CN111010118A

CN111010118A - Bulk acoustic wave resonator, filter and electronic device having cavity support structure

Info

Publication number: CN111010118A
Application number: CN201910751463.4A
Authority: CN
Inventors: 张孟伦; 庞慰; 杨清瑞; 张全德; 徐利军
Original assignee: Tianjin University; ROFS Microsystem Tianjin Co Ltd
Current assignee: Tianjin University; ROFS Microsystem Tianjin Co Ltd
Priority date: 2019-08-15
Filing date: 2019-08-15
Publication date: 2020-04-14
Anticipated expiration: 2039-08-15
Also published as: CN111010118B; WO2021027320A1

Abstract

The invention relates to a bulk acoustic wave resonator comprising: a substrate; an acoustic mirror cavity; a bottom electrode; a top electrode; a piezoelectric layer, wherein: the overlapped area of the acoustic mirror cavity, the bottom electrode, the piezoelectric layer and the top electrode in the thickness direction of the substrate is an effective area of the resonator; and a supporting structure is arranged in the acoustic mirror cavity, the lower end of the supporting structure is arranged at the bottom of the acoustic mirror cavity, the upper end of the supporting structure is arranged at the high-temperature area of the effective area and is connected or contacted with the lower side of the effective area, the high-temperature area refers to an area which takes the mass center of the effective area as the center of a circle and r as the radius, the radius r is 50% of the radius of an equivalent circle of the effective area where the high-temperature area is located, and the equivalent circle is: and a circle having the center of mass of the effective region as the center and having an area equal to that of the effective region. The invention also relates to a filter and an electronic device.

Description

Bulk acoustic wave resonator, filter and electronic device having cavity support structure

Technical Field

Embodiments of the present invention relate to the field of semiconductors, and in particular, to a bulk acoustic wave resonator, a filter, and an electronic device having one of the above components.

Background

A Film Bulk Acoustic Resonator (FBAR, also called Bulk Acoustic Resonator, BAW) plays an important role in the field of communications as a MEMS chip, and an FBAR filter has excellent characteristics of small size (μm), high resonant frequency (GHz), high quality factor (1000), large power capacity, good roll-off effect, and the like, is gradually replacing a conventional Surface Acoustic Wave (SAW) filter and a ceramic filter, plays a great role in the field of radio frequency for wireless communications, and has the advantage of high sensitivity that can also be applied to the sensing fields of biology, physics, medicine, and the like.

The structural main body of the film bulk acoustic resonator is a sandwich structure consisting of an electrode, a piezoelectric film and an electrode, namely a piezoelectric film material is sandwiched between two metal electrode layers. By inputting a sinusoidal signal between the two electrodes, the FBAR converts the input electrical signal into mechanical resonance using the inverse piezoelectric effect, and converts the mechanical resonance into an electrical signal for output using the piezoelectric effect. Since the film bulk acoustic resonator mainly utilizes the longitudinal piezoelectric coefficient (d33) of the piezoelectric film to generate the piezoelectric effect, the main operation Mode thereof is a longitudinal wave Mode (TE Mode) in the Thickness direction.

Fig. 7A is a top view of a prior art bulk acoustic wave resonator, and fig. 7B is a cross-sectional view taken along a broken line A1OA2 in fig. 7A. As shown in fig. 7A-7B, by removing the piezoelectric layer 50 above the fold line B1O' B2, portions of the bottom electrode 40, and the bottom electrode lead 35 and substrate 10 may be exposed in plan view, with details of the portions as follows:

10: the substrate is usually selected from monocrystalline silicon, gallium arsenide, sapphire, quartz, etc.

20: an acoustic mirror, in the example above an air cavity, may also employ a bragg reflector layer or other equivalent acoustic reflecting structure.

40(35)/60(65): the bottom electrode (pin)/top electrode (pin) can adopt molybdenum, ruthenium, gold, aluminum, magnesium, tungsten, copper, titanium, iridium, osmium, chromium or the compound of the above metals or the alloy thereof.

