Bulk acoustic wave resonator, manufacturing method thereof, and electronic device

Abstract

The present invention provides a bulk acoustic wave resonator, which includes a substrate; a lower electrode, a piezoelectric layer, and an upper electrode, wherein the lower electrode, the piezoelectric layer, and the upper electrode are sequentially formed on the substrate from bottom to top; an acoustic reflection structure, wherein the acoustic reflection structure is formed within the substrate or between the substrate and the lower electrode, and the horizontal projection overlapping area of ​​the acoustic reflection structure and the lower electrode, the piezoelectric layer, and the upper electrode constitutes the resonance region of the bulk acoustic wave resonator; and a heat dissipation structure, wherein the heat dissipation structure includes a first heat dissipation portion and / or a second heat dissipation portion formed outside the resonance region, wherein the first heat dissipation portion is formed on the lower surface of the piezoelectric layer, and the second heat dissipation portion is formed on the upper surface of the piezoelectric layer. Accordingly, the present invention also provides a method for manufacturing a bulk acoustic wave resonator and an electronic device formed based on the bulk acoustic wave resonator. Implementation of the present invention is conducive to improving the heat dissipation capability of the device.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a bulk acoustic wave resonator, a manufacturing method thereof, and an electronic device. Background Art

[0002] Please refer to Figure 1 , Figure 1 The figure is a cross-sectional schematic diagram of a common BAW resonator in the prior art. As shown in the figure, the BAW resonator includes a substrate 10, a laminated structure, and an acoustic reflection structure. The laminated structure includes, from bottom to top, a lower electrode 11, a piezoelectric layer 12, and an upper electrode 13. The acoustic reflection structure is a cavity 14 formed below the laminated structure by etching the surface of the substrate 10. The horizontally projected overlapping area of ​​the upper electrode 13, the piezoelectric layer 12, the lower electrode 11, and the cavity 14 constitutes the resonant region of the BAW resonator. Correspondingly, the area outside the resonant region constitutes the non-resonant region of the BAW resonator.

[0003] BAW resonators generate heat during operation. Heat in the resonant region can be transferred outward through the upper and lower electrodes, while heat in the non-resonant region can only be transferred outward through the piezoelectric layer. Because the piezoelectric layer is currently primarily made of materials with poor thermal conductivity, such as AlN, existing BAW resonators cannot achieve efficient heat dissipation. Summary of the Invention

[0004] In order to overcome the above-mentioned defects in the prior art, the present invention provides a bulk acoustic wave resonator, which includes:

[0005] substrate;

[0006] A lower electrode, a piezoelectric layer, and an upper electrode, wherein the lower electrode, the piezoelectric layer, and the upper electrode are sequentially formed on the substrate from bottom to top;

[0007] an acoustic reflection structure, wherein the acoustic reflection structure is formed in the substrate or between the substrate and the lower electrode, and the horizontally projected overlapping area of ​​the acoustic reflection structure, the lower electrode, the piezoelectric layer, and the upper electrode constitutes a resonant region of the bulk acoustic wave resonator;

[0008] The heat dissipation structure includes a first heat dissipation portion and / or a second heat dissipation portion formed outside the resonance zone, the first heat dissipation portion is formed on the lower surface of the piezoelectric layer, and the second heat dissipation portion is formed on the upper surface of the piezoelectric layer.

[0009] According to one aspect of the present invention, in the bulk acoustic wave resonator, the first heat dissipation portion is a first metal heat dissipation layer having a first annular gap formed between the first heat dissipation portion and the lower electrode, or a first insulating heat dissipation layer in contact with the lower electrode; the second heat dissipation portion is a second metal heat dissipation layer having a second annular gap formed between the second heat dissipation portion and the upper electrode, or a second insulating heat dissipation layer in contact with the upper electrode.

[0010] According to another aspect of the present invention, in the BAW resonator, the first metal heat dissipation layer and the lower electrode have different materials and / or thicknesses; the second metal heat dissipation layer and the upper electrode have different materials and / or thicknesses.

[0011] According to another aspect of the present invention, in the bulk acoustic wave resonator, the heat dissipation structure also includes a first thermally conductive insulating structure and / or a second thermally conductive insulating structure; the first thermally conductive insulating structure is located in the first annular gap for connecting the lower electrode and the first metal heat dissipation layer; the second thermally conductive insulating structure is located in the second annular gap for connecting the upper electrode and the second metal heat dissipation layer.

[0012] According to another aspect of the present invention, in the bulk acoustic wave resonator, the first thermally conductive insulating structure includes a plurality of first thermally conductive insulating units spaced apart in the circumferential direction of the first annular gap, and each of the first thermally conductive insulating units is connected to the lower electrode and the first metal heat dissipation layer; the second thermally conductive insulating structure includes a plurality of second thermally conductive insulating units spaced apart in the circumferential direction of the second annular gap, and each of the second thermally conductive insulating units is connected to the upper electrode and the second metal heat dissipation layer.

[0013] According to another aspect of the present invention, in the bulk acoustic wave resonator, the piezoelectric layer includes a first piezoelectric portion and a second piezoelectric portion, the first piezoelectric portion is formed between the upper electrode and the lower electrode, and the second piezoelectric portion is formed outside the resonance region and a third annular gap is formed between the first piezoelectric portion and the second piezoelectric portion.

[0014] The present invention also provides a method for manufacturing a bulk acoustic wave resonator, the method comprising a substrate providing step, an upper electrode forming step, a piezoelectric layer forming step, a lower electrode forming step, and an acoustic reflection structure forming step, wherein the horizontally projected overlapping area of ​​the upper electrode, the piezoelectric layer, the lower electrode, and the acoustic reflection structure constitutes a resonant region of the bulk acoustic wave resonator, the method further comprising:

[0015] A heat dissipation structure is formed outside the resonance zone, wherein the heat dissipation structure includes a first heat dissipation portion and / or a second heat dissipation portion, the first heat dissipation portion is formed on the lower surface of the piezoelectric layer, and the second heat dissipation portion is formed on the upper surface of the piezoelectric layer.

[0016] According to one aspect of the present invention, in the manufacturing method, the first heat dissipation part is a first metal heat dissipation layer with a first annular gap formed between the first heat dissipation part and the lower electrode, or a first insulating heat dissipation layer in contact with the lower electrode; the second heat dissipation part is a second metal heat dissipation layer with a second annular gap formed between the second heat dissipation part and the upper electrode, or a second insulating heat dissipation layer in contact with the lower electrode.

[0017] According to another aspect of the present invention, in the manufacturing method, the steps of forming a lower electrode above the groove on the substrate and forming a first metal heat dissipation layer outside the resonance region include: depositing a first metal heat dissipation material layer on the substrate and etching it to form a first metal heat dissipation layer outside the resonance region; depositing a first metal electrode material layer to cover the substrate and the first metal heat dissipation layer, and etching the first metal electrode material layer to retain only the portion located inside the first metal heat dissipation layer to form a lower electrode, wherein a first annular gap is formed between the lower electrode and the first metal heat dissipation layer; forming an upper electrode on the piezoelectric layer and forming a second metal heat dissipation layer outside the resonance region include: depositing a second metal heat dissipation material layer on the piezoelectric layer and etching it to form a second metal heat dissipation layer outside the resonance region; depositing a second metal electrode material layer to cover the piezoelectric layer and the second metal heat dissipation layer, and etching the second metal electrode material layer to retain only the portion located inside the second metal heat dissipation layer to form an upper electrode, wherein a second annular gap is formed between the upper electrode and the second metal heat dissipation layer.

[0018] According to one aspect of the present invention, in the manufacturing method, the first metal heat dissipation layer and the lower electrode have different materials and / or thicknesses; the second metal heat dissipation layer and the upper electrode have different materials and / or thicknesses.

[0019] According to another aspect of the present invention, in the manufacturing method, after the steps of forming a lower electrode located above the groove on the substrate and forming a first metal heat dissipation layer outside the resonance region, the manufacturing method further includes: forming a first thermally conductive insulating structure for connecting the lower electrode and the first metal heat dissipation layer in the first annular gap; and / or after the steps of forming an upper electrode on the piezoelectric layer and forming a second metal heat dissipation layer outside the resonance region, the manufacturing method further includes: forming a second thermally conductive insulating structure for connecting the upper electrode and the second metal heat dissipation layer in the second annular gap.

[0020] According to another aspect of the present invention, in the manufacturing method, the first thermally conductive insulating structure includes a plurality of first thermally conductive insulating units spaced apart in the circumferential direction of the first annular gap, and each of the first thermally conductive insulating units is connected to the lower electrode and the first metal heat dissipation layer; the second thermally conductive insulating structure includes a plurality of second thermally conductive insulating units spaced apart in the circumferential direction of the second annular gap, and each of the second thermally conductive insulating units is connected to the upper electrode and the second metal heat dissipation layer.

[0021] According to another aspect of the present invention, in the manufacturing method, the piezoelectric layer includes a first piezoelectric portion and a second piezoelectric portion; the step of forming the piezoelectric layer on the substrate includes: depositing a piezoelectric material layer on the substrate and etching the piezoelectric material layer to form a first piezoelectric portion located above the lower electrode, a second piezoelectric portion located outside the resonance region, and a third annular gap located therebetween; after forming the piezoelectric layer, the manufacturing method further includes: filling the third annular gap with a second sacrificial layer; and after forming an upper electrode on the piezoelectric layer, the manufacturing method further includes: removing the second sacrificial layer.

[0022] The present invention also provides a bulk acoustic wave resonator, which includes:

[0023] substrate;

[0024] A lower electrode, a piezoelectric layer, and an upper electrode, wherein the lower electrode, the piezoelectric layer, and the upper electrode are sequentially formed on the substrate from bottom to top, wherein a horizontal projection area of ​​the piezoelectric layer is smaller than a horizontal projection area of ​​the substrate;

[0025] an acoustic reflection structure, wherein the acoustic reflection structure is formed in the substrate or between the substrate and the lower electrode, and the horizontally projected overlapping area of ​​the acoustic reflection structure, the lower electrode, the piezoelectric layer, and the upper electrode constitutes a resonant region of the bulk acoustic wave resonator;

[0026] A heat dissipation structure is formed outside the resonance zone, wherein the heat dissipation structure is a first heat dissipation portion formed on the substrate and thermally connected to the lower electrode; or the heat dissipation structure is a second heat dissipation portion formed on the substrate and thermally connected to the upper electrode, wherein a fourth annular gap is formed between the second heat dissipation portion and the piezoelectric layer, and the fourth annular gap is formed by removing the third sacrificial layer; or the heat dissipation structure includes a first heat dissipation portion corresponding to the lower electrode and a second heat dissipation portion corresponding to the upper electrode, the first heat dissipation portion is formed on the substrate, and the second heat dissipation portion is formed on the first heat dissipation portion, wherein at least one of the first heat dissipation portion and the second heat dissipation portion is thermally connected to the corresponding electrode, and a fourth annular gap is formed between the second heat dissipation portion and the piezoelectric layer.

[0027] The present invention also provides a method for manufacturing a bulk acoustic wave resonator, the method comprising a substrate providing step, an upper electrode forming step, a piezoelectric layer forming step, a lower electrode forming step, and an acoustic reflection structure forming step, wherein the horizontally projected overlapping area of ​​the upper electrode, the piezoelectric layer, the lower electrode, and the acoustic reflection structure constitutes a resonant region of the bulk acoustic wave resonator, wherein:

[0028] The horizontal projection area of ​​the piezoelectric layer is smaller than the horizontal projection area of ​​the substrate;

[0029] Before forming the upper electrode, the manufacturing method further comprises: forming a third sacrificial layer surrounding the sidewall of the piezoelectric layer;

[0030] forming an upper electrode on the piezoelectric layer;

[0031] After the upper electrode is formed, the manufacturing method further includes: removing the third sacrificial layer;

[0032] The manufacturing method also includes: forming a heat dissipation structure outside the resonance zone, the heat dissipation structure is a first heat dissipation portion formed on the substrate and thermally connected to the lower electrode; or the heat dissipation structure is a second heat dissipation portion formed on the substrate and thermally connected to the upper electrode, wherein a fourth annular gap is formed between the second heat dissipation portion and the piezoelectric layer; or the heat dissipation structure includes a first heat dissipation portion corresponding to the lower electrode and a second heat dissipation portion corresponding to the upper electrode, the first heat dissipation portion is formed on the substrate, and the second heat dissipation portion is formed on the first heat dissipation portion, wherein at least one of the first heat dissipation portion and the second heat dissipation portion is thermally connected to the corresponding electrode, and a fourth annular gap is formed between the second heat dissipation portion and the piezoelectric layer, and the fourth annular gap is formed by removing the third sacrificial layer.

[0033] The present invention also provides a bulk acoustic wave resonator, which includes:

[0034] substrate;

[0035] A lower electrode, a piezoelectric layer, and an upper electrode, wherein the lower electrode, the piezoelectric layer, and the upper electrode are sequentially formed on the substrate from bottom to top, wherein a horizontal projection area of ​​the piezoelectric layer is smaller than a horizontal projection area of ​​the substrate;

[0036] an acoustic reflection structure, wherein the acoustic reflection structure is formed in the substrate or between the substrate and the lower electrode, and the horizontally projected overlapping area of ​​the acoustic reflection structure, the lower electrode, the piezoelectric layer, and the upper electrode constitutes a resonant region of the bulk acoustic wave resonator;

[0037] A heat dissipation structure is formed outside the resonance zone, wherein the heat dissipation structure is a second heat dissipation portion formed on the substrate and covering the side wall of the piezoelectric layer; or the heat dissipation structure includes a first heat dissipation portion and a second heat dissipation portion, the first heat dissipation portion is formed on the substrate, and the second heat dissipation portion is formed on the first heat dissipation portion and covers the side wall of the piezoelectric layer.

