Preparation method and device of film bulk acoustic resonator and electronic equipment

Abstract

The invention provides a thin film bulk acoustic resonator preparation method and device and electronic equipment. The method comprises the steps that a seed layer is deposited on one side of a substrate, and an upper electrode is deposited on the other side, opposite to the substrate, of the seed layer; a piezoelectric layer is constructed on the other side, opposite to the substrate, of the upper electrode in a deposition mode; a lower electrode is generated on the other side, opposite to the upper electrode, of the piezoelectric layer in a deposition mode to generate a resonance structure; enclosing the substrate, the lower electrode and the piezoelectric layer to form a cavity; and removing the substrate, and etching on the resonant structure to form an electrode connection area to obtain the film bulk acoustic resonator. Therefore, as a release hole is not needed, a completely closed cavity can be formed, and the lower electrode is protected; meanwhile, the manufacturing process is simpler, and the performance and the manufacturing reliability of the resonator are improved.

Description

Technical Field

[0001] The present application relates to a resonator, and in particular to a method, device and electronic device for preparing a thin film bulk acoustic wave resonator. Background Art

[0002] With the increasing development of 5G communication technology, the requirements for data transmission rate are getting higher and higher. Corresponding to the data transmission rate is the high utilization rate of spectrum resources and the complexity of spectrum. The complexity of communication protocols puts forward strict requirements on various performances of RF systems. In RF front-end modules, RF filters play a vital role. They can filter out out-of-band interference and noise to meet the requirements of RF systems and communication protocols for signal-to-noise ratio. Traditionally, the resonator that makes up the filter is manufactured by a release process to form a cavity. In the release process, the etching liquid etches the sacrificial material at the bottom of the resonant structure through the release hole to form a cavity. Due to the slow release process and harsh conditions, during the cavity formation process, the resonator is placed in the etching liquid for a long time, which is easy to cause damage to the resonator's electrode and piezoelectric layer and other structures, affecting the performance of the resonator. Secondly, since the release hole is usually very small, after the sacrificial material is etched, the etching liquid in the cavity is not easy to clean, affecting the performance of the resonator. Thirdly, the cavity formed by the release process generally has a small cavity depth (2-5μm), so it is easy to cause adhesion between the resonant structure and the bottom of the cavity, causing the resonator to fail. On the other hand, conventional resonators use polycrystalline AlN or polycrystalline doped AlN to implement the piezoelectric layer. The uneven piezoelectric layer can lead to performance degradation and reliability issues in the resonator. Summary of the invention

[0003] The purpose of the present application is to provide a method, device and electronic device for preparing a thin film bulk acoustic wave resonator, so that the resonator preparation process does not require a release hole, a completely closed cavity can be formed, and a lower electrode can be protected.

[0004] To achieve the above-mentioned purpose, the method for preparing a thin film bulk acoustic wave resonator provided in the present application specifically comprises:

[0005] Depositing a seed layer on one side of the substrate, and depositing an upper electrode on the other side of the seed layer opposite to the substrate;

[0006] constructing a piezoelectric layer on the other side of the upper electrode relative to the substrate by deposition;

[0007] A lower electrode is formed on the other side of the piezoelectric layer relative to the upper electrode to generate a resonant structure by deposition; a substrate, the lower electrode and the piezoelectric layer are enclosed to form a cavity; the substrate is removed, and an electrode connection area is etched on the resonant structure to obtain a thin film bulk acoustic wave resonator; wherein the piezoelectric layer is composed of polycrystalline aluminum nitride or doped polycrystalline aluminum nitride.

[0008] In one embodiment of the present application, optionally, enclosing the substrate, the lower electrode in the resonant structure and the piezoelectric layer to form a cavity includes: depositing a dielectric layer on the lower electrode side of the resonant structure, and etching through holes on the dielectric layer; bonding the substrate to the other side of the dielectric layer relative to the lower electrode, and enclosing the substrate, the dielectric layer, the lower electrode and the piezoelectric layer in the resonant structure to form a cavity.

[0009] In an embodiment of the present application, optionally, the piezoelectric layer is a flat structure.

[0010] In an embodiment of the present application, optionally, the cavity depth is greater than 5 microns.

[0011] In one embodiment of the present application, optionally, removing the substrate includes: depositing a stripping layer and a seed layer in sequence on one side of the substrate; and removing the substrate by etching the stripping layer.