50: the piezoelectric layer film can be made of materials such as aluminum nitride, zinc oxide, PZT and the like and contains rare earth element doped materials with certain atomic ratios of the materials.

Fig. 7C shows a schematic diagram of the temperature gradient distribution of the active area AR of the resonator corresponding to fig. 7A (where dark places indicate low temperature and light places indicate high temperature), and the temperature peak is located at Σ in the diagram.

When the resonator works, a part of sound vibration energy and electric energy are inevitably converted into heat energy, and along with the increase of the power of the resonator, the heating problem becomes more and more obvious, so that the working temperature of the resonator is overhigh. High temperatures not only adversely affect the electrical properties of the resonator, but also accelerate the aging and destruction of the component parts of the device. The heating problem is particularly pronounced in the central region of the active area of the resonator.

Disclosure of Invention

The invention provides a power enhancement structure arranged at or near the center of a top view of an effective acoustic area of a bulk wave resonator, which can enable the vibration frequency at the highest temperature point and near the highest temperature point in the resonator to deviate from the resonance point, thereby achieving the purpose of reducing the temperature of the resonator.

According to an aspect of an embodiment of the present invention, there is provided a bulk acoustic wave resonator including:

a substrate;

an acoustic mirror cavity;

a bottom electrode;

a top electrode;

a piezoelectric layer is formed on the substrate,

wherein:

the overlapped area of the acoustic mirror cavity, the bottom electrode, the piezoelectric layer and the top electrode in the thickness direction of the substrate is an effective area of the resonator; and is

The acoustic mirror is characterized in that a supporting structure is arranged in the acoustic mirror cavity, the lower end of the supporting structure is arranged at the bottom of the acoustic mirror cavity, the upper end of the supporting structure is arranged at the high-temperature area of the effective area and is connected or contacted with the lower side of the effective area, the high-temperature area is an area which takes the mass center of the effective area as the circle center and r as the radius, the radius r is 50% of the radius of an equivalent circle of the effective area where the high-temperature area is located, and the equivalent circle is: and a circle having the center of mass of the effective region as the center and having an area equal to that of the effective region.

Optionally, the radius r is 20% of the radius of an equivalent circle of the effective area where the high-temperature area is located.

Optionally, the upper end of the support structure is connected or in contact with the underside of the active area only in the high temperature region of the active area.

Optionally, the supporting structure is a frustum-shaped structure, the cross-sectional area of the upper end of the supporting structure is smaller than that of the lower end of the supporting structure, a supporting surface is formed at the top of the frustum-shaped structure, and the supporting surface is connected with the bottom side of the bottom electrode.

Optionally, the frustum-shaped structure is a quadrangular prism structure, a triangular prism structure, or a truncated cone structure.

Optionally, the upper end of the support structure has a support surface, and the support surface is connected with the bottom side of the bottom electrode; the lower end of the supporting structure is provided with a fixing surface, and the fixing surface is connected with the bottom of the acoustic mirror cavity; the support structure further includes an elastic connection portion connected between the support surface and the fixing surface, the elastic connection portion providing an elastic force that causes the support surface to face upward to abut the bottom electrode.

Optionally, the elastic connection portion is a wing.

Optionally, a first oblique angle is formed between the wing part and the fixing surface, and the first oblique angle is in the range of 10-80 degrees.

Optionally, the wing is a trapezoid, an upper base of the trapezoid being connected to the supporting surface, and a lower base of the trapezoid being connected to the fixing surface.

Optionally, the wing is serpentine. Further, the end of the snake shape contacting the supporting surface is smaller than the end of the snake shape contacting the fixing surface.

Optionally, the wing comprises a plurality of wings equally angularly spaced in a top view of the resonator, the plurality of wings having the same first oblique angle; and the fixing surface is an annular fixing surface or comprises a plurality of fixing surfaces which are equally spaced at an angle in a top view of the resonator, and the plurality of fixing surfaces respectively correspond to the plurality of wing parts.