[0038] The present invention also provides a method for manufacturing a bulk acoustic wave resonator, the method comprising a substrate providing step, an upper electrode forming step, a piezoelectric layer forming step, a lower electrode forming step, and an acoustic reflection structure forming step, wherein the horizontally projected overlapping area of ​​the upper electrode, the piezoelectric layer, the lower electrode, and the acoustic reflection structure constitutes a resonant region of the bulk acoustic wave resonator, wherein:

[0039] The horizontal projection area of ​​the piezoelectric layer is smaller than the horizontal projection area of ​​the substrate;

[0040] The manufacturing method also includes: forming a heat dissipation structure outside the resonance zone, wherein the heat dissipation structure is a second heat dissipation portion formed on the substrate and covering the side wall of the piezoelectric layer; or the heat dissipation structure includes a first heat dissipation portion and a second heat dissipation portion, wherein the first heat dissipation portion is formed on the substrate, and the second heat dissipation portion is formed on the first heat dissipation portion and covers the side wall of the piezoelectric layer.

[0041] The present invention also provides an electronic device, which includes the aforementioned BAW resonator or a BAW resonator formed by the aforementioned manufacturing method.

[0042] According to one aspect of the present invention, in the electronic device, the electronic device further comprises a metal sealing portion formed at an edge of the device, and the metal sealing portion is in contact with the heat dissipation structure.

[0043] The BAW resonator and its manufacturing method provided by the present invention form a heat dissipation structure within the non-resonant region of the BAW resonator, effectively improving the heat dissipation capability of the BAW resonator. Accordingly, electronic devices formed based on the BAW resonator provided by the present invention have excellent heat dissipation properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Other features, objects and advantages of the present invention will become more apparent upon reading the detailed description of non-limiting embodiments made with reference to the following drawings:

[0045] Figure 1 It is a cross-sectional schematic diagram of a common bulk acoustic wave resonator in the prior art;

[0046] Figure 2 is a flow chart of a method for forming a bulk acoustic wave resonator according to a specific embodiment of the present invention;

[0047] Figure 3(a) to Figure 3(g) is in accordance with Figure 2 The method flow shown is a schematic cross-sectional view of various stages of forming a bulk acoustic wave resonator;

[0048] FIG3( c ′) is a schematic top view of the structure shown in FIG3( c );

[0049] Figure 4 and Figure 5 is a schematic cross-sectional view of a bulk acoustic wave resonator according to two specific embodiments of the present invention;

[0050] Figure 6(a) to Figure 6(e) is a cross-sectional schematic diagram of various stages of forming a bulk acoustic wave resonator based on the structure shown in FIG3( c ) according to a specific embodiment of the present invention;

[0051] Figures 7 to 10 are cross-sectional schematic diagrams of bulk acoustic wave resonators according to four specific embodiments of the present invention;

[0052] Figure 11 is a schematic top view of a structure formed after forming a first thermally conductive insulating structure according to a preferred embodiment of the present invention, wherein the first thermally conductive insulating structure includes a plurality of first thermally conductive insulating units;

[0053] Figure 12(a) to Figure 12(d) is a cross-sectional schematic diagram of various stages of forming a bulk acoustic wave resonator according to another preferred embodiment of the present invention;

[0054] FIG12( a ′) is a schematic top view of the structure shown in FIG12( a );

[0055] Figures 13 to 16 Schematic cross-sectional views of bulk acoustic wave resonators according to four specific embodiments of the present invention;

[0056] Figure 17 is a flow chart of a method for manufacturing a bulk acoustic wave resonator according to another specific embodiment of the present invention;

[0057] Figure 18(a) to Figure 18(d) is in accordance with Figure 17 The method flow shown is a schematic cross-sectional view of various stages of forming a bulk acoustic wave resonator;

[0058] Figures 19 to 22 are cross-sectional schematic diagrams of bulk acoustic wave resonators according to four specific embodiments of the present invention;

[0059] Figure 23 is a flow chart of a method for manufacturing a bulk acoustic wave resonator according to another specific embodiment of the present invention;

[0060] Figure 24(a) to Figure 24(d) is in accordance with Figure 23 The method flow shown is a schematic cross-sectional view of various stages of forming a bulk acoustic wave resonator;

[0061] Figures 25 to 29 is a schematic cross-sectional view of a bulk acoustic wave resonator according to five specific embodiments of the present invention;

[0062] Figure 30 is a schematic cross-sectional view of an electronic device according to a specific embodiment of the present invention.

[0063] The same or similar reference numerals in the drawings represent the same or similar components. DETAILED DESCRIPTION

[0064] In order to better understand and illustrate the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0065] The present invention provides a bulk acoustic wave resonator, which includes:

[0066] substrate;

[0067] A lower electrode, a piezoelectric layer, and an upper electrode, wherein the lower electrode, the piezoelectric layer, and the upper electrode are sequentially formed on the substrate from bottom to top;

[0068] an acoustic reflection structure, wherein the acoustic reflection structure is formed in the substrate or between the substrate and the lower electrode, and the horizontally projected overlapping area of ​​the acoustic reflection structure, the lower electrode, the piezoelectric layer, and the upper electrode constitutes a resonant region of the bulk acoustic wave resonator;

[0069] A heat dissipation structure includes a first heat dissipation portion and / or a second heat dissipation portion formed outside the resonance region, the first heat dissipation portion is formed on the lower surface of the piezoelectric layer, and the second heat dissipation portion is formed on the upper surface of the piezoelectric layer.

[0070] The various components of the bulk acoustic wave resonator are described in detail below.

[0071] Specifically, the BAW resonator provided by the present invention includes a substrate. The present invention does not impose any restrictions on the material and thickness of the substrate, and the material and thickness can be selected and determined according to conventional designs.

[0072] The BAW resonator provided by the present invention further includes a lower electrode and an electrode above the piezoelectric layer, formed sequentially from bottom to top on the substrate. The present invention does not impose any restrictions on the materials or thicknesses of the upper electrode, piezoelectric layer, and lower electrode. The upper and lower electrodes can be implemented using conventional electrode materials such as molybdenum, and the piezoelectric layer can be implemented using conventional piezoelectric materials such as AlN. The thicknesses of the upper electrode, piezoelectric layer, and lower electrode can be tailored to actual design requirements.

[0073] The BAW resonator provided by the present invention also includes an acoustic reflection structure for reflecting acoustic waves. The acoustic reflection structure can be a cavity formed between the substrate and the lower electrode, a Bragg reflection layer formed between the substrate and the lower electrode, or an opening extending through the substrate and below the lower electrode. The horizontally projected overlapping area of ​​the upper electrode, the piezoelectric layer, the lower electrode, and the acoustic reflection structure is defined as the resonant region of the BAW resonator, and the remaining area of ​​the BAW resonator is correspondingly defined as the non-resonant region of the BAW resonator.

[0074] The BAW resonator provided by the present invention also includes a heat dissipation structure, which is formed in the non-resonant region of the BAW resonator. In this embodiment, the heat dissipation structure includes a first heat dissipation portion and a second heat dissipation portion, wherein the first heat dissipation portion is formed in the non-resonant region and is located on the lower surface of the piezoelectric layer (which can also be understood as being located between the substrate and the piezoelectric layer), and the second heat dissipation portion is formed in the non-resonant region and is located on the upper surface of the piezoelectric layer. In other embodiments, the heat dissipation structure may only include the first heat dissipation portion formed in the non-resonant region and is located on the lower surface of the piezoelectric layer, or only include the second heat dissipation portion formed in the non-resonant region and is located on the upper surface of the piezoelectric layer.

[0075] The present invention does not impose any restrictions on the specific materials of the first and second heat dissipation portions. Preferred materials include metal materials with excellent heat dissipation properties, such as Cu, Au, Ag, Al, Ni, Ti, Cr, TiW, Fe, Mo, and W. Those skilled in the art will appreciate that the materials of the first and second heat dissipation portions may also be alloy materials, combinations thereof, or non-metallic materials, combinations thereof, as long as they exhibit superior heat dissipation properties to the piezoelectric layer and are suitable for BAW resonator fabrication. For the sake of simplicity, all possible materials for the heat dissipation structure are not listed here.

[0076] With respect to the bulk acoustic wave resonator provided by the present invention, a heat dissipation portion having better heat dissipation performance than the piezoelectric layer is formed on at least one surface of the piezoelectric layer in the non-resonant region. Therefore, the heat in the non-resonant region can be efficiently transferred outward through the heat dissipation portion, thereby effectively improving the heat dissipation capacity of the device.

[0077] The present invention does not impose any restrictions on the specific shape, size, and position of the first heat dissipation part and the second heat dissipation part. In terms of shape, they can be common layered, block-shaped, strip-shaped, etc. In terms of size, they can cover part or all of the surface of the piezoelectric layer in the non-resonant region. In terms of position, they can be located at any position on the surface of the piezoelectric layer in the non-resonant region. It can be understood by those skilled in the art that any structure that is located in the non-resonant region of the bulk acoustic wave resonator and contacts the surface of the piezoelectric layer and can achieve heat dissipation is applicable to the first heat dissipation part and the second heat dissipation part of the present invention. It should be noted here that when the first heat dissipation part is implemented using a conductive material such as metal, there is no direct contact between it and the lower electrode to prevent the two from conducting. Similarly, when the second heat dissipation part is implemented using a conductive material such as metal, there is no direct contact between it and the upper electrode to prevent the two from conducting. In addition, it should be noted that in subsequent electronic devices (such as filter chips, etc.) formed based on the bulk acoustic wave resonator, the metal sealing part used for packaging in the electronic device must also maintain a non-conductive insulation state between the upper electrode and the lower electrode.

[0078] The bulk acoustic wave resonator provided by the present invention is described below with reference to specific embodiments.

[0079] In one specific embodiment, the heat dissipation structure includes both a first heat dissipation portion and a second heat dissipation portion, wherein the first heat dissipation portion is a first metal heat dissipation layer, and the second heat dissipation portion is a second metal heat dissipation layer. Specifically, as shown in FIG3( g ), the bulk acoustic wave resonator includes a substrate 100, a lower electrode 102a, a piezoelectric layer 104, an upper electrode 105a, a cavity 107, a first metal heat dissipation layer 102b, and a second metal heat dissipation layer 105b. The lower electrode 102a and the first metal heat dissipation layer 102b are formed on the substrate 100, wherein the lower electrode 102a is located on the cavity 107, and the first metal heat dissipation layer 102b is located in the non-resonant region of the device. The piezoelectric layer 104 is formed on the substrate 100 to cover the lower electrode 102a and the first metal heat dissipation layer 102b. The upper electrode 105a and the second metal heat dissipation layer 105b are formed on the piezoelectric layer 104, wherein the upper electrode 105a is located above the lower electrode 102a, and the second metal heat dissipation layer 105b is located in the non-resonant region of the device. To prevent contact and conduction between the first metal heat dissipation layer 102b and the lower electrode 102a, an annular gap (hereinafter referred to as a first annular gap, which in this embodiment is filled by the piezoelectric layer 104) is formed between the first metal heat dissipation layer 102b and the lower electrode 102a. Similarly, to prevent contact and conduction between the second metal heat dissipation layer 105b and the upper electrode 105a, an annular gap 106 (hereinafter referred to as a second annular gap 106) is also formed between the second metal heat dissipation layer 105b and the upper electrode 105a.

[0080] In another specific embodiment, the heat dissipation structure only includes the first heat dissipation portion, which is the first metal heat dissipation layer. Figure 4 As shown, the BAW resonator includes a substrate 100, a lower electrode 102a, a piezoelectric layer 104, an upper electrode 105a, a cavity 107, and a first metal heat dissipation layer 102b. The lower electrode 102a and the first metal heat dissipation layer 102b are formed on the substrate 100, wherein the lower electrode 102a is located on the cavity 107, and the first metal heat dissipation layer 102b is located in the non-resonant region of the device. The piezoelectric layer 104 is formed on the substrate 100 to cover the lower electrode 102a and the first metal heat dissipation layer 102b. The upper electrode 105a is formed on the piezoelectric layer 104. A first annular gap is formed between the first metal heat dissipation layer 102b and the lower electrode 102a (in this embodiment, the first annular gap is filled by the piezoelectric layer 104).

[0081] In another specific implementation, the heat dissipation structure only includes the second heat dissipation portion, which is a second metal heat dissipation layer. Figure 5 As shown, the BAW resonator includes a substrate 100, a lower electrode 102a, a piezoelectric layer 104, an upper electrode 105a, a cavity 107, and a second metal heat dissipation layer 105b. The lower electrode 102a is formed on the substrate 100 above the cavity 107. The piezoelectric layer 104 is formed on the substrate 100 to cover the lower electrode 102a. The upper electrode 105a and the second metal heat dissipation layer 105b are formed on the piezoelectric layer 104. The upper electrode 105a is located above the lower electrode 102a, and the second metal heat dissipation layer 105b is located in the non-resonant region of the device. A second annular gap 106 is formed between the second metal heat dissipation layer 105b and the upper electrode 105a.

