Film bulk acoustic resonator and preparation method therefor

Abstract

The present application relates to the technical field of semiconductor devices. In particular, disclosed are a film bulk acoustic resonator and a preparation method therefor. The film bulk acoustic resonator comprises a substrate, and a lower electrode, a piezoelectric layer, an upper electrode and a passivation layer which are stacked on the substrate, wherein an overlapping portion of projections of the lower electrode, the piezoelectric layer and the upper electrode on the substrate is an active region; and a compensation layer is further formed on the piezoelectric layer, a hollowed-out groove is formed in the compensation layer, and the hollowed-out groove is formed along a projection edge of the active region, such that the passivation layer sags at the position where the passivation layer covers the hollowed-out groove to form a recess. In the present application, the hollowed-out design of a compensation layer enables the natural formation of a recess in the surface of a passivation layer located above the compensation layer, thereby effectively improving the manufacturing yield.

Description

Thin-film bulk acoustic resonator and its fabrication method

[0001] Cross-reference to related applications

[0002] This application claims priority to Chinese Patent Application No. 202411426082.6, filed on October 12, 2024, entitled "Thin Film Bulk Acoustic Resonator and Preparation Method Thereof", the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of semiconductor device technology, and more specifically, to a thin-film bulk acoustic resonator and its fabrication method. Background Technology

[0004] In thin-film bulk acoustic resonators (FBARs), groove structures are typically incorporated into the active region to eliminate parasitic effects appearing on the left side of the FBAR impedance curve. However, inappropriate groove width or depth can lead to parasitic problems on the right side of the impedance curve. Conversely, excessively shallow or narrow grooves reduce their effectiveness in eliminating parasitic effects on the left side. Current technology involves etching grooves onto the passivation layer. Unlike typical etching processes, the etching depth of the groove structure generally does not exceed 100 nm, which is less than the thickness of the film to be etched, thus avoiding the need to penetrate the film. The groove depth is typically controlled by adjusting the etching time and calculating the average etching rate. However, this method has several drawbacks. First, the etching rate varies with the groove depth, leading to significant errors when controlling dimensions solely through etching rate and time. Second, the uneven film thickness distribution across the wafer, along with inconsistent etching rates at the wafer center and edges, makes it difficult to control the groove depth. Based on the above factors, the yield of existing technology for fabricating groove structures is extremely low, resulting in parasitic problems still existing in the impedance curve, which is not conducive to improving device performance.

[0005] Application content

[0006] The purpose of this application is to provide a thin-film bulk acoustic resonator and its fabrication method, which improves the manufacturing yield by hollowing out the compensation layer so that the surface of the passivation layer above the compensation layer naturally forms grooves.

[0007] The embodiments of this application are implemented as follows:

[0008] In a first aspect, embodiments of this application provide a thin-film bulk acoustic resonator, including a substrate and a lower electrode, a piezoelectric layer, an upper electrode, and a passivation layer stacked on the substrate; the overlapping portion of the projections of the lower electrode, the piezoelectric layer, and the upper electrode onto the substrate is an active region; a compensation layer is also formed on the piezoelectric layer, and a cutout groove is formed on the compensation layer, the cutout groove being formed along the projection edge of the active region, so that the passivation layer collapses at the position covering the cutout groove to form a groove.

[0009] As an optional implementation, the compensation layer is located between the upper electrode and the passivation layer.

[0010] As an optional implementation, the compensation layer is located between the piezoelectric layer and the upper electrode, and the compensation layer is made of a metallic material.

[0011] As an optional implementation, the upper electrode includes a first upper electrode and a second upper electrode stacked together, with a compensation layer located between the first upper electrode and the second upper electrode.

[0012] As an optional implementation, the cutout groove includes an annular cutout groove that extends circumferentially along the projected edge of the active region and is connected end to end.

[0013] As an optional implementation, the cutout groove includes multiple strip-shaped cutout grooves arranged at intervals around the projected edge of the active region; each strip-shaped cutout groove extends along the projected edge path of the active region.

[0014] As an optional implementation, a thickening layer is provided between the piezoelectric layer and the upper electrode, and an air wing and an air bridge are formed between the thickening layer and the piezoelectric layer; the projection of the compensation layer on the substrate and the projection of the thickening layer on the substrate have an overlap.