[0012] In an embodiment of the present application, optionally, obtaining the thin film bulk acoustic wave resonator further includes: adjusting the thickness of the seed layer through a thinning process to adjust the frequency of the thin film bulk acoustic wave resonator to a preset frequency.

[0013] In one embodiment of the present application, optionally, depositing a dielectric layer on the lower electrode side of the resonant structure includes: generating a dielectric layer on the other side of the lower electrode and the piezoelectric layer relative to the upper electrode by deposition; and flattening the other side of the dielectric layer relative to the lower electrode; wherein the thickness of the dielectric layer is greater than the cavity depth.

[0014] In one embodiment of the present application, optionally, before generating a dielectric layer on the other side of the lower electrode and the piezoelectric layer relative to the upper electrode by deposition, the method further includes: generating a passivation layer on the other side of the lower electrode and the piezoelectric layer relative to the upper electrode by deposition; and graphing the passivation layer.

[0015] In an embodiment of the present application, optionally, etching to form a through hole on the dielectric layer further includes: etching to form a through hole on the dielectric layer and the passivation layer, so that a preset area of ​​the lower electrode and the piezoelectric layer is exposed in the cavity.

[0016] In an embodiment of the present application, optionally, forming a through hole by etching on the dielectric layer and the passivation layer further includes: forming a through hole by wet etching the passivation layer.

[0017] In an embodiment of the present application, optionally, etching to form a through hole on the dielectric layer includes: etching to form a through hole on the dielectric layer so that a preset area of ​​the lower electrode and the piezoelectric layer is exposed in the cavity.

[0018] In one embodiment of the present application, optionally, bonding the substrate to the other side of the dielectric layer relative to the lower electrode includes: generating a bonding layer on the other side of the dielectric layer relative to the lower electrode by deposition or etching, and / or generating a bonding layer on one side of the substrate; bonding the substrate to the dielectric layer through the bonding layer.

[0019] In an embodiment of the present application, optionally, removing the substrate includes: removing the substrate by etching.

[0020] In one embodiment of the present application, optionally, etching on the resonant structure to form an electrode connection area includes: constructing a conductive through hole by etching the piezoelectric layer, and using the conductive through hole to expose the electrical connection area of ​​the lower electrode to obtain a first connection area; etching on the other side of the upper electrode relative to the piezoelectric layer to construct a second connection area; and obtaining an electrode connection area based on the first connection area and the second connection area.

[0021] In one embodiment of the present application, optionally, enclosing the substrate, the lower electrode in the resonant structure and the piezoelectric layer to form a cavity includes: patterning the lower electrode of the resonant structure to generate a bonding layer; and enclosing the substrate of the groove with the piezoelectric layer in the resonant structure through the bonding layer to form a cavity.

[0022] The present application also provides a thin film bulk acoustic wave resonator device, which is prepared by the above-mentioned thin film bulk acoustic wave resonator preparation method.

[0023] The present application also provides an electrical product, which has the above-mentioned thin film bulk acoustic wave resonance device.

[0024] The beneficial technical effect of the present application is that since no release hole is required, a completely closed cavity can be formed, which protects the lower electrode; at the same time, the manufacturing process is simpler, thereby improving the performance and manufacturing reliability of the resonator. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The drawings described herein are used to provide a further understanding of the present application, constitute a part of the present application, and do not constitute a limitation of the present application. In the drawings:

[0026] Figure 1A A schematic flow chart of a method for preparing a thin film bulk acoustic wave resonator provided in one embodiment of the present application;

[0027] Figure 1B A schematic diagram of a process for constructing a cavity provided in an embodiment of the present application;

[0028] Figure 1C A schematic diagram of a process for constructing a cavity provided in an embodiment of the present application;

[0029] Figure 1DA schematic diagram of a substrate construction process of a resonant structure provided in an embodiment of the present application;

[0030] Figures 2 to 4 A schematic diagram of the construction process of a resonant structure provided in one embodiment of the present application;

[0031] Figure 5A and Figure 5B A schematic diagram of a dielectric layer structure provided in an embodiment of the present application;

[0032] Figure 6 A schematic diagram of a through hole construction provided in an embodiment of the present application;

[0033] Figure 7 A schematic diagram of a bonding layer structure provided in an embodiment of the present application;

[0034] Figure 8 A schematic diagram of a bonding cavity provided in an embodiment of the present application;

[0035] Fig. 9 A schematic diagram of substrate removal provided in one embodiment of the present application;

[0036] Fig.10 A schematic diagram of the seed layer and the upper electrode patterning provided in one embodiment of the present application;

