Film bulk acoustic resonator and method for preparing film bulk acoustic resonator by using wet chemical method substrate stripping technology

Abstract

The invention provides a film bulk acoustic resonator and a method for preparing the film bulk acoustic resonator by using a wet chemical method substrate stripping technology. The method comprises the following steps: growing a BaF2 and / or CaF2 stripping layer, an AlN material piezoelectric layer, a bottom electrode layer and a supporting layer on the surface of a substrate A; growing a cavity layer on the surface of the substrate B; the substrate A and the substrate B are bonded together, the stripping layer is etched, and the substrate A is stripped; and growing a patterned top electrode on the surface of the exposed piezoelectric layer after stripping. The film is effectively stripped by utilizing the differential dissolving capacity of the solvent to the stripping layer and the functional layer, and the damage to the film in the stripping process can be reduced, so that the performance of the resonator is effectively improved, the energy loss during working of the resonator is reduced, and the signal quality of the filter formed by the resonator is greatly ensured.

Description

Technical Field

[0001] The present application relates to the technical field of semiconductor devices, and in particular to a thin film bulk acoustic wave resonator and a method for preparing the thin film bulk acoustic wave resonator by using a wet chemical substrate stripping technique. Background Art

[0002] The development of artificial intelligence technology has put forward higher requirements on the performance of communication, and there is an urgent need for low-latency and high-information communication methods. This has greatly promoted the development of high-frequency communication technology with fast transmission speed and large data bandwidth. Among them, the RF filter is one of the core components in the field of high-frequency communication, and its operating frequency mainly depends on the operating frequency band of the resonator. Therefore, the development of high-frequency communication technology has put forward higher requirements on the energy loss of the resonator. The development of high-quality bulk acoustic wave resonators is of great significance to the development of communication technology.

[0003] As for traditional cavity-type BAW resonators, when the sacrificial layer is released, there will be damage to the film and incomplete release, which will lead to serious consequences such as loss of resonator performance. Therefore, the use of flip-chip bonding and substrate peeling processes in the preparation process can reduce the damage to the device film during the release of the sacrificial layer, greatly improve the performance of the resonator, and thus improve the filtering performance of the BAW filter. In addition, with the continuous advancement of intelligence, flexible wearable communications and other bendable communication components have been greatly developed; flip-chip bonding and substrate peeling techniques are also reliable solutions for preparing flexible filter chips.

[0004] However, the current mainstream stripping technology mainly uses physical, chemical polishing (CMP) or laser stripping technology. This stripping technology not only damages the substrate and increases the preparation cost, but also introduces additional film surface damage during the physical stripping process, resulting in a decrease in device performance. Therefore, it is necessary to provide a more reliable solution for the preparation of resonators. Summary of the invention

[0005] The embodiments of the present application provide a thin film bulk acoustic wave resonator and a method for preparing the thin film bulk acoustic wave resonator using a wet chemical substrate stripping technique to solve the problems existing in the related art. The technical solution is as follows:

[0006] In a first aspect, an embodiment of the present application provides a method for preparing a thin film bulk acoustic wave resonator using a wet chemical substrate peeling technique, comprising the following steps:

[0007] Step S1, growing a peeling layer, a piezoelectric layer, a bottom electrode layer, and a support layer on the surface of substrate A; the peeling layer is BaF2 and / or CaF2;

[0008] Step S2, growing a cavity layer on the surface of substrate B;

[0009] Step S3, bonding substrate A and substrate B together, etching the peeling layer, and peeling off substrate A;

[0010] Step S4, growing a patterned top electrode on the surface of the piezoelectric layer exposed after peeling.

[0011] In one embodiment, substrate A is any one of Si, sapphire or SiC.

[0012] In one embodiment, the piezoelectric layer is AlN, Al x Ga 1-x N、ScxAl 1-x N or Al x Si 1-x Any one of N.

[0013] In one embodiment, the bottom electrode layer is one or a combination of two or more of Au, Ag, Ru, W, Mo, Ir, Al, Pt, Nb or Hf.

[0014] In one embodiment, the support layer is one or a combination of two or more of Si3N4, SiO2 or SiC.