[0015] As an optional implementation, a columnar structure is provided in the air bridge at intervals; the columnar structure extends perpendicularly to the substrate, one end of the columnar structure is connected to the piezoelectric layer, and the other end is in contact with the thickened layer.

[0016] Secondly, embodiments of this application provide a method for fabricating a thin-film bulk acoustic resonator, the method comprising:

[0017] A lower electrode and a piezoelectric layer are sequentially disposed on the substrate;

[0018] An upper electrode is disposed on the piezoelectric layer; the overlapping portion of the projection of the lower electrode, the piezoelectric layer, and the upper electrode onto the substrate constitutes the active region.

[0019] A compensation layer is formed on a substrate with a piezoelectric layer, and the edge position of the projection of the active region corresponding to the compensation layer is hollowed out to form a hollow groove.

[0020] A passivation layer is set on the compensation layer so that the passivation layer collapses at the position covering the hollow groove to form a groove.

[0021] Furthermore, an upper electrode is disposed on the piezoelectric layer, including:

[0022] A first upper electrode and a second upper electrode are sequentially formed on the upper surface of the piezoelectric layer;

[0023] A compensation layer is formed on a substrate with a piezoelectric layer, including:

[0024] A compensation layer is provided on the surface of the first upper electrode so that the second upper electrode is laid on the upper surface of the compensation layer.

[0025] Furthermore, before setting the top electrode on the piezoelectric layer, the process includes:

[0026] A first sacrificial layer and a second sacrificial layer are formed on opposite sides of the active region on the piezoelectric layer;

[0027] Thickening layers are formed on the first and second sacrificial layers;

[0028] After setting a passivation layer on the compensation layer, the following steps are included:

[0029] Release the first and second sacrificial layers to form an air wing and an air bridge between the thickened layer and the piezoelectric layer. Attached Figure Description

[0030] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 is a schematic diagram of one of the structures of a thin-film bulk acoustic resonator according to an embodiment of this application;

[0032] Figure 2 is a second schematic diagram of the structure of the thin-film bulk acoustic resonator according to an embodiment of this application;

[0033] Figure 3 is a third schematic diagram of the structure of the thin-film bulk acoustic resonator according to an embodiment of this application;

[0034] Figure 4 is a fourth schematic diagram of the structure of the thin-film bulk acoustic resonator according to an embodiment of this application;

[0035] Figure 5 is a fifth schematic diagram of the structure of the thin-film bulk acoustic resonator according to an embodiment of this application;

[0036] Figure 6 is a schematic diagram of the structure of the thin-film bulk acoustic resonator according to an embodiment of this application;

[0037] Figure 7 is the seventh schematic diagram of the structure of the thin-film bulk acoustic resonator according to an embodiment of this application;

[0038] Figure 8 is the eighth schematic diagram of the structure of the thin-film bulk acoustic resonator according to an embodiment of this application.

[0039] Icons: 100-Substrate; 101-Lower electrode; 102-Piezoelectric layer; 103-Upper electrode; 104-Passivation layer; 105-Compensation layer; 106-Groove; 107-First upper electrode; 108-Second upper electrode; 109-Thickening layer; 110-Air wing; 111-Air bridge; 112-Columnar structure; 113-Cavity; 114-Aluminum nitride seed layer; 115-Tilt angle; 116-Left sacrificial layer; 117-Right sacrificial layer; 118-Tap hole. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. It should be noted that, in the absence of conflict, the various features in the embodiments of this application can be combined with each other, and the combined embodiments are still within the protection scope of this application.

[0041] In the description of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and therefore should not be construed as limiting this application. Furthermore, the terms "first," "second," and "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0042] In the description of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "set up," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a direct connection, an indirect connection through an intermediate medium, or a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0043] Referring to Figures 1, 2, and 3, this application provides a thin-film bulk acoustic resonator, including a substrate 100 and a lower electrode 101, a piezoelectric layer 102, an upper electrode 103, and a passivation layer 104 stacked on the substrate 100; the overlapping portion of the projection of the lower electrode 101, the piezoelectric layer 102, and the upper electrode 103 onto the substrate 100 is the active region; a compensation layer 105 is also formed on the piezoelectric layer 102, and a cutout groove is formed on the compensation layer 105. The cutout groove is formed along the projection edge of the active region, so that the passivation layer 104 collapses at the position covering the cutout groove to form a groove 106.