[0037] Fig.11A and Fig. 11B A schematic diagram of the electrode connection area provided in one embodiment of the present application;

[0038] FIG. 12A to FIG. 12C A schematic diagram of the application of the passivation layer construction provided in one embodiment of the present application;

[0039] Fig.13 A schematic diagram of a groove-substrate bonding structure provided in an embodiment of the present application;

[0040] Fig.14 A schematic diagram of the location of cavity boundaries provided in an embodiment of the present application. DETAILED DESCRIPTION

[0041] The following will describe the implementation methods of the present application in detail in conjunction with the accompanying drawings and embodiments, so that the implementation process of how the present application applies technical means to solve technical problems and achieve technical effects can be fully understood and implemented accordingly. It should be noted that as long as there is no conflict, the various embodiments in the present application and the various features in the embodiments can be combined with each other, and the technical solutions formed are all within the protection scope of the present application.

[0042] In addition, the steps shown in the flowcharts of the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowcharts, in some cases, the steps shown or described can be performed in an order different from that shown here.

[0043] Please refer to Figure 1A As shown, the method for preparing a thin film bulk acoustic wave resonator provided in the present application specifically comprises:

[0044] S101 deposits a seed layer on one side of a substrate, and deposits an upper electrode on the other side of the seed layer opposite to the substrate;

[0045] S102 constructing a piezoelectric layer on the other side of the upper electrode relative to the substrate by deposition;

[0046] S103 generates a resonant structure by depositing a lower electrode on the other side of the piezoelectric layer relative to the upper electrode;

[0047] S104: enclosing the substrate, the lower electrode and the piezoelectric layer to form a cavity;

[0048] S105: removing the substrate, and etching the resonant structure to form an electrode connection region, thereby obtaining a thin film bulk acoustic wave resonator.

[0049] Among them, the piezoelectric layer is a flat structure; the piezoelectric layer is composed of polycrystalline aluminum nitride or doped polycrystalline aluminum nitride; using polycrystalline AlN or polycrystalline doped AlN to realize the piezoelectric layer can solve the performance degradation and reliability problems of the resonator caused by the uneven piezoelectric layer. In actual work, the construction process of the resonant structure is mainly divided into four steps, as follows:

[0050] Step 1, please refer to Figure 1D As shown, a stripping layer 102 and a seed layer 103 are sequentially deposited on the substrate layer 101, wherein the stripping layer 102 is used to remove the substrate layer 101 by etching the stripping layer 102. Those skilled in the art may also not provide the stripping layer 102 when the substrate layer 101 is removed by directly etching the substrate layer 101.

[0051] Step 2, please refer to Figure 2 As shown, an upper electrode 201 is deposited on the seed layer 103 , and its structure is arranged from top to bottom as the upper electrode 201 , the seed layer 103 , the peeling layer 102 and the substrate layer 101 .

[0052] Step 3, please refer to Figure 3 As shown, a piezoelectric layer 202 is deposited on the upper surface of the upper electrode 201. The material of the piezoelectric layer may include polycrystalline aluminum nitride and doped polycrystalline aluminum nitride.

[0053] Step 4, please refer to Figure 4 As shown, a lower electrode 203 is formed, wherein the formation method of the lower electrode 203 includes deposition and etching, so that the upper electrode 201, the piezoelectric layer 202 and the upper electrode 203 constitute a complete resonant structure.

[0054] Specifically, the resonant structure is composed of upper and lower electrodes and a piezoelectric layer. There are two ways to enclose the cavity, namely, etching the dielectric layer and pre-setting a groove on the substrate; wherein the dielectric layer etching method can refer to Figure 1B As shown, the substrate, the lower electrode in the resonant structure and the piezoelectric layer are enclosed to form a cavity, which includes:

[0055] S1021 depositing a dielectric layer on the lower electrode side of the resonant structure, and etching the dielectric layer to form a through hole;

[0056] S1022: Bonding the substrate to the other side of the dielectric layer relative to the lower electrode, and forming a cavity by enclosing the substrate, the dielectric layer, the lower electrode and the piezoelectric layer in the resonant structure.