[0082] It should be noted that (1) for the case where the first heat dissipation portion is the first metal heat dissipation layer, preferably, the material and thickness of the first metal heat dissipation layer and the lower electrode are the same. On the one hand, it is convenient to form the lower electrode and the first metal heat dissipation layer at the same time during the manufacturing process, which is conducive to simplifying the process. On the other hand, the same thickness of the lower electrode and the first metal heat dissipation layer is also conducive to the subsequent formation of a piezoelectric layer with a good crystal orientation. In addition, more preferably, by controlling the etching process, the etching angle between the side wall and the bottom surface of the first metal heat dissipation layer is less than or equal to 30°, and the etching angle between the side wall and the bottom surface of the lower electrode is less than or equal to 30°, which can further make the subsequent piezoelectric layer have a better crystal orientation. Similarly, for the case where the second heat dissipation portion is the second metal heat dissipation layer, preferably, the material and thickness of the second metal heat dissipation layer and the upper electrode are the same, so that the upper electrode and the second metal heat dissipation layer are formed at the same time during the manufacturing process, which is conducive to simplifying the process. In another specific embodiment, the first metal heat dissipation layer and the lower electrode have different materials and / or thicknesses. Similarly, the second metal heat dissipation layer and the upper electrode may also have different materials and / or thicknesses. In particular, the metal heat dissipation layer is made of a metal that is cheaper than the electrode material, which is beneficial to reducing the manufacturing cost of the device; the thickness of the metal heat dissipation layer is greater than that of the electrode, which is more conducive to heat dissipation (in actual production, the thickness of the metal heat dissipation layer can be determined according to actual needs to achieve a balance between the crystal orientation of the piezoelectric layer and the heat dissipation effect). (2) If the first heat dissipation part is a first insulating heat dissipation layer (that is, made of an insulating heat dissipation material), the first insulating heat dissipation layer and the lower electrode are preferably in direct contact to form a thermal connection. Of course, there may also be an annular gap, and the present invention does not impose any restrictions on this. Similarly, if the second heat dissipation part is a second insulating heat dissipation layer (that is, made of an insulating heat dissipation material), the second insulating heat dissipation layer and the upper electrode are preferably in direct contact to form a thermal connection. Of course, there may also be an annular gap, and the present invention does not impose any restrictions on this. It should be noted here that the thermal connection between the above-mentioned insulating heat dissipation layer and the electrode means that there is only heat transfer between the insulating heat dissipation layer and the electrode, and no electrical signal is transferred.

[0083] In the case where the first heat dissipation portion is a first metal heat dissipation layer, a thermally conductive insulating structure (hereinafter referred to as the first thermally conductive insulating structure) is preferably formed between the first metal heat dissipation layer and the lower electrode. This first thermally conductive insulating structure is formed within the first annular gap and serves as a connection between the lower electrode and the first metal heat dissipation layer. In the case where the second heat dissipation portion is a second metal heat dissipation layer, a thermally conductive insulating structure (hereinafter referred to as the second thermally conductive insulating structure) is preferably formed between the second metal heat dissipation layer and the upper electrode. This second thermally conductive insulating structure is formed within the second annular gap and serves as a connection between the upper electrode and the second metal heat dissipation layer. The thermally conductive insulating structure ensures that there is no electrical conduction between the metal heat dissipation layer and the electrode while facilitating heat transfer from the electrode to the metal heat dissipation layer, thereby improving heat dissipation efficiency. Materials for the thermally conductive insulating structure include, but are not limited to, silicon nitride, aluminum nitride, beryllium oxide, or silicone grease. Any insulating material that can be used for heat transfer is suitable for the first and second thermally conductive insulating structures of the present invention. Furthermore, the materials of the first and second thermally conductive insulating structures can be the same or different. This is described below with reference to specific embodiments.

[0084] In one specific embodiment, as shown in FIG6(e), the heat dissipation structure includes both a first heat dissipation portion and a second heat dissipation portion, wherein the first heat dissipation portion is the first metal heat dissipation layer 102b, and the second heat dissipation portion is the second metal heat dissipation layer 105b, wherein a first heat conductive insulating structure 108 is formed between the lower electrode 102a and the first metal heat dissipation layer 102b, and a second heat conductive insulating structure 109 is formed between the upper electrode 105a and the second metal heat dissipation layer 105b. In another specific embodiment, as Figure 7 As shown, the heat dissipation structure includes a first heat dissipation portion and a second heat dissipation portion, wherein the first heat dissipation portion is the first metal heat dissipation layer 102b, and the second heat dissipation portion is the second metal heat dissipation layer 105b, wherein the first heat conductive insulating structure 108 is formed only between the lower electrode 102a and the first metal heat dissipation layer 102b. In another specific embodiment, as Figure 8 As shown, the heat dissipation structure includes a first heat dissipation portion and a second heat dissipation portion, wherein the first heat dissipation portion is the first metal heat dissipation layer 102b, and the second heat dissipation portion is the second metal heat dissipation layer 105b, wherein the second heat conductive insulating structure 109 is formed only between the upper electrode 105a and the second metal heat dissipation layer 105b. In another specific embodiment, as Figure 9 As shown, the heat dissipation structure only includes the first heat dissipation portion and the first heat dissipation portion is the first metal heat dissipation layer 102b, wherein a first heat conductive insulating structure 108 is formed between the lower electrode 102a and the first metal heat dissipation layer 102b. In another specific embodiment, as Figure 10As shown, the heat dissipation structure only includes the second heat dissipation portion, and the second heat dissipation portion is the second metal heat dissipation layer 105b, wherein a second heat-conducting insulating structure 109 is formed between the upper electrode 105a and the second metal heat dissipation layer 105b.

[0085] As for the first heat-conducting insulating structure, it can be a whole structure formed between the lower electrode and the first metal heat dissipation layer, or it can be a plurality of units discretely distributed between the lower electrode and the first metal heat dissipation layer. Figure 11 As shown, the first heat-conducting insulation structure includes a plurality of heat-conducting insulation units 108a (hereinafter referred to as first heat-conducting insulation units 108a) spaced apart in the circumferential direction of the first annular gap, wherein each first heat-conducting insulation unit 108a is connected to the lower electrode 102a and the first metal heat dissipation layer 102b. More preferably, the plurality of first heat-conducting insulation units 108a are spaced apart. It should be noted that, in order to clearly illustrate the first heat-conducting insulation structure, Figure 11 The upper electrode, piezoelectric layer and second heat dissipation portion are omitted. The first heat-conducting insulating structure includes a plurality of first heat-conducting insulating structural units discretely distributed between the lower electrode and the first metal heat dissipation layer, which is beneficial for reducing the loss of acoustic waves.

[0086] Similarly, for the second thermally conductive insulating structure, it can be a whole structure formed between the upper electrode and the second metal heat dissipation layer, or it can be a plurality of units discretely distributed between the upper electrode and the second metal heat dissipation layer. For the latter case, in a preferred embodiment, the second thermally conductive insulating structure includes a plurality of thermally conductive insulating units (hereinafter referred to as second thermally conductive insulating units) spaced apart in the circumferential direction of the second annular gap, wherein each second thermally conductive insulating unit is connected to the upper electrode 105a and the second metal heat dissipation layer 105b. More preferably, the plurality of second thermally conductive insulating units are arranged at equal intervals. The second thermally conductive insulating structure includes a plurality of second thermally conductive insulating structural units discretely distributed between the upper electrode and the second metal heat dissipation layer, which is conducive to reducing the loss of acoustic waves.

[0087] Preferably, the piezoelectric layer includes a first piezoelectric portion and a second piezoelectric portion. The first piezoelectric portion is formed between the upper electrode and the lower electrode, and the horizontal overlapping area thereof with the upper electrode, the lower electrode and the acoustic reflection structure constitutes the resonant region of the device. The second piezoelectric portion is formed in the non-resonant region of the device, and an annular gap (hereinafter referred to as the third annular gap) is formed between the second piezoelectric portion and the first piezoelectric portion. The third annular gap between the first piezoelectric portion and the second piezoelectric portion can effectively reduce the lateral leakage of sound waves in the piezoelectric layer. Preferably, the third annular gap between the first piezoelectric portion and the second piezoelectric portion can be through the piezoelectric layer, that is, there is no connection between the first piezoelectric portion and the second piezoelectric portion, thereby maximally reducing the lateral leakage of sound waves in the piezoelectric layer. Of course, it will be understood by those skilled in the art that the third annular gap can also be non-through the piezoelectric layer, that is, the first piezoelectric portion and the second piezoelectric portion are partially connected, thereby reducing the lateral leakage of sound waves in the piezoelectric layer to a certain extent. It should be noted that, for the case where the third annular gap passes through the piezoelectric layer (i.e., there is no connection between the first piezoelectric portion and the second piezoelectric portion), and the heat dissipation portion is a metal heat dissipation layer, preferably, there is a thermal connection between the metal heat dissipation layer and the corresponding electrode (if the heat dissipation portion includes both the first metal heat dissipation layer and the second metal heat dissipation layer, then at least one of the two is thermally connected to its corresponding electrode), so that the heat in the resonator is transferred outward through the metal heat dissipation layer. In addition, it should be noted that in order to minimize the lateral leakage of sound waves in the piezoelectric layer as much as possible, the first piezoelectric portion should not be located too much in the non-resonant region of the device. Preferably, the first piezoelectric portion is located only above the lower electrode, that is, the horizontal projection of the first piezoelectric portion coincides with the horizontal projection of the lower electrode. This will be described below with specific embodiments.

[0088] In one specific embodiment, as shown in FIG12( d ), a BAW resonator includes a substrate 100, a cavity 107, a lower electrode 102a, a first metal heat dissipation layer 102b, a first thermally conductive insulating structure 108, a first piezoelectric portion 104a, a second piezoelectric portion 104b, an upper electrode 105a, a second metal heat dissipation layer 105b, and a second thermally conductive insulating structure 109. The lower electrode 102a and the first metal heat dissipation layer 102b are formed on the substrate 100 and connected by the first thermally conductive insulating structure 108. The first piezoelectric portion 104a is formed on the lower electrode, and the second piezoelectric portion 104b is formed in a non-resonant region on the first metal heat dissipation layer 102b. A third annular gap 110 is formed between the first piezoelectric portion 104a and the second piezoelectric portion 104b to separate them. The upper electrode 105a is formed on the first piezoelectric portion 104a, and the second metal heat dissipation layer 105b is formed on the second piezoelectric portion 104b. The upper electrode 105a and the second metal heat dissipation layer 105b are connected by a second thermally conductive insulating structure 109. For other embodiments in which the piezoelectric layer includes a first piezoelectric portion and a second piezoelectric portion, reference may be made to Figures 13 to 19 .in, Figure 13 The middle heat dissipation structure includes a first metal heat dissipation layer 102 b and a second metal heat dissipation layer 105 b , wherein only the first metal heat dissipation layer 102 b and the lower electrode 102 a are connected via a first heat-conducting insulating structure 108 . Figure 14 The middle heat dissipation structure only includes the first metal heat dissipation layer 102 b , and the first metal heat dissipation layer 102 b and the lower electrode 102 a are connected via a first heat-conducting insulating structure 108 . Figure 15 The middle heat dissipation structure includes a first metal heat dissipation layer 102 b and a second metal heat dissipation layer 105 b , wherein only the second metal heat dissipation layer 105 b and the upper electrode 105 a are connected via a second heat-conducting insulating structure 109 . Figure 16 The middle heat dissipation structure only includes the second metal heat dissipation layer 105 b , and the second metal heat dissipation layer 105 b and the upper electrode 105 a are connected via a second heat-conducting insulating structure 109 .

[0089] The present invention also provides a method for manufacturing a bulk acoustic wave resonator, wherein the bulk acoustic wave resonator includes a heat dissipation structure, and the heat dissipation structure further includes a first heat dissipation portion and / or a second heat dissipation portion. The manufacturing method provided by the present invention will be described below by taking the case where the sound reflection structure of the bulk acoustic wave resonator is a cavity and the heat dissipation structure includes both the first heat dissipation portion and the second heat dissipation portion as an example. Figure 2 As shown, the manufacturing method includes:

[0090] In step S101, a groove is formed on a substrate and a first sacrificial layer is filled in the groove;

[0091] In step S102, a lower electrode and a first heat dissipation portion are formed on the substrate, wherein the lower electrode is located above the groove, and the first heat dissipation portion is located outside the resonance region of the BAW resonator;

[0092] In step S103, a piezoelectric layer is formed on the lower electrode;

[0093] In step S104, an upper electrode and a second heat dissipation portion are formed on the piezoelectric layer, where the second heat dissipation portion is located outside the resonance region;

[0094] In step S105 , the first sacrificial layer is removed to form a cavity between the lower electrode and the substrate, wherein the upper electrode, the piezoelectric layer, the lower electrode, and the horizontally projected overlapping area of ​​the cavity constitute a resonant region of the BAW resonator.

[0095] The following will be combined Figure 3(a) to Figure 3(g)The above steps S101 to S105 are described in detail. It should be noted that the following description only focuses on the manufacturing method of each component of the BAW resonator. The specific materials, shapes, dimensions, etc. of each component can be found in the previous description of the BAW resonator structure. For the sake of brevity, the description will not be repeated here.

[0096] Specifically, in step S101, as shown in FIG3(a), a substrate 100 is provided, the substrate 100 is etched to form a groove on its surface, and a sacrificial material (hereinafter referred to as a first sacrificial material) is filled in the groove to form a sacrificial layer 101 (hereinafter referred to as the first sacrificial layer 101). The first sacrificial material includes, but is not limited to, SiO2, LTO, PSG, etc.