[0015] In one embodiment, the substrate B is any one of Si, SiC, glass or an organic flexible substrate.

[0016] In one embodiment, the cavity layer is patterned SiO2 or Si3N4 having a cavity structure.

[0017] In one embodiment, a cavity structure is grown on the surface of substrate B using photolithography technology, mask or etching technology.

[0018] In one embodiment, the bonding is metallic bonding, non-metallic bonding, or organic bonding.

[0019] In one embodiment, an alcohol solvent is used to etch the lift-off layer.

[0020] In one embodiment, the alcohol solvent is one or a combination of two or more of ethanol, methanol or glycerol.

[0021] In one embodiment, the release layer has a thickness of 30-100 nm.

[0022] In a second aspect, an embodiment of the present application provides a thin film bulk acoustic wave resonator, which is prepared by any of the above-mentioned methods for preparing a thin film bulk acoustic wave resonator using wet chemical substrate stripping technology.

[0023] In one embodiment, the thickness of the bottom electrode and the top electrode is 200-1500 nm, the thickness of the cavity layer is 0.5-4 μm, the thickness of the piezoelectric layer is 0.1-3.5 μm; and the thickness of the support layer is 20-300 nm.

[0024] In one embodiment, the surface roughness of the piezoelectric layer is less than 2.5 nm.

[0025] In one embodiment, the surface roughness of the piezoelectric layer is 0.1-2 nm.

[0026] The advantages or beneficial effects of the above technical solution include at least:

[0027] The method for preparing a thin film bulk acoustic wave resonator using wet chemical substrate stripping technology of the present application uses wet chemical stripping technology to realize substrate stripping, which can effectively avoid the damage of the functional layer film by the traditional stripping technology and improve the quality factor of the prepared resonator. At the same time, it can effectively reduce the damage to the substrate during the physical stripping process, which is conducive to the reuse of the substrate and reduces the production cost.

[0028] In particular, the lattice mismatch between the peeling layer and the piezoelectric layer provided in the present application is small, so when the piezoelectric layer is grown on the peeling layer, it is beneficial to obtain a piezoelectric layer film with high crystalline quality; the defect density is reduced, thereby reducing the energy loss of the device.

[0029] Therefore, the preparation method of the present application can effectively improve the performance of the resonator and reduce the preparation cost, thereby obtaining a low-energy-loss, easy-to-integrate, and flexible bulk acoustic wave resonator.

[0030] The above summary is for illustrative purposes only and is not intended to be limiting in any way. In addition to the illustrative aspects, embodiments and features described above, further aspects, embodiments and features of the present application will be readily apparent by reference to the accompanying drawings and the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In the accompanying drawings, unless otherwise specified, the same reference numerals throughout the multiple drawings represent the same or similar parts or elements. These drawings are not necessarily drawn to scale. It should be understood that these drawings only depict some embodiments disclosed in the present application and should not be regarded as limiting the scope of the present application.

[0032] Figure 1 is a schematic diagram of the structure of the resonator in Example 1;

[0033] Figure 2 A cross-sectional view of the substrate A prepared in Example 1;

[0034] Figure 3It is a cross-sectional view of the cavity layer structure grown on substrate B in Example 1;

[0035] Figure 4 is a cross-sectional view of the bonding structure of Example 1;

[0036] Figure 5 It is a schematic diagram of the preparation process of the present invention;

[0037] Figure 6 This is an AFM photo of AlN after peeling in Example 1;

[0038] Figure 7 The quality factor curve of the resonator prepared in Example 1;

[0039] Figure 8 This is an AFM photo of AlN after peeling in Comparative Example 1;

[0040] Fig. 9 This is the quality factor curve of the resonator prepared in Comparative Example 1. DETAILED DESCRIPTION

[0041] In the following, only some exemplary embodiments are briefly described. As those skilled in the art will appreciate, the described embodiments may be modified in various ways without departing from the spirit or scope of the present application. Therefore, the drawings and descriptions are considered to be exemplary and non-restrictive in nature.