[0057] In actual work, when the preparation method of dielectric layer etching is adopted, the process is as follows: 1. First, a resonant structure (upper and lower electrodes and piezoelectric layer) is formed on the substrate; 2. A dielectric layer is deposited on one side of the lower electrode, and a through hole is etched on the dielectric layer; 3. The substrate is bonded to the dielectric layer through a bonding layer, and a cavity is enclosed by the substrate, dielectric layer, bonding layer, piezoelectric layer and lower electrode; 4. The substrate is removed; 5. The upper electrode is etched and an electrode connection area (pad) is formed. The scheme of the present invention can quickly form a resonant cavity, and the cavity depth depends on the thickness of the dielectric layer, and a larger cavity depth (for example, greater than 5μm) can be formed; a cavity depth greater than 5 microns can avoid adhesion between the resonant structure and the bottom of the cavity, which makes the resonator ineffective.

[0058] In another embodiment of the present application, the method of pre-setting the groove on the substrate can refer to Figure 1C As shown, the substrate, the lower electrode in the resonant structure and the piezoelectric layer are enclosed to form a cavity, which includes:

[0059] S1023 patterning the lower electrode of the resonant structure to generate a bonding layer;

[0060] S1024: The base of the groove is enclosed with the piezoelectric layer in the resonant structure through the bonding layer to form a cavity.

[0061] In order to facilitate a clearer understanding of the specific structure of the above-mentioned cavity, the specific construction process of the resonator in this application will be described in sequence in combination with the connection relationship of other components, and will not be described in detail here.

[0062] After the resonant structure is constructed, the subsequent cavity structure construction can be completed. Please refer to Figure 5A and Figure 5B As shown, in one embodiment of the present application, depositing a dielectric layer on the lower electrode side of the resonant structure includes:

[0063] S501 generates a dielectric layer 301 on the other side of the lower electrode 203 and the piezoelectric layer 202 relative to the upper electrode 201 by deposition;

[0064] S502 performs a planarization process on the other side of the dielectric layer 301 relative to the lower electrode 203; wherein the thickness of the dielectric layer 301 is greater than the depth of the cavity.

[0065] In an embodiment of the present application, etching to form a through hole on the dielectric layer includes: etching to form a through hole on the dielectric layer so that a preset area of ​​the lower electrode and the piezoelectric layer is exposed in the cavity.

[0066] Please refer to Figure 6 As shown, after the dielectric layer 301 is formed, the dielectric layer 301 may be etched to form a through hole (cavity region) so that the lower electrode 203 and the piezoelectric layer 202 in the cavity region are exposed. Figure 6 The side wall of the through hole forms an obtuse angle with the upper surface of the piezoelectric layer; of course, depending on the design requirements and process, the angle between the side wall of the through hole and the upper surface of the piezoelectric layer 202 can be any angle, which can be a right angle, an obtuse angle, or an acute angle.

[0067] Please refer to Figure 7 As shown, a bonding layer 302 is formed on the upper surface of the dielectric layer 301, wherein the bonding layer 302 can be deposited and etched on the dielectric layer 301. In one embodiment of the present application, bonding the substrate to the other side of the dielectric layer relative to the lower electrode includes: generating a bonding layer on the other side of the dielectric layer relative to the lower electrode by deposition or etching, and / or generating a bonding layer on one side of the substrate; bonding the substrate to the dielectric layer through the bonding layer. For details, please refer to Figure 8 As shown, the substrate 303 and the dielectric layer 301 are bonded together by the bonding layer 302 to form a cavity. The bonding layer 302 may only exist on the dielectric layer 301 or only exist on the substrate 303. For this reason, the actual bonding layer 302 may be omitted, or a bonding layer may be formed on the substrate and the dielectric layer respectively, and the bonding is the bonding of two bonding layers.

[0068] In one embodiment of the present application, removing the substrate may include: removing the substrate by etching. Fig. 9 As shown, the substrate layer is removed by etching the lift-off layer.

[0069] In one embodiment of the present application, obtaining the thin film bulk acoustic wave resonator further includes: adjusting the thickness of the seed layer by a thinning process to adjust the frequency of the thin film bulk acoustic wave resonator to a preset frequency. Fig.10 As shown, in actual work, the frequency of the resonator can be adjusted by patterning the seed layer 103 and the upper electrode 201, that is, after the resonator is formed, the frequency of the resonator can be adjusted by thinning the seed layer of appropriate thickness (trim process). When the trim process is not required, the seed layer can be removed. According to actual needs, the seed layer can also be removed, and a dielectric layer can be re-deposited for the trim process to adjust the frequency of the resonator.