[0044] Regarding the depth of the groove 106 formed on the surface of the passivation layer 104, it should be noted that:

[0045] In this embodiment, the thickness of the compensation layer 105 is equal to the depth of the groove 106 formed by the passivation layer 104 at the location covering the cutout groove. For example, a compensation layer 105 with a thickness of 80 nm is provided. After the compensation layer 105 is cut out, the passivation layer 104 collapses at the location covering the cutout groove to form a groove 106 with a depth of the same 80 nm.

[0046] It should be noted that the thickness distance data of the compensation layer 105 can be set by those skilled in the art according to the required depth of the groove 106, and there is no special limitation thereto. For example, the thickness of the compensation layer 105 is 30-100nm.

[0047] Regarding the width of the groove 106 formed on the surface of the passivation layer 104, it should be noted that:

[0048] The width of the perforated groove on the compensation layer 105 is equal to the width of the groove 106 on the passivation layer 104. By controlling the width of the perforated groove in the compensation layer 105, the width of the groove 106 on the surface of the passivation layer 104 can be controlled.

[0049] It should be noted that the hollowing process of the compensation layer 105 in this embodiment can employ etching, photolithography, or other types of hollowing techniques. Compared to the prior art's direct etching of the passivation layer 104, the etching of the compensation layer 105 in this embodiment can directly penetrate the compensation layer 105, using the underlying layer structure as a stop layer to ensure the accuracy of the hollowing groove depth. The prior art directly etches the passivation layer 104, which cannot directly penetrate it, leading to difficulties in controlling the depth of the groove 106.

[0050] This application embodiment essentially avoids etching the passivation layer 104, directly forming a groove 106 of a predetermined size on the passivation layer 104. The groove 106 on the surface of the passivation layer 104 can be precisely set by controlling the thickness of the compensation layer 105 and the width of the cutout groove. Compared to the prior art, this application embodiment can effectively improve manufacturing yield.

[0051] The specific shape of the groove 106 can be set by those skilled in the art as needed, and no special limitation is made thereto.

[0052] For example, the cutout includes multiple strip-shaped cutouts spaced apart around the projected edge of the active region; each strip-shaped cutout extends along the projected edge path of the active region.

[0053] As an optional implementation, the cutout groove includes an annular cutout groove that extends circumferentially along the projected edge of the active region and is connected end to end.

[0054] Regarding the specific location of compensation layer 105, it should be noted that:

[0055] The compensation layer 105 needs to be placed below the passivation layer 104 and above the piezoelectric layer 102, and the following are some specific placement schemes.

[0056] Firstly, as shown in FIG1, the compensation layer 105 is located between the upper electrode 103 and the passivation layer 104.

[0057] Secondly, as shown in FIG2, the compensation layer 105 is located between the piezoelectric layer 102 and the upper electrode 103, and the compensation layer 105 is made of metal material.

[0058] When the compensation layer 105 is located between the piezoelectric layer 102 and the upper electrode 103, the compensation layer 105 is made of a metallic material. This ensures that the piezoelectric layer 102 and the upper electrode 103 have an effective electrical connection surface in the active region.

[0059] Third, referring to FIG3, the upper electrode 103 includes a first upper electrode 107 and a second upper electrode 108 stacked together, and the compensation layer 105 is located between the first upper electrode 107 and the second upper electrode 108.

[0060] It should be noted that when the compensation layer 105 is located on the surface of the piezoelectric layer 102, the hierarchical structure above the compensation layer 105 will naturally collapse, ensuring that the surface of the uppermost passivation layer 104 can form the groove 106. Similarly, when the compensation layer 105 is located on the surface of the first upper electrode 107, the hierarchical structure above the compensation layer 105 will naturally collapse, ensuring that the surface of the uppermost passivation layer 104 can form the groove 106.

[0061] For setting the groove 106, the preferred method is the first option, where the compensation layer 105 is directly set on the lower surface of the passivation layer 104, allowing a high-precision groove 106 structure to be formed on the surface of the passivation layer 104. This avoids the need to sandwich other layers between the compensation layer 105 and the passivation layer 104, which would affect the accuracy of the groove 106 structure.