[0042] Whether using physical or chemical grinding and polishing (CMP) or laser lift-off technology, the substrate will be damaged, resulting in an increase in preparation costs. In the physical lift-off process, additional film surface damage will be introduced, resulting in a decrease in device performance. In addition, in the device preparation process, the piezoelectric layer, especially the piezoelectric layer of AlN material, is grown directly on a Si-containing substrate. Because the lattice mismatch between Si and AlN will also limit the crystal quality of the AlN film, increase the defect density, and thus increase the energy loss of the device. Therefore, how to effectively peel off the film and reduce the damage to the film during the peeling process, thereby effectively improving the performance of the resonator, reducing its energy loss during operation, and greatly ensuring the signal quality of the filter it constitutes. This is a problem that needs to be solved in the device preparation process.

[0043] In response to the above problems, the present application provides a method for preparing a thin film bulk acoustic wave resonator using a wet chemical substrate stripping technique, which can effectively avoid damage to the film when the cavity is released, and use a wet chemical method to avoid damage to the functional layer during the substrate stripping process, thereby greatly ensuring the performance of the resonator. This method can effectively improve the performance of the resonator and reduce the preparation cost, thereby obtaining a low energy loss, easy to integrate, and flexible bulk acoustic wave resonator.

[0044] The present invention provides a method for preparing a thin film bulk acoustic wave resonator by using a wet chemical substrate peeling technique, comprising the following steps:

[0045] Step S1, growing a peeling layer, a piezoelectric layer, a bottom electrode layer, and a support layer on the surface of substrate A; the peeling layer is BaF2 and / or CaF2;

[0046] Step S2, growing a cavity layer on the surface of substrate B;

[0047] Step S3, bonding substrate A and substrate B together, etching the peeling layer, and peeling off substrate A;

[0048] Step S4, growing a patterned top electrode on the surface of the piezoelectric layer exposed after peeling.

[0049] A stripping layer and a piezoelectric layer are grown on the surface of substrate A; and after bonding with substrate B, the stripping layer is etched to strip substrate A. The stripping layer is BaF2 and / or CaF2, and BaF2 and CaF2 can be grown on the substrate by PVD growth method, and the piezoelectric layer can continue to be grown on the formed BaF2 and / or CaF2 stripping layer. Because BaF2 and / or CaF2 are soluble, the stripping layer is etched away by dissolving the stripping layer and the functional layer by utilizing the differential solubility of the solvent. The substrate will also be separated from the piezoelectric layer due to the etching of the stripping layer, so that the piezoelectric layer is exposed, and the substrate is stripped. The method of etching the stripping layer does not cause physical damage to the substrate and the contact surface of the piezoelectric layer and the stripping layer, so it is helpful to reuse the substrate and reduce production costs; at the same time, it improves the quality of the piezoelectric layer, thereby improving the performance of the resonator.

[0050] As one embodiment, substrate A is any one of Si, sapphire or SiC.

[0051] As one embodiment, the piezoelectric layer is AlN, Al x Ga 1-x N、ScxAl 1-x N or Al x Si 1-x Any one of N.

[0052] When growing the piezoelectric layer, if the substrate is a Si-containing material and the piezoelectric layer is an AlN material, the lattice mismatch between Si and AlN also limits the crystal quality of the AlN film, increases the defect density, and thus leads to an increase in the energy loss of the device. The method of the present application grows the AlN material on BaF2 and CaF2 through the technical solution of growing a peeling layer between the substrate and the piezoelectric layer. The AlN material does not grow in direct contact with the Si-containing substrate, which reduces the lattice mismatch and is conducive to obtaining a piezoelectric film of AlN material with high crystalline quality, further improving the performance of the device.

[0053] As one embodiment, the bottom electrode layer is one or a combination of two or more of Au, Ag, Ru, W, Mo, Ir, Al, Pt, Nb or Hf.

[0054] As one embodiment, the support layer is one or a combination of two or more of Si3N4, SiO2 or SiC.

[0055] As one embodiment, the substrate B is any one of Si, SiC, glass or an organic flexible substrate.

[0056] As one implementation method, the cavity layer is patterned SiO2 or Si3N4 having a cavity structure.

[0057] As one implementation method, a cavity structure is grown on the surface of substrate B by using photolithography technology, mask plate or etching technology.

[0058] As one embodiment, the bonding is metal bonding, non-metal bonding or organic bonding.

