of ​​the first bonding layer 50, reduce the warping or fracture of the first bonding layer 50 caused by the difference in thermal expansion coefficient, and the oxide layer can also be etched with alignment marks, which can improve the bonding accuracy of the first bonding layer 50 and the second bonding layer 70 during subsequent bonding. The material of the second oxide layer 200 may include SiO2.

[0149] It should be understood that, although the steps in the flowchart of the method for preparing a thin film bulk acoustic wave resonator are displayed in sequence as indicated by the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified in this document, there is no strict order restriction on the execution of these steps, and these steps can be executed in other orders. Moreover, at least part of the steps in the flowchart of the method for preparing a thin film bulk acoustic wave resonator may include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be executed in turn or alternately with other steps or at least part of the steps or stages in other steps.

[0150] Please refer to Fig.25 and Fig. 27 This embodiment also provides a thin film bulk acoustic wave resonator, which is prepared by using any of the above methods for preparing a thin film bulk acoustic wave resonator. The thin film bulk acoustic wave resonator has both good temperature stability and excellent performance.

[0151] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for preparing a thin film bulk acoustic wave resonator, characterized in that: include: Providing a first substrate structure, and forming a first piezoelectric layer on the first substrate structure; forming a first temperature compensation layer on the first piezoelectric layer, wherein the first temperature compensation layer covers a portion of the first piezoelectric layer; forming a first electrode layer and a first bonding layer in sequence on the first temperature compensation layer, wherein the first electrode layer covers the first temperature compensation layer and a portion of the first piezoelectric layer; providing a second substrate structure, and forming a second bonding layer on the second substrate structure; bonding the first bonding layer and the second bonding layer; The first substrate structure is removed, and a second temperature compensating layer and a second electrode layer are sequentially formed on the exposed first piezoelectric layer, wherein the second temperature compensating layer covers a portion of the first piezoelectric layer, the second temperature compensating layer corresponds to the position of the first temperature compensating layer, and the second electrode layer covers the temperature compensating layer and a portion of the first piezoelectric layer.

2. The method for preparing a thin film bulk acoustic wave resonator according to claim 1, characterized in that: After forming the first temperature compensation layer on the first piezoelectric layer, the method further includes: forming a second piezoelectric layer on the first piezoelectric layer and the first temperature compensation layer; The step of sequentially forming a first electrode layer and a first bonding layer on the first temperature compensation layer comprises: A first electrode layer and a first bonding layer are sequentially formed on the second piezoelectric layer.

3. The method for preparing a thin film bulk acoustic wave resonator according to claim 1, characterized in that: The step of sequentially forming a second temperature compensation layer and a second electrode layer on the exposed first piezoelectric layer comprises: forming a second temperature compensation layer on the exposed first piezoelectric layer, wherein the second temperature compensation layer covers a portion of the first piezoelectric layer; forming a third piezoelectric layer on the first piezoelectric layer and the second temperature compensation layer; A second electrode layer is formed on the third piezoelectric layer, wherein the second electrode layer covers a portion of the third piezoelectric layer.

4. The method for preparing a thin film bulk acoustic wave resonator according to claim 1, characterized in that: The forming of a first temperature compensation layer on the first piezoelectric layer comprises: forming a third electrode layer on the first piezoelectric layer, and forming a first temperature compensation layer on the third electrode layer, wherein the third electrode layer covers a portion of the first piezoelectric layer, and the first temperature compensation layer covers a portion of the third electrode layer; The step of sequentially forming a first electrode layer and a first bonding layer on the first temperature compensation layer comprises: A first electrode layer is formed on the third electrode layer and the first temperature compensation layer, and a first bonding layer is formed on the first electrode layer.

5. The method for preparing a thin film bulk acoustic wave resonator according to claim 1, characterized in that: The step of sequentially forming a second temperature compensation layer and a second electrode layer on the exposed first piezoelectric layer comprises: forming a fourth electrode layer on the exposed first piezoelectric layer, and forming a second temperature compensation layer on the fourth electrode layer, wherein the fourth electrode layer covers a portion of the first piezoelectric layer, and the second temperature compensation layer covers a portion of the fourth electrode layer; A second electrode layer is formed on the fourth electrode layer and the second temperature compensating layer.

6. The method for preparing a thin film bulk acoustic wave resonator according to claim 1, characterized in that: After removing the first substrate structure and sequentially forming a second temperature compensation layer and a second electrode layer on the exposed first piezoelectric layer, the method further includes: A passivation layer is formed on the second electrode layer, and an annular groove is formed on the passivation layer, wherein the annular groove is used to suppress parasitics of the series resonance frequency of the thin film bulk acoustic resonator.

7. The method for preparing a thin film bulk acoustic wave resonator according to claim 6, characterized in that: The first temperature compensating layer includes a first sub-temperature compensating layer and a second sub-temperature compensating layer surrounding the first sub-temperature compensating layer and spaced apart from the first sub-temperature compensating layer. The orthographic projection of the outer edge of the annular groove on the first sub-temperature compensating layer coincides with the outer edge of the first sub-temperature compensating layer.

8. The method for preparing a thin film bulk acoustic wave resonator according to claim 7, characterized in that: The second temperature compensating layer includes a third sub-temperature compensating layer and a fourth sub-temperature compensating layer surrounding the third sub-temperature compensating layer and spaced apart from the third sub-temperature compensating layer. The third sub-temperature compensating layer corresponds to the first sub-temperature compensating layer in position, and the fourth sub-temperature compensating layer corresponds to the second sub-temperature compensating layer in position.

9. The method for preparing a thin film bulk acoustic wave resonator according to claim 8, characterized in that: The orthographic projection of the outer edge of the third sub-temperature compensation layer on the first sub-temperature compensation layer is located within the outer edge of the first sub-temperature compensation layer; The step of forming a passivation layer on the second electrode layer and forming an annular groove on the passivation layer, wherein the annular groove is used to suppress the parasitic of the series resonance frequency of the thin film bulk acoustic resonator, comprises: forming a thickening layer on the second electrode layer, wherein the thickening layer is spaced apart from a region of the second electrode layer directly above the third sub-temperature compensation layer; A passivation layer is deposited on the second electrode layer and the thickening layer, wherein an annular groove is formed between the passivation layer and the thickening layer in a region directly above the third sub-temperature compensation layer.

10. The method for preparing a thin film bulk acoustic wave resonator according to claim 8, characterized in that: The orthographic projection of the outer edge of the second sub-temperature compensation layer on the first electrode layer is located within the outer edge of the first electrode layer, and a plurality of first through holes are arranged at intervals on the second sub-temperature compensation layer; and / or, The orthographic projection of the outer edge of the fourth sub-temperature compensation layer on the second electrode layer is located within the outer edge of the second electrode layer, and a plurality of second through holes are arranged at intervals on the fourth sub-temperature compensation layer.

11. The method for preparing a thin film bulk acoustic wave resonator according to claim 1, characterized in that: The step of sequentially forming a first electrode layer and a first bonding layer on the first temperature compensation layer comprises: forming a first electrode layer on the first temperature compensation layer, and forming a cavity layer on the first electrode layer, wherein the cavity layer covers a portion of the first electrode layer; forming a first bonding layer on the cavity layer; After removing the first substrate structure and sequentially forming a second temperature compensation layer and a second electrode layer on the exposed first piezoelectric layer, the method further includes: A release hole is etched, and the cavity layer is removed through the release hole.

12. A thin film bulk acoustic resonator, characterized in that: The thin film bulk acoustic wave resonator is prepared by the method for preparing the thin film bulk acoustic wave resonator according to any one of claims 1 to 11.

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