[0062] As an optional implementation, a thickening layer 109 is provided between the piezoelectric layer 102 and the upper electrode 103, and an air wing 110 and an air bridge 111 are formed between the thickening layer 109 and the piezoelectric layer 102; the projection of the compensation layer 105 on the substrate 100 and the projection of the thickening layer 109 on the substrate 100 have an overlap.

[0063] Furthermore, in this embodiment, the compensation layer 105 is positioned within the thickening layer 109 region through the aforementioned configuration. On one hand, the compensation layer 105 thickens the thickening layer 109 region, thereby improving the resonator's quality factor. On the other hand, the compensation layer 105 uses a low acoustic impedance material such as silicon dioxide, which, together with the high acoustic impedance material below the compensation layer 105, forms an acoustic reflection layer. This acoustic reflection layer can reflect longitudinal waves in the resonator, effectively reducing parasitic modes and improving the resonator's quality factor.

[0064] For example, the lower electrode 101 may be made of a high acoustic impedance material such as Mo.

[0065] More preferably, the compensation layer 105 in this embodiment can be made of a material with the opposite temperature drift coefficient to the resonator, thereby compensating for the temperature drift coefficient of the resonator and improving the frequency temperature stability of the resonator.

[0066] For example, the compensation layer 105 can be a positive temperature coefficient material such as silicon dioxide, silicon fluoride, polycrystalline silicon, or borophosphate glass.

[0067] As an optional implementation, columnar structures 112 are provided in the air bridge 111 at intervals; the columnar structures 112 extend perpendicularly to the substrate 100, one end of the columnar structures 112 is connected to the piezoelectric layer 102, and the other end is in contact with the thickened layer 109.

[0068] Referring to FIG4, in this embodiment of the application, two spaced columnar structures are formed in the air bridge 111 between the thickened layer 109 and the piezoelectric layer 102. The piezoelectric layer 102 is specifically inclined in the air bridge. The first columnar structure is arranged near the upper end of the inclined surface, and the second columnar structure is arranged near the lower end of the inclined surface.

[0069] It should be noted that the columnar structure can be made of metallic materials such as molybdenum, aluminum, copper, and gold. On the one hand, the columnar structure in this embodiment significantly increases the metal area, which is beneficial to improving the heat dissipation capacity of the device. On the other hand, the columnar structure in this embodiment can provide longitudinal support and divide the air bridge 111 into multiple air cavities, which is beneficial to the lateral reflection of sound waves.

[0070] This application provides a method for fabricating a thin-film bulk acoustic resonator, the method comprising:

[0071] A lower electrode 101 and a piezoelectric layer 102 are sequentially disposed on a substrate 100;

[0072] An upper electrode 103 is disposed on the piezoelectric layer 102; the overlapping portion of the projection of the lower electrode 101, the piezoelectric layer 102, and the upper electrode 103 onto the substrate 100 is the active region;

[0073] A compensation layer 105 is provided on a substrate 100 on which a piezoelectric layer 102 is formed, and the edge position of the compensation layer 105 corresponding to the projection of the active region is hollowed out to form a hollow groove.

[0074] A passivation layer 104 is provided on the compensation layer 105 so that the passivation layer 104 collapses at the position covering the hollow groove to form a groove 106.

[0075] Regarding the provision of a compensation layer 105 on a substrate 100 where a piezoelectric layer 102 is formed, it should be noted that:

[0076] A compensation layer 105 can be provided between the piezoelectric layer 102 and the upper electrode 103, or between the upper electrode 103 and the passivation layer 104.

[0077] In other words, a compensation layer 105 can be first set on the piezoelectric layer 102, and then the upper electrode 103 and passivation layer 104 can be formed on the compensation layer 105 in sequence.

[0078] Alternatively, an upper electrode 103 can be disposed on the piezoelectric layer 102, and a compensation layer 105 and a passivation layer 104 can be sequentially formed on the surface of the upper electrode 103.

[0079] In this embodiment, a hollowed-out groove is formed in the compensation layer 105, resulting in a groove 106 on the surface of the passivation layer 104. The depth of the groove 106 is consistent with the thickness of the compensation layer 105. Unlike the prior art, this embodiment does not require etching of the passivation layer 104, nor does it require controlling data such as etching time and average etching rate of the passivation layer 104 to control the depth of the groove 106. By directly hollowing out the compensation layer 105, the groove 106 on the surface of the passivation layer 104 is precisely set, avoiding dimensional fluctuations when setting the groove 106 structure. This embodiment can precisely control the depth of the groove 106.