[0059] As one embodiment, an alcohol solvent is used to etch the stripping layer.

[0060] As one embodiment, the alcohol solvent is one or a combination of two or more of ethanol, methanol or glycerol.

[0061] Alcohol solvents, especially ethanol, methanol or glycerol, have good solubility for BaF2 and CaF2 of the stripping layer, and will not dissolve the piezoelectric layer, support layer, cavity layer and substrate of the AlN material. This makes it possible to utilize the difference in solubility of alcohol solvents for the stripping layer and the functional layer to etch the stripping layer, thereby separating the substrate from the piezoelectric layer, without affecting the substrate and other layers. Alcohol solvents are highly volatile and can be easily removed after use without residue in the device. Preferably, the alcohol solvent on the device is dried by blowing in an inert gas.

[0062] In one embodiment, the thickness of the peeling layer is 30-100 nm. The thickness of the peeling layer can be adjusted according to actual needs.

[0063] In one embodiment, substrate A and substrate B are cleaned before use; preferably, the substrates are cleaned with acetone or hydrofluoric acid and then dried.

[0064] The embodiment of the present application further provides a thin film bulk acoustic wave resonator, which is prepared by any of the above-mentioned methods for preparing a thin film bulk acoustic wave resonator using wet chemical substrate stripping technology.

[0065] The thin film bulk acoustic wave resonator prepared by the above method of the present application has a piezoelectric layer with low surface roughness and high growth quality; therefore, the overall quality factor of the resonator is significantly improved.

[0066] As one embodiment, the thickness of the bottom electrode and the top electrode is 200-1500 nm, the thickness of the cavity layer is 0.5-4 μm, the thickness of the piezoelectric layer is 0.1-3.5 μm; and the thickness of the support layer is 20-300 nm.

[0067] As one embodiment, the surface roughness of the piezoelectric layer is less than 2.5 nm.

[0068] As one embodiment, the surface roughness of the piezoelectric layer is 0.1-2 nm.

[0069] The following is a further description of a specific implementation method.

[0070] Example 1

[0071] This embodiment provides a method for preparing a thin film bulk acoustic wave resonator using a wet chemical substrate peeling technique. Figure 1 As shown, it includes a silicon substrate 101, a cavity layer 102, a support layer 103, a bottom electrode 104, a piezoelectric layer 105, and a top electrode 106;

[0072] Preparation method Figure 5 As shown, the following steps are included:

[0073] like Figure 2 As shown, a (111) surface Si substrate is selected as substrate A 107, and the substrate is cleaned and dried using acetone and hydrofluoric acid;

[0074] A 50nm thick BaF2 peeling layer 108 and a 1μm thick AlN piezoelectric layer 105 are grown by PVD; a 500nm thick metal Mo layer is deposited on the surface of the piezoelectric layer 105 by PVD as a bottom electrode 104; and a 50nm thick Si3N4 support layer 103 is grown by plasma enhanced CVD technology;

[0075] like Figure 3 As shown, a Si substrate is selected as substrate B 101, and the substrate is cleaned and dried using acetone and hydrofluoric acid; a 3 μm patterned SiO2 film 109 is grown using PVD technology, and a cavity structure is formed to form a cavity layer 102;

[0076] like Figure 4 As shown, two wafers are bonded together using amorphous bonding technology;

[0077] Then, the substrate A was stripped by immersing it in an ethanol solution, etching the stripping layer, and stripping the substrate A. After stripping, the substrate A was blown dry with nitrogen. The surface of the AlN piezoelectric layer was observed using an atomic force microscope. The AFM photo is shown in FIG. Figure 6 As shown; a 500nm thick metal Mo layer is grown on the AlN piezoelectric layer 105 by PVD as the top electrode 106, thereby preparing Figure 1 The resonator shown.

