Bulk acoustic wave resonator group, bulk acoustic wave filter, and communication device

Abstract

The application discloses a bulk acoustic resonator group, a bulk acoustic filter and a communication device. The bulk acoustic resonator group comprises: at least two bulk acoustic resonators, each bulk acoustic resonator comprising a stacked structure of a first electrode, a piezoelectric layer and a second electrode; and adjacent two bulk acoustic resonators in a right V-shaped structure or in an upside-down V-shaped structure. The technical scheme provided by the embodiment of the application reduces the size of the bulk acoustic resonator group, and further realizes the miniaturization of the bulk acoustic resonator group, the bulk acoustic filter and the communication device.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and in particular to a bulk acoustic wave resonator array, a bulk acoustic wave filter, and a communication device. Background Technology

[0002] With the continuous development of wireless communication technology, high-performance, small-sized communication devices are being used more and more widely.

[0003] A bulk acoustic wave resonator group includes at least one film bulk acoustic wave resonator, also known as a bulk acoustic wave (BAS). Due to its small size, high operating frequency, low power consumption, high quality factor, and compatibility with CMOS technology, the BAS resonator has become an important device in the field of communication devices and is widely used.

[0004] The existing bulk acoustic wave resonator arrays are too large, which is not conducive to the miniaturization of bulk acoustic wave resonator arrays, bulk acoustic wave filters and communication devices. Figure 1 This is a schematic diagram of the structure of a bulk acoustic wave filter in the prior art. See also... Figure 1 The bulk acoustic wave filter includes a substrate 001, and the first surface 101 of the substrate 001 includes a bulk acoustic wave resonator group composed of bulk acoustic wave resonators 21, 22, and 23. Each bulk acoustic wave resonator includes a stacked structure of a first electrode 20a, a piezoelectric layer 20b, and a second electrode 20c. In one aspect, because the bulk acoustic wave resonators 21, 22, and 23 are laid flat on the first surface 101 of the substrate 10, the size of the bulk acoustic wave filter in the thickness direction perpendicular to the substrate 10 is too large, which is detrimental to the miniaturization of the bulk acoustic wave filter and communication devices. Secondly, since the bulk acoustic wave resonators 21, 22, and 23 are laid flat on the first surface 101 of the substrate 10, in order to reduce the acoustic wave loss of the bulk acoustic wave filter, an acoustic reflection structure 40 needs to be provided for each of the bulk acoustic wave resonators 21, 22, and 23 on the surface or inside the substrate 10. This results in a complicated manufacturing process and high manufacturing cost. In particular, when the acoustic reflection structure 40 includes a cavity structure 40a or a back groove, it will also reduce the structural stability of the bulk acoustic wave filter. It should be noted that the thickness direction parallel to the substrate 001 is the Y direction in the XOY plane rectangular coordinate system, and the thickness direction perpendicular to the substrate 001 is the X direction in the XOY plane rectangular coordinate system. Summary of the Invention

[0005] Therefore, the body acoustic wave resonator group, the body acoustic wave filter and the communication device are miniaturized.

[0006] The body acoustic wave resonator group provided by the embodiment of the present application comprises at least two body acoustic wave resonators, each of the body acoustic wave resonators comprises a first electrode, a piezoelectric layer and a second electrode in a stacked structure.

[0007] The two adjacent body acoustic wave resonators are in a right V-shaped structure or an upside-down V-shaped structure.

[0008] Optionally, the two adjacent body acoustic wave resonators are in an upside-down V-shaped structure and support each other.

[0009] Alternatively, the two adjacent body acoustic wave resonators are in an upside-down V-shaped structure and are supported by a support layer.

[0010] Alternatively, the two adjacent body acoustic wave resonators are supported by a support layer, and the two adjacent body acoustic wave resonators are in a right V-shaped structure and support each other.

[0011] Optionally, an angle formed by a V-shaped side of the V-shaped structure is greater than or equal to 0° and less than or equal to 90°.

[0012] Optionally, the electrodes of the two adjacent body acoustic wave resonators are electrically connected through an intermediate conductive part.

[0013] Alternatively, the electrodes of the two adjacent body acoustic wave resonators are directly in contact to realize electrical connection.

[0014] Alternatively, the electrodes of the two adjacent body acoustic wave resonators are insulated.

[0015] Optionally, the body acoustic wave resonator further comprises a temperature compensation layer, and the temperature compensation layer comprises a positive frequency drift coefficient material.

[0016] Optionally, the temperature compensation layer is located at least one of the following positions: in the piezoelectric layer, on a surface of the piezoelectric layer adjacent to the first electrode, on a surface of the piezoelectric layer adjacent to the second electrode, in the first electrode, on a surface of the first electrode away from the piezoelectric layer, in the second electrode and on a surface of the second electrode away from the piezoelectric layer.

[0017] The embodiment of the present application further provides a body acoustic wave filter, comprising at least one substrate, the substrate comprises a first surface and a second surface arranged opposite to the first surface, and the first surface of the substrate is provided with at least one body acoustic wave resonator group as described in any of the above technical solutions.

[0018] The substrate and the bulk acoustic resonators of the bulk acoustic resonator group supported by the substrate form a preset included angle.

[0019] Optionally, the substrate comprises adjacent first and second substrates.

[0020] The first surface of the first substrate is provided with at least one bulk acoustic resonator group, the second surface of the second substrate is provided with at least one bulk acoustic resonator group, and the bulk acoustic resonator groups between the first and second substrates are distributed in an interdigital manner.

[0021] Optionally, the substrate further comprises a conductive interconnection structure.