Optionally, the support surface has only one support surface, and the plurality of wings are each connected to the one support surface; or the supporting surface is provided with a plurality of supporting surfaces, and the plurality of wing-shaped parts are respectively connected with the plurality of supporting surfaces.

Optionally, the wing comprises two wings arranged mirror-symmetrically in a top view of the resonator, the support surface having only one support surface, and both wings being connected to the one support surface.

Optionally, the wing comprises a plurality of wings arranged rotationally symmetrically in a top view of the resonator, the support face having only one support face, and the plurality of wings each being connected to the one support face.

Optionally, the support structure is a cylindrical structure with the same cross section, and a support surface is formed on the top surface of the cylindrical structure and connected with the bottom side of the bottom electrode.

Optionally, the support structure is a thermally conductive structure adapted to conduct heat from the high temperature region of the active area from the support structure to the substrate.

Optionally, the support structure is connected to the bottom electrode forming surface, and the support structure is connected to the bottom forming surface of the acoustic mirror cavity.

Optionally, the contact area of the support structure with the lower side of the active area is not more than 1% of the area of the active area; or the side length of the longest edge of the contact surface of the support structure and the lower side of the effective area does not exceed 1/10 of the longest side length of the effective area; or the length of the longest side or diameter of the contact surface of the support structure with the underside of the active area is in the range of 0.1-20 μm. Further, the contact area of the support structure and the lower side of the effective area is not more than 0.1% of the area of the effective area; or the side length of the longest edge of the contact surface of the support structure and the lower side of the effective area is not more than 1/30 of the longest side length of the effective area.

Optionally, the support structure is a first support structure; and the resonator further comprises a plurality of auxiliary supporting structures, the plurality of auxiliary supporting structures are arranged around the first supporting structure, the lower ends of the auxiliary supporting structures are arranged at the bottom of the cavity of the acoustic mirror, and the upper ends of the auxiliary supporting structures are connected or contacted with the lower side of the effective area. Further, the plurality of auxiliary support structures are distributed on at least one circle with the center of mass of the effective area as the center, and are equally and angularly spaced on the circle.

Optionally, the height of the support structure ranges from H ± 1 μm, where H is the depth of the corresponding acoustic mirror cavity.

According to a further aspect of an embodiment of the present invention, there is provided a filter including the resonator described above.

According to a further aspect of an embodiment of the present invention, there is provided an electronic device including the resonator described above, or the filter described above.

Drawings

These and other features and advantages of the various embodiments of the disclosed invention will be better understood from the following description taken in conjunction with the accompanying drawings, in which like reference characters designate like parts throughout, and in which:

figure 1A is a schematic cross-sectional view of a bulk acoustic wave resonator according to an exemplary embodiment of the present invention;

FIG. 1B is a schematic illustration of a support structure disposed in the acoustic mirror cavity of FIG. 1A in accordance with an exemplary embodiment of the present invention;

FIG. 1C is a schematic view of the support structure of FIG. 1A, according to an exemplary embodiment of the present invention;

FIG. 1D is a schematic illustration of the support structure of FIG. 1A, according to an exemplary embodiment of the present invention;

figure 2A is a schematic diagram of a support structure for a bulk acoustic wave resonator according to an exemplary embodiment of the present invention;

FIG. 2B is a side view of the support structure of FIG. 2A;

figure 3 is a schematic diagram of a support structure for a bulk acoustic wave resonator according to an exemplary embodiment of the present invention;

figure 4A is a schematic diagram of a support structure for a bulk acoustic wave resonator according to an exemplary embodiment of the present invention;

FIG. 4B is a schematic top view of the support structure of FIG. 4A;

figure 5A is a schematic illustration of a support structure for a bulk acoustic wave resonator according to an exemplary embodiment of the present invention;