[0078] Example 2

[0079] This embodiment provides a method for preparing a thin film bulk acoustic wave resonator using a wet chemical substrate peeling technique. Figure 1 As shown, it includes a silicon substrate 101, a cavity layer 102, a support layer 103, a bottom electrode 104, a piezoelectric layer 105, and a top electrode 106;

[0080] Preparation method Figure 5 As shown, the following steps are included:

[0081] like Figure 2 As shown, a sapphire substrate is selected as substrate A 107, and the substrate is cleaned and dried using acetone and hydrofluoric acid;

[0082] A 100nm thick CaF2 peeling layer 108 and a 2μm thick AlN piezoelectric layer 105 are grown by PVD; a 200nm thick metal Mo layer is deposited on the surface of the piezoelectric layer 105 by PVD as a bottom electrode 104; and a 20nm thick Si3N4 support layer 103 is grown by plasma enhanced CVD technology;

[0083] like Figure 3 As shown, a SiC substrate is selected as substrate B 101, and the substrate is cleaned and dried using acetone and hydrofluoric acid; a 4 μm patterned Si3N4 film 109 is grown using PVD technology, and a cavity structure is formed to form a cavity layer 102;

[0084] like Figure 4 As shown, two wafers are bonded together using amorphous bonding technology;

[0085] Then, the substrate A is immersed in a solution of methanol and glycerol in a volume ratio of 9:1, the peeling layer is etched, and the substrate A is peeled off; after the peeling is completed, it is blown dry with nitrogen; a layer of metal Mo with a thickness of 1000 nm is grown on the AlN piezoelectric layer 105 by PVD as the top electrode 106, thereby preparing Figure 1 The resonator shown.

[0086] Example 3

[0087] This embodiment provides a method for preparing a thin film bulk acoustic wave resonator using a wet chemical substrate peeling technique. Figure 1 As shown, it includes a silicon substrate 101, a cavity layer 102, a support layer 103, a bottom electrode 104, a piezoelectric layer 105, and a top electrode 106;

[0088] Preparation method Figure 5 As shown, the following steps are included:

[0089] like Figure 2 As shown, a SiC substrate is selected as substrate A 107, and the substrate is cleaned and dried using acetone and hydrofluoric acid;

[0090] A 30nm peeling layer 108 with a mass ratio of CaF2 to BaF2 of 1:1 and a 3μm AlN piezoelectric layer 105 are grown by PVD; a 1500nm thick metal Mo layer is deposited on the surface of the piezoelectric layer 105 as a bottom electrode 104 by PVD; and a 300nm thick SiO2 support layer 103 is grown by plasma enhanced CVD technology;

[0091] like Figure 3 As shown, an organic flexible substrate is selected as substrate B 101, and the substrate is cleaned and dried using acetone and hydrofluoric acid; a 1 μm patterned Si3N4 film 109 is grown using PVD technology, and a cavity structure is formed to form a cavity layer 102;

[0092] like Figure 4 As shown, two wafers are bonded together using amorphous bonding technology;

[0093] Then, the substrate A is immersed in a solution of methanol and glycerol in a volume ratio of 9:1, the peeling layer is etched, and the substrate A is peeled off; after the peeling is completed, it is blown dry with nitrogen; a layer of metal Mo with a thickness of 500nm is grown on the AlN piezoelectric layer 105 by PVD as the top electrode 106, thereby preparing Figure 1 The resonator shown.

[0094] Comparative Example 1

[0095] A thin film bulk acoustic wave resonator, this embodiment provides a method for preparing a thin film bulk acoustic wave resonator using a wet chemical substrate stripping technique, the resonator comprising a silicon substrate, a cavity, a support layer, a bottom electrode, a piezoelectric layer, and a top electrode;

[0096] The preparation method comprises the following steps:

[0097] A (111) surface Si substrate was selected as substrate A, and the substrate was cleaned and dried using acetone and hydrofluoric acid;

[0098] A 500nm thick metal Mo layer is deposited on the surface of the piezoelectric layer by PVD as the bottom electrode; and a 50nm thick Si3N4 support layer is grown by plasma enhanced CVD technology;

[0099] A Si substrate is selected as substrate B, and the substrate is cleaned and dried using acetone and hydrofluoric acid; a 3 μm patterned SiO2 film is grown using PVD technology, and a cavity structure is formed to form a cavity layer;

[0100] Bond two wafers together using amorphous bonding technology;

[0101] The substrate A was peeled off using laser lift-off technology to expose the AlN piezoelectric layer. The surface of the AlN piezoelectric layer was observed using an atomic force microscope. The AFM photo is shown in the figure. Figure 8 As shown; a 500nm thick metal Mo layer is grown on the AlN piezoelectric layer by PVD as a top electrode to prepare a resonator.

