Integrated bulk acoustic wave filter manufacturing method and integrated bulk acoustic wave filter

Abstract

The present application discloses a method for manufacturing an integrated bulk acoustic wave filter and an integrated bulk acoustic wave filter, comprising: manufacturing a first substrate; forming a plurality of bulk acoustic wave filters on the first substrate, specifically comprising: forming at least one mixed layer on the first substrate, wherein the at least one mixed layer comprises a first sacrificial layer etched with a plurality of first regions and a first upper electrode layer deposited in each first region, wherein the thickness of the first sacrificial layer corresponds to the difference in resonant frequencies of the plurality of bulk acoustic wave filters, and the thickness of the first upper electrode layer is the same as the thickness of the first sacrificial layer; and depositing a second upper electrode layer on the at least one mixed layer to form a plurality of bulk acoustic wave filters, wherein the thickness of the second upper electrode layer corresponds to the minimum resonant frequency of the plurality of bulk acoustic wave filters, and the sum of the number of the at least one mixed layer and the second upper electrode layer corresponds to the number of the plurality of bulk acoustic wave filters. The technical effect of having different operating frequencies is achieved.

Description

Technical Field

[0001] The present application relates to the technical field of filter manufacturing, and in particular to a manufacturing method of an integrated bulk acoustic wave filter and the integrated bulk acoustic wave filter. Background Art

[0002] In the field of wireless communication technology, SAW filters and BAW filters are two crucial components that play a key role in different application scenarios.

[0003] BAW filters, or bulk acoustic wave filters, are based on bulk acoustic wave technology. When an alternating electric field is applied across a piezoelectric material, the material generates mechanical vibrations, which propagate through the material in the form of bulk acoustic waves. By cleverly designing the structure and dimensions of a BAW filter, BAWs of specific frequencies are allowed to propagate smoothly through the filter while suppressing waves of other frequencies, thus achieving a filtering function.

[0004] D-BAW filters, or double-sided patterned bulk acoustic wave filters, are fabricated using a double-sided bonding process. Specifically, during the fabrication process, several fabrication steps are first performed on the front side of the wafer, and then the wafer is flipped over through bonding for subsequent fabrication steps. During packaging, the wafer is flipped again through bonding, and several fabrication steps are performed on the back side, achieving a double-sided process.

[0005] At present, in order to ensure the reliability of chip design, process and function, and to avoid catastrophic failure during large-scale mass production, it is usually necessary to conduct chip tape-out testing on the chip. The existing method of conducting chip tape-out testing is usually to first manufacture multiple bulk acoustic wave filters, then conduct individual tape-out testing on each bulk acoustic wave filter, and finally package the tested bulk acoustic wave filters together. However, there are certain defects in using the above method to conduct tape-out testing on bulk acoustic wave filters. For example, since each bulk acoustic wave filter is tested on a separate chip, the development cycle is relatively long. For another example, the use of multiple bulk acoustic wave filters in combination can easily lead to a waste of resources.

[0006] To address the aforementioned issues, existing technologies have proposed integrating multiple BAW filters into a single chip to create an integrated BAW filter, allowing for a single-chip tape-out and test. While this approach can reduce manufacturing and testing costs, it fails to meet the requirement of having different operating frequencies for each BAW filter. This results in poor frequency adaptability and waste of resources.

[0007] Publication number CN119995555A, titled "Bulk Acoustic Wave Filter, Preparation Method, and Radio Frequency Module," describes the BAW filter as comprising at least: a substrate; a first film layer located on one side of the substrate, comprising a first region and a second region surrounding the first region, the second region comprising a photosensitive dry film surrounding the first region; and a piezoelectric film located on a side of the first film layer away from the substrate. The piezoelectric film comprises a lithium niobate film and / or a lithium tantalate film. The substrate, photosensitive dry film, and piezoelectric film collectively form a cavity.