[0070] Please refer to Fig.11A As shown, in one embodiment of the present application, etching to form an electrode connection area on the resonant structure includes:

[0071] S1101 constructs a conductive through hole by etching the piezoelectric layer, and uses the conductive through hole to expose the electrical connection area of ​​the lower electrode to obtain a first connection area;

[0072] S1102 etching to form a second connection region on the other side of the upper electrode relative to the piezoelectric layer;

[0073] S1103: Obtain an electrode connection area according to the first connection area and the second connection area.

[0074] Please refer to Fig. 11B As shown, in actual work, the piezoelectric layer 202 can be first etched to form a conductive through hole to expose the electrode connection area 402 of the lower electrode; then the connection area (Pad) between the two electrodes, namely the upper electrode connection area 401 and the lower electrode connection area 402, is formed, which includes the deposition and etching of the material forming the Pad.

[0075] In one embodiment of the present application, before generating the dielectric layer on the other side of the lower electrode and the piezoelectric layer relative to the upper electrode by deposition, it may also include: generating a passivation layer on the other side of the lower electrode and the piezoelectric layer relative to the upper electrode by deposition; and patterning the passivation layer. Further, etching the dielectric layer to form a through hole also includes: etching the dielectric layer and the passivation layer to form a through hole, so that the preset area of ​​the lower electrode and the piezoelectric layer is exposed in the cavity. Wherein etching the dielectric layer and the passivation layer to form a through hole also includes: forming a through hole by wet etching the passivation layer.

[0076] Please refer to FIG. 12A to FIG. 12C As shown, a passivation layer 304 is deposited and patterned before depositing the dielectric layer 301. The passivation layer 304 can protect the lower electrode when etching the dielectric layer 301 to form a through hole (especially for dry etching of the dielectric layer). Accordingly, after etching the dielectric layer, the passivation layer needs to be etched (such as Fig. 12B As shown), the passivation layer 304 can be etched by wet etching, which causes less damage to the electrode.

[0077] Please refer to Fig.13 As shown, in one embodiment of the present application, when the substrate adopts a groove design, the dielectric layer 301 can be removed, that is, after the lower electrode is patterned, a bonding layer 302 is formed, and then the substrate 303 with a groove and the piezoelectric layer 202 are bonded together to form a cavity. Therefore, there is no need to etch the dielectric layer to construct the cavity.

[0078] Please refer to Fig.14 As shown, in the above embodiment, the left side boundary of the cavity is on the left side of the left side boundary of the lower electrode. Of course, the left side boundary of the cavity can also be between the left side boundary of the lower electrode and the left side boundary of the upper electrode (so that the working area is enclosed in the cavity area).

[0079] The present application also provides a thin film bulk acoustic wave resonator device, which is prepared by the above-mentioned thin film bulk acoustic wave resonator preparation method.

[0080] The present application also provides an electrical product, which has the above-mentioned thin film bulk acoustic wave resonance device.

[0081] The beneficial technical effects of the present application are: since no release hole is required, a completely closed cavity can be formed, which protects the lower electrode; since no release hole process is required, the manufacturing process is simpler, thereby improving the performance and manufacturing reliability of the resonator.

[0082] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. Moreover, the term "include", "comprise" or any other variant thereof is intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or equipment. In the absence of more restrictions, the elements defined by the sentence "including one..." do not exclude the existence of other identical elements in the process, method, article or equipment including the elements. The orientation or positional relationship indicated by the terms "upper", "lower", etc. is based on the orientation or positional relationship shown in the accompanying drawings, only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present application. Unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" 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 an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0083] Each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In the description of this specification, the description of reference terms such as "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 embodiments of this specification. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples without contradiction.

[0084] Specific embodiments are used in this application to illustrate the principles and implementation methods of this application. The description of the above embodiments is only used to help understand the method and core idea of ​​this application. At the same time, for those skilled in the art, according to the idea of ​​this application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on this application.

Claims

1. A method for preparing a thin film bulk acoustic wave resonator, characterized in that: The method comprises: Depositing a seed layer on one side of the substrate, and depositing an upper electrode on the other side of the seed layer opposite to the substrate; constructing a piezoelectric layer on the other side of the upper electrode relative to the substrate by deposition; Generating a resonant structure by depositing a lower electrode on the other side of the piezoelectric layer relative to the upper electrode; Enclosing the substrate, the lower electrode and the piezoelectric layer to form a cavity; removing the substrate, and etching the resonant structure to form an electrode connection region to obtain a thin film bulk acoustic wave resonator; Wherein, the piezoelectric layer is composed of polycrystalline aluminum nitride or doped polycrystalline aluminum nitride.