[0102] from Figure 6 The AFM photo of the AlN surface after peeling in Example 1 shows that its surface roughness is 0.51 nm, indicating that the damage to the film during the peeling process is negligible. Figure 8 From the AFM photograph of the AlN surface after peeling in Comparative Example 1, it can be seen that the surface roughness is 4.46 nm, and the damage to the film during the peeling process is much greater than that in Example 1.

[0103] The quality factor of the resonator prepared in Example 1 is as follows Figure 7 As shown, the quality factor of the resonator prepared in Comparative Example 1 is as follows Fig. 9 shown; from Figure 7 and Fig. 9 It can be seen that the maximum value of the quality factor of the resonator prepared in Example 1 is 2780; while the maximum value of the quality factor of the resonator prepared in Comparative Example 1 is only 1909. It can be seen that the performance of the resonator prepared in Comparative Example 1 is far inferior to that of the resonator prepared in Example 1.

[0104] Therefore, it is shown that the wet chemical stripping technology of the present application effectively reduces the damage to the substrate during the physical stripping process and improves the performance of the resonator.

[0105] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples, unless they are contradictory.

[0106] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0107] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of various changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A method for preparing a thin film bulk acoustic wave resonator using a wet chemical substrate stripping technique, characterized in that: The following steps are involved: Step S1, growing a peeling layer, a piezoelectric layer, a bottom electrode layer, and a support layer on the surface of substrate A; the peeling layer is BaF2 and / or CaF2; Step S2, growing a cavity layer on the surface of substrate B; Step S3, bonding substrate A and substrate B together, etching the peeling layer, and peeling off substrate A; Step S4, growing a patterned top electrode on the surface of the piezoelectric layer exposed after peeling.

2. The method for preparing a thin film bulk acoustic wave resonator using wet chemical substrate stripping technology according to claim 1, characterized in that: Substrate A is any one of Si, sapphire or SiC; The piezoelectric layer is AlN, Al x Ga 1-x N、ScxAl 1-x N or Al x Si 1-x Any of N; The bottom electrode layer is one or a combination of two or more of Au, Ag, Ru, W, Mo, Ir, Al, Pt, Nb or Hf; The supporting layer is one or a combination of two or more of Si3N4, SiO2 or SiC.

3. The method for preparing a thin film bulk acoustic wave resonator using wet chemical substrate stripping technology according to claim 1, characterized in that: Substrate B is any one of Si, SiC, glass or organic flexible substrate; The cavity layer is patterned SiO2 or Si3N4 and has a cavity structure.

4. The method for preparing a thin film bulk acoustic wave resonator using wet chemical substrate stripping technology according to claim 3, characterized in that: A cavity structure is grown on the surface of substrate B using photolithography technology, mask plate or etching technology.

5. The method for preparing a thin film bulk acoustic wave resonator using a wet chemical substrate stripping technique according to claim 1, characterized in that: The bonding is metallic bonding, non-metallic bonding or organic bonding.

6. The method for preparing a thin film bulk acoustic wave resonator using a wet chemical substrate stripping technique according to claim 1, characterized in that: An alcohol solvent is used to etch the stripping layer; the alcohol solvent is one or a combination of two or more of ethanol, methanol or glycerol.

7. The method for preparing a thin film bulk acoustic wave resonator using wet chemical substrate stripping technology according to claim 1, characterized in that: The thickness of the peeling layer is 30-100 nm.

8. 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 by using wet chemical substrate stripping technology as described in any one of claims 1 to 7.

9. The thin film bulk acoustic resonator according to claim 8, characterized in that: The thickness of the bottom electrode and the top electrode is 200-1500nm, the thickness of the cavity layer is 0.5-4μm, the thickness of the piezoelectric layer is 0.1-3.5μm; and the thickness of the support layer is 20-300nm.

10. The thin film bulk acoustic resonator according to claim 8, characterized in that: The surface roughness of the piezoelectric layer is less than 2.5 nm; preferably, the surface roughness of the piezoelectric layer is 0.1-2 nm.

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