A bulk acoustic wave resonator array and a method for manufacturing the same

Abstract

The present invention discloses a bulk acoustic wave resonator array and a preparation method thereof, which are applied to the technical field of bulk acoustic wave resonators, and include a plurality of bulk acoustic wave resonators; an electrode connecting portion is provided between adjacent bulk acoustic wave resonators, the electrode connecting portion connects electrodes located on the same side of a piezoelectric layer in adjacent bulk acoustic wave resonators, and the thickness of the electrode connecting portion is greater than the thickness of the connecting electrode. By increasing the thickness of the electrode connecting portion located between adjacent bulk acoustic wave resonators and used to connect adjacent bulk acoustic wave resonators, lower ohmic losses can be achieved between adjacent bulk acoustic wave resonators, thereby increasing the Q value of the resonator and improving the performance of the filter.

Description

Technical Field

[0001] The present invention relates to the technical field of bulk acoustic wave resonators, and in particular to a bulk acoustic wave resonator array and a method for preparing the bulk acoustic wave resonator array. Background Art

[0002] In communication base stations, the receiving and transmitting power of RF signals is particularly large, especially the transmitting power, which places high demands on the RF front end. Therefore, the power capacity of filters in RF front-end devices needs to be increased urgently. In the 5G communication era, the main filters used are BAW (bulk acoustic wave) filters.

[0003] How to increase the power capacity of BAW filters while maintaining low passband insertion loss has become a major difficulty. The existing technology increases the power capacity by increasing the area of ​​the resonator in the BAW filter or changing a single resonator into multiple resonators in series or parallel. Both methods inevitably increase the propagation path of the filter's electrical signal, thereby increasing the ohmic loss in the electrode. Therefore, how to reduce the ohmic loss of the BAW resonator array is an urgent problem that technicians in this field need to solve. Summary of the invention

[0004] An object of the present invention is to provide a bulk acoustic wave resonator array having lower ohmic loss; another object of the present invention is to provide a method for preparing a bulk acoustic wave resonator array, which can reduce the ohmic loss of the bulk acoustic wave resonator array.

[0005] In order to solve the above technical problems, the present invention provides a bulk acoustic wave resonator array, comprising a plurality of bulk acoustic wave resonators;

[0006] An electrode connecting portion is provided between adjacent BAW resonators, the electrode connecting portion connects electrodes located on the same side of the piezoelectric layer in adjacent BAW resonators, and the thickness of the electrode connecting portion is greater than the thickness of the connecting electrodes.

[0007] Optionally, in the piezoelectric layer formed with the plurality of BAW resonators, an etching hole exposing a bottom electrode below the piezoelectric layer is provided in a region between adjacent BAW resonators;

[0008] An electrode thickening portion in contact with the exposed bottom electrode is arranged in the etching hole to form the electrode connecting portion.

[0009] Optionally, the electrode connecting portion is located on the upper surface of the piezoelectric layer and is connected to the top electrode of the adjacent BAW resonator.

[0010] Optionally, the electrode connecting portion includes:

[0011] An electrode connection portion formed by an electrode thickening portion is arranged on the surface of the top electrode, and an electrode connection portion formed by an electrode thickening portion is arranged on the surface of the piezoelectric layer.

[0012] Optionally, the plurality of BAW resonators are linearly distributed, and the electrode connecting portion is located between two adjacent BAW resonators to connect electrodes of the two adjacent BAW resonators.

[0013] Optionally, the plurality of BAW resonators are distributed in an array, and the electrode connecting portion located between at least three BAW resonators connects electrodes of at least three adjacent BAW resonators.

[0014] The present invention also provides a method for preparing a bulk acoustic wave resonator array, comprising:

[0015] Disposing a plurality of bulk acoustic wave resonators;

[0016] An electrode connecting portion is arranged between adjacent BAW resonators to form the BAW resonator array; the electrode connecting portion connects electrodes located on the same side of the piezoelectric layer in adjacent BAW resonators, and the thickness of the electrode connecting portion is greater than the thickness of the connecting electrodes.

[0017] Optionally, providing an electrode connection portion between adjacent BAW resonators includes:

[0018] Etching a region of the piezoelectric layer between adjacent BAW resonators to form an etching hole exposing a bottom electrode below the piezoelectric layer;

[0019] An electrode thickening portion in contact with the exposed bottom electrode is arranged in the etched hole to form the electrode connecting portion.