FIG. 5B is a schematic top view of the support structure of FIG. 5A;

fig. 6A is a schematic diagram of a first support structure and an auxiliary support structure of a bulk acoustic wave resonator according to an exemplary embodiment of the present invention;

FIG. 6B is a schematic view of the distribution of auxiliary support structures according to an exemplary embodiment of the present invention;

FIG. 6C is a schematic view of the distribution of auxiliary support structures according to an exemplary embodiment of the present invention;

FIG. 7A is a top view of a prior art bulk acoustic wave resonator;

FIG. 7B is a cross-sectional view taken along line A1OA2 in FIG. 7A;

fig. 7C is a schematic diagram of the temperature gradient distribution of the active area AR of the resonator corresponding to fig. 7A, where the dark place represents low temperature, the light place represents high temperature, and the highest point of temperature is located at Σ in the diagram.

Detailed Description

The technical scheme of the invention is further specifically described by the following embodiments and the accompanying drawings. In the specification, the same or similar reference numerals denote the same or similar components. The following description of the embodiments of the present invention with reference to the accompanying drawings is intended to explain the general inventive concept of the present invention and should not be construed as limiting the invention.

Fig. 1A is a schematic cross-sectional view of a bulk acoustic wave resonator according to an exemplary embodiment of the present invention.

The details of each part are as follows:

20: an acoustic mirror cavity.

30: a support structure.

As shown in fig. 1A and 1B, the support structure 30 is disposed in the acoustic mirror cavity 20, the lower end of the support structure 30 is disposed at the bottom of the acoustic mirror cavity 20, the upper end of the support structure is connected to the bottom side of the bottom electrode 40 in the high temperature region of the active region, and the height between the lower end and the upper end of the support structure 30 is the depth of the acoustic mirror cavity.

Note that, in the present invention, the "high temperature region" refers to a region having a center at the centroid of the effective region and a radius r of 50% and further 20% of the radius of an equivalent circle of the effective region, where the equivalent circle is: and a circle having the center of mass of the effective region as the center and having an area equal to that of the effective region.

In the present invention, it is within the scope of the present invention that only a portion of the upper end of the support structure may be located within the high temperature region, or that all of the upper end of the support structure may be located within the high temperature region.

Since the working process of the resonator is essentially the piezoelectric substance-field interaction, the spatial distribution of the thermal power density of the resonator is directly related to the spatial distribution of the substance of the active area of the resonator, and for resonators with convex geometry of the active area, the position of highest thermal power density is located near the center (centroid) of the substance distribution. Although the resonator effective area is formed of different materials such as the metal electrode layer and the piezoelectric layer in the thickness direction, since the thicknesses of the respective material layers are generally uniform (or nearly uniform), the equivalent areal density of the effective area can be considered to be uniform in a plan view. In the above case, the position of the planar centroid of the active area is the planar geometric center of the area.

Due to the support structure 30, the vibration frequency at or near the highest temperature point of the resonator may be shifted away from the resonance point. This helps to reduce the temperature at or near the highest temperature point of the resonator, thereby increasing the power capacity of the overall resonator.

In case the support structure 30 itself also has a heat transfer function, it helps to conduct the heat in the bottom electrode to the substrate, providing an additional heat dissipation channel for heat dissipation from the active area of the resonator, besides the resonator edges, helping to further reduce the temperature of the resonator and thus increase the power capacity of the resonator. In this regard, in one embodiment of the invention, the support structure is a thermally conductive structure adapted to conduct heat from the high temperature region of the active area from the support structure to the substrate. Furthermore, the support structure is connected with the bottom electrode forming surface, and the support structure is connected with the bottom forming surface of the acoustic mirror cavity.

The support structure 30 is shown only schematically in fig. 1A as being arranged between the bottom electrode and the bottom of the acoustic mirror cavity. The structure of the support structure 30 is described in detail below.