[0080] Furthermore, an upper electrode 103 is disposed on the piezoelectric layer 102, including:

[0081] A first upper electrode 107 and a second upper electrode 108 are sequentially formed on the upper surface of the piezoelectric layer 102;

[0082] A compensation layer 105 is formed on a substrate 100 on which a piezoelectric layer 102 is formed, including:

[0083] A compensation layer 105 is provided on the surface of the first upper electrode 107 so that the second upper electrode 108 is laid on the upper surface of the compensation layer 105.

[0084] Furthermore, before the upper electrode 103 is disposed on the piezoelectric layer 102, the following steps are included:

[0085] A first sacrificial layer and a second sacrificial layer are formed on opposite sides of the active region on the piezoelectric layer 102;

[0086] A thickened layer 109 is formed on the first sacrificial layer and the second sacrificial layer;

[0087] After the passivation layer 104 is provided on the compensation layer 105, the following is included:

[0088] Referring to Figures 1, 2 and 3, the first sacrificial layer and the second sacrificial layer are released to form an air wing 110 and an air bridge 111 between the thickened layer 109 and the piezoelectric layer 102.

[0089] Specifically, the preparation steps of this application embodiment are as follows:

[0090] (1) Referring to Figure 5, firstly, the cavity 113 is etched on the substrate 100 and the cavity 113 is filled with a cavity sacrificial layer structure. Then, the cavity sacrificial layer is polished by chemical mechanical polishing until the substrate 100 and the cavity sacrificial layer are flush.

[0091] (2) Referring to FIG5, an aluminum nitride seed layer 114 is deposited on the substrate 100, which can make the lower electrode 101 and the piezoelectric layer 102 have better lattice orientation.

[0092] (3) Referring to FIG6, a lower electrode 101 is deposited and patterned on an aluminum nitride seed layer 114. The lower electrode 101 has a tilt angle 115, which is kept as small as possible to facilitate the subsequent growth of the piezoelectric layer 102. For example, the tilt angle 115 is between 0° and 30°.

[0093] (4) Referring to FIG6, deposit a piezoelectric layer 102 and pattern the piezoelectric layer to form a lead-out hole 118.

[0094] It should be noted that the preferred orientation growth of the c-axis of the piezoelectric layer 102 depends on a flat surface. That is, the smaller the tilt angle 115 of the lower electrode 101, the higher the crystal quality of the piezoelectric layer 102 at that location.

[0095] (5) Referring to FIG7, sacrificial layers are deposited and patterned on the piezoelectric layer 102, configured as the left sacrificial layer 116 of the air wing 110 and the right sacrificial layer 117 configured as the air bridge 111.

[0096] (6) Referring to FIG8, a thickening layer 109 is deposited and patterned, including a left thickening layer above the left sacrificial layer 116 and a thickening layer 109 above the right sacrificial layer 117. In addition, there is a thickening layer 109 falling on the lead-out hole 118 of the piezoelectric layer 102. When the thickening layer 109 is a metallic material, the thickening layer 109 falling on the lead-out hole 118 has the function of leading out the lower electrode 101.

[0097] (7) Referring to FIG8, deposit and pattern the upper electrode 103, including the lower electrode lead-out area on the left side. The upper electrode 103 falling on the lead-out hole 118 also has the function of leading out the lower electrode 101.

[0098] (8) Referring to Figures 1, 3 and 4, a compensation layer 105 is deposited and patterned on the upper electrode 103. The compensation layer 105 is located in the active region and is hollowed out to form a recessed region.

[0099] (9) Referring to Figures 1, 3 and 4, a passivation layer 104 is deposited on the upper surface of the compensation layer 105. Since the height difference is formed by the compensation layer 105 in the previous step, there is no need to etch the recessed area. The groove 106 is automatically formed on the passivation layer 104.

[0100] (10) A patterned passivation layer 104 is formed to form a lower electrode passivation layer lead-out hole and an upper electrode passivation layer lead-out hole, and is covered with a protective layer material, wherein the protective layer material can be gold.

[0101] (11) Etching the release hole structure: In order to open the release hole, the passivation layer 104, the piezoelectric layer 102, and the aluminum nitride seed layer 114 are etched in sequence.