[0097] In step S102, as shown in FIG3(b), a metal electrode material layer 102 (hereinafter referred to as the first metal electrode material layer 102) is first deposited on the structure shown in FIG3(a). Then, as shown in FIG3(c) and FIG3(c') ( FIG3(c) is a schematic cross-sectional view of the structure shown in FIG3(c') along line AB), the first metal electrode material layer 102 is etched to form an annular opening (hereinafter referred to as the first annular gap 103) exposing the surface of the substrate 100. After etching, the first metal electrode material layer located inside the first annular gap 103 forms the lower electrode 102a located above the groove. After etching, the first metal electrode material layer located outside the first annular gap 103 forms the first metal heat dissipation layer 102a (i.e., the first heat dissipation portion) located within the non-resonant region of the BAW resonator. In this embodiment, the resonant region of the BAW resonator refers to the horizontally projected overlapping region of the upper electrode, piezoelectric layer, lower electrode, and cavity in the BAW resonator, while the remaining region outside the BAW resonator is the non-resonant region of the BAW resonator. It should be noted that although the piezoelectric layer, top electrode, and cavity are formed in subsequent steps, the parameters of the BAW resonator's piezoelectric layer, top electrode, and cavity are pre-designed before actual production. In other words, the ranges of the BAW resonator's resonant and non-resonant regions are predetermined before actual production. Therefore, etching the first metal electrode material layer 102 ensures that the first metal heat dissipation layer 102b is located within the device's non-resonant region. In this embodiment, the first metal heat dissipation layer 102b and the lower electrode 102a are formed simultaneously, using the same material and thickness. This simultaneous formation of the first metal heat dissipation layer 102b and the lower electrode 102a not only simplifies the process but also facilitates the subsequent formation of a piezoelectric layer with a favorable crystal orientation due to the same thickness as the lower electrode. Furthermore, more preferably, by controlling the etching process to ensure that the etching angle between the sidewalls and bottom surface of the first metal heat dissipation layer is less than or equal to 30°, and the etching angle between the sidewalls and bottom surface of the lower electrode is less than or equal to 30°, further improving the crystal orientation of the subsequent piezoelectric layer. It should also be noted that in this embodiment, since the first heat dissipation portion (i.e., first metal heat dissipation layer 102b) is made of a metal material, a barrier is required between the first metal heat dissipation layer 102b and the lower electrode 102a (in this embodiment, this barrier is implemented by a first annular gap 103) to prevent electrical conduction between the two. In other embodiments, if the first heat dissipation portion is a first insulating heat dissipation layer (i.e., implemented using an insulating heat dissipation material), then the first insulating heat dissipation layer and the lower electrode 102a are preferably in direct contact to form a thermal connection. However, a first annular gap may also be formed between the first insulating heat dissipation layer and the lower electrode 102a.

[0098] In the above embodiment, the first metal heat dissipation layer 102b and the lower electrode 102a are formed simultaneously. In other embodiments, the first metal heat dissipation layer 102b can also be formed successively with the lower electrode 102a. Specifically, first, a first metal heat dissipation material layer is deposited on the substrate and etched (e.g., photolithography) to form a first metal heat dissipation layer in the non-resonant region of the device; then, a first metal electrode material layer is deposited on the substrate, and the first metal electrode material layer covers the substrate and the first metal heat dissipation layer; then, the first metal electrode material layer is etched (e.g., photolithography) to retain only the portion located inside the first metal heat dissipation layer to form the lower electrode, wherein a first annular gap is formed between the lower electrode and the first metal heat dissipation layer. It should be noted that (1) in this embodiment, the first metal heat dissipation layer 102b and the lower electrode 102a can have different materials and / or thicknesses. In particular, the first metal heat dissipation layer can be made of a metal that is cheaper than the lower electrode material, which is beneficial to reducing the manufacturing cost of the device; the thickness of the first metal heat dissipation layer can also be set to be greater than the thickness of the lower electrode, so as to be more conducive to heat dissipation (in actual production, the thickness of the first metal heat dissipation layer can be set according to actual needs to achieve a balance between the crystal orientation of the piezoelectric layer and the heat dissipation effect); (2) the lower electrode can also be formed first and then the first metal heat dissipation layer is formed. However, in this case, the lower electrode needs to be protected after it is formed to avoid damage to the lower electrode when etching to form the first metal heat dissipation layer.

[0099] In step S103 , as shown in FIG3( d ), a piezoelectric layer 104 covering the substrate 100 , the lower electrode 102 a and the first metal heat dissipation layer 102 b is formed on the structure shown in FIG3( c ).

[0100] In step S104, first, as shown in FIG3(e), a metal electrode material layer 105 (hereinafter referred to as the second metal electrode material layer 105) is deposited on the structure shown in FIG3(d); then, as shown in FIG3(f), the second metal electrode material layer 105 is etched to form an annular opening (hereinafter referred to as the second annular gap 106) exposing the surface of the piezoelectric layer 104. After etching, the second metal electrode material layer located inside the second annular gap 106 forms an upper electrode 105a located above the lower electrode 102a. After etching, the second metal electrode material layer located outside the second annular gap 106 forms a second metal heat dissipation layer 105b (i.e., a second heat dissipation portion) located within the non-resonant region of the device. In this embodiment, the second metal heat dissipation layer 105b is formed simultaneously with the upper electrode 105a, and the two have the same material and thickness. Forming the second metal heat dissipation layer 105b and the upper electrode 105a simultaneously facilitates process simplification. It should also be noted that in this embodiment, since the second heat dissipation portion (i.e., second metal heat dissipation layer 105b) is made of a metal material, a barrier is required between the second metal heat dissipation layer 105b and the lower electrode 105a (in this embodiment, this barrier is implemented by a second annular gap 106) to prevent electrical conduction between the two. In other embodiments, if the second heat dissipation portion is a second insulating heat dissipation layer (i.e., implemented using an insulating heat dissipation material), the second insulating heat dissipation layer and the upper electrode 105a are preferably in direct contact to form a thermal connection. However, a second annular gap may also be formed between the second insulating heat dissipation layer and the upper electrode 105a.

[0101] In the above embodiment, the second metal heat dissipation layer 105b and the upper electrode 105a are formed simultaneously. In other embodiments, the second metal heat dissipation layer 105b can also be formed successively with the upper electrode 105a. Specifically, first, a second metal heat dissipation material layer is deposited on the piezoelectric layer and etched (e.g., photolithography) to form a second metal heat dissipation layer in the non-resonant region of the device; then, a second metal electrode material layer is deposited on the piezoelectric layer, and the second metal electrode material layer covers the piezoelectric layer and the second metal heat dissipation layer; then, the second metal electrode material layer is etched (e.g., photolithography) to retain only the portion located inside the second metal heat dissipation layer to form the upper electrode, wherein a second annular gap is formed between the upper electrode and the second metal heat dissipation layer. It should be noted that (1) in this embodiment, the second metal heat dissipation layer 105b and the upper electrode 105a can have different materials and / or thicknesses. In particular, the second metal heat dissipation layer can be made of a metal that is cheaper than the upper electrode material, which is beneficial to reducing the manufacturing cost of the device; the thickness of the second metal heat dissipation layer can also be set to be greater than the thickness of the upper electrode, which is more conducive to heat dissipation; (2) the upper electrode can also be formed first and then the second metal heat dissipation layer is formed. However, in this case, the upper electrode needs to be protected after it is formed to avoid damage to the upper electrode when etching the second metal heat dissipation layer.

[0102] In step S105, as shown in FIG3(g), a release channel (not shown) is formed to expose the first sacrificial layer 101. An etching solution is used to remove the first sacrificial layer 101 through the release channel to form a cavity 107 between the lower electrode 102a and the substrate 100. At this point, the BAW resonator is fabricated.

[0103] In a bulk acoustic wave resonator formed by implementing the manufacturing method provided by the present invention, a heat dissipation portion having better heat dissipation performance than the piezoelectric layer is formed on at least one surface of the piezoelectric layer in the non-resonant region. Therefore, heat in the non-resonant region can be efficiently transferred to the outside through the heat dissipation portion, thereby effectively improving the heat dissipation capacity of the device.

[0104] It will be understood by those skilled in the art that the heat dissipation structure of the bulk acoustic wave resonator in the above-mentioned embodiment includes both the first heat dissipation portion and the second heat dissipation portion. In other examples, the heat dissipation structure may also include only the first heat dissipation portion or the second heat dissipation portion. For the sake of simplicity, the process of the manufacturing method of forming only the first heat dissipation portion or the second heat dissipation portion will not be repeated here.

[0105] Preferably, after forming the lower electrode 102a and the first metal heat dissipation layer 102 in step S102, the manufacturing method provided by the present invention further includes: forming a first thermally conductive insulating structure for connecting the lower electrode 102a and the first metal heat dissipation layer 102b within the first annular gap 103; and after forming the upper electrode 105a and the second metal heat dissipation layer 105b in step S104, the manufacturing method provided by the present invention further includes: forming a second thermally conductive insulating structure for connecting the upper electrode 105a and the second metal heat dissipation layer 105b within the second annular gap 106. The first and second thermally conductive insulating structures facilitate transfer of heat from the electrodes to the metal heat dissipation layer, thereby improving heat dissipation efficiency. Specifically, after executing step S102 to obtain the structure shown in FIG3(c), first, as shown in FIG6(a), a thermally conductive insulating material (hereinafter referred to as a first thermally conductive insulating material) is deposited on the structure shown in FIG3(c) and planarized until the upper surfaces of the lower electrode 102a and the first metal heat dissipation layer 102b are exposed, thereby forming a first thermally conductive insulating structure 108 within the first annular gap 103. Then, as shown in FIG6(b), a piezoelectric layer 104 is formed. Then, as shown in FIG6(c), an upper electrode 105a and a second metal heat dissipation layer 105 are formed on the piezoelectric layer 104. Then, as shown in FIG6(d), a thermally conductive insulating material (hereinafter referred to as a second thermally conductive insulating material) is deposited on the structure shown in FIG6(d) and planarized until the upper surfaces of the upper electrode 105a and the second metal heat dissipation layer 105b are exposed, thereby forming a second thermally conductive insulating structure 109 within the second annular gap 106. Finally, as shown in FIG6(e), the first sacrificial layer 101 is removed to form a cavity 107 below the lower electrode 102a. It should be noted that (1) the material of the first thermally conductive insulating structure 108 and the material of the second thermally conductive insulating structure 109 can be the same or different; (2) when the first heat dissipation portion is the first metal heat dissipation layer and the second heat dissipation portion is the second metal heat dissipation layer, in other embodiments, the first thermally conductive insulating structure can be formed only between the lower electrode and the first metal heat dissipation layer, or the second thermally conductive insulating structure can be formed only between the upper electrode and the second metal heat dissipation layer.

[0106] In the case where a first thermally conductive insulating structure is formed between the lower electrode and the first metal heat dissipation layer, in a preferred embodiment, after the first thermally conductive insulating material is planarized, the planarized first thermally conductive insulating material is patterned to form the first thermally conductive insulating structure, wherein, Figure 11As shown, the first thermally conductive insulating structure includes a plurality of first thermally conductive insulating units 108a spaced apart circumferentially within the first annular gap. Each first thermally conductive insulating unit 108 is connected to the lower electrode 102a and the first metal heat dissipation layer 102b. The first thermally conductive insulating structure comprises a plurality of first thermally conductive insulating structural units discretely distributed between the lower electrode and the first metal heat dissipation layer, thereby reducing acoustic wave losses.

[0107] Regarding the case where a second thermally conductive insulating structure is formed between the top electrode and the second metal heat dissipation layer, in a preferred embodiment, after the second thermally conductive insulating material is planarized, the planarized second thermally conductive insulating material is patterned to form the second thermally conductive insulating structure. The second thermally conductive insulating structure includes a plurality of second thermally conductive insulating units spaced apart circumferentially around the second annular gap, each of which is connected to the top electrode and the second metal heat dissipation layer. The second thermally conductive insulating structure comprises a plurality of second thermally conductive insulating units discretely distributed between the top electrode and the second metal heat dissipation layer, which helps reduce acoustic wave loss.