Fig. 1B is a schematic view of a support structure provided in a cavity of the acoustic mirror in fig. 1A according to an exemplary embodiment of the present invention, and fig. 1C is a schematic view of the support structure in fig. 1A according to an exemplary embodiment of the present invention. As shown in fig. 1B-1C, the supporting structure is a rectangular pyramid structure with a small top and a large bottom, and the top surface of the rectangular pyramid structure is the supporting surface.

Referring to fig. 1C, the contact surface of the top of the tapered quadrangular prism with the lower electrode is rectangular, the length a0 of one side of the rectangle is in the range of 0.1-20 μm, preferably in the range of 0.1-10 μm, the length b0 of the other side of the rectangle is in the range of 0.1-20 μm, preferably in the range of 0.1-10 μm, the first included angle α 0 of the side surface of the prism with the vertical direction is in the range of 10-80 degrees, the second included angle β 0 is in the range of 10-80 degrees, and the height H01 of the prism is in the range of H ± 1 μm, wherein H is the depth of the corresponding acoustic mirror cavity of the.

Fig. 1B illustrates the support structure in the shape of a quadrangular frustum of pyramid, but the present invention is not limited thereto. For example, as shown in fig. 1D, the support structure is in the shape of a truncated cone. As shown in FIG. 1D, the top and bottom surfaces of the tapered cylinder are both rounded, with a top rounded radius R0 in the range of 0.05-10 μm, preferably in the range of 0.05-5 μm, a bottom rounded radius R0 in the range of 1-50 μm, and a tapered cylinder height H02 in the range of H + -1 μm, where H is the depth of the corresponding resonator acoustic mirror cavity.

Furthermore, although not shown, the support structure may also be in the shape of, for example, a triangular pyramid frustum; alternatively, the support structure is a cylindrical structure having the same cross-section, such as a cylinder, a square cylinder, or the like.

In addition to the support structure shown in fig. 1A-1D, the support structure may also be of another form, in particular the support structure is resilient in the thickness direction of the resonator. In this way, the rigidity of the support structure in the thickness direction of the resonator can be reduced, thereby reducing the impact of the support structure on the resonator and reducing the energy loss.

Figure 2A is a schematic diagram of a support structure for a bulk acoustic wave resonator according to an exemplary embodiment of the present invention; fig. 2B is a side view of the support structure of fig. 2A.

Shown in FIG. 2A is a support structure 30 having a rectangular base with a first side a3 in the range of 10-50 μm and a second side b3 in the range of 10-50 μm; the top contact is rectangular, the first side length a1 of the contact is in the range of 0.1-20 μm, preferably in the range of 0.1-10 μm, the second side length b1 is in the range of 0.1-20 μm, preferably in the range of 0.1-10 μm; furthermore, an inclined connecting part is arranged between the base part and the contact part, the connecting part is in a trapezoid shape, the length b2 of the lower bottom of the trapezoid is in the range of 2-40 μm, and the upper bottom of the trapezoid is superposed with the second side of the contact part.

FIG. 2B is a side view of the structure of FIG. 4A, wherein the connecting portions of the structure have an angle α 1 with the horizontal in the range of 10-80 degrees, an overall height H03 in the range of H + -1 μm, where H is the depth of the corresponding resonator acoustic mirror cavity, and a thickness T1 of the support structure in the range of 0.01-0.5 μm.

It is noted that the range H ± 1 μm of the height H03 of the support structure is not only applicable to this embodiment, but also applicable to other embodiments of the present invention.

Based on the above, in the present invention, the upper end of the support structure has a support surface connected with the bottom side of the bottom electrode, the lower end of the support structure has a fixing surface connected with the bottom of the acoustic mirror cavity, the support structure further includes an elastic connection portion connected between the support surface and the fixing surface, the elastic connection portion providing an elastic force that makes the support surface face upward to abut against the bottom electrode, as shown in fig. 2A, the elastic connection portion may be a wing, as shown in fig. 2B, a first oblique angle α 1 is formed between the wing and the fixing surface, and the first oblique angle is in a range of 10-80 degrees.