[0022] The conductive interconnection structure is used to lead the electrical signals of the bulk acoustic resonator group to the first surface side of the uppermost substrate, and / or the conductive interconnection structure is used to lead the electrical signals of the bulk acoustic resonator group out to the second surface side of the lowermost substrate.

[0023] Optionally, the substrate further comprises a wafer cover plate located on the first surface side of the uppermost substrate.

[0024] The conductive interconnection structure is used to lead the electrical signals of the bulk acoustic resonator group to the surface of the wafer cover plate away from the uppermost substrate.

[0025] Optionally, the first or second electrode of the bulk acoustic resonator adjacent to the conductive interconnection structure is connected to the conductive interconnection structure through a conductive connection part.

[0026] Optionally, the first surface of the first substrate is provided with a first bulk acoustic resonator group, and the first bulk acoustic resonator group comprises a first bulk acoustic resonator, a second bulk acoustic resonator, a third bulk acoustic resonator and a fourth bulk acoustic resonator.

[0027] The first and second bulk acoustic resonators are arranged in an inverted V shape, the third and fourth bulk acoustic resonators are arranged in an inverted V shape, and the second and third bulk acoustic resonators are arranged in a normal V shape.

[0028] Optionally, the second surface of the second substrate is provided with a second bulk acoustic resonator group, and the second bulk acoustic resonator group comprises a fifth bulk acoustic resonator and a sixth bulk acoustic resonator, and the fifth and sixth bulk acoustic resonators are arranged in a normal V shape.

[0029] The connected part of the fifth and sixth bulk acoustic resonators is located in the normal V shape space of the second and third bulk acoustic resonators.

[0030] Optionally, in the thickness direction of the substrate, the spacing between adjacent substrates is less than the sum of the heights of the groups of bulk acoustic resonators distributed in an interdigital manner between adjacent substrates.

[0031] Optionally, in the horizontal direction, the two groups of bulk acoustic resonators distributed in an interdigital manner are spaced apart by a preset spacing.

[0032] The embodiment of the present application also provides a communication device comprising the bulk acoustic wave filter according to any of the above technical solutions.

[0033] The communication device comprises at least one of a filter, a diplexer and a multiplexer.

[0034] The technical solution provided by the embodiment of the present application has the following advantages: first, the two adjacent bulk acoustic resonators are arranged in a V-shaped structure, which reduces the size of the group of bulk acoustic resonators in the horizontal direction and helps to form a small-sized group of bulk acoustic resonators; second, as the angle formed by the V-shaped side of the V-shaped structure decreases, the size of the group of bulk acoustic resonators in the horizontal direction decreases; third, the two adjacent bulk acoustic resonators are arranged in a V-shaped structure, and the V-shaped structure forms an air gap structure, so that the sound wave can be reflected back to the two adjacent bulk acoustic resonators, thereby reducing the loss of the sound wave and improving the quality factor of the group of bulk acoustic resonators; and fourth, in the embodiment of the present application, the sound reflection structure is not arranged on the substrate by means of groove digging, which simplifies the preparation process, reduces the preparation cost, and also improves the structural stability of the group of bulk acoustic resonators. BRIEF DESCRIPTION OF DRAWINGS

[0035] Figure 1 FIG. 1 is a structural schematic diagram of a bulk acoustic wave filter in the prior art;

[0036] Figure 2 FIG. 2 is a structural schematic diagram of a group of bulk acoustic resonators provided by the embodiment of the present application;

[0037] Figure 3 FIG. 3 is a structural schematic diagram of another group of bulk acoustic resonators provided by the embodiment of the present application;

[0038] Figure 4 FIG. 4 is a structural schematic diagram of still another group of bulk acoustic resonators provided by the embodiment of the present application;

[0039] Figure 5 FIG. 5 is a structural schematic diagram of still another group of bulk acoustic resonators provided by the embodiment of the present application;

[0040] Figure 6 FIG. 6 is a structural schematic diagram of still another group of bulk acoustic resonators provided by the embodiment of the present application;

[0041] Figure 7A structure diagram of a body acoustic resonator group provided by an embodiment of the present application;

[0042] Figure 8 A structure diagram of a body acoustic wave filter provided by an embodiment of the present application;

[0043] Figure 9 A structure diagram of another body acoustic wave filter provided by an embodiment of the present application;

[0044] Figure 10 A structure diagram of another body acoustic wave filter provided by an embodiment of the present application;

[0045] Figure 11 A structure diagram of another body acoustic wave filter provided by an embodiment of the present application;

[0046] Figure 12 A structure diagram of another body acoustic wave filter provided by an embodiment of the present application;

[0047] Figure 13 A structure diagram of another body acoustic wave filter provided by an embodiment of the present application;

[0048] Figure 14 A structure diagram of another body acoustic wave filter provided by an embodiment of the present application;

[0049] Figure 15 A structure diagram of a body acoustic wave filter in Figure 10 An equivalent circuit connection diagram of the body acoustic wave filter in

[0050] Figure 16 An equivalent circuit connection diagram of the body acoustic wave filter in Figure 14

[0051] A preparation method flow chart of a body acoustic resonator group in Figure 17 Figure 3 A structure diagram of a cross section corresponding to each step of the preparation method of the body acoustic resonator group in

[0052] Figure 18 Figure 17 A structure diagram of a cross section corresponding to each step of the preparation method of the body acoustic resonator group in

[0053] Figure 19 A preparation method flow chart of a body acoustic resonator group in Figure 6

[0054] A structure diagram of a cross section corresponding to each step of the preparation method of the body acoustic resonator group in Figure 20 Figure 19 A structure diagram of a cross section corresponding to each step of the preparation method of the body acoustic resonator group in

[0055] ​​​​The application will be further described below in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely intended for the purpose of interpretation of the application and are not intended to limit the application. In addition, it should be noted that only the parts related to the application are shown in the drawings for the purpose of description.