2. The method for preparing a thin film bulk acoustic wave resonator according to claim 1, characterized in that: Enclosing the substrate, the lower electrode in the resonant structure and the piezoelectric layer to form a cavity comprises: Depositing a dielectric layer on the lower electrode side of the resonant structure, and etching a through hole on the dielectric layer; The substrate is bonded to the other side of the dielectric layer relative to the lower electrode, and a cavity is formed by enclosing the substrate, the dielectric layer, the lower electrode and the piezoelectric layer in the resonant structure.

3. The method for preparing a thin film bulk acoustic wave resonator according to claim 1, characterized in that: The piezoelectric layer is a flat structure.

4. The method for preparing a thin film bulk acoustic wave resonator according to claim 1, characterized in that: The cavity depth is greater than 5 microns.

5. The method for preparing a thin film bulk acoustic wave resonator according to claim 1, characterized in that: Removing the substrate includes: Depositing a peeling layer and a seed layer in sequence on one side of the substrate; The substrate is removed by etching the lift-off layer.

6. The method for preparing a thin film bulk acoustic wave resonator according to claim 1, characterized in that: Obtaining a thin film bulk acoustic wave resonator further comprises: The thickness of the seed layer is adjusted through a thinning process, and the frequency of the thin film bulk acoustic wave resonator is adjusted to a preset frequency.

7. The method for preparing a thin film bulk acoustic wave resonator according to claim 2, characterized in that: Depositing a dielectric layer on the lower electrode side of the resonant structure includes: Generating a dielectric layer on the other side of the lower electrode and the piezoelectric layer relative to the upper electrode by deposition; performing a planarization process on the other side of the dielectric layer relative to the lower electrode; Wherein, the thickness of the dielectric layer is greater than the depth of the cavity.

8. The method for preparing a thin film bulk acoustic wave resonator according to claim 7, characterized in that: Before forming a dielectric layer on the other side of the lower electrode and the piezoelectric layer relative to the upper electrode by deposition, the method further comprises: Generating a passivation layer on the other side of the lower electrode and the piezoelectric layer relative to the upper electrode by deposition; The passivation layer is patterned.

9. The method for preparing a thin film bulk acoustic wave resonator according to claim 8, characterized in that: Etching a through hole on the dielectric layer further comprises: Through holes are formed by etching the dielectric layer and the passivation layer, so that the lower electrode and the preset areas of the piezoelectric layer are exposed in the cavity.

10. The method for preparing a thin film bulk acoustic wave resonator according to claim 9, characterized in that: Forming a through hole by etching the dielectric layer and the passivation layer further includes: forming a through hole by wet etching the passivation layer.

11. The method for preparing a thin film bulk acoustic wave resonator according to claim 7, characterized in that: Etching a through hole on the dielectric layer comprises: Through holes are formed by etching on the dielectric layer so that the lower electrode and the preset areas of the piezoelectric layer are exposed in the cavity.

12. The method for preparing a thin film bulk acoustic wave resonator according to claim 2, characterized in that: Bonding the substrate to the other side of the dielectric layer relative to the lower electrode comprises: Generating a bonding layer on the other side of the dielectric layer relative to the lower electrode and / or generating a bonding layer on one side of the substrate by deposition or etching; The substrate is bonded to the dielectric layer through a bonding layer.

13. The method for preparing a thin film bulk acoustic wave resonator according to claim 1, characterized in that: Removing the substrate includes removing the substrate by etching.

14. The method for preparing a thin film bulk acoustic wave resonator according to claim 1, characterized in that: Etching to form an electrode connection area on the resonant structure comprises: A conductive through hole is formed by etching the piezoelectric layer, and the electrical connection area of ​​the lower electrode is exposed by using the conductive through hole to obtain a first connection area; Etching a second connection region on the other side of the upper electrode relative to the piezoelectric layer; An electrode connection region is obtained based on the first connection region and the second connection region.

15. The method for preparing a thin film bulk acoustic wave resonator according to claim 1, characterized in that: Enclosing the substrate, the lower electrode in the resonant structure and the piezoelectric layer to form a cavity comprises: Patterning the lower electrode of the resonant structure to generate a bonding layer; The base of the groove is enclosed by the bonding layer and the piezoelectric layer in the resonant structure to form a cavity.

16. A thin film bulk acoustic wave resonator device, characterized in that: The device is prepared by the thin film bulk acoustic wave resonator preparation method according to any one of claims 1 to 15.

17. An electrical product, characterized in that: The electrical product comprises the thin film bulk acoustic resonator device according to claim 16.

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