[0020] Optionally, etching a region of the piezoelectric layer between adjacent BAW resonators to form an etching hole exposing a bottom electrode below the piezoelectric layer comprises:

[0021] At the same time, the region of the piezoelectric layer between adjacent BAW resonators and the preset release hole region are etched to form an etched hole exposing the bottom electrode below the piezoelectric layer and a release hole.

[0022] Optionally, providing an electrode connection portion between adjacent BAW resonators includes:

[0023] An electrode thickening portion connected to the top electrodes of the adjacent BAW resonators is provided in the region where the piezoelectric layer surface is located between the adjacent BAW resonators and the region where the top electrode surface is located between the adjacent BAW resonators to form the electrode connecting portion.

[0024] A BAW resonator array provided by the present invention comprises a plurality of BAW resonators; an electrode connecting portion is arranged between adjacent BAW resonators, the electrode connecting portion connects electrodes located on the same side of a piezoelectric layer in adjacent BAW resonators, and the thickness of the electrode connecting portion is greater than the thickness of the connecting electrode.

[0025] By increasing the thickness of the electrode connection portion between adjacent BAW resonators and used to connect adjacent BAW resonators, lower ohmic loss can be achieved between adjacent BAW resonators, thereby increasing the Q value of the resonator and improving the performance of the filter.

[0026] The present invention also provides a method for preparing a bulk acoustic wave resonator array, which also has the above-mentioned beneficial effects and will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions of the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0028] Figure 1 A schematic diagram of the structure of a bulk acoustic wave resonator array provided by an embodiment of the present invention;

[0029] Figure 2 A schematic structural diagram of a first specific bulk acoustic wave resonator array provided by an embodiment of the present invention;

[0030] Figure 3 A schematic structural diagram of a second specific bulk acoustic wave resonator array provided in an embodiment of the present invention;

[0031] Figure 4 A comparison diagram of the Q values ​​of the bulk acoustic wave resonator before and after the electrode connection portion is set in the first embodiment of the present invention;

[0032] Figure 5 A comparison diagram of the Q values ​​of the bulk acoustic wave resonator before and after the electrode connection portion is set in the second embodiment of the present invention;

[0033] Figure 6 A schematic structural diagram of a third specific BAW resonator array provided in an embodiment of the present invention;

[0034] Figure 7 A schematic structural diagram of a fourth specific BAW resonator array provided by an embodiment of the present invention;

[0035] Figure 8A flow chart of a method for preparing a bulk acoustic wave resonator array provided by an embodiment of the present invention;

[0036] Fig. 9 The present invention provides a flow chart of a specific method for preparing a bulk acoustic wave resonator array.

[0037] In the figure: 1. BAW resonator, 2. acoustic reflection layer, 3. bottom electrode, 4. piezoelectric layer, 5. top electrode, 6. electrode connecting part, 61. electrode thickening part. DETAILED DESCRIPTION

[0038] The core of the present invention is to provide a bulk acoustic wave resonator array. In the prior art, the power capacity is increased by increasing the area of ​​the resonator in the BAW filter or by changing a single resonator into multiple resonators connected in series or in parallel. Both methods inevitably increase the propagation path of the electric signal of the filter, thereby increasing the ohmic loss in the electrode.

[0039] The present invention provides a BAW resonator array, comprising a plurality of BAW resonators; an electrode connecting portion is provided between adjacent BAW resonators, the electrode connecting portion connects electrodes located on the same side of the piezoelectric layer in adjacent BAW resonators, and the thickness of the electrode connecting portion is greater than the thickness of the connecting electrode.

[0040] By increasing the thickness of the electrode connection portion between adjacent BAW resonators and used to connect adjacent BAW resonators, lower ohmic loss can be achieved between adjacent BAW resonators, thereby increasing the Q value of the resonator and improving the performance of the filter.

[0041] In order to enable those skilled in the art to better understand the scheme of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0042] Please refer to Figures 1 to 5 , Figure 1 A schematic diagram of the structure of a bulk acoustic wave resonator array provided by an embodiment of the present invention; Figure 2 A schematic structural diagram of a first specific bulk acoustic wave resonator array provided by an embodiment of the present invention; Figure 3 A schematic structural diagram of a second specific bulk acoustic wave resonator array provided in an embodiment of the present invention; Figure 4 A comparison diagram of the Q values ​​of the bulk acoustic wave resonator before and after the electrode connection portion is set in the first embodiment of the present invention; Figure 5This is a comparison diagram of the Q values ​​of the second bulk acoustic wave resonator before and after the electrode connection portion is set according to an embodiment of the present invention.