[0108] In a preferred embodiment, the piezoelectric layer includes a first piezoelectric portion and a second piezoelectric portion. The following is an example of forming the first piezoelectric portion and the second piezoelectric portion on the structure shown in Figure 6(a). Specifically, as shown in Figures 12(a) and 12(a') (12(a) is a schematic cross-sectional view of the structure shown in Figure 12(a') along line AB), a piezoelectric material layer is deposited on the structure shown in Figure 6(a) and etched to form an annular opening (hereinafter referred to as a third annular gap 110) that passes through the piezoelectric material layer in the thickness direction. After etching, the piezoelectric material layer located on the inner side of the third annular gap 110 forms the first piezoelectric portion 104a located above the lower electrode 102a, and after etching, the piezoelectric material layer located on the outer side of the third annular gap 110 forms the second piezoelectric portion 104b located in the non-resonant region of the bulk acoustic wave resonator. Then, as shown in FIG12( b ), a sacrificial material (hereinafter referred to as the second sacrificial material) is filled into the third annular gap 110 to form a sacrificial layer 111 (hereinafter referred to as the second sacrificial layer 111 ). Then, as shown in FIG12( c ), an upper electrode 105 a, a second metal heat dissipation layer 105 b, and a second thermally conductive insulating structure 109 are formed on the structure shown in FIG12( b ). Finally, as shown in FIG12( d ), the first sacrificial layer 101 is removed to form a cavity 107 between the substrate 100 and the lower electrode 102 a, and the second sacrificial layer 111 is removed to release the third annular gap 110. The third annular gap 110 between the first piezoelectric portion 104 a and the second piezoelectric portion 104 b can effectively reduce the lateral leakage of acoustic waves within the piezoelectric layer. Preferably, as shown in FIG12( d ), the third annular gap 110 between the first piezoelectric portion 104a and the second piezoelectric portion 104b may be through the piezoelectric layer, that is, there is no connection between the first piezoelectric portion 104a and the second piezoelectric portion 104b, thereby minimizing the lateral leakage of the acoustic wave in the piezoelectric layer. Of course, it will be understood by those skilled in the art that the third annular gap 110 may also be non-through the piezoelectric layer, that is, the first piezoelectric portion 104a and the second piezoelectric portion 104b are partially connected, thereby minimizing the lateral leakage of the acoustic wave in the piezoelectric layer to a certain extent. In addition, it should be noted that (1) in order to minimize the lateral leakage of the acoustic wave in the piezoelectric layer as much as possible, the first piezoelectric portion 104a should not be located too much in the non-resonant region of the device. Preferably, the first piezoelectric portion 104a is only located above the lower electrode 102a, that is, the horizontal projection of the first piezoelectric portion 104a and the horizontal projection of the lower electrode 102a coincide. (2) The first sacrificial material and the second sacrificial material may be the same or different. When the materials of the two are the same, they can be removed at the same time.

[0109] In the above-mentioned method for manufacturing a bulk acoustic wave resonator, the acoustic reflection structure is a cavity. In the case where the acoustic reflection structure is a Bragg reflection layer, the steps differ from the above-mentioned manufacturing method in that, after providing a substrate, a Bragg reflection layer is formed on the substrate, and then the subsequent steps of forming a lower electrode, a piezoelectric layer, an upper electrode, and a heat dissipation structure are completed on the Bragg reflection layer. In the case where the acoustic reflection structure is an opening that penetrates the substrate, the steps differ from the above-mentioned manufacturing method in that, after providing a substrate, completing the steps of forming a lower electrode, a piezoelectric layer, an upper electrode, and a heat dissipation structure on the substrate, the substrate is etched from the back to form an opening. For the sake of simplicity, the manufacturing method of a bulk acoustic wave resonator in which the acoustic reflection structure is a Bragg reflection layer and a back opening will not be described in detail here.

[0110] The present invention also provides a bulk acoustic wave resonator, which includes:

[0111] substrate;

[0112] A lower electrode, a piezoelectric layer, and an upper electrode, wherein the lower electrode, the piezoelectric layer, and the upper electrode are sequentially formed on the substrate from bottom to top, wherein a horizontal projection area of ​​the piezoelectric layer is smaller than a horizontal projection area of ​​the substrate;

[0113] an acoustic reflection structure, wherein the acoustic reflection structure is formed in the substrate or between the substrate and the lower electrode, and the horizontally projected overlapping area of ​​the acoustic reflection structure, the lower electrode, the piezoelectric layer, and the upper electrode constitutes a resonant region of the bulk acoustic wave resonator;

[0114] A heat dissipation structure, which is formed outside the resonance zone, wherein the heat dissipation structure is a first heat dissipation portion formed on the substrate and thermally connected to the lower electrode; or the heat dissipation structure is a second heat dissipation portion formed on the substrate and thermally connected to the upper electrode, wherein a fourth annular gap is formed between the second heat dissipation portion and the piezoelectric layer; or the heat dissipation structure includes a first heat dissipation portion corresponding to the lower electrode and a second heat dissipation portion corresponding to the upper electrode, the first heat dissipation portion is formed on the substrate, and the second heat dissipation portion is formed on the first heat dissipation portion, wherein at least one of the first heat dissipation portion and the second heat dissipation portion is thermally connected to the corresponding electrode, and a fourth annular gap is formed between the second heat dissipation portion and the piezoelectric layer.

[0115] The various components of the bulk acoustic wave resonator are described in detail below.

[0116] Specifically, the bulk acoustic wave resonator provided by the present invention includes a substrate, a lower electrode formed on the substrate, a piezoelectric layer formed on the lower electrode, an upper electrode formed on the piezoelectric layer, and a cavity formed between the substrate and the lower electrode. In this embodiment, the horizontal projection area of ​​the piezoelectric layer is smaller than the horizontal projection area of ​​the substrate, that is, the piezoelectric layer no longer covers the entire surface of the substrate. Making the horizontal projection area of ​​the piezoelectric layer smaller than the horizontal projection area of ​​the substrate is beneficial to reducing the lateral area of ​​the piezoelectric layer, and further helps to reduce the lateral leakage of sound waves in the piezoelectric layer. Preferably, the horizontal projection of the piezoelectric layer coincides with the horizontal projection of the lower electrode, thereby minimizing the lateral leakage of sound waves in the piezoelectric layer while ensuring that the bulk acoustic wave resonator can operate normally.

[0117] The BAW resonator provided by the present invention also includes a heat dissipation structure, which is formed in the non-resonant region of the BAW resonator, wherein the heat dissipation structure includes a first heat dissipation portion and / or a second heat dissipation portion. In one case, the heat dissipation structure only includes a first heat dissipation portion formed on the substrate and thermally connected to the lower electrode. In another case, the heat dissipation structure only includes a second heat dissipation portion formed on the substrate and thermally connected to the upper electrode, wherein a fourth annular gap is formed between the second heat dissipation portion and the piezoelectric layer. In another case, the heat dissipation structure includes both a first heat dissipation portion and a second heat dissipation portion, the first heat dissipation portion corresponding to the lower electrode, and the second heat dissipation portion corresponding to the upper electrode. Specifically, the first heat dissipation portion is formed on the substrate, and the second heat dissipation portion is formed on the first heat dissipation portion. In which, at least one of the first heat dissipation portion and the second heat dissipation portion is thermally connected to the electrode corresponding thereto, and a fourth annular gap is formed between the second heat dissipation portion and the piezoelectric layer. In the case where the heat dissipation portion is implemented using a metal material, an annular gap is formed between the heat dissipation portion and the corresponding electrode to ensure that the two are not conductive (the first annular gap is between the first heat dissipation portion and the lower electrode, and the second annular gap is between the second heat dissipation portion and the upper electrode). In this case, a thermal connection can be formed between the heat dissipation portion and the corresponding electrode via a thermally conductive insulating structure. This thermally conductive insulating structure ensures that there is no electrical conduction between the heat dissipation portion and the electrode while facilitating heat transfer from the electrode to the heat dissipation portion via the thermally conductive insulating structure, thereby improving the heat dissipation performance of the device. This will be described below using specific embodiments.

[0118] In one specific implementation, as shown in FIG18( d ), the heat dissipation structure includes both a first metal heat dissipation layer 102 b and a second metal heat dissipation layer 105 b . A first thermally conductive insulating structure 108 is formed between the lower electrode 102 a and the first metal heat dissipation layer 102 b , and a second thermally conductive insulating structure 109 is formed between the upper electrode 105 a and the second metal heat dissipation layer 105 b . The second metal heat dissipation layer 105 b is formed on the first metal heat dissipation layer 102 b , and a fourth annular gap 113 is formed between the second metal heat dissipation layer 105 b and the sidewall of the piezoelectric layer 104 .

[0119] In another specific embodiment, Figure 19 As shown, the heat dissipation structure includes a first metal heat dissipation layer 102b and a second metal heat dissipation layer 105b. A first thermally conductive insulating structure 108 is formed only between the lower electrode 102a and the first metal heat dissipation layer 102b. The second metal heat dissipation layer 105b is formed on the first metal heat dissipation layer 102b, and a fourth annular gap 113 is formed between the second metal heat dissipation layer 105b and the sidewall of the piezoelectric layer 104.

[0120] In another specific embodiment, Figure 20 As shown, the heat dissipation structure only includes the first metal heat dissipation layer 102 b , and a first thermally conductive insulating structure 108 is formed between the lower electrode 102 a and the first metal heat dissipation layer 102 b .

[0121] In another specific embodiment, Figure 21 As shown, the heat dissipation structure includes a first metal heat dissipation layer 102b and a second metal heat dissipation layer 105b. A second thermally conductive insulating structure 109 is formed only between the upper electrode 105a and the second metal heat dissipation layer 105b. The second metal heat dissipation layer 105b is formed on the first metal heat dissipation layer 102b, and a fourth annular gap 113 is formed between the second metal heat dissipation layer 105b and the sidewall of the piezoelectric layer 104.

[0122] In another specific embodiment, Figure 22 As shown, the heat dissipation structure includes only the second metal heat dissipation layer 105b, and a second thermally conductive insulating structure 109 is formed between the upper electrode 105a and the second metal heat dissipation layer 105b. The second metal heat dissipation layer 105b is formed on the substrate 100, and a fourth annular gap 113 is formed between the second metal heat dissipation layer 105b and the sidewall of the piezoelectric layer 104.

[0123] Preferably, the first thermally conductive insulating structure includes a plurality of first thermally conductive insulating units spaced apart circumferentially around the first annular gap, wherein each first thermally conductive insulating unit is connected to the lower electrode and the first metal heat dissipation layer. More preferably, the plurality of first thermally conductive insulating units are equally spaced apart. The first thermally conductive insulating structure includes a plurality of first thermally conductive insulating structural units discretely distributed between the lower electrode and the first metal heat dissipation layer, which helps reduce acoustic wave losses.

[0124] Preferably, the second thermally conductive insulating structure includes a plurality of second thermally conductive insulating units spaced apart circumferentially about the second annular gap, wherein each second thermally conductive insulating unit is connected to the upper electrode and the second metal heat dissipation layer. More preferably, the plurality of second thermally conductive insulating units are equally spaced apart. The second thermally conductive insulating structure includes a plurality of second thermally conductive insulating structural units discretely distributed between the upper electrode and the second metal heat dissipation layer, which helps reduce acoustic wave loss.

[0125] Furthermore, the materials of the first and second heat dissipation portions may also be alloys, combinations thereof, or non-metallic materials with good heat dissipation properties. For the sake of simplicity, all possible materials for the heat dissipation portions are not listed here. When the heat dissipation portion is made of an insulating heat dissipation material, the heat dissipation portion preferably directly contacts its corresponding electrode to achieve thermal connection.

[0126] The present invention also provides a method for manufacturing a bulk acoustic wave resonator, wherein the bulk acoustic wave resonator includes a heat dissipation structure, and the heat dissipation structure further includes a first heat dissipation portion and / or a second heat dissipation portion. The manufacturing method provided by the present invention will be described below by taking the case where the sound reflection structure of the bulk acoustic wave resonator is a cavity and the heat dissipation structure includes both the first heat dissipation portion and the second heat dissipation portion as an example. Figure 17 As shown, the manufacturing method includes:

[0127] In step S201, a groove is formed on a substrate and a first sacrificial layer is filled in the groove;

[0128] In step S202, a lower electrode and a first heat dissipation portion are formed on the substrate, wherein the lower electrode is located above the groove, and the first heat dissipation portion is located outside the resonance region of the BAW resonator and is thermally connected to the lower electrode;

[0129] In step S203, a piezoelectric layer is formed above the lower electrode, and a third sacrificial layer is formed on a sidewall of the piezoelectric layer to surround the piezoelectric layer, wherein a horizontal projection area of ​​the piezoelectric layer is smaller than a horizontal projection area of ​​the substrate;

[0130] In step S204, an upper electrode is formed on the piezoelectric layer, and a second heat dissipation portion is formed outside the resonance region, wherein the second heat dissipation portion is formed on the first heat dissipation portion and the third sacrificial layer and is thermally connected to the upper electrode;

[0131] In step S205, the first sacrificial layer is removed to form a cavity between the lower electrode and the substrate, and the third sacrificial layer is removed to form a fourth annular gap between the second heat dissipation portion and the piezoelectric layer, wherein the horizontal projection overlapping area of ​​the upper electrode, the piezoelectric layer, the lower electrode and the cavity constitutes the resonant region of the bulk acoustic wave resonator.

[0132] The following will be combined Figure 18(a) to Figure 18(d) The above steps S201 to S205 are described in detail. It should be noted that the following description only focuses on the manufacturing method of each component of the BAW resonator. The specific materials, shapes, dimensions, etc. of each component can be found in the previous description of the BAW resonator structure. For the sake of brevity, the description will not be repeated here.

[0133] Specifically, step S201 can refer to the description of the aforementioned step S101, and the formation of the first heat dissipation portion in step S202 can refer to the aforementioned step S102. In this embodiment, the first heat dissipation portion is a first metal heat dissipation layer. The difference from the aforementioned step S102 is that in step S202, after forming the lower electrode and the first metal heat dissipation layer, it is also necessary to form a first thermally conductive insulating structure between the two (i.e., within the first annular gap) so that the heat in the lower electrode can be quickly transferred to the first metal heat dissipation layer, thereby improving the heat dissipation efficiency. The structure obtained after executing step S202 can be referred to Figure 6(a). The following description of the subsequent steps will be based on the structure shown in 6(a).