[0056] In order to solve the technical problem of the size of the existing bulk acoustic resonator group being too large, which is not conducive to miniaturization of the bulk acoustic resonator group, the bulk acoustic resonator group, the bulk acoustic filter and the communication device, the embodiments of the application provide a bulk acoustic resonator group, which comprises at least two bulk acoustic resonators, each bulk acoustic resonator comprising a laminated structure of a first electrode, a piezoelectric layer and a second electrode; and the two adjacent bulk acoustic resonators are in an upright V-shaped structure or an inverted V-shaped structure.

[0057] For example, referring to Figures 2-4 , the bulk acoustic resonator group comprises a bulk acoustic resonator 24 and a bulk acoustic resonator 25. Each bulk acoustic resonator comprises a laminated structure of a first electrode 20a, a piezoelectric layer 20b and a second electrode 20c. Referring to Figure 2 and Figure 3 , the two adjacent bulk acoustic resonators 24 and 25 are in an inverted V-shaped structure. It should be noted that Figure 2 , the first electrodes 20a of the two adjacent bulk acoustic resonators 24 and 25 are in an inverted V-shaped structure under the support of the support layer 30. And Figure 3 , the first electrodes 20a of the two adjacent bulk acoustic resonators 24 and 25 support each other to be in an inverted V-shaped structure. Referring to Figure 4 , the second electrodes 20c of the two adjacent bulk acoustic resonators 24 and 25 support each other, and the bulk acoustic resonators 24 and 25 are in an upright V-shaped structure under the support of the support layer 30. The above technical solution reduces the size of the bulk acoustic resonator group in the horizontal direction, which is conducive to forming a miniaturized bulk acoustic resonator group. It should be noted that in the embodiments of the application, the X direction in the XOY coordinate system is parallel to the horizontal direction.

[0058] For example, referring to Figure 5 and Figure 6The bulk acoustic resonator group comprises a bulk acoustic resonator 24, a bulk acoustic resonator 25, a bulk acoustic resonator 26 and a bulk acoustic resonator 27. Each bulk acoustic resonator comprises a laminated structure of a first electrode 20a, a piezoelectric layer 20b and a second electrode 20c. Two adjacent bulk acoustic resonators 24 and 25 support each other to form an inverted V-shaped structure. Two adjacent bulk acoustic resonators 26 and 27 support each other to form an inverted V-shaped structure. Two adjacent bulk acoustic resonators 25 and 26 support each other to form a normal V-shaped structure. The technical solution reduces the size of the bulk acoustic resonator group in the horizontal direction, and helps to form a miniaturized bulk acoustic resonator group. Figures 1-5 The bulk acoustic resonator group shown in the figure, Figure 6 In the embodiment, the angle β formed by the V-shaped edges of the inverted V-shaped structure of the two adjacent bulk acoustic resonators 24 and 25 is small, so that the size of the bulk acoustic resonator group in the horizontal direction can be further reduced.

[0059] The technical solution provided by the embodiment of the present application has the following advantages. First, the two adjacent bulk acoustic resonators form a normal V-shaped structure or an inverted V-shaped structure, which reduces the size of the bulk acoustic resonator group in the horizontal direction, and helps to form a miniaturized bulk acoustic resonator group. As the angle of the V-shaped edges of the V-shaped structure decreases, the size of the bulk acoustic resonator group in the horizontal direction decreases. Second, the two adjacent bulk acoustic resonators are arranged in a V-shaped structure, which forms an air gap structure, so that the sound wave can be reflected back to the two adjacent bulk acoustic resonators, thereby reducing the loss of the sound wave and improving the quality factor of the bulk acoustic resonator group. Third, in the embodiment of the present application, the sound reflection structure is not arranged on the substrate by the groove method, which simplifies the preparation process, reduces the preparation cost, and also improves the structural stability of the bulk acoustic resonator group.

[0060] Optionally, the two adjacent bulk acoustic resonators support each other to form an inverted V-shaped structure; or the two adjacent bulk acoustic resonators support each other to form an inverted V-shaped structure under the support of a support layer; or the two adjacent bulk acoustic resonators are supported by a support layer, and the two adjacent bulk acoustic resonators support each other to form a normal V-shaped structure.

[0061] For example, Figure 3 In the embodiment, the first electrodes 20a of the two adjacent bulk acoustic resonators 24 and 25 support each other to form an inverted V-shaped structure. Figure 2 In the embodiment, the two adjacent bulk acoustic resonators 24 and 25 support each other to form an inverted V-shaped structure under the support of a support layer 30. The support layer 30 can be a conductive support layer or an insulating support layer. Figure 4The first electrode 20a of the adjacent bulk acoustic resonators 24 and 25 is supported by the support layer 30, and the second electrode 20c of the adjacent bulk acoustic resonators 24 and 25 support each other in an upright V-shaped structure.

[0062] Optional, see Figure 6 The angle β formed by the V-shaped sides of the V-shaped structure is greater than or equal to 0° and less than or equal to 90°. Preferably, the angle β formed by the V-shaped sides of the V-shaped structure is greater than 0° and less than 90°. Specifically, as the angle formed by the V-shaped sides of the V-shaped structure decreases, the horizontal dimension of the bulk acoustic resonator assembly decreases accordingly.

[0063] Optionally, the electrodes of two adjacent bulk acoustic resonators are electrically connected through a central conductive part; or, the electrodes of two adjacent bulk acoustic resonators are in direct contact to achieve electrical connection; or, the electrodes of two adjacent bulk acoustic resonators are insulated from each other.