[0008] Publication number CN222776195U, titled "A Bulk Acoustic Wave Filter," comprises a substrate and a plurality of resonators cascaded on the substrate, the plurality of resonators comprising at least one front resonator and one end resonator. The front resonator comprises a lower electrode, a piezoelectric layer, and an upper electrode sequentially disposed on the substrate. The outer periphery of the upper electrode extends away from the upper electrode along a hierarchical direction to form an elevated portion, an air gap is formed between the elevated portion and the piezoelectric layer, and a capacitance compensation structure is formed between the elevated portion and the upper electrode or between the elevated portion and the lower electrode.

[0009] Currently, no effective solution has been proposed to the technical problem that the existing integrated BAW filters in the prior art cannot meet the requirement of having different operating frequencies, resulting in poor frequency band adaptability and waste of resources. Summary of the Invention

[0010] The present disclosure provides a method for manufacturing an integrated bulk acoustic wave filter and an integrated bulk acoustic wave filter, so as to at least solve the technical problem in the prior art that existing integrated bulk acoustic wave filters cannot meet the requirement of having different operating frequencies, thereby resulting in poor frequency band adaptability and waste of resources in the integrated bulk acoustic wave filters.

[0011] According to one aspect of the present application, a method for manufacturing an integrated bulk acoustic wave filter is provided, comprising: manufacturing a first substrate; forming a plurality of bulk acoustic wave filters on the first substrate, the specific steps comprising: forming at least one mixed layer on the first substrate, wherein the at least one mixed layer comprises a first sacrificial layer etched with a plurality of first regions and a first upper electrode layer deposited in each of the first regions, and wherein the thickness of the first sacrificial layer corresponds to the difference in resonant frequencies of the plurality of bulk acoustic wave filters, and the thickness of the first upper electrode layer is the same as the thickness of the first sacrificial layer; and depositing a second upper electrode layer on the at least one mixed layer, and forming a plurality of bulk acoustic wave filters, wherein the thickness of the second upper electrode layer corresponds to the minimum value of the resonant frequency among the plurality of bulk acoustic wave filters, and the sum of the number of the at least one mixed layer and the second upper electrode layer corresponds to the number of the plurality of bulk acoustic wave filters.

[0012] Optionally, the operation of forming a plurality of bulk acoustic wave filters on the first substrate includes: forming a first bulk acoustic wave filter and a second bulk acoustic wave filter on the first substrate.

[0013] Optionally, the operation of forming the first bulk acoustic wave filter and the second bulk acoustic wave filter on the first substrate includes: depositing and etching a first sacrificial layer on the first substrate, and forming a plurality of second regions for exposing the first substrate, wherein the thickness of the first sacrificial layer corresponds to the difference between the first bulk acoustic wave filter and the second bulk acoustic wave filter; depositing and smoothing a first upper electrode layer on the first sacrificial layer, and making the thickness of the first upper electrode layer in the plurality of second regions the same as the thickness of the first sacrificial layer; depositing a second upper electrode layer on the mixed layer, wherein the thickness of the second upper electrode layer corresponds to the minimum value of the resonant frequency in the first bulk acoustic wave filter and the second bulk acoustic wave filter; and depositing a piezoelectric layer on the second upper electrode layer, and forming the first bulk acoustic wave filter and the second bulk acoustic wave filter, wherein the thickness of the piezoelectric layer corresponds to the maximum value of the resonant frequency in the first bulk acoustic wave filter and the second bulk acoustic wave filter.

[0014] Optionally, the operation of depositing a piezoelectric layer on the first upper electrode layer and forming a first bulk acoustic wave filter and a second bulk acoustic wave filter includes: depositing and etching a first lower electrode layer on the piezoelectric layer, and forming a plurality of third regions for exposing the piezoelectric layer, wherein the plurality of third regions correspond to the plurality of second regions, and wherein the thickness of the first lower electrode layer corresponds to the difference between the first bulk acoustic wave filter and the second bulk acoustic wave filter; and depositing and etching a second lower electrode layer on the first lower electrode layer, and forming a fourth region for exposing the piezoelectric layer, wherein the thickness of the first lower electrode layer corresponds to the minimum value of the resonant frequency in the first bulk acoustic wave filter and the second bulk acoustic wave filter.