As shown in fig. 2A, the wing is a trapezoid, the upper base of which is connected to the supporting surface and the lower base of which is connected to the fixing surface.

Fig. 3 is a schematic view of a support structure of a bulk acoustic wave resonator according to an exemplary embodiment of the present invention. As shown in fig. 3, the elastic connection portion or wing portion has a serpentine shape to further reduce its rigidity and increase its degree of freedom. As shown in fig. 3, the end of the serpentine in contact with the support surface is smaller than the end of the serpentine in contact with the fixing surface, in other words, in fig. 3, the lower end of the wing of the serpentine is larger and the upper end is smaller, which facilitates the deformation of the wing.

Fig. 2A and 3 illustrate only a support structure having a single wing, but the present invention is not limited thereto.

Figure 4A is a schematic diagram of a support structure for a bulk acoustic wave resonator according to an exemplary embodiment of the present invention; fig. 4B is a schematic top view of the support structure in fig. 4A. Fig. 4A and 4B show mirror-symmetrical support structures. To enhance the stability of the support structure, the structure of fig. 2A may be mirror extended to form the symmetrical power enhancing structure of fig. 4A. As can be seen from the top view of the structure in fig. 4B, the support structure is symmetrical about lines L1L2 and L3L 4. In other words, in the embodiment of fig. 4A and 4B, the wings comprise two wings arranged mirror-symmetrically in a top view of the resonator, the support face having only one support face, and both wings being connected to the one support face.

Fig. 5A is a schematic view of a support structure of a bulk acoustic wave resonator according to an exemplary embodiment of the invention, fig. 5B is a schematic top view of the support structure of fig. 5A, fig. 5A and 5B show the support structure in the form of a rotationally symmetric structure, in particular, the support structure is made as shown in fig. 5A with a ring-shaped base, a circular contact and 3 fan-shaped connections, the support structure has an overall thickness T2, T2 in the range of 0.01-0.5 μm, an overall height H04 in the range H ± 1 μm, where H is the depth of the corresponding resonator acoustic mirror cavity, fig. 5B is a top view of the structure of fig. 5A showing the critical dimensions of the support structure, an inner radius R1 in the range of 1-50 μm in the base ring, an outer radius R2 in the range of 5-100 μm, a contact circular radius R1 in the range of 0.05-10 μm, preferably in the range of 0.05-5 μm, a projected range of 2-10 μm, a projected angle of the base ring, a support structure has a reduced stability, and a more rigid support structure is arranged in the top view of the support structure with a more rigid support structure.

Although in the embodiment shown in the above drawings, only one supporting surface is shown, the present invention is not limited thereto, and a plurality of supporting surfaces may be provided, however, these supporting surfaces are connected to the high temperature region of the active region.

In addition, the present invention may also be provided with additional auxiliary support structures in addition to the support structures described above, as shown in fig. 6A-6C.

Referring to fig. 6A, in addition to employing support structure 30 in the heat generating central region, a number of secondary support structures 31 are added around it. The advantages of the multi-support structure are: the heat conduction capacity can be further enhanced by increasing the number of contact surfaces; the structural stability is increased; the multiple supporting structures can also play a role in inhibiting the vibration of a parasitic mode in the resonator by adopting a certain distribution mode.

As shown in fig. 6B, the contact surfaces of the support structure and the effective acoustic region of the resonator (the circular region is shaded in the figure, and a rectangle may be used), are distributed on a plurality of concentric circles with the geometric center of the central contact surface as the center, and the radiuses of the concentric circles from inside to outside are Rm1, Rm2, Rm3 and the like respectively. Wherein the radius of the innermost circle ranges from 1 to 50 μm, and the difference between the radius of each circle from inside to outside and the radius of the adjacent inner circle ranges from 1 to 50 μm. Furthermore, several contact surfaces are distributed in a plurality of radial directions and the radial directions equally divide the circumference, for example, the radial direction equally divides the circumference by 4 in fig. 6B and 5 in fig. 6C, although the number of equally divided parts may be other integers such as 3,6,8, 9 …, etc.