[0064] For example, Figure 2 The second electrodes 20c of two adjacent bulk acoustic resonators 24 and 25 are electrically connected through the intermediate conductive part 20d. Figure 5 The second electrodes 20c of two adjacent bulk acoustic resonators 25 and 26 are in direct contact to achieve electrical connection. Figure 5 The second electrodes 20c of two adjacent bulk acoustic resonators 24 and 25 are spaced apart by a predetermined area to achieve insulation.

[0065] Optionally, the bulk acoustic resonator may also include a temperature compensation layer, which comprises a material with a positive frequency drift coefficient.

[0066] For example, see Figure 7 The bulk acoustic wave resonator 24 and the bulk acoustic wave resonator 25 also include a temperature compensation layer 20e, which is located on the surface of the second electrode 20c away from the piezoelectric layer 20b.

[0067] Optionally, the temperature compensation layer 20e is located at at least one of the following locations: within the piezoelectric layer 20b, on the surface of the piezoelectric layer 20b adjacent to the first electrode 20a, on the surface of the piezoelectric layer 20b adjacent to the second electrode 20c, within the first electrode 20a, on the surface of the first electrode 20a facing away from the piezoelectric layer 20b, within the second electrode 20c, and on the surface of the second electrode 20c facing away from the piezoelectric layer 20b.

[0068] Specifically, the temperature compensation layer 20e includes a positive frequency drift coefficient material, which can compensate for the changes in the electrical and mechanical properties of the bulk acoustic wave resonator caused by temperature variations, thereby improving the temperature stability of the bulk acoustic wave resonator. For example, the temperature compensation layer 20e can be selected from a positive frequency drift coefficient material such as silicon dioxide.

[0069] The application further provides a bulk acoustic wave filter, comprising at least one substrate, the substrate comprising a first surface and a second surface arranged opposite to the first surface, the first surface of the substrate being provided with at least one bulk acoustic wave resonator group as described in any of the above technical solutions; the substrate and the bulk acoustic wave resonators of the bulk acoustic wave resonator group supported by the substrate form a preset included angle.

[0070] For example, referring to Figures 8-12 , the bulk acoustic wave filter comprises a substrate 001, the substrate 001 comprising a first surface 101 and a second surface 102 arranged opposite to the first surface 101, the first surface 101 of the substrate 001 being provided with a bulk acoustic wave resonator group 2, the substrate 001 and the bulk acoustic wave resonators of the bulk acoustic wave resonator group 2 supported by the substrate 001 form a preset included angle α.

[0071] Optionally, when the number of substrates is at least two, a bonding structure can be arranged to seal and connect different substrates. For example, referring to Figure 13 , the bulk acoustic wave filter comprises two substrates, namely a substrate 001 and a substrate 002, the first surface 101 of the substrate 001 being provided with a bulk acoustic wave resonator group 2, the substrate 001 and the bulk acoustic wave resonators of the bulk acoustic wave resonator group 2 supported by the substrate 001 form a preset included angle α. The first surface 101 of the substrate 002 is provided with a bulk acoustic wave resonator group 3. The substrate 002 and the bulk acoustic wave resonators of the bulk acoustic wave resonator group 3 supported by the substrate 002 form a preset included angle α.

[0072] The preset included angle α is in a range greater than 0° and less than 90°, and the greater the value of the preset included angle α, the smaller the size of the bulk acoustic wave filter in a direction perpendicular to the thickness of the substrate 001. For ease of description, the direction perpendicular to the thickness of the substrate 001 is the X direction in the XOY plane rectangular coordinate system, and the direction parallel to the thickness of the substrate 001 is the Y direction in the XOY plane rectangular coordinate system.

[0073] The technical scheme provided by the embodiment of the present application, in a first aspect, the body acoustic wave resonators of the body acoustic wave resonator group supported by the substrate and the substrate are at a preset included angle, that is, the two adjacent body acoustic wave resonators are in a right V-shaped structure or an upside-down V-shaped structure, which reduces the size of the body acoustic wave resonator group in the horizontal direction, and helps to form a miniaturized body acoustic wave filter. And with the increase of the preset included angle between the body acoustic wave resonators of the body acoustic wave resonator group supported by the substrate and the substrate, the size of the body acoustic wave resonator group in the horizontal direction is reduced, and the size of the body acoustic wave filter perpendicular to the thickness direction is reduced. In a second aspect, the two adjacent body acoustic wave resonators are arranged in a V-shaped structure, and the V-shaped structure forms an air gap structure, so that the sound wave can be reflected back to the two adjacent body acoustic wave resonators, thereby reducing the loss of the sound wave and improving the quality factor of the body acoustic wave filter. In a third aspect, in the embodiment of the present application, the sound reflection structure is not arranged on the substrate by the groove method, which simplifies the preparation process, reduces the preparation cost, and also improves the structural stability of the body acoustic wave resonator group.

[0074] Optionally, the substrate comprises adjacent first and second substrates; the first surface of the first substrate is provided with at least one body acoustic wave resonator group, and the second surface of the second substrate is provided with at least one body acoustic wave resonator group, and the body acoustic wave resonator groups between the first and second substrates are distributed in an interdigital manner.

[0075] For example, referring to Figure 14 , the first substrate is substrate 001, the first surface 101 of the substrate 001 is provided with a body acoustic wave resonator group 2, the second substrate is substrate 002, the second surface 102 of the substrate 002 is provided with a body acoustic wave resonator group 3, and the body acoustic wave resonator group 2 and the body acoustic wave resonator group 3 between the substrate 001 and the substrate 002 are distributed in an interdigital manner.