[0134] In step S203, as shown in FIG18( a ), a piezoelectric layer 104 is formed above the lower electrode 102 a, and a third sacrificial layer 112 is formed on the sidewalls of the piezoelectric layer 104 to surround it. The horizontal projection area of ​​the piezoelectric layer 104 is smaller than the horizontal projection area of ​​the substrate 100. In this embodiment, after forming the lower electrode 102 a, the first metal heat dissipation layer 102 b, and the first thermally conductive insulating structure 108, a piezoelectric material layer is first deposited to cover the substrate 100, the lower electrode 102 a, the first metal heat dissipation layer 102 b, and the first thermally conductive insulating structure 108. The piezoelectric material layer is then etched to form an annular gap extending through the piezoelectric material layer, forming the piezoelectric layer 104 within the annular gap. The annular gap is then filled with a third sacrificial material to form the third sacrificial layer 112. Finally, the piezoelectric material layer located outside the third sacrificial layer 112 is removed. Preferably, as shown in FIG18( a ), the horizontal projection area of ​​the piezoelectric layer 104 coincides with the horizontal projection area of ​​the lower electrode 102 a , so as to minimize the lateral leakage of acoustic waves within the piezoelectric layer 104 .

[0135] In step S204, first, as shown in Figure 18(b), a second metal electrode material layer 105 is deposited on the structure shown in Figure 18(a), and the second metal electrode material layer 105 covers the first metal heat dissipation layer 102b, the third sacrificial layer 112 and the piezoelectric layer 104; then, as shown in Figure 18(c), the second metal electrode material layer 105 is etched to form an upper electrode 105a on the piezoelectric layer 104, and a second metal heat dissipation layer 105b is formed on the surface of the first metal heat dissipation layer 102b and the third sacrificial layer 112, and a second thermally conductive insulating structure 109 is formed in the second annular gap between the upper electrode 105a and the second metal heat dissipation layer 105b, so that the heat in the upper electrode 105a can be quickly transferred to the second metal heat dissipation layer 105b, thereby improving the heat dissipation efficiency.

[0136] In step S205, as shown in FIG18( d ), the first sacrificial layer 101 is removed to form a cavity 107 between the lower electrode 102 a and the substrate 100 , and the third sacrificial layer 112 is removed to form a fourth annular gap 113 between the second metal heat dissipation layer 105 b and the piezoelectric layer 104 . The horizontally projected overlapping region of the upper electrode 105 a, the piezoelectric layer 104 , the lower electrode 102 a, and the cavity 107 constitutes the resonant region of the BAW resonator, while the remaining region outside of this resonant region constitutes the non-resonant region of the BAW resonant region. The first sacrificial material and the third sacrificial material may be the same or different. If they are the same material, they may be removed simultaneously.

[0137] The BAW resonator formed by implementing the manufacturing method provided by the present invention, on the one hand, has a heat dissipation structure formed in its non-resonant region and thermally connected to at least the upper electrode or the lower electrode. Therefore, the heat in the resonant region can be effectively transferred outward through the heat dissipation portion, thereby effectively improving the heat dissipation capacity of the device. On the other hand, the horizontal projected area of ​​the piezoelectric layer is smaller than the horizontal projected area of ​​the substrate, which helps to reduce the lateral area of ​​the piezoelectric layer and, in turn, helps to reduce the lateral leakage of acoustic waves in the piezoelectric layer.

[0138] It will be understood by those skilled in the art that (1) the heat dissipation structure of the bulk acoustic wave resonator in the above embodiment includes both the first heat dissipation portion and the second heat dissipation portion. In other examples, the heat dissipation structure may also include only the first heat dissipation portion or the second heat dissipation portion (when only the second heat dissipation portion is included, the second heat dissipation portion is directly formed on the substrate). For the sake of simplicity, the manufacturing method of forming only the first heat dissipation portion or the second heat dissipation portion will not be described repeatedly here. (2) In the above embodiment, the first heat dissipation portion and the second heat dissipation portion are both thermally connected to the corresponding electrode through a thermally conductive insulating structure. In other embodiments, only the first heat dissipation portion and the lower electrode may be thermally connected through the first thermally conductive insulating structure, or only the second heat dissipation portion and the upper electrode may be thermally connected through the second thermally conductive insulating structure. For the sake of simplicity, the manufacturing process of the above two cases will not be described repeatedly here. (3) The materials of the first heat dissipation portion and the second heat dissipation portion may also be, for example, alloy materials and combinations thereof, non-metallic materials with good heat dissipation properties, etc. For the sake of simplicity, all possible materials of the heat dissipation portion will not be listed here one by one. When the heat dissipation portion material is an insulating heat dissipation material, the heat dissipation portion is preferably directly in contact with its corresponding electrode to achieve thermal connection.

[0139] Preferably, the first thermally conductive insulating structure includes a plurality of first thermally conductive insulating units spaced apart circumferentially around the first annular gap, wherein each first thermally conductive insulating unit is connected to the lower electrode and the first metal heat dissipation layer. More preferably, the plurality of first thermally conductive insulating units are equally spaced apart. The first thermally conductive insulating structure includes a plurality of first thermally conductive insulating structural units discretely distributed between the lower electrode and the first metal heat dissipation layer, which helps reduce acoustic wave losses.

[0140] Preferably, the second thermally conductive insulating structure includes a plurality of second thermally conductive insulating units spaced apart circumferentially about the second annular gap, wherein each second thermally conductive insulating unit is connected to the upper electrode and the second metal heat dissipation layer. More preferably, the plurality of second thermally conductive insulating units are equally spaced apart. The second thermally conductive insulating structure includes a plurality of second thermally conductive insulating structural units discretely distributed between the upper electrode and the second metal heat dissipation layer, which helps reduce acoustic wave loss.

[0141] In the above-described BAW resonator manufacturing method, the acoustic reflective structure is a cavity. For cases where the acoustic reflective structure is a Bragg reflector or an open-back structure, the steps differ from the above-described manufacturing method only in the formation of the acoustic reflective structure. For the sake of simplicity, the manufacturing method for BAW resonators with Bragg reflectors and open-back structures will not be described in detail here.

[0142] The present invention also provides a bulk acoustic wave resonator, which includes:

[0143] substrate;

[0144] A lower electrode, a piezoelectric layer, and an upper electrode, wherein the lower electrode, the piezoelectric layer, and the upper electrode are sequentially formed on the substrate from bottom to top, wherein a horizontal projection area of ​​the piezoelectric layer is smaller than a horizontal projection area of ​​the substrate;

[0145] an acoustic reflection structure, wherein the acoustic reflection structure is formed in the substrate or between the substrate and the lower electrode, and the horizontally projected overlapping area of ​​the acoustic reflection structure, the lower electrode, the piezoelectric layer, and the upper electrode constitutes a resonant region of the bulk acoustic wave resonator;

[0146] A heat dissipation structure is formed outside the resonance zone, wherein the heat dissipation structure is a second heat dissipation portion formed on the substrate and covering the side wall of the piezoelectric layer; or the heat dissipation structure includes a first heat dissipation portion and a second heat dissipation portion, the first heat dissipation portion is formed on the substrate, and the second heat dissipation portion is formed on the first heat dissipation portion and covers the side wall of the piezoelectric layer.

[0147] The various components of the bulk acoustic wave resonator are described in detail below.

[0148] Specifically, the bulk acoustic wave resonator provided by the present invention includes a substrate, a lower electrode formed on the substrate, a piezoelectric layer formed on the lower electrode, an upper electrode formed on the piezoelectric layer, and a cavity formed between the substrate and the lower electrode. In this embodiment, the horizontal projected area of ​​the piezoelectric layer is smaller than the horizontal projected area of ​​the substrate; that is, the piezoelectric layer no longer covers the entire surface of the substrate. This smaller horizontal projected area of ​​the piezoelectric layer helps reduce the lateral area of ​​the piezoelectric layer, thereby reducing lateral leakage of acoustic waves within the piezoelectric layer.

[0149] The BAW resonator provided by the present invention also includes a heat dissipation structure, which is formed in the non-resonant region of the BAW resonator. In one case, the heat dissipation structure only includes a second heat dissipation portion formed on the substrate and covering the side wall of the piezoelectric layer. In another case, the heat dissipation structure includes both a first heat dissipation portion and a second heat dissipation portion, wherein the first heat dissipation portion is formed on the substrate and the second heat dissipation portion is formed on the first heat dissipation portion and covers the side wall of the piezoelectric layer. Since the second heat dissipation structure is formed on the side wall of the piezoelectric layer, the heat in the piezoelectric layer can be effectively and efficiently transferred to the outside.

[0150] In addition, it should be noted that (1) when the first heat dissipation part is made of metal material, there is a first annular gap between the first heat dissipation part and the lower electrode to ensure that the two are not conductive. Similarly, when the second heat dissipation part is made of metal, there is a second annular gap between the second heat dissipation part and the upper electrode to ensure that the two are not conductive. (2) when the second heat dissipation part is made of metal material, preferably, the horizontal projection of the piezoelectric layer is slightly larger than the horizontal projection of the lower electrode. On the one hand, it can effectively avoid the second heat dissipation part from contacting and conductive with the lower electrode. On the other hand, it can minimize the lateral leakage of sound waves in the piezoelectric layer while ensuring that the BAW resonator can work normally.

[0151] The following describes the specific embodiments.

[0152] In one embodiment, as shown in FIG24( d ), the heat dissipation structure includes a first metal heat dissipation layer 102 b and a second metal heat dissipation layer 105 b . The first heat dissipation metal layer 102 b is formed on the surface of the substrate 100 , and the second metal heat dissipation layer 105 b is formed on the first metal heat dissipation layer 102 b and covers the sidewalls of the piezoelectric layer 104 .

[0153] In another specific embodiment, Figure 25 As shown, the heat dissipation structure only includes the second metal heat dissipation layer 105 b , wherein the second metal heat dissipation layer 105 b is directly formed on the substrate 100 and covers the sidewall of the piezoelectric layer 104 .

[0154] Preferably, when the first heat dissipation portion is a first metal heat dissipation layer, a first thermally conductive insulating structure is formed within the first annular gap between the first metal heat dissipation layer and the lower electrode to thermally connect the two. Similarly, when the second heat dissipation portion is a second metal heat dissipation layer, a second thermally conductive insulating structure is formed within the second annular gap between the second metal heat dissipation layer and the upper electrode to thermally connect the two. This is described below using specific embodiments.

[0155] In a specific embodiment, if Figure 26 As shown, the heat dissipation structure includes a first metal heat dissipation layer 102b and a second metal heat dissipation layer 105b. The second metal heat dissipation layer 105b is formed on the first metal heat dissipation layer 102b and covers the sidewalls of the piezoelectric layer 104, and the first thermally conductive insulating structure 108 is formed only between the lower electrode 102a and the first metal heat dissipation layer 102b.

[0156] In another specific embodiment, Figure 27 As shown, the heat dissipation structure includes a first metal heat dissipation layer 102b and a second metal heat dissipation layer 105b. The second metal heat dissipation layer 105b is formed on the first metal heat dissipation layer 102b and covers the sidewalls of the piezoelectric layer 104, and a second thermally conductive insulating structure 109 is formed only between the upper electrode 105a and the second metal heat dissipation layer 105b.

[0157] In another specific implementation, Figure 28 As shown, the heat dissipation structure includes a first metal heat dissipation layer 102b and a second metal heat dissipation layer 105b. The first metal heat dissipation layer 102b is formed on the substrate 100, and the second metal heat dissipation layer 105b is formed on the first metal heat dissipation layer 102b and covers the sidewalls of the piezoelectric layer 104. A first thermally conductive insulating structure 108 is formed between the lower electrode 102a and the first metal heat dissipation layer 102b, and a second thermally conductive insulating structure 109 is formed between the upper electrode 105a and the second metal heat dissipation layer 105b.

[0158] In another specific embodiment, Figure 29 As shown, the heat dissipation structure only includes the second metal heat dissipation layer 105b, and a second thermal conductive insulation structure 109 is formed between the upper electrode 105a and the second metal heat dissipation layer 105b. The second metal heat dissipation layer 105b is formed on the substrate 100 and covers the sidewalls of the piezoelectric layer 104.

[0159] Preferably, the first thermally conductive insulating structure includes a plurality of first thermally conductive insulating units spaced apart circumferentially around the first annular gap, wherein each first thermally conductive insulating unit is connected to the lower electrode and the first metal heat dissipation layer. More preferably, the plurality of first thermally conductive insulating units are equally spaced apart. The first thermally conductive insulating structure includes a plurality of first thermally conductive insulating structural units discretely distributed between the lower electrode and the first metal heat dissipation layer, which helps reduce acoustic wave losses.

[0160] Preferably, the second thermally conductive insulating structure includes a plurality of second thermally conductive insulating units spaced apart circumferentially about the second annular gap, wherein each second thermally conductive insulating unit is connected to the upper electrode and the second metal heat dissipation layer. More preferably, the plurality of second thermally conductive insulating units are equally spaced apart. The second thermally conductive insulating structure includes a plurality of second thermally conductive insulating structural units discretely distributed between the upper electrode and the second metal heat dissipation layer, which helps reduce acoustic wave loss.

[0161] Furthermore, the materials of the first and second heat dissipation portions may also be alloys, combinations thereof, or non-metallic materials with good heat dissipation properties. For the sake of simplicity, all possible materials for the heat dissipation portions are not listed here. When the heat dissipation portion is made of an insulating heat dissipation material, the heat dissipation portion preferably directly contacts its corresponding electrode to achieve thermal connection.