[0043] In an embodiment of the present invention, the BAW resonator array includes a plurality of BAW resonators 1; an electrode connecting portion 6 is provided between adjacent BAW resonators 1, the electrode connecting portion 6 connects electrodes located on the same side of the piezoelectric layer 4 in adjacent BAW resonators 1, and the thickness of the electrode connecting portion 6 is greater than the thickness of the connecting electrode.

[0044] For a BAW resonator array, the electrodes of its BAW resonators 1 need to be interconnected, and in this embodiment, the interconnection of the electrodes in the BAW resonators 1 is achieved specifically through the electrode connecting portion 6. Specifically, the electrode connecting portion 6 connects the electrodes on the same side of the piezoelectric layer 4 in adjacent BAW resonators 1, that is, the electrode connecting portion 6 will connect the bottom electrode 3 or the top electrode 5 of the adjacent BAW resonators 1. In this embodiment, the thickness of the electrode connecting portion 6 is greater than the thickness of the connecting electrode, so that the resistance of the electrode connecting portion 6 per unit area is lower than the resistance of the top electrode 5 or the bottom electrode 3. Compared with the traditional method of directly interconnecting only through the electrode layer, this embodiment realizes the interconnection between BAW resonators 1 through the electrode connecting portion 6 whose thickness is greater than the thickness of the connecting electrode, which can effectively reduce the ohmic loss between adjacent BAW resonators 1, thereby increasing the Q value of the resonator and improving the performance of the filter.

[0045] Accordingly, in this embodiment, two BAW resonator arrays are specifically provided, which respectively interconnect bottom electrodes 3 of adjacent BAW resonators 1 through electrode connecting portions 6 , and interconnect top electrodes 5 of adjacent BAW resonators 1 through electrode connecting portions 6 .

[0046] For the first one, please refer to Figure 1 In the piezoelectric layer 4 formed with multiple BAW resonators 1, an etching hole exposing the bottom electrode 3 below the piezoelectric layer 4 is provided in the area between adjacent BAW resonators 1; an electrode thickening portion 61 in contact with the exposed bottom electrode 3 is provided in the etching hole to form the electrode connecting portion 6.

[0047] First, in this embodiment, the bottom electrodes 3 of adjacent BAW resonators 1 are connected to each other, that is, the bottom electrodes 3 are provided between adjacent BAW resonators 1 and below the piezoelectric layer 4. In order to form the electrode connecting portion 6, in this embodiment, an etched hole needs to be etched in the piezoelectric layer 4, and the etched hole is specifically located between adjacent BAW resonators 1. Since the etched hole is formed by etching the piezoelectric layer 4, the bottom electrode 3 located between the adjacent BAW resonators 1 and below the piezoelectric layer 4 can be exposed through the etched hole.

[0048] In this embodiment, an electrode thickening portion 61 in contact with the bottom electrode 3 is specifically provided in the etching hole, and the electrode thickening portion 61 and the bottom electrode 3 exposed by the etching hole together form an electrode connecting portion 6. Due to the existence of the electrode thickening portion 61, the resistance of the electrode connecting portion 6 per unit area is lower than the resistance of the bottom electrode 3 per unit area, so that the electrode connecting portion 6 can effectively reduce the lower ohmic loss between the bulk acoustic wave resonators 1, thereby increasing the Q value of the resonator and improving the performance of the filter.

[0049] The second one, see Figure 2 , the electrode connection part 6 is located on the upper surface of the piezoelectric layer 4, and is connected to the top electrode 5 of the adjacent BAW resonator 1. In this embodiment, the top electrodes 5 of the adjacent BAW resonators 1 are connected to each other through the electrode connection part 6, and the thickness of the electrode connection part 6 needs to be greater than the thickness of the top electrode 5 in the BAW resonator 1. Compared with the existing BAW resonators 1 interconnected by the top electrode 5 themselves, the use of the electrode connection part 6 can effectively reduce the lower ohmic loss between the BAW resonators 1, thereby increasing the Q value of the resonator and improving the performance of the filter.