[0076] Specifically, when the number of substrates is greater than or equal to two, the body acoustic wave resonator groups between the two adjacent substrates are distributed in an interdigital manner, which reduces the size of the body acoustic wave filter parallel to the thickness direction of the substrate, thereby helping to form a miniaturized body acoustic wave filter.

[0077] Optionally, it also includes a conductive interconnection structure; the conductive interconnection structure is used to lead the electrical signal of the body acoustic wave resonator group to the first surface side of the uppermost substrate, and / or the conductive interconnection structure is used to lead the electrical signal of the body acoustic wave resonator group out to the second surface side of the lowermost substrate.

[0078] For example, referring to Figure 13 and Figure 14The conductive interconnection structure 60 is used to lead out the electrical signals of the bulk acoustic resonator groups 2 and 3 to the side of the second surface 102 of the lowermost substrate 001, and is also used to lead out the electrical signals of the bulk acoustic resonator groups 2 and 3 to the side of the first surface 101 of the uppermost substrate 001.

[0079] Specifically, the conductive interconnection structure 60 is used to lead out the electrical signals of the bulk acoustic resonator groups, so as to facilitate the electrical connection of the compensation circuit composed of at least one of the capacitance, inductance, resistance and functional chip and the electrical signals of the bulk acoustic filter.

[0080] Optionally, the bulk acoustic filter further comprises a wafer cover plate, the wafer cover plate being located on the side of the first surface of the uppermost substrate; and the conductive interconnection structure is used to lead the electrical signals of the bulk acoustic resonator groups to the surface of the wafer cover plate away from the uppermost substrate.

[0081] Specifically, referring to FIG. 13, the bulk acoustic filter further comprises a wafer cover plate 50 located on the side of the first surface 101 of the uppermost substrate 001. On the basis of the conductive interconnection structure 60 being used to lead out the electrical signals of the bulk acoustic resonator groups to the side of the second surface 102 of the lowermost substrate 001, the conductive interconnection structure 60 can also be used to lead the electrical signals of the bulk acoustic resonator groups to the surface of the wafer cover plate 50 away from the uppermost substrate 001. Figures 8-12 In the embodiment, only one substrate is shown, and the lowermost substrate and the uppermost substrate are both the substrate 001. Specifically, the material of the substrate 001 and the wafer cover plate 50 can be the same or different.

[0082] Optionally, referring to FIG. 13, Figure 13 the wafer cover plate 50 is provided with a groove 50a adjacent to the surface of the side of the uppermost substrate. Specifically, Figure 13 In the embodiment, there are two substrates, the uppermost substrate is the substrate 002, and the lowermost substrate is the substrate 001. The groove 50a can reflect the acoustic wave back to the bulk acoustic resonator group on the side of the uppermost substrate, so as to improve the quality factor of the bulk acoustic filter.

[0083] Optionally, the first electrode or the second electrode of the bulk acoustic resonator adjacent to the conductive interconnection structure is connected with the conductive interconnection structure through a conductive connection part.

[0084] Specifically, referring to FIG. 13, Figure 8 the first electrode 20a of the bulk acoustic resonator 24 adjacent to the conductive interconnection structure 60 is connected with the conductive interconnection structure 60 through a conductive connection part 70. The first electrode 20a of the bulk acoustic resonator 25 adjacent to the conductive interconnection structure 60 is connected with the conductive interconnection structure 60 through a conductive connection part 71.

[0085] Referring to FIG. 13, Figure 9 and Figure 12The second electrode 20c of the bulk acoustic resonator 24 adjacent to the conductive interconnection structure 60 is connected with the conductive interconnection structure 60 through the conductive connection 74. The second electrode 20c of the bulk acoustic resonator 25 adjacent to the conductive interconnection structure 60 is connected with the conductive interconnection structure 60 through the conductive connection 75.

[0086] Referring to Figure 10 , Figure 11 and Figure 14 The second electrode 20c of the bulk acoustic resonator 24 adjacent to the conductive interconnection structure 60 is connected with the conductive interconnection structure 60 through the conductive connection 72. The second electrode 20c of the bulk acoustic resonator 27 adjacent to the conductive interconnection structure 60 is connected with the conductive interconnection structure 60 through the conductive connection 73.

[0087] Referring to Figure 14 The second electrode 20c of the bulk acoustic resonator 28 adjacent to the conductive interconnection structure 60 is connected with the conductive interconnection structure 60 through the conductive connection 76. The second electrode 20c of the bulk acoustic resonator 29 adjacent to the conductive interconnection structure 60 is connected with the conductive interconnection structure 60 through the conductive connection 77.

[0088] In summary, the first electrode or the second electrode of the bulk acoustic resonator adjacent to the conductive interconnection structure is connected with the conductive interconnection structure through the conductive connection. In combination with the connection mode of the conductive interconnection structure and the bulk acoustic resonator group, the electrical signal of the bulk acoustic resonator group is led out, and the electrical connection of the compensation circuit composed of at least one of the capacitance, the inductance, the resistance and the functional chip and the electrical signal of the bulk acoustic filter is realized.

[0089] In one bulk acoustic resonator group, the electrodes of two adjacent bulk acoustic resonators are electrically connected through direct contact or through an intermediate conductive part. For example, referring to Figure 10 and Figure 15 In the bulk acoustic resonator group 2, the bulk acoustic resonator 24, the bulk acoustic resonator 25, the bulk acoustic resonator 26 and the bulk acoustic resonator 27 are connected in series. Referring to Figure 14 and Figure 16 The bulk acoustic resonator group 2 and the bulk acoustic resonator group 3 are connected in parallel, the bulk acoustic resonator 24, the bulk acoustic resonator 25, the bulk acoustic resonator 26 and the bulk acoustic resonator 27 in the bulk acoustic resonator group 2 are connected in series. The bulk acoustic resonator 28 and the bulk acoustic resonator 29 in the bulk acoustic resonator group 3 are connected in series.