[0162] The present invention also provides a method for manufacturing a bulk acoustic wave resonator, wherein the bulk acoustic wave resonator includes a heat dissipation structure, and the heat dissipation structure further includes a first heat dissipation portion and / or a second heat dissipation portion. The manufacturing method provided by the present invention will be described below by taking the case where the sound reflection structure of the bulk acoustic wave resonator is a cavity and the heat dissipation structure includes both the first heat dissipation portion and the second heat dissipation portion as an example. Figure 23 As shown, the manufacturing method includes:

[0163] In step S301, a groove is formed on a substrate and a first sacrificial layer is filled in the groove;

[0164] In step S302, a lower electrode and a first heat dissipation portion are formed on the substrate, wherein the lower electrode is located above the groove, and the first heat dissipation portion is located outside the resonance region of the BAW resonator;

[0165] In step S303, a piezoelectric layer is formed above the lower electrode, wherein a horizontal projection area of ​​the piezoelectric layer is smaller than a horizontal projection area of ​​the substrate;

[0166] In step S304, an upper electrode is formed on the piezoelectric layer, and a second heat dissipation portion is formed outside the resonance region, wherein the second heat dissipation portion is formed on the first heat dissipation portion and the side wall of the piezoelectric layer;

[0167] In step S305 , the first sacrificial layer is removed to form a cavity between the lower electrode and the substrate, wherein the upper electrode, the piezoelectric layer, the lower electrode, and the horizontally projected overlapping area of ​​the cavity constitute a resonant region of the BAW resonator.

[0168] The following will be combined Figure 24(a) to Figure 24(d) Steps S301 to S305 are described in detail. It should be noted that the following description only focuses on the manufacturing methods of the various components of the BAW resonator. The specific materials, shapes, dimensions, etc. of each component can be found in the previous description of the BAW resonator structure. For the sake of brevity, the description will not be repeated here.

[0169] Specifically, step S301 and step S302 may refer to the description of step S101 and step S102. The structure obtained after step S302 is executed may refer to FIG3(c). The following description of the following steps will be based on the structure shown in FIG3(c).

[0170] In step S303, as shown in FIG24( a), a piezoelectric layer 104 is formed above the lower electrode 102a, wherein the horizontal projection area of ​​the piezoelectric layer 104 is smaller than the horizontal projection area of ​​the substrate 100. In this embodiment, after forming the lower electrode 102a and the first metal heat dissipation layer 102b, a piezoelectric material layer is first deposited to cover the substrate 100, the lower electrode 102a, and the first metal heat dissipation layer 102b. The piezoelectric material layer is then etched to remove most of the piezoelectric material layer located in the non-resonant region, thereby forming the piezoelectric layer 104 above the lower electrode 102a. Preferably, as shown in FIG24( a), the horizontal projection area of ​​the piezoelectric layer 104 is slightly larger than the horizontal projection area of ​​the lower electrode 102a. This helps prevent the subsequent second heat dissipation portion made of metal material from contacting and conducting with the lower electrode 102a, and minimizes lateral leakage of acoustic waves within the piezoelectric layer 104.

[0171] In step S304, first, as shown in Figure 24(b), a second metal electrode material layer 105 is deposited on the structure shown in Figure 24(a), and the second metal electrode material layer 105 covers the first metal heat dissipation layer 102b and the piezoelectric layer 104; then, as shown in Figure 24(c), the second metal electrode material layer 105 is etched to form an upper electrode 105a on the piezoelectric layer 104, a second metal heat dissipation layer 105b on the side walls of the first metal heat dissipation layer 102b and the piezoelectric layer 104, and a second annular gap 106 between the upper electrode 105a and the second metal heat dissipation layer 105b.

[0172] In step S305, as shown in Figure 24(d), the first sacrificial layer 101 is removed to form a cavity 107 between the lower electrode 102a and the substrate 100, wherein the horizontal projection overlapping area of ​​the upper electrode 105a, the piezoelectric layer 104, the lower electrode 102a and the cavity 107 constitutes the resonant region of the bulk acoustic wave resonator, and the other areas outside the resonant region are the non-resonant regions of the bulk acoustic wave resonant region.

[0173] The BAW resonator formed by implementing the manufacturing method provided by the present invention, on the one hand, can effectively transfer heat in the resonant region to the outside through the heat dissipation portion because a heat dissipation structure is formed in the non-resonant region and the heat dissipation structure is in direct contact with the side wall of the piezoelectric layer. In this way, the heat dissipation capacity of the device can be effectively improved. On the other hand, the horizontal projected area of ​​the piezoelectric layer is smaller than the horizontal projected area of ​​the substrate, which is beneficial to reducing the lateral area of ​​the piezoelectric layer and, in turn, reducing the lateral leakage of acoustic waves in the piezoelectric layer.

[0174] It will be understood by those skilled in the art that (1) the heat dissipation structure of the BAW resonator in the above embodiment includes both the first heat dissipation portion and the second heat dissipation portion. In other examples, the heat dissipation structure may also include only the second heat dissipation portion (when only the second heat dissipation portion is included, the second heat dissipation portion is directly formed on the substrate). For the sake of simplicity, the manufacturing method for forming only the second heat dissipation portion will not be described repeatedly here. (2) The materials of the first heat dissipation portion and the second heat dissipation portion may also be, for example, alloy materials and combinations thereof, non-metallic materials with good heat dissipation properties, etc. For the sake of simplicity, all possible materials of the heat dissipation portion will not be listed here one by one. When the heat dissipation portion material is an insulating heat dissipation material, the heat dissipation portion is preferably in direct contact with its corresponding electrode to achieve thermal connection.

[0175] In the case where the first heat dissipation portion is a first metal heat dissipation layer, preferably, after forming the first metal heat dissipation layer, a first thermally conductive insulating structure is formed in the first annular gap between the first metal heat dissipation layer and the lower electrode to thermally connect the two. Similarly, in the case where the second heat dissipation portion is a second metal heat dissipation layer, preferably, after forming the second metal heat dissipation layer, a second thermally conductive insulating structure is formed in the second annular gap between the second metal heat dissipation layer and the upper electrode to thermally connect the two. The thermally conductive insulating structure between the metal heat dissipation layer and the electrode ensures that the two are not electrically connected while facilitating the transfer of heat from the electrode to the metal heat dissipation layer, thereby improving heat dissipation efficiency.

[0176] Preferably, the first thermally conductive insulating structure includes a plurality of first thermally conductive insulating units spaced apart circumferentially around the first annular gap, wherein each first thermally conductive insulating unit is connected to the lower electrode and the first metal heat dissipation layer. More preferably, the plurality of first thermally conductive insulating units are equally spaced apart. The first thermally conductive insulating structure includes a plurality of first thermally conductive insulating structural units discretely distributed between the lower electrode and the first metal heat dissipation layer, which helps reduce acoustic wave losses.

[0177] Preferably, the second thermally conductive insulating structure includes a plurality of second thermally conductive insulating units spaced apart circumferentially about the second annular gap, wherein each second thermally conductive insulating unit is connected to the upper electrode and the second metal heat dissipation layer. More preferably, the plurality of second thermally conductive insulating units are equally spaced apart. The second thermally conductive insulating structure includes a plurality of second thermally conductive insulating structural units discretely distributed between the upper electrode and the second metal heat dissipation layer, which helps reduce acoustic wave loss.

[0178] In the above-described BAW resonator manufacturing method, the acoustic reflective structure is a cavity. For cases where the acoustic reflective structure is a Bragg reflector or an open-back structure, the steps differ from the above-described manufacturing method only in the formation of the acoustic reflective structure. For the sake of simplicity, the manufacturing method for BAW resonators with Bragg reflectors and open-back structures will not be described in detail here.

[0179] The present invention also provides an electronic device including a bulk acoustic wave resonator. The bulk acoustic wave resonator can be implemented using the aforementioned bulk acoustic wave resonator with a heat dissipation structure or formed using the aforementioned manufacturing method. Since the bulk acoustic wave resonator with a heat dissipation structure and its manufacturing method have been described in detail above, they will not be repeated here for the sake of brevity.

[0180] The present invention does not impose any restrictions on the specific type of electronic device. It can be a device chip such as a filter chip, a duplexer chip, a multiplexer chip, and a sensor chip, or a packaging structure such as a filter, a duplexer, a multiplexer, and a sensor. All electronic devices that can be implemented based on a bulk acoustic wave resonator fall within the scope of protection of the present invention. For the sake of simplicity, all possible electronic devices are not listed here one by one.

[0181] It should be noted that an electronic device usually includes multiple BAW resonators, wherein all BAW resonators may include a heat dissipation structure, or some BAW resonators may include a heat dissipation structure while the other BAW resonators are still implemented using existing conventional BAW resonators.

[0182] Preferably, the electronic device also includes a metal sealing portion formed on the edge of the device, and the metal sealing portion is in contact with the heat dissipation structure of the bulk acoustic wave resonator. The heat dissipation structure in the bulk acoustic wave resonator is made to contact the metal sealing portion through reasonable design (for example, the first heat dissipation portion covers the area at the edge of the substrate so that the metal sealing portion is in contact by being formed on the first heat dissipation portion, or for example, the second heat dissipation portion is formed at a position close to the edge of the substrate so that the metal sealing portion can be in contact with the side of the second heat dissipation portion, etc.). In this way, the heat in the heat dissipation structure can be further transferred outward through the metal sealing portion, thereby further improving the heat dissipation of the device. For unpackaged device chips, the metal sealing portion is a metal bonding portion, which is used for subsequent bonding and fixing with the cap that matches it; for the packaging structure, the metal sealing portion is a sealing ring. In a specific embodiment, such as Figure 30 As shown, the electronic device is a filter chip, which includes a metal sealing portion 200 formed at the edge of the device. The heat dissipation structure of the bulk acoustic wave resonator in the filter chip includes both a first metal heat dissipation layer 102b and a second metal heat dissipation layer 105b. The metal sealing layer 200 is formed on the first metal heat dissipation layer 102b and simultaneously contacts the side surfaces of the second metal heat dissipation layer 105b. It should be noted that in other embodiments, the metal sealing portion may contact only the first metal heat dissipation layer 102b or only the second metal heat dissipation layer 105b.

[0183] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be regarded as exemplary and non-restrictive from any point of view, and the scope of the invention is defined by the appended claims rather than the above description, and it is intended that all variations that fall within the meaning and scope of the equivalents of the claims be encompassed within the present invention. Any reference numerals in the claims should not be regarded as limiting the claims to which they relate. Furthermore, it is apparent that the word "comprising" does not exclude other components, units or steps, and the singular does not exclude the plural. Multiple components, units or devices stated in a system claim may also be implemented by one component, unit or device through software or hardware.

[0184] The above disclosures are merely some preferred embodiments of the present invention, which certainly cannot be used to limit the scope of the present invention. Therefore, equivalent changes made according to the claims of the present invention are still within the scope of the present invention.

Claims

1. A bulk acoustic wave resonator, comprising: substrate; A lower electrode, a piezoelectric layer, and an upper electrode, wherein the lower electrode, the piezoelectric layer, and the upper electrode are sequentially formed on the substrate from bottom to top; an acoustic reflection structure, wherein the acoustic reflection structure is formed in the substrate or between the substrate and the lower electrode, and the horizontally projected overlapping area of ​​the acoustic reflection structure, the lower electrode, the piezoelectric layer, and the upper electrode constitutes a resonant region of the bulk acoustic wave resonator; A heat dissipation structure, which includes a first metal heat dissipation layer and a first thermally conductive insulating structure formed outside the resonance zone, the first metal heat dissipation layer is formed on the lower surface of the piezoelectric layer and a first annular gap is formed between the first metal heat dissipation layer and the lower electrode, the first thermally conductive insulating structure includes a plurality of first thermally conductive insulating units located in the first annular gap and spaced apart in the circumferential direction of the first annular gap, each of the first thermally conductive insulating units is connected to the lower electrode and the first metal heat dissipation layer; and / or the heat dissipation structure includes a second metal heat dissipation layer and a second thermally conductive insulating structure, the second metal heat dissipation layer is formed on the upper surface of the piezoelectric layer and a second annular gap is formed between the upper electrode, the second thermally conductive insulating structure includes a plurality of second thermally conductive insulating units located in the second annular gap and spaced apart in the circumferential direction of the second annular gap, each of the second thermally conductive insulating units is connected to the upper electrode and the second metal heat dissipation layer.

2. The BAW resonator according to claim 1, wherein: The first metal heat dissipation layer and the lower electrode have different materials and / or thicknesses; The second metal heat dissipation layer and the upper electrode have different materials and / or thicknesses.

3. The BAW resonator according to claim 1 or 2, wherein: The piezoelectric layer includes a first piezoelectric portion and a second piezoelectric portion. The first piezoelectric portion is formed between the upper electrode and the lower electrode. The second piezoelectric portion is formed outside the resonance region with a third annular gap formed between the second piezoelectric portion and the first piezoelectric portion.