[0102] (12) Referring to FIG1, the cavity sacrificial layer, the left sacrificial layer 116 and the right sacrificial layer 117 are released by dry or wet methods to form a cavity 113, an air wing 110 and an air bridge 111.

[0103] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the scope of protection of this application. Industrial applicability

[0104] The thin-film bulk acoustic resonator and its fabrication method disclosed in this application can achieve precise setting of the grooves on the passivation layer surface by controlling the thickness of the compensation layer and the width of the perforation groove. This application can effectively improve the manufacturing yield in industrial production.

Claims

1. A thin-film bulk acoustic resonator, characterized in that, The device includes a substrate and a lower electrode, a piezoelectric layer, an upper electrode, and a passivation layer stacked on the substrate. The overlapping portion of the projections of the lower electrode, the piezoelectric layer, and the upper electrode onto the substrate is an active region. A compensation layer is also formed on the piezoelectric layer, and a cutout groove is formed on the compensation layer. The cutout groove is formed along the projection edge of the active region so that the passivation layer collapses at the position covering the cutout groove to form a groove.

2. The thin-film bulk acoustic resonator according to claim 1, characterized in that, The compensation layer is located between the upper electrode and the passivation layer.

3. The thin-film bulk acoustic resonator according to claim 1, characterized in that, The compensation layer is located between the piezoelectric layer and the upper electrode, and the compensation layer is made of a metallic material.

4. The thin-film bulk acoustic resonator according to claim 1, characterized in that, The upper electrode includes a first upper electrode and a second upper electrode stacked together, and the compensation layer is located between the first upper electrode and the second upper electrode.

5. The thin-film bulk acoustic resonator according to any one of claims 1-4, characterized in that, The hollowed-out groove includes an annular hollowed-out groove that extends circumferentially along the projected edge of the active region and is connected end to end.

6. The thin-film bulk acoustic resonator according to any one of claims 1-4, characterized in that, The hollowed-out groove includes multiple strip-shaped hollowed-out grooves arranged at intervals around the projected edge of the active region; each strip-shaped hollowed-out groove extends along the projected edge path of the active region.

7. The thin-film bulk acoustic resonator according to any one of claims 1-4, characterized in that, A thickening layer is provided between the piezoelectric layer and the upper electrode, and an air wing and an air bridge are formed between the thickening layer and the piezoelectric layer; the projection of the compensation layer on the substrate and the projection of the thickening layer on the substrate have an overlap.

8. The thin-film bulk acoustic resonator according to claim 7, characterized in that, The air bridge contains spaced columnar structures; the columnar structures extend perpendicularly to the substrate, one end of the columnar structure is connected to the piezoelectric layer, and the other end is in contact with the thickened layer.

9. A method for fabricating a thin-film bulk acoustic resonator, characterized in that, The method includes: A lower electrode and a piezoelectric layer are sequentially disposed on the substrate; An upper electrode is disposed on the piezoelectric layer; the overlapping portion of the projection of the lower electrode, the piezoelectric layer, and the upper electrode onto the substrate constitutes an active region; A compensation layer is formed on a substrate on which a piezoelectric layer is formed, and the edge position of the compensation layer corresponding to the projection of the active region is hollowed out to form a hollow groove. A passivation layer is provided on the compensation layer so that the passivation layer collapses to form a groove at the position covering the hollowed-out groove.

10. The method for fabricating a thin-film bulk acoustic resonator according to claim 9, characterized in that, The provision of an upper electrode on the piezoelectric layer includes: A first upper electrode and a second upper electrode are sequentially formed on the upper surface of the piezoelectric layer; The provision of a compensation layer on a substrate having a piezoelectric layer includes: A compensation layer is provided on the surface of the first upper electrode so that the second upper electrode is laid on the upper surface of the compensation layer.

11. The method for fabricating a thin-film bulk acoustic resonator according to claim 9, characterized in that, Before the upper electrode is disposed on the piezoelectric layer, the following steps are included: A first sacrificial layer and a second sacrificial layer are formed on opposite sides of the active region on the piezoelectric layer; A thickened layer is formed on the first sacrificial layer and the second sacrificial layer; After a passivation layer is applied to the compensation layer, the following steps are included: Release the first sacrificial layer and the second sacrificial layer to form an air wing and an air bridge between the thickened layer and the piezoelectric layer.

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