The contact area between the support structure and the effective area is too small, the heat dissipation effect is not obvious, but the too large area causes the Q value of the resonator to be reduced, and meanwhile, the parasitic mode can be enhanced and other negative effects. Therefore, it is also noted that, in the present invention, the contact area of the support structure with the lower side of the active region or with the bottom electrode in the active region can be limited. Specifically, the contact area of the support structure and the lower side of the effective region is not more than 1% of the area of the effective region, and further not more than 0.1%; or the side length of the longest edge of the contact surface of the support structure and the lower side of the effective area is not more than 1/10 of the longest edge length of the effective area, and further not more than 1/30; or the length of the longest side or diameter of the contact surface of the support structure with the underside of the active area is in the range of 0.1-20 μm.

In addition, in the present invention, the value of a numerical range may be, for example, the median of the range or the like, in addition to the endpoints (inclusive) or the adjacent endpoints in the range (exclusive).

Based on the above, the invention provides the following technical scheme:

1. a bulk acoustic wave resonator comprising:

a substrate;

an acoustic mirror;

a bottom electrode;

a top electrode;

a piezoelectric layer is formed on the substrate,

wherein:

the overlapped area of the acoustic mirror, the bottom electrode, the piezoelectric layer and the top electrode in the thickness direction of the substrate is an effective area of the resonator; and is

2. A filter comprises the resonator.

3. An electronic device comprising the resonator or the filter. It should be noted that the electronic device herein includes, but is not limited to, intermediate products such as a radio frequency front end and a filtering and amplifying module, and terminal products such as a mobile phone, WIFI, and an unmanned aerial vehicle.

Although embodiments of the present invention have been shown and described, it would be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the claims and their equivalents.

Claims

1. A bulk acoustic wave resonator comprising:

a substrate;

an acoustic mirror cavity;

a bottom electrode;

a top electrode;

a piezoelectric layer is formed on the substrate,

wherein:

The acoustic mirror is characterized in that a supporting structure is arranged in the acoustic mirror cavity, the lower end of the supporting structure is arranged at the bottom of the acoustic mirror cavity, at least one part of the upper end of the supporting structure in a high-temperature area of the effective area is connected or contacted with the lower side of the effective area, the high-temperature area refers to an area which takes the mass center of the effective area as the center of a circle and r as the radius, the radius r is 50% of the radius of an equivalent circle of the effective area where the high-temperature area is located, and the equivalent circle is: and a circle having the center of mass of the effective region as the center and having an area equal to that of the effective region.

2. The resonator of claim 1, wherein:

the radius r is 20% of the radius of an equivalent circle of an effective area where the high temperature area is located.

3. The resonator of claim 1, wherein:

the upper end of the support structure is connected or in contact with the lower side of the active area only in the high temperature region of the active area.

4. The resonator of any of claims 1-3, wherein:

the support structure is a frustum-shaped structure, the cross section area of the upper end of the support structure is smaller than that of the lower end of the support structure, a support surface is formed at the top of the frustum-shaped structure, and the support surface is connected with the bottom side of the bottom electrode.

5. The resonator of claim 4, wherein:

the frustum-shaped structure is a quadrangular prism structure, a triangular prism structure or a truncated cone structure.

6. The resonator of any of claims 1-3, wherein:

the upper end of the supporting structure is provided with a supporting surface which is connected with the bottom side of the bottom electrode; the lower end of the supporting structure is provided with a fixing surface, and the fixing surface is connected with the bottom of the acoustic mirror cavity; the support structure further includes an elastic connection portion connected between the support surface and the fixing surface, the elastic connection portion providing an elastic force that causes the support surface to face upward to abut the bottom electrode.