[0090] Optionally, referring to Figure 14, the first surface 101 of the first substrate 001 is provided with a first bulk acoustic resonator group 2, the first bulk acoustic resonator group 2 comprises a first bulk acoustic resonator 24, a second bulk acoustic resonator 25, a third bulk acoustic resonator 26 and a fourth bulk acoustic resonator 27; the first bulk acoustic resonator 24 and the second bulk acoustic resonator 25 are arranged in an inverted V-shaped manner, the third bulk acoustic resonator 26 and the fourth bulk acoustic resonator 27 are arranged in an inverted V-shaped manner, and the second bulk acoustic resonator 25 and the third bulk acoustic resonator 26 are arranged in a normal V-shaped manner.

[0091] Optionally, referring to Figure 14 , the second surface 102 of the second substrate 002 is provided with a second bulk acoustic resonator group 3, the second bulk acoustic resonator group 3 comprises a fifth bulk acoustic resonator 28 and a sixth bulk acoustic resonator 29, and the fifth bulk acoustic resonator 28 and the sixth bulk acoustic resonator 29 are arranged in a normal V-shaped manner; the connected parts of the fifth bulk acoustic resonator 28 and the sixth bulk acoustic resonator 29 are located in the normal V-shaped space 80 formed by the second bulk acoustic resonator 25 and the third bulk acoustic resonator 26.

[0092] The technical scheme provided by the embodiment of the present application, in a first aspect, the bulk acoustic resonators of the bulk acoustic resonator group supported by the substrate and the substrate are arranged at a preset included angle, that is, the two adjacent bulk acoustic resonators are arranged in a normal V-shaped structure or an inverted V-shaped structure, which reduces the size of the bulk acoustic resonator group in the horizontal direction and helps to form a miniaturized bulk acoustic filter. Moreover, as the preset included angle between the bulk acoustic resonators of the bulk acoustic resonator group supported by the substrate and the substrate increases, the angle formed by the V-shaped side of the V-shaped structure of the bulk acoustic resonator group decreases, and the size of the bulk acoustic filter in the direction perpendicular to the thickness direction decreases. When the number of the substrate is greater than or equal to two, the bulk acoustic resonator groups between the two adjacent substrates are arranged in a finger-shaped manner, which reduces the size of the bulk acoustic filter in the direction parallel to the thickness direction of the substrate, thereby helping to form a miniaturized bulk acoustic filter. In a second aspect, the V-shaped structure forms an air gap structure bulk acoustic resonator, which can reflect the acoustic wave back to the adjacent lower and upper bulk acoustic resonators, thereby reducing the loss of the acoustic wave and improving the quality factor of the bulk acoustic filter. In a third aspect, in the embodiment of the present application, the acoustic reflection structure is not arranged on the substrate by means of groove, which simplifies the preparation process, reduces the preparation cost, and also improves the structural stability of the bulk acoustic resonator group.

[0093] Optionally, in the direction parallel to the thickness direction of the substrate, the spacing between the adjacent substrates is less than the sum of the heights of the bulk acoustic resonator groups arranged in a finger-shaped manner between the adjacent substrates.

[0094] Exemplarily, referring to Figure 14In the thickness direction parallel to the substrate 001, the height M1 of the bulk acoustic resonator group 2 is less than the interval M2 between the substrate 001 and the substrate 002, and the height M3 of the bulk acoustic resonator group 3 is less than the interval M2 between the substrate 001 and the substrate 002. The interval M2 between the adjacent substrates 001 and 002 is less than the sum of the height M1 of the bulk acoustic resonator group 2 and the height M3 of the bulk acoustic resonator group 3 which are distributed in an interdigital manner between the adjacent substrates 001 and 001.

[0095] Optionally, in the horizontal direction, the two bulk acoustic resonator groups distributed in an interdigital manner are spaced apart by a preset interval.

[0096] For example, referring to Figure 14 In the horizontal direction, the two bulk acoustic resonator groups 2 and 3 distributed in an interdigital manner are spaced apart by a preset interval, which is embodied as follows: in the horizontal direction, the second bulk acoustic resonator 25 of the first bulk acoustic resonator group 2 and the fifth bulk acoustic resonator 28 of the second bulk acoustic resonator group 3 are spaced apart by a preset distance M4, the third bulk acoustic resonator 26 of the first bulk acoustic resonator group 2 and the sixth bulk acoustic resonator 29 of the second bulk acoustic resonator group 3 are spaced apart by a preset distance M5, and the connected parts of the fifth bulk acoustic resonator 28 and the sixth bulk acoustic resonator 29 are located in the V-shaped space 80 in which the second bulk acoustic resonator 25 and the third bulk acoustic resonator 26 are vertically arranged. The above technical solution increases the isolation degree of the two bulk acoustic resonator groups 2 and 3 distributed in an interdigital manner, thereby avoiding signal crosstalk.

[0097] For example, referring to Figure 3 For the bulk acoustic resonator group shown, the embodiment of the present application further provides a preparation method of the bulk acoustic resonator group, referring to Figure 17 The preparation method comprises the following steps:

[0098] In step 110, a substrate is provided, and a first sacrificial layer is formed on a first surface of the substrate.