[0015] Optionally, the operation of forming the first bulk acoustic wave filter and the second bulk acoustic wave filter also includes: depositing a second sacrificial layer on the second lower electrode layer and the piezoelectric layer; etching the second sacrificial layer, and forming a plurality of fifth regions for exposing the second lower electrode layer and a sixth region for exposing the piezoelectric layer, wherein each fifth region is located on both sides of the sixth region; depositing a supporting layer on the first lower electrode, the piezoelectric layer and the layer to be etched; etching the first sacrificial layer and the second sacrificial layer, and forming a first resonant cavity corresponding to the first bulk acoustic wave filter and a second resonant cavity corresponding to the second bulk acoustic wave filter, respectively; and depositing a second substrate on the supporting layer, flipping the entire layer, and removing the first substrate.

[0016] Optionally, the operation of forming the first bulk acoustic wave filter and the second bulk acoustic wave filter further includes: etching the second upper electrode layer and forming a seventh region for exposing the piezoelectric layer, wherein the seventh region corresponds to the fourth region.

[0017] Optionally, the operation of forming a first bulk acoustic wave filter and a second bulk acoustic wave filter on a first substrate includes: depositing and etching a first sacrificial layer on the first substrate, and forming a plurality of second regions for exposing the first substrate, wherein the thickness of the first sacrificial layer corresponds to the difference between the first bulk acoustic wave filter and the second bulk acoustic wave filter; depositing and smoothing a first upper electrode layer on the first sacrificial layer, and making the thickness of the first upper electrode layer in the plurality of second regions correspond to the thickness of the first sacrificial layer; depositing a second upper electrode layer on the mixed layer, wherein the thickness of the second upper electrode layer corresponds to the minimum value of the resonant frequency in the first bulk acoustic wave filter and the second bulk acoustic wave filter; and depositing and etching a piezoelectric layer on the second upper electrode layer, and forming a first bulk acoustic wave filter and a second bulk acoustic wave filter, wherein the thickness of the piezoelectric layer corresponding to the second bulk acoustic wave filter is different from the thickness of the piezoelectric layer corresponding to the first bulk acoustic wave filter, and the maximum thickness of the piezoelectric layer corresponds to the maximum value of the resonant frequency in the first bulk acoustic wave filter and the second bulk acoustic wave filter.

[0018] Optionally, the operation of depositing a piezoelectric layer on the first upper electrode layer and forming a first bulk acoustic wave filter and a second bulk acoustic wave filter includes: depositing and etching a first lower electrode layer on the piezoelectric layer, and forming a plurality of eighth regions for exposing the piezoelectric layer, wherein the plurality of eighth regions correspond to the plurality of first regions, and the thickness of the first lower electrode layer corresponds to the difference between the first bulk acoustic wave filter and the second bulk acoustic wave filter; depositing and etching a second lower electrode layer on the first lower electrode layer, and forming a ninth region for exposing the piezoelectric layer, wherein the thickness of the second lower electrode layer corresponds to the minimum value of the resonant frequency in the first bulk acoustic wave filter and the second bulk acoustic wave filter.

[0019] Optionally, the operation of forming the first bulk acoustic wave filter and the second bulk acoustic wave filter also includes: depositing a second sacrificial layer on the second lower electrode layer and the piezoelectric layer; etching the second sacrificial layer, and forming a plurality of tenth regions for exposing the second lower electrode layer and an eleventh region for exposing the piezoelectric layer, wherein each tenth region is located on both sides of the eleventh region; depositing a supporting layer on the second lower electrode, the piezoelectric layer and the layer to be etched; etching the first sacrificial layer and the second sacrificial layer, and forming a first resonant cavity corresponding to the first bulk acoustic wave filter and a second resonant cavity corresponding to the second bulk acoustic wave filter, respectively; and depositing a second substrate on the supporting layer, flipping the entire layer over, and removing the first substrate.