7. The resonator of claim 6, wherein:

the elastic connecting part is a wing-shaped part.

8. The resonator of claim 7, wherein:

a first oblique angle is formed between the wing part and the fixing surface, and the first oblique angle is in the range of 10-80 degrees.

9. The resonator of claim 7 or 8, wherein:

the wing part is trapezoidal, the upper bottom of the trapezoid is connected to the supporting surface, and the lower bottom of the trapezoid is connected to the fixing surface.

10. The resonator of claim 7 or 8, wherein:

the wing is serpentine.

11. The resonator of claim 10, wherein:

the end of the snake shape contacting the supporting surface is smaller than the end of the snake shape contacting the fixing surface.

12. The resonator of claim 7 or 8, wherein:

the wing comprises a plurality of wings equally angularly spaced in a top view of the resonator, the plurality of wings having the same first oblique angle; and is

The fixing surface is an annular fixing surface or includes a plurality of fixing surfaces equally angularly spaced in a plan view of the resonator, the plurality of fixing surfaces corresponding to the plurality of wing portions, respectively.

13. The resonator of claim 12, wherein:

the support surface has only one support surface and the plurality of wings are each connected to the one support surface; or

The supporting surface has a plurality of supporting surfaces, just a plurality of wings respectively with a plurality of supporting surface are connected.

14. The resonator of claim 13, wherein:

the wing comprises two wings arranged mirror-symmetrically in a top view of the resonator, the support face having only one support face and both wings being connected to the one support face.

15. The resonator of claim 13, wherein:

the wing comprises a plurality of wings arranged rotationally symmetrically in a top view of the resonator, the support face having only one support face and the plurality of wings each being connected to the one support face.

16. The resonator of any of claims 1-3, wherein:

the supporting structure is a cylindrical structure with the same section, the top surface of the cylindrical structure forms a supporting surface, and the supporting surface is connected with the bottom side of the bottom electrode.

17. The resonator of any of claims 1-16, wherein:

the support structure is a thermally conductive structure adapted to conduct heat from the high temperature region of the active area from the support structure to the substrate.

18. The resonator of claim 17, wherein:

the supporting structure is connected with the bottom electrode forming surface, and the supporting structure is connected with the bottom forming surface of the acoustic mirror cavity.

19. The resonator of any of claims 1-3, wherein:

the contact area of the support structure and the lower side of the active area is not more than 1% of the area of the active area; or

The side length of the longest edge of the contact surface of the support structure and the lower side of the effective area does not exceed 1/10 of the longest side length of the effective area; or

The length of the longest side or diameter of the contact surface of the support structure with the underside of the active area is in the range 0.1-20 μm.

20. The resonator of claim 19, wherein:

the contact area of the support structure and the lower side of the active area is not more than 0.1% of the area of the active area; or

The longest edge of the contact surface of the support structure with the underside of the active area has a length that does not exceed 1/30 the longest edge of the active area.

21. The resonator of any of claims 1-3, wherein:

the support structure is a first support structure; and is

The resonator further comprises a plurality of auxiliary supporting structures, the plurality of auxiliary supporting structures are arranged around the first supporting structure, the lower ends of the auxiliary supporting structures are arranged at the bottom of the cavity of the acoustic mirror, and the upper ends of the auxiliary supporting structures are connected or contacted with the lower side of the effective area.

22. The resonator of claim 21, wherein:

the plurality of auxiliary support structures are distributed on at least one circumference centered on a centroid of the active area and are equally angularly spaced apart on the circumference.

23. The resonator of any of claims 1-22, wherein:

the height of the support structure ranges from H + -1 μm, where H is the depth of the corresponding acoustic mirror cavity.

24. A filter, comprising:

the bulk acoustic wave resonator according to any one of claims 1-23.

25. An electronic device comprising the bulk acoustic wave resonator of any one of claims 1-23, or the filter of claim 24.