[0099] Referring to Figure 18 In step 110, a substrate is provided, and a first sacrificial layer is formed on a first surface of the substrate. For example, the substrate 001 can be made of single crystal silicon, gallium arsenide, sapphire, quartz or other materials. For example, the first sacrificial layer 100 can be made of an oxide containing silicon, such as phosphosilicate glass (PSG), which can be formed by a deposition process. The thickness of the first sacrificial layer 100 can be controlled by the process parameters of the deposition process.

[0100] In step 120, the first sacrificial layer is subjected to a patterning process.

[0101] Referring toFigure 18 The first sacrificial layer 100 is patterned by a photolithography and etching process.

[0102] Step 130, forming a first electrode on the surface of the first sacrificial layer away from the substrate.

[0103] Referring to Figure 18 The first electrode 20a can be formed on the surface of the first sacrificial layer 100 away from the substrate 001 by a sputtering or evaporation process. For example, the first electrode 20a can be selected from at least one of molybdenum, ruthenium, gold, aluminum, magnesium, tungsten, copper and titanium.

[0104] Step 140, forming a piezoelectric layer on the surface of the first electrode.

[0105] Referring to Figure 18 The piezoelectric layer 20b can be formed on the surface of the first electrode 20a by a deposition process. For example, the piezoelectric layer 20b can be selected from at least one of single-crystal piezoelectric thin film materials such as aluminum nitride, zinc oxide, lead zirconate titanate piezoelectric ceramic, lithium niobate, lithium tantalate, potassium niobate and polycrystalline piezoelectric thin film materials. A certain proportion of rare earth elements can also be doped in the piezoelectric layer 20b to improve the performance of the piezoelectric material layer. It should be noted that the aluminum nitride piezoelectric layer has better performance as a bulk acoustic wave resonator of the piezoelectric layer due to its small intrinsic loss, low temperature coefficient and good thermal conductivity.

[0106] Step 150, forming a second electrode on the surface of the piezoelectric layer.

[0107] Referring to Figure 18 The second electrode 20c can be formed on the surface of the piezoelectric layer 20b by a sputtering or evaporation process. For example, the second electrode 20c can be selected from at least one of molybdenum, ruthenium, gold, aluminum, magnesium, tungsten, copper and titanium.

[0108] Step 160, releasing the first sacrificial layer.

[0109] Referring to Figure 18 and Figure 3 The first sacrificial layer 100 can be released by the etching liquid.

[0110] For example, the first sacrificial layer 100 can be silicon oxide, and the etching liquid can be hydrofluoric acid solution, so that the first sacrificial layer 100 can be quickly released.

[0111] For example, for the bulk acoustic resonator group shown in Figure 6 The embodiment of the present application also provides a preparation method of the bulk acoustic wave resonator group, referring to Figure 19 The preparation method comprises the following steps:

[0112] Step 210, providing a substrate, and forming a first sacrificial layer on a first surface of the substrate.

[0113] Referring to Figure 20 , a substrate 001 is provided, and a first sacrificial layer 100 is formed on a first surface 101 of the substrate 001.

[0114] Step 220, patterning the first sacrificial layer.

[0115] Referring to Figure 20 , the first sacrificial layer 100 is patterned by a photolithography and etching process.

[0116] Step 230, forming a first electrode on a surface of the first sacrificial layer away from the substrate.

[0117] Referring to Figure 20 , the first electrode 20a can be formed on a surface of the first sacrificial layer 200 away from the substrate 001 by a sputtering or evaporation process.

[0118] Step 240, forming a piezoelectric layer on a surface of the first electrode.

[0119] Referring to Figure 20 , the piezoelectric layer 20b can be formed on a surface of the first electrode 20a by a deposition process.

[0120] Step 250, forming a second electrode on a surface of the piezoelectric layer.

[0121] Referring to Figure 20 , the second electrode 20c can be formed on a surface of the piezoelectric layer 20b by a sputtering or evaporation process.

[0122] Step 260, forming a second sacrificial layer.

[0123] Referring to Figure 20 , the second sacrificial layer 200 can be formed on a surface side of the substrate 001 by a deposition process.

[0124] Step 270, planarizing the second sacrificial layer.

[0125] Referring to Figure 20 , a Chemical Mechanical Polishing (CMP) process can be selected to planarize the second sacrificial layer 200.

[0126] Step 280, releasing the first sacrificial layer and the second sacrificial layer.

[0127] Referring to Figure 20 and Figure 6 , an etching solution can be selected to release the first sacrificial layer 100 and the second sacrificial layer 200.

[0128] For example, the first and second sacrificial layers 100 and 200 can be made of silicon oxide, and the etching solution can be hydrofluoric acid solution, so that the first sacrificial layer 100 can be quickly released.

[0129] The embodiment of the present application also provides a communication device, which comprises the bulk acoustic wave filter in any of the above technical solutions.

[0130] Specifically, the duplex can be simply understood as the operation of two bulk acoustic wave filters, one of which is a receiving bulk acoustic wave filter for receiving signals, and the other is a transmitting bulk acoustic wave filter for transmitting signals.

[0131] The communication device provided by the embodiment of the present application comprises the bulk acoustic wave filter in any of the above technical solutions, and thus has the beneficial effects of the bulk acoustic wave filter, which will not be repeated here.

[0132] Note that the above are only the preferred embodiments of the present application and the technical principles applied. Those skilled in the art will understand that the present application is not limited to the specific embodiments described herein, and those skilled in the art can make various obvious changes, readjustments and substitutions without departing from the scope of the present application. Therefore, although the present application has been described in more detail through the above embodiments, the present application is not limited to the above embodiments, and can include more other equivalent embodiments without departing from the concept of the present application, and the scope of the present application is determined by the scope of the appended claims.