[0050] Specifically, the electrode connection portion 6 includes: an electrode connection portion 6 formed by arranging an electrode thickening portion 61 on the surface of the top electrode 5, and an electrode connection portion 6 formed by arranging an electrode thickening portion 61 on the surface of the piezoelectric layer 4. That is, the top electrodes 5 of adjacent BAW resonators 1 can be connected to each other or disconnected from each other before the electrode connection portion 6 is arranged. In this embodiment, the electrode connection portion 6 connecting the top electrodes 5 between adjacent BAW resonators 1 can be formed by arranging an electrode thickening portion 61 on the surface of the top electrode 5 between adjacent BAW resonators 1; it can also be formed by directly arranging an electrode thickening portion 61 on the surface of the piezoelectric layer 4, and connecting the top electrodes 5 between adjacent BAW resonators 1 through the electrode thickening portion 61 to form the electrode connection portion 6.

[0051] The specific thickness of the electrode thickening portion 61 in each of the above embodiments needs to be set according to the actual situation and is not specifically limited here. The material of the electrode thickening portion 61 can be the same as or different from the material of the top electrode 5 or the bottom electrode 3 in contact with it, but it usually needs to have good electrical conductivity to reduce the resistance of the electrode connecting portion 6. As a preferred material, the electrode thickening portion 61 can be the same as the material of the top electrode 5 or the bottom electrode 3 in contact with it.

[0052] In this embodiment, the BAW resonator 1 can specifically set a cavity as the acoustic reflection layer 2 under the bottom electrode 3, or a Bragg reflection layer (DBR reflection layer) can be set as the acoustic reflection layer 2 under the bottom electrode 3, that is, an acoustic reflection layer 2 formed by alternating filling of high acoustic impedance material and low acoustic impedance material is set, which is not specifically limited in the embodiment of the present invention. The material of the piezoelectric layer 4 can be one or a combination of polycrystalline aluminum nitride, single crystal aluminum nitride, aluminum nitride doped with scandium, lithium niobate, and zinc oxide. The materials of the top electrode 5, the bottom electrode 3, and the electrode thickening portion 61 can all be one or a combination of gold, aluminum, molybdenum, silver, nickel, titanium, and tungsten. For the electrode thickening portion 61 set on the surface of the bottom electrode 3 or the top electrode 5, an adhesion layer can also be included between the electrode layer and the electrode thickening portion 61 to increase the firmness of the connection between the electrode thickening portion 61 and the electrode layer. The material of the adhesion layer can be one or more of titanium, tungsten, and titanium-tungsten alloy.

[0053] According to the known technology, the impedance of the acoustic resonator at the series resonator point is about 0.1Ω, and the impedance at the parallel resonator point is about several thousand ohms. Assuming that the length of the electrode connection portion 6 is 50um, the impedance of the conventional method of connecting the bulk acoustic wave resonator 1 only through a single-layer electrode is 0.0975Ω, and the impedance of this connection method has a great influence on the impedance of the series resonator point.

[0054] Please refer to Figure 4 as well as Figure 5 , Figure 4 The diagram of the influence of the bottom electrode 3 on the resonator Q value calculated by the Bode method based on the above conditions before and after the bottom electrode 3 is interconnected by the electrode connecting portion 6;

[0055] Figure 5 This is a diagram showing the influence of the top electrode 5 on the Q value of the resonator before and after the top electrode 5 is interconnected through the electrode connecting portion 6 and calculated by the Bode method based on the above conditions.

[0056] from Figure 4 It can be seen from the figure that after the electrode connecting portion 6 is interconnected with the bottom electrode 3 in this embodiment, the interconnection impedance value is reduced, resulting in the Q value of the resonator increasing by about 150. Figure 5 It can be seen in the figure that after the electrode connecting portion 6 interconnects the top electrode 5 in this embodiment, the interconnection impedance value of the top electrode 5 is reduced, resulting in the Q value of the resonator increasing by about 170, which will reduce the insertion loss of the filter passband.

[0057] When the electrode connection portion 6 of the present invention has the same length, the impedance is only 0.041Ω, which can greatly improve the influence of the impedance of the interconnection portion on the impedance of the series resonator point and reduce the degradation of the Q value.