4. A method for manufacturing a bulk acoustic wave resonator, the method comprising providing a substrate, forming an upper electrode, forming a piezoelectric layer, forming a lower electrode, and forming an acoustic reflection structure, wherein a horizontally projected overlapping area of ​​the upper electrode, the piezoelectric layer, the lower electrode, and the acoustic reflection structure constitutes a resonant region of the bulk acoustic wave resonator, the method further comprising: A heat dissipation structure is formed outside the resonance zone, wherein the heat dissipation structure includes a first metal heat dissipation layer and a first thermally conductive insulating structure, the first metal heat dissipation layer is formed on the lower surface of the piezoelectric layer and a first annular gap is formed between the first metal heat dissipation layer and the lower electrode, the first thermally conductive insulating structure includes a plurality of first thermally conductive insulating units located in the first annular gap and spaced apart in the circumferential direction of the first annular gap, each of the first thermally conductive insulating units is connected to the lower electrode and the first metal heat dissipation layer; and / or the heat dissipation structure includes a second metal heat dissipation layer and a second thermally conductive insulating structure, the second metal heat dissipation layer is formed on the upper surface of the piezoelectric layer and a second annular gap is formed between the upper electrode, the second thermally conductive insulating structure includes a plurality of second thermally conductive insulating units located in the second annular gap and spaced apart in the circumferential direction of the second annular gap, each of the second thermally conductive insulating units is connected to the upper electrode and the second metal heat dissipation layer.

5. The manufacturing method according to claim 4, wherein: The steps of forming a lower electrode on the substrate and forming a first metal heat dissipation layer and a first thermally conductive insulating structure outside the resonance region include: depositing a first metal heat dissipation material layer on the substrate and etching the first metal heat dissipation material layer to form a first metal heat dissipation layer outside the resonance region; depositing a first metal electrode material layer to cover the substrate and the first metal heat dissipation layer, and etching the first metal electrode material layer to retain only a portion located inside the first metal heat dissipation layer to form a lower electrode, wherein a first annular gap is formed between the lower electrode and the first metal heat dissipation layer; and forming the first thermally conductive insulating structure for connecting the lower electrode and the first metal heat dissipation layer within the first annular gap. The steps of forming an upper electrode on the piezoelectric layer and forming a second metal heat dissipation layer and a second thermally conductive insulating structure outside the resonance region include: depositing a second metal heat dissipation material layer on the piezoelectric layer and etching it to form a second metal heat dissipation layer outside the resonance region; depositing a second metal electrode material layer to cover the piezoelectric layer and the second metal heat dissipation layer, and etching the second metal electrode material layer to retain only the portion located inside the second metal heat dissipation layer to form an upper electrode, wherein a second annular gap is formed between the upper electrode and the second metal heat dissipation layer; and forming the second thermally conductive insulating structure for connecting the upper electrode and the second metal heat dissipation layer in the second annular gap.

6. The manufacturing method according to claim 5, wherein: The first metal heat dissipation layer and the lower electrode have different materials and / or thicknesses; The second metal heat dissipation layer and the upper electrode have different materials and / or thicknesses.

7. The manufacturing method according to any one of claims 4 to 6, wherein: The piezoelectric layer includes a first piezoelectric portion and a second piezoelectric portion; The step of forming a piezoelectric layer on the substrate includes: depositing a piezoelectric material layer on the substrate and etching the piezoelectric material layer to form a first piezoelectric portion located above the lower electrode, a second piezoelectric portion located outside the resonance region, and a third annular gap located therebetween; After forming the piezoelectric layer, the manufacturing method further includes: filling a second sacrificial layer in the third annular gap; and After forming the upper electrode on the piezoelectric layer, the manufacturing method further includes: removing the second sacrificial layer.

8. A bulk acoustic wave resonator, comprising: substrate; A lower electrode, a piezoelectric layer, and an upper electrode, wherein the lower electrode, the piezoelectric layer, and the upper electrode are sequentially formed on the substrate from bottom to top, wherein a horizontal projection area of ​​the piezoelectric layer is smaller than a horizontal projection area of ​​the substrate; an acoustic reflection structure, wherein the acoustic reflection structure is formed in the substrate or between the substrate and the lower electrode, and the horizontally projected overlapping area of ​​the acoustic reflection structure, the lower electrode, the piezoelectric layer, and the upper electrode constitutes a resonant region of the bulk acoustic wave resonator; A heat dissipation structure, which is formed outside the resonance zone, wherein the heat dissipation structure includes a first metal heat dissipation layer and a first thermally conductive insulating structure, the first metal heat dissipation layer is formed on the substrate and a first annular gap is formed between the first metal heat dissipation layer and the lower electrode, the first thermally conductive insulating structure includes a plurality of first thermally conductive insulating units located in the first annular gap and spaced apart in the circumferential direction of the first annular gap, each of the first thermally conductive insulating units is connected to the lower electrode and the first metal heat dissipation layer; or the heat dissipation structure includes a second metal heat dissipation layer and a second thermally conductive insulating structure, the second metal heat dissipation layer is formed on the substrate and a second annular gap is formed between the second metal heat dissipation layer and the upper electrode, and a fourth annular gap is formed between the second metal heat dissipation layer and the piezoelectric layer, the second thermally conductive insulating structure includes a plurality of second thermally conductive insulating units located in the second annular gap and spaced apart in the circumferential direction of the second annular gap, each of the second thermally conductive insulating units is connected to the upper electrode and the second metal heat dissipation layer; or the The heat dissipation structure includes a first metal heat dissipation layer corresponding to the lower electrode and a second metal heat dissipation layer corresponding to the upper electrode, the first metal heat dissipation layer is formed on the substrate and a first annular gap is formed between the first metal heat dissipation layer and the lower electrode, and a fourth annular gap is formed between the second metal heat dissipation layer and the piezoelectric layer. The heat dissipation structure also includes a first thermally conductive insulating structure and / or a second thermally conductive insulating structure, wherein the first thermally conductive insulating structure includes a plurality of first thermally conductive insulating units located in the first annular gap and spaced apart in the circumferential direction of the first annular gap, each of the first thermally conductive insulating units is connected to the lower electrode and the first metal heat dissipation layer, and the second thermally conductive insulating structure includes a plurality of second thermally conductive insulating units located in the second annular gap and spaced apart in the circumferential direction of the second annular gap, each of the second thermally conductive insulating units is connected to the upper electrode and the second metal heat dissipation layer.

9. A method for manufacturing a bulk acoustic wave resonator, the method comprising providing a substrate, forming an upper electrode, forming a piezoelectric layer, forming a lower electrode, and forming an acoustic reflection structure, wherein a horizontally projected overlapping area of ​​the upper electrode, the piezoelectric layer, the lower electrode, and the acoustic reflection structure constitutes a resonant region of the bulk acoustic wave resonator, wherein: The horizontal projection area of ​​the piezoelectric layer is smaller than the horizontal projection area of ​​the substrate; Before forming the upper electrode, the manufacturing method further comprises: forming a third sacrificial layer surrounding the sidewall of the piezoelectric layer; After the upper electrode is formed, the manufacturing method further includes: removing the third sacrificial layer; and The manufacturing method also includes: forming a heat dissipation structure outside the resonance zone, the heat dissipation structure including a first metal heat dissipation layer and a first heat-conducting insulating structure, the first metal heat dissipation layer is formed on the substrate and a first annular gap is formed between the first metal heat dissipation layer and the lower electrode, the first heat-conducting insulating structure includes a plurality of first heat-conducting insulating units located in the first annular gap and spaced apart in a circumferential direction of the first annular gap, each of the first heat-conducting insulating units is connected to the lower electrode and the first metal heat dissipation layer; or the heat dissipation structure includes a second metal heat dissipation layer and a second heat-conducting insulating structure, the second metal heat dissipation layer is formed on the substrate and a second annular gap is formed between the second metal heat dissipation layer and the upper electrode, and a fourth annular gap is formed between the second metal heat dissipation layer and the piezoelectric layer, the fourth annular gap is formed by removing the third sacrificial layer, the second heat-conducting insulating structure includes a plurality of second heat-conducting insulating units located in the second annular gap and spaced apart in a circumferential direction of the second annular gap, each of the second heat-conducting insulating units is connected to the upper electrode and the second metal heat dissipation layer; or The heat dissipation structure includes a first metal heat dissipation layer corresponding to the lower electrode and a second metal heat dissipation layer corresponding to the upper electrode, the first metal heat dissipation layer is formed on the substrate and a first annular gap is formed between the first metal heat dissipation layer and the lower electrode, the second metal heat dissipation layer is formed on the first metal heat dissipation layer and a second annular gap is formed between the second metal heat dissipation layer and the upper electrode, and a fourth annular gap is formed between the second metal heat dissipation layer and the piezoelectric layer, the fourth annular gap being formed by removing the third sacrificial layer, the heat dissipation structure also includes a first thermally conductive insulating structure and / or a second thermally conductive insulating structure, wherein the first thermally conductive insulating structure includes a plurality of first thermally conductive insulating units located in the first annular gap and spaced apart in the circumferential direction of the first annular gap, each of the first thermally conductive insulating units being connected to the lower electrode and the first metal heat dissipation layer, and the second thermally conductive insulating structure includes a plurality of second thermally conductive insulating units located in the second annular gap and spaced apart in the circumferential direction of the second annular gap, each of the second thermally conductive insulating units being connected to the upper electrode and the second metal heat dissipation layer.

10. A bulk acoustic wave resonator, comprising: substrate; A lower electrode, a piezoelectric layer, and an upper electrode, wherein the lower electrode, the piezoelectric layer, and the upper electrode are sequentially formed on the substrate from bottom to top, wherein a horizontal projection area of ​​the piezoelectric layer is smaller than a horizontal projection area of ​​the substrate; an acoustic reflection structure, wherein the acoustic reflection structure is formed in the substrate or between the substrate and the lower electrode, and the horizontally projected overlapping area of ​​the acoustic reflection structure, the lower electrode, the piezoelectric layer, and the upper electrode constitutes a resonant region of the bulk acoustic wave resonator; A heat dissipation structure, which is formed outside the resonance zone, wherein the heat dissipation structure includes a second metal heat dissipation layer and a second heat-conducting insulation structure, the second metal heat dissipation layer is formed on the substrate and covers the side wall of the piezoelectric layer, and a second annular gap is formed between the second metal heat dissipation layer and the upper electrode, the second heat-conducting insulation structure includes a plurality of second heat-conducting insulation units located in the second annular gap and spaced apart in the circumferential direction of the second annular gap, each of the second heat-conducting insulation units is connected to the upper electrode and the second metal heat dissipation layer; or the heat dissipation structure includes a first metal heat dissipation layer and a second metal heat dissipation layer, the first metal heat dissipation layer is formed on the substrate and a first annular gap is formed between the second metal heat dissipation layer and the lower electrode, the second metal heat dissipation layer A second annular gap is formed on the first metal heat dissipation layer and covers the side wall of the piezoelectric layer, and is formed between the upper electrode and the heat dissipation structure. The heat dissipation structure also includes a first thermally conductive insulating structure and / or a second thermally conductive insulating structure, wherein the first thermally conductive insulating structure includes a plurality of first thermally conductive insulating units located in the first annular gap and spaced apart in the circumferential direction of the first annular gap, each of the first thermally conductive insulating units is connected to the lower electrode and the first metal heat dissipation layer, and the second thermally conductive insulating structure includes a plurality of second thermally conductive insulating units located in the second annular gap and spaced apart in the circumferential direction of the second annular gap, each of the second thermally conductive insulating units is connected to the upper electrode and the second metal heat dissipation layer.

11. A method for manufacturing a bulk acoustic wave resonator, the method comprising providing a substrate, forming an upper electrode, forming a piezoelectric layer, forming a lower electrode, and forming an acoustic reflection structure, wherein a horizontally projected overlapping area of ​​the upper electrode, the piezoelectric layer, the lower electrode, and the acoustic reflection structure constitutes a resonant region of the bulk acoustic wave resonator, wherein: The horizontal projection area of ​​the piezoelectric layer is smaller than the horizontal projection area of ​​the substrate; The manufacturing method further includes: forming a heat dissipation structure outside the resonance zone, the heat dissipation structure including a second metal heat dissipation layer and a second heat-conducting insulating structure, the second metal heat dissipation layer being formed on the substrate and covering the side wall of the piezoelectric layer, and forming a second annular gap between the second metal heat dissipation layer and the upper electrode, the second heat-conducting insulating structure including a plurality of second heat-conducting insulating units located in the second annular gap and spaced apart in the circumferential direction of the second annular gap, each of the second heat-conducting insulating units being connected to the upper electrode and the second metal heat dissipation layer; or the heat dissipation structure including a first metal heat dissipation layer and a second metal heat dissipation layer, the first metal heat dissipation layer being formed on the substrate and forming a first annular gap between the second metal heat dissipation layer and the lower electrode, the second metal heat dissipation layer A second annular gap is formed on the first metal heat dissipation layer and covers the side wall of the piezoelectric layer, and is formed between the upper electrode and the heat dissipation structure. The heat dissipation structure also includes a first thermally conductive insulating structure and / or a second thermally conductive insulating structure, wherein the first thermally conductive insulating structure includes a plurality of first thermally conductive insulating units located in the first annular gap and spaced apart in the circumferential direction of the first annular gap, each of the first thermally conductive insulating units is connected to the lower electrode and the first metal heat dissipation layer, and the second thermally conductive insulating structure includes a plurality of second thermally conductive insulating units located in the second annular gap and spaced apart in the circumferential direction of the second annular gap, each of the second thermally conductive insulating units is connected to the upper electrode and the second metal heat dissipation layer.

12. An electronic device comprising the BAW resonator according to any one of claims 1 to 3, 8, and 10, or a BAW resonator formed by the manufacturing method according to any one of claims 4 to 7, 9, and 11.

13. The electronic device according to claim 12, wherein: The electronic device further includes a metal sealing portion formed at an edge of the device, wherein the metal sealing portion is in contact with the heat dissipation structure.

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