Claims

1. A bulk acoustic resonator array, characterized in that, include: At least two bulk acoustic wave resonators, each of the bulk acoustic wave resonators comprising a stacked structure of a first electrode, a piezoelectric layer, and a second electrode, the stacked structure being used to generate bulk acoustic waves; Two adjacent bulk acoustic resonators are in an upright V-shaped structure or an inverted V-shaped structure, and the upright or inverted V-shaped structure encloses an air gap, which provides an acoustic wave reflection structure for each bulk acoustic resonator. The bulk acoustic wave resonator assembly is supported by a substrate, the substrate being made of any one of wafer, gallium arsenide, sapphire, and quartz.

2. The bulk acoustic resonator assembly according to claim 1, characterized in that, The two adjacent bulk acoustic resonators support each other in an inverted V-shaped structure; Alternatively, two adjacent bulk acoustic resonators may form an inverted V-shaped structure supported by a support layer. Alternatively, two adjacent bulk acoustic resonators are supported by a support layer, and the two adjacent bulk acoustic resonators support each other in an upright V-shaped structure.

3. The bulk acoustic resonator assembly according to claim 2, characterized in that, The angle formed by the V-shaped sides of the V-shaped structure is greater than or equal to 0° and less than or equal to 90°.

4. The bulk acoustic resonator assembly according to claim 1, characterized in that, The two adjacent bulk acoustic resonator electrodes are electrically connected through a middle conductive part. Alternatively, two adjacent bulk acoustic resonator electrodes may be in direct contact to achieve electrical connection; Alternatively, the electrodes of two adjacent bulk acoustic resonators may be insulated.

5. The bulk acoustic resonator assembly according to claim 1, characterized in that, The bulk acoustic resonator also includes a temperature compensation layer, which comprises a material with a positive frequency drift coefficient.

6. The bulk acoustic resonator array according to claim 5, characterized in that, The temperature compensation layer is located at at least one of the following locations: within the piezoelectric layer, on the surface of the piezoelectric layer adjacent to the first electrode, on the surface of the piezoelectric layer adjacent to the second electrode, within the first electrode, on the surface of the first electrode facing away from the piezoelectric layer, within the second electrode, and on the surface of the second electrode facing away from the piezoelectric layer.

7. A bulk acoustic wave filter, comprising at least one substrate, the substrate including a first surface and a second surface disposed opposite to the first surface, characterized in that, The first surface of the substrate is provided with at least one bulk acoustic resonator group as described in any one of claims 1-6; The substrate and the bulk acoustic wave resonators of the bulk acoustic wave resonator group supported by the substrate form a predetermined angle. The substrate material includes any one of wafer, gallium arsenide, sapphire, and quartz.

8. The bulk acoustic wave filter according to claim 7, characterized in that, The substrate includes an adjacent first substrate and a second substrate; The first substrate has at least one bulk acoustic wave resonator group disposed on its first surface, and the second substrate has at least one bulk acoustic wave resonator group disposed on its second surface. The bulk acoustic wave resonator groups between the first substrate and the second substrate are distributed in an interdigitated pattern.

9. The bulk acoustic wave filter according to claim 7 or 8, characterized in that, It also includes conductive interconnect structures; The conductive interconnect structure is used to lead the electrical signal of the bulk acoustic wave resonator group to the first surface side of the uppermost substrate, and / or, the conductive interconnect structure is used to lead the electrical signal of the bulk acoustic wave resonator group to the second surface side located on the lowermost substrate.

10. The bulk acoustic wave filter according to claim 9, characterized in that, It also includes a wafer cover plate, which is located on the first surface side of the uppermost substrate; The conductive interconnect structure is used to direct the electrical signals of the bulk acoustic resonator group to the surface of the wafer cover away from the uppermost substrate.

11. The bulk acoustic wave filter according to claim 9, characterized in that, The first or second electrode of the bulk acoustic resonator adjacent to the conductive interconnect structure is connected to the conductive interconnect structure via a conductive connection portion.

12. The bulk acoustic wave filter according to claim 8, characterized in that, A first bulk acoustic wave resonator group is disposed on the first surface of the first substrate, the first bulk acoustic wave resonator group including a first bulk acoustic wave resonator, a second bulk acoustic wave resonator, a third bulk acoustic wave resonator and a fourth bulk acoustic wave resonator. The first and second body acoustic resonators are arranged in an inverted V-shape, the third and fourth body acoustic resonators are arranged in an inverted V-shape, and the second and third body acoustic resonators are arranged in an upright V-shape.

13. The bulk acoustic wave filter according to claim 12, characterized in that, The second substrate has a second bulk acoustic wave resonator group on its second surface. The second bulk acoustic wave resonator group includes a fifth bulk acoustic wave resonator and a sixth bulk acoustic wave resonator. The fifth bulk acoustic wave resonator and the sixth bulk acoustic wave resonator are arranged in an upright V-shape. The portion where the fifth body acoustic resonator and the sixth body acoustic resonator are connected is located within the V-shaped space where the second body acoustic resonator and the third body acoustic resonator are upright.

14. The bulk acoustic wave filter according to claim 8, characterized in that, In the thickness direction parallel to the substrate, the spacing between adjacent substrates is less than the sum of the heights of the bulk acoustic wave resonator groups that are interdigitated between adjacent substrates.

15. The bulk acoustic wave filter according to claim 8, characterized in that, In the horizontal direction, the two acoustic resonator groups, which are distributed in an interdigital pattern, are spaced apart by a predetermined distance.

16. A communication device, characterized in that, Includes the bulk acoustic wave filter according to any one of claims 7-15; The communication device includes at least one of a filter, a duplexer, and a multiplexer.

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