[0020] Optionally, the operation of forming the first bulk acoustic wave filter and the second bulk acoustic wave filter further includes: etching the second upper electrode layer and forming a twelfth region for exposing the piezoelectric layer, wherein the twelfth region corresponds to the ninth region.

[0021] According to another aspect of the present application, an integrated bulk acoustic wave filter is provided, comprising: a second substrate and a plurality of bulk acoustic wave filters, wherein the bulk acoustic wave filter comprises a second upper electrode layer formed on the second substrate, wherein the thickness of the second upper electrode layer corresponds to the minimum value of the resonant frequency among the plurality of bulk acoustic wave filters; and at least one first upper electrode layer formed on the second upper electrode layer, wherein the first upper electrode layer is formed with a plurality of thirteenth regions for exposing the second upper electrode layer, wherein the plurality of thirteenth regions correspond to a pre-etched first sacrificial layer, the thickness of the first sacrificial layer corresponds to the difference in the resonant frequencies of the plurality of bulk acoustic wave filters, the thickness of the first upper electrode layer is the same as the thickness of the first sacrificial layer, and the sum of the number of at least one first upper electrode layer and the second upper electrode layer corresponds to the number of the plurality of bulk acoustic wave filters.

[0022] Optionally, the plurality of BAW filters include: a first BAW filter and a second BAW filter, and the first BAW filter and the second BAW filter include: a support layer, a second lower electrode layer, a first lower electrode layer and a piezoelectric layer, wherein the support layer is formed on the second substrate; the second lower electrode layer is formed on the support layer, the first lower electrode layer is formed on the second lower electrode layer, and the second lower electrode layer and the first lower electrode layer are formed with a fourth area for exposing the piezoelectric layer, wherein the thickness of the first lower electrode layer corresponds to the difference between the first BAW filter and the second BAW filter, and the thickness of the second lower electrode layer corresponds to the minimum resonant frequency in the first BAW filter and the second BAW filter; the piezoelectric layer is deposited on the first lower electrode layer, the second lower electrode layer and the support layer, and the thickness of the piezoelectric layer corresponds to the maximum resonant frequency in the first BAW filter and the second BAW filter; and a first resonant cavity corresponding to the first BAW filter and a second resonant cavity corresponding to the second BAW filter are formed between the support layer and the first lower electrode layer, the second lower electrode layer and the piezoelectric layer.

[0023] Optionally, the second upper electrode layer is deposited on the piezoelectric layer; the first upper electrode layer is deposited on the second upper electrode layer, and the second upper electrode layer and the first upper electrode layer form a seventh region for exposing the piezoelectric layer, wherein the seventh region corresponds to the fourth region, and the thickness of the second upper electrode layer corresponds to the minimum value of the resonant frequency in the first bulk acoustic wave filter and the second bulk acoustic wave filter, and the thickness of the first upper electrode layer corresponds to the difference in resonant frequency between the first bulk acoustic wave filter and the second bulk acoustic wave filter.