[0058] A BAW resonator array provided in an embodiment of the present invention can increase the thickness of an electrode connecting portion 6 located between adjacent BAW resonators 1 and used to connect adjacent BAW resonators 1, so that the ohmic loss between adjacent BAW resonators 1 is lowered, thereby increasing the Q value of the resonator and improving the performance of the filter.

[0059] The specific contents of a bulk acoustic wave resonator array provided by the present invention will be described in detail in the following invention embodiments.

[0060] Please refer to Figure 6 as well as Figure 7 , Figure 6 A schematic structural diagram of a third specific BAW resonator array provided in an embodiment of the present invention; Figure 7 This is a schematic structural diagram of a fourth specific BAW resonator array provided in an embodiment of the present invention.

[0061] Different from the above-mentioned invention embodiment, the present invention embodiment further defines the structure of the BAW resonator array on the basis of the above-mentioned invention embodiment. The rest of the contents have been described in detail in the above-mentioned invention embodiment and will not be repeated here.

[0062] Please refer to Figure 6 In the embodiment of the present invention, the plurality of BAW resonators 1 are linearly distributed, and the electrode connecting portion 6 is located between two adjacent BAW resonators 1 to connect the electrodes of the two adjacent BAW resonators 1 .

[0063] That is, when the BAW resonator array is distributed in a line, an electrode connecting portion 6 will be provided with BAW resonators 1 only on two sides. Therefore, in the BAW resonator array with this structural distribution, the electrode connecting portion 6 will be specifically located between two adjacent BAW resonators 1, connecting the electrodes of the two adjacent BAW resonators 1.

[0064] Please refer to Figure 7 In the embodiment of the present invention, the plurality of BAW resonators 1 are distributed in an array, and the electrode connecting portion 6 located between at least three BAW resonators 1 connects the electrodes of at least three adjacent BAW resonators 1 .

[0065] That is, when the BAW resonators 1 are distributed in an array, one BAW resonator 1 will be adjacent to at least two BAW resonators 1, and the electrode connecting portion 6 can be located between at least three BAW resonators 1, and one electrode connecting portion 6 can connect the electrodes of at least three adjacent BAW resonators 1. Of course, among the BAW resonators 1 distributed in an array, there may also be an electrode connecting portion 6 that only connects two adjacent BAW resonators 1, and in this embodiment, not every electrode connecting portion 6 needs to be connected to the electrodes of at least three BAW resonators 1.

[0066] A BAW resonator array provided in an embodiment of the present invention can increase the thickness of an electrode connecting portion 6 located between adjacent BAW resonators 1 and used to connect adjacent BAW resonators 1, so that the ohmic loss between adjacent BAW resonators 1 is lowered, thereby increasing the Q value of the resonator and improving the performance of the filter.

[0067] A method for preparing a BAW resonator array provided in an embodiment of the present invention is introduced below. The preparation method described below and the BAW resonator array described above can be referred to each other.

[0068] Please refer to Figure 8 , Figure 8 The present invention provides a flow chart of a method for preparing a bulk acoustic wave resonator array.

[0069] See also Figure 8 In an embodiment of the present invention, a method for preparing a bulk acoustic wave resonator array includes:

[0070] S101: Arrange a plurality of bulk acoustic wave resonators.

[0071] In this step, a plurality of BAW resonators 1 can be arranged based on a piezoelectric layer 4. The specific process of arranging the BAW resonator 1 can be referred to the prior art, and will not be described in detail here.

[0072] S102: Electrode connecting portions are provided between adjacent BAW resonators to form a BAW resonator array.

[0073] In the embodiment of the present invention, the electrode connecting portion 6 connects the electrodes located on the same side of the piezoelectric layer 4 in the adjacent BAW resonators 1, and the thickness of the electrode connecting portion 6 is greater than the thickness of the connected electrodes. The specific structure of the BAW resonator 1 has been described in detail in the above invention embodiment, and will not be repeated here.

[0074] In this step, after the BAW resonators 1 are set, the electrode connection parts 6 for interconnecting the BAW resonators 1 are set. Depending on the position of the electrode connection parts 6, different processes are required to achieve the desired effect, and the specific contents will be described in detail in the following embodiments of the invention, which will not be described in detail here.

[0075] A method for preparing a BAW resonator array provided in an embodiment of the present invention can increase the thickness of an electrode connecting portion 6 located between adjacent BAW resonators 1 and used to connect adjacent BAW resonators 1, thereby allowing lower ohmic losses between adjacent BAW resonators 1, thereby increasing the Q value of the resonator and improving the performance of the filter.

[0076] The specific contents of the method for preparing a bulk acoustic wave resonator array provided by the present invention will be described in detail in the following invention embodiments.

[0077] Please refer to Fig. 9 , Fig. 9 The present invention provides a flow chart of a specific method for preparing a bulk acoustic wave resonator array.

[0078] See also Fig. 9 In an embodiment of the present invention, a method for preparing a bulk acoustic wave resonator array includes:

[0079] S201: Arrange a plurality of bulk acoustic wave resonators.

[0080] This step is basically the same as S101 in the above-mentioned embodiment of the invention. Please refer to the above-mentioned embodiment of the invention for details, and will not be described again here.

[0081] S202: etching a region of the piezoelectric layer between adjacent BAW resonators to form an etching hole exposing a bottom electrode below the piezoelectric layer.

[0082] In this step, the piezoelectric layer 4 needs to be etched to obtain etching holes located in the area between the BAW resonators 1 to expose the bottom electrode 3 located in the area between the BAW resonators 1 .

[0083] Furthermore, this step may include: simultaneously etching the region of the piezoelectric layer 4 between the adjacent BAW resonators 1 and the preset release hole region to form an etching hole and a release hole exposing the bottom electrode 3 below the piezoelectric layer 4 .

[0084] That is, this step can be integrated with the conventional process of etching release holes in the electrode layer. In the existing process of preparing the BAW resonator 1, a cavity is usually set as the acoustic reflection layer 2. In the preparation, it is necessary to first fill the cavity with a sacrificial layer, and then prepare the release hole, and release the sacrificial layer in the cavity through the release hole to complete the preparation of the BAW resonator 1. Correspondingly, this step can be integrated into the process of preparing the release hole, so this step will not increase the preparation cost too much.

[0085] S203: Arranging an electrode thickening portion in contact with the exposed bottom electrode in the etched hole to form an electrode connecting portion.

[0086] In this step, the electrode thickening portion 61 is specifically provided in the above-mentioned etching hole by deposition or other processes to form the electrode connecting portion 6. It should be noted that the electrode thickening portion 61 provided in the etching hole and in contact with the bottom electrode 3 needs to avoid contact with the top electrode 5 to avoid a direct short circuit connection between the top electrode 5 and the bottom electrode 3.

[0087] S204: In an area where the surface of the piezoelectric layer is located between adjacent BAW resonators and in an area where the surface of the top electrode is located between adjacent BAW resonators, an electrode thickening portion connected to the top electrodes of adjacent BAW resonators is provided to form an electrode connecting portion.

[0088] In this step, the electrode connecting portion 6 interconnected with the top electrode 5 is formed by setting the electrode thickening portion 61. Specifically, the electrode thickening portion 61 can be directly set on the surface of the top electrode 5 located between the bulk acoustic wave resonators 1, or the electrode thickening portion 61 can be directly set on the surface of the piezoelectric layer 4, and contact with the top electrode 5 through its side to form the electrode connecting portion 6 interconnected with the top electrode 5.

[0089] There are two points to be explained here. The first point is that the setting of the electrode thickening portion 61 in this step can be performed simultaneously with the setting of the electrode thickening portion 61 in the above S203 to reduce the preparation process. The second point is that the electrode thickening portion 61 is set on the surface of the piezoelectric layer 4 in this step, which is equivalent to the step of setting an interconnection structure between the bulk acoustic wave resonators 1 in the prior art. Therefore, the process of setting the electrode thickening portion 61 in this embodiment can be further integrated with the process of setting the interconnection structure in the traditional process, which usually only needs to adjust the thickness and position of the setting material, thereby reducing the process flow.

[0090] A method for preparing a BAW resonator array provided in an embodiment of the present invention can increase the thickness of an electrode connecting portion 6 located between adjacent BAW resonators 1 and used to connect adjacent BAW resonators 1, thereby allowing lower ohmic losses between adjacent BAW resonators 1, thereby increasing the Q value of the resonator and improving the performance of the filter.

[0091] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0092] Professionals may further appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented by electronic hardware, computing software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described in terms of function in the above description. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians may use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0093] The steps of the method or algorithm described in conjunction with the embodiments disclosed herein may be implemented directly using hardware, a software module executed by a processor, or a combination of the two. The software module may be placed in random access memory (RAM), internal memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium known in the art.

[0094] Finally, it should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0095] The above is a detailed introduction to a bulk acoustic wave resonator array and a preparation method thereof provided by the present invention. This article uses specific examples to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A bulk acoustic wave resonator array, characterized in that: comprising a plurality of bulk acoustic wave resonators (1); An electrode connection portion (6) is provided between adjacent BAW resonators (1), the electrode connection portion (6) connects electrodes located on the same side of the piezoelectric layer (4) in adjacent BAW resonators (1), the thickness of the electrode connection portion (6) is greater than the thickness of the connecting electrodes; the resistance of the electrode connection portion (6) per unit area is lower than the resistance of the top electrode (5) or the bottom electrode (3); In a piezoelectric layer (4) formed with a plurality of the BAW resonators (1), an etching hole for exposing a bottom electrode (3) below the piezoelectric layer (4) is provided in a region between adjacent BAW resonators (1); An electrode thickening portion (61) in contact with the exposed bottom electrode (3) is arranged in the etched hole to form the electrode connecting portion (6); the etched hole is arranged in a region of the piezoelectric layer (4) between adjacent bulk acoustic wave resonators (1); the release hole is arranged in a preset release hole region of the piezoelectric layer (4); the etched hole and the release hole are hole structures formed by etching the piezoelectric layer (4) simultaneously.

2. The BAW resonator array according to claim 1, characterized in that: The electrode connection portion (6) is also located on the upper surface of the piezoelectric layer (4) and is connected to the top electrode (5) of the adjacent bulk acoustic wave resonator (1).

3. The BAW resonator array according to claim 2, characterized in that: The electrode connecting portion (6) comprises: An electrode connecting portion (6) formed by an electrode thickening portion (61) is arranged on the surface of a top electrode (5), and an electrode connecting portion (6) formed by an electrode thickening portion (61) is arranged on the surface of a piezoelectric layer (4).

4. The BAW resonator array according to claim 1, characterized in that: The plurality of BAW resonators (1) are linearly distributed, and the electrode connecting portion (6) is located between two adjacent BAW resonators (1) to connect the electrodes of the two adjacent BAW resonators (1).

5. The BAW resonator array according to claim 1, characterized in that: The plurality of BAW resonators (1) are distributed in an array, and the electrode connecting portion (6) located between at least three BAW resonators (1) connects the electrodes of at least three adjacent BAW resonators (1).

6. A method for preparing a bulk acoustic wave resonator array, characterized in that: include: Providing a plurality of bulk acoustic wave resonators (1); Providing electrode connecting portions (6) between adjacent BAW resonators (1) to form the BAW resonator array; The electrode connecting portion (6) connects electrodes located on the same side of the piezoelectric layer (4) in adjacent bulk acoustic wave resonators (1), the thickness of the electrode connecting portion (6) is greater than the thickness of the connecting electrodes; the resistance of the electrode connecting portion (6) per unit area is lower than the resistance of the top electrode (5) or the bottom electrode (3); Providing an electrode connection portion (6) between adjacent BAW resonators (1) comprises: Etching a region of the piezoelectric layer (4) between adjacent bulk acoustic wave resonators (1) to form an etching hole exposing a bottom electrode (3) below the piezoelectric layer (4); An electrode thickening portion (61) in contact with the exposed bottom electrode (3) is provided in the etched hole to form the electrode connecting portion (6); Etching a region of the piezoelectric layer (4) between adjacent bulk acoustic wave resonators (1) to form an etching hole exposing a bottom electrode (3) below the piezoelectric layer (4) comprises: At the same time, the region of the piezoelectric layer (4) located between adjacent bulk acoustic wave resonators (1) and the preset release hole region are etched to form an etched hole and a release hole that expose the bottom electrode (3) below the piezoelectric layer (4).

7. The method according to claim 6, characterized in that The electrode connection portion (6) is provided between adjacent bulk acoustic wave resonators (1) and further comprises: An electrode thickening portion (61) connected to the top electrodes (5) of the adjacent BAW resonators (1) is provided in an area where the surface of the piezoelectric layer (4) is located between adjacent BAW resonators (1), and in an area where the surface of the top electrode (5) is located between adjacent BAW resonators (1), thereby forming the electrode connecting portion (6).

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