[0024] Optionally, the first bulk acoustic wave filter and the second bulk acoustic wave filter include: a supporting layer, a second lower electrode layer, a first lower electrode layer and a piezoelectric layer, wherein the supporting layer is formed on the second substrate; the second lower electrode layer is formed on the supporting layer, the first lower electrode layer is formed on the second lower electrode layer, and the second lower electrode layer and the first lower electrode layer are formed with a ninth region for exposing the piezoelectric layer, wherein the thickness of the first lower electrode layer corresponds to the difference between the first bulk acoustic wave filter and the second bulk acoustic wave filter, and the thickness of the second lower electrode layer corresponds to the minimum resonant frequency in the first bulk acoustic wave filter and the second bulk acoustic wave filter; the piezoelectric layer is deposited on the first lower electrode layer, the second lower electrode layer and the supporting layer, and the thickness of the piezoelectric layer corresponding to the second bulk acoustic wave filter is different from the thickness of the piezoelectric layer corresponding to the first bulk acoustic wave filter, wherein the maximum thickness of the piezoelectric layer corresponds to the maximum resonant frequency in the first bulk acoustic wave filter and the second bulk acoustic wave filter; and a first resonant cavity corresponding to the first bulk acoustic wave filter and a second resonant cavity corresponding to the second bulk acoustic wave filter are formed between the supporting layer and the first lower electrode layer, the second lower electrode layer and the piezoelectric layer.

[0025] Optionally, the second upper electrode is deposited on the piezoelectric layer; the first upper electrode layer is deposited on the second upper electrode layer, and the second upper electrode and the first upper electrode layer form a twelfth region for exposing the piezoelectric layer, wherein the twelfth region corresponds to the ninth region, and the thickness of the second upper electrode layer corresponds to the minimum value of the resonant frequency in the first bulk acoustic wave filter and the second bulk acoustic wave filter, and the thickness of the first upper electrode layer corresponds to the difference in resonant frequency between the first bulk acoustic wave filter and the second bulk acoustic wave filter.

[0026] This application provides a method for manufacturing an integrated BAW filter and an integrated BAW filter. Because the integrated BAW filter in this application includes multiple BAW filters formed on a first substrate, multiple BAW filters can be integrated into a single chip, enabling simultaneous tape-out testing of the multiple BAW filters.

[0027] Furthermore, when manufacturing an integrated bulk acoustic wave filter, the present application first forms at least one mixed layer on a first substrate, wherein the at least one mixed layer includes a first sacrificial layer etched with multiple first regions and a first upper electrode layer deposited in each first region, so that when the thickness of the first sacrificial layer corresponds to the difference in resonant frequencies of the multiple bulk acoustic wave filters, the thickness of the first upper electrode layer is set to be the same as the thickness of the first sacrificial layer, so that the thickness of the first upper electrode layer can be ensured to correspond to the difference in resonant frequencies of the multiple bulk acoustic wave filters. Thereafter, a second upper electrode layer is deposited on the at least one mixed layer, and multiple bulk acoustic wave filters are formed. The thickness of the second upper electrode layer corresponds to the minimum value of the resonant frequency among the multiple bulk acoustic wave filters. Thus, the integrated bulk acoustic wave filter manufactured by the present application can meet the requirement of having different operating frequencies.

[0028] In addition, since the etching process of two adjacent layer structures made of different materials is more mature and easier to control than that of two adjacent layers made of the same material, compared with generating integrated bulk acoustic wave filters with different operating frequencies by etching the electrodes, the operation disclosed in the present application of first depositing the first sacrificial layer on the first substrate, then etching the first sacrificial layer deposited on the first substrate, and forming multiple first regions for depositing the first upper electrode layer can achieve the technical effect of accurately producing the first upper electrode layer on the first substrate.

[0029] In addition, when the first upper electrode layer is manufactured using the first sacrificial layer including the plurality of first regions, the present application can simultaneously manufacture a semiconductor lead frame structure (ie, a Frame structure), thereby saving a photomask.

[0030] This solves the technical problem in the prior art that the existing integrated BAW filter cannot meet the requirement of having different operating frequencies, which leads to poor frequency band adaptability and waste of resources.

[0031] Based on the detailed description of the specific embodiments of the present application in conjunction with the accompanying drawings below, those skilled in the art will become more aware of the above and other objects, advantages and features of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Hereinafter, some specific embodiments of the present application will be described in detail in an exemplary and non-limiting manner with reference to the accompanying drawings. The same reference numerals in the drawings indicate the same or similar components or parts. It should be understood by those skilled in the art that these drawings are not necessarily drawn to scale. In the drawings:

[0033] Figure 1 is a flow chart of a method for manufacturing an integrated bulk acoustic wave filter according to Example 1 of the present application;

[0034] Figure 2 is a schematic diagram of the first substrate, multiple mixed layers, and the second top electrode layer according to Example 1 of the present application;

[0035] Figure 3 is a schematic diagram of the first substrate and the first sacrificial layer according to embodiment 1 of the present application;

[0036] Figure 4 is a schematic diagram of the first substrate, the first sacrificial layer, and the first upper electrode layer according to Embodiment 1 of the present application;

[0037] Figure 5 is a schematic diagram of the first substrate, the first sacrificial layer, the first upper electrode layer, the second upper electrode layer, and the piezoelectric layer according to Example 1 of the present application;

[0038] Figure 6 is a schematic diagram of the first substrate, the first sacrificial layer, the first upper electrode layer, the second upper electrode layer, the piezoelectric layer, and the first lower electrode layer according to Example 1 of the present application;

[0039] Figure 7 Schematic diagram of the first substrate, the first sacrificial layer, the first upper electrode layer, the second upper electrode layer, the piezoelectric layer, the first lower electrode layer, and the second lower electrode layer according to Embodiment 1 of the present application;

[0040] Figure 8 Schematic diagram of the first substrate, the first sacrificial layer, the first upper electrode layer, the second upper electrode layer, the piezoelectric layer, the first lower electrode layer, the second lower electrode layer, and the second sacrificial layer according to Embodiment 1 of the present application;

[0041] Figure 9 is a schematic diagram of the second substrate, the first upper electrode layer, the second upper electrode layer, the piezoelectric layer, the first lower electrode layer, the second lower electrode layer, and the support layer according to Example 1 of the present application;

[0042] Figure 10 is a schematic diagram of an integrated bulk acoustic wave filter according to Example 1 of the present application;

[0043] Figure 11 is a schematic diagram of depositing and etching a first substrate, a first sacrificial layer, a first upper electrode layer, a second upper electrode layer, a piezoelectric layer, and a first lower electrode layer according to Example 2 of the present application;

[0044] Figure 12 is a schematic diagram of the eighth region according to Example 2 of the present application;

[0045] Figure 13 is a schematic diagram of the ninth region according to Example 2 of the present application;

[0046] Figure 14 is a schematic diagram of the tenth region and the eleventh region according to Example 2 of the present application;

[0047] Figure 15 is a schematic diagram of the first resonant cavity and the second resonant cavity according to Example 2 of the present application;

[0048] Figure 16 is a schematic diagram of the second substrate, the first upper electrode layer, the second upper electrode layer, the piezoelectric layer, the first lower electrode layer, the second lower electrode layer, and the support layer according to Example 2 of the present application;

[0049] Figure 17 This is a schematic diagram of another integrated bulk acoustic wave filter according to Example 2 of the present application. DETAILED DESCRIPTION

[0050] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in the present disclosure may be combined with each other. The present disclosure will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0051] In order to enable those skilled in the art to better understand the solutions of the present disclosure, the technical solutions in the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings in the embodiments of the present disclosure. Obviously, the embodiments described are only part of the embodiments of the present disclosure, not all of the embodiments. Based on the embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present disclosure.

[0052] It should be noted that the terms "first," "second," and the like in the specification and claims of the present disclosure and the accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate for the embodiments of the present disclosure described herein. In addition, the terms "including" and "having," and any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus comprising a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units that are not explicitly listed or inherent to these processes, methods, products, or apparatuses.

[0053] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0054] Secondly, this application is described in detail with reference to schematic diagrams. When describing the embodiments of this application, for ease of illustration, cross-sectional views of device structures may be partially enlarged and not to scale. Furthermore, these schematic diagrams are merely illustrative and should not limit the scope of protection of this application. Furthermore, in actual production, the three-dimensional dimensions of length, width, and depth should be included.

[0055] According to a first aspect of this embodiment, a method for manufacturing an integrated bulk acoustic wave filter is provided. Figure 1 A schematic flow chart of the method is shown. Figure 1 As shown, the method includes:

[0056] S101: preparing a first substrate;

[0057] S102: forming a plurality of bulk acoustic wave filters on a first substrate, wherein the specific steps include:

[0058] forming at least one mixed layer on a first substrate, wherein the at least one mixed layer includes a first sacrificial layer having a plurality of first regions etched therein and a first upper electrode layer deposited within each of the first regions, wherein a thickness of the first sacrificial layer corresponds to a difference in resonant frequencies of the plurality of bulk acoustic wave filters, and a thickness of the first upper electrode layer is the same as a thickness of the first sacrificial layer; and

[0059] S103: Depositing a second upper electrode layer on at least one mixed layer to form a plurality of bulk acoustic wave filters, wherein the thickness of the second upper electrode layer corresponds to the minimum value of the resonant frequency in the plurality of bulk acoustic wave filters, and the sum of the number of the at least one mixed layer and the second upper electrode layer corresponds to the number of the plurality of bulk acoustic wave filters.

[0060] The manufacturing method of the integrated bulk acoustic wave filter provided by the embodiment of the present disclosure is adopted, by manufacturing a first substrate and forming at least one mixed layer on the first substrate. The at least one mixed layer includes a first sacrificial layer etched with multiple first regions and a first upper electrode layer deposited in each first region, and the thickness of the first sacrificial layer corresponds to the difference in resonant frequencies of the multiple bulk acoustic wave filters, and the thickness of the first upper electrode layer is the same as the thickness of the first sacrificial layer. Then, a second upper electrode layer is deposited on the at least one mixed layer, and multiple bulk acoustic wave filters are formed. The thickness of the second upper electrode layer corresponds to the minimum value of the resonant frequency in the multiple bulk acoustic wave filters, and the sum of the number of the at least one mixed layer and the second upper electrode layer corresponds to the number of the multiple bulk acoustic wave filters.

[0061] Specifically, refer to Figure 2 As shown, first, a first substrate 110 to be removed is prepared. Then, at least one mixed layer 120 (such as Figure 2Two mixed layers are shown). For example, in the case where the integrated BAW filter that the operator needs to manufacture includes three BAW filters, two mixed layers are formed on the first substrate 110. In one embodiment, the thickness of the first upper electrode layer 122 in the first mixed layer corresponds to the difference in resonant frequency between BAW filter 1 and BAW filter 2, and the thickness of the first upper electrode layer 122 in the second mixed layer corresponds to the difference in resonant frequency between BAW filter 1 and BAW filter 3. In another embodiment, the thickness of the first upper electrode layer 122 in the first mixed layer corresponds to the difference in resonant frequency between BAW filter 1 and BAW filter 2, and the thickness of the first upper electrode layer 122 in the second mixed layer corresponds to the difference in resonant frequency between BAW filter 2 and BAW filter 3. That is, the thicknesses of the first mixed layer and the second mixed layer correspond to the difference in resonant frequency between any two BAW filters among the multiple BAW filters, which will not be described in detail here.

[0062] The specific steps for making at least one mixed layer include: first, depositing a first sacrificial layer 121 on a first substrate 110, and etching the first sacrificial layer 121 to generate a plurality of first regions 1211. The thickness of the first sacrificial layer 121 corresponds to the difference in resonant frequencies of the plurality of bulk acoustic wave filters. Thereafter, the operator deposits a first upper electrode layer 122 on the first sacrificial layer 121 and the first substrate 110, and grinds the first upper electrode layer 122 flat, so that the thickness of the first upper electrode layer 122 in each first region 1211 is the same as the thickness of the first sacrificial layer 121. Thus, the operator can use the same method and steps as above to make other mixed layers, which will not be described in detail here.

[0063] Then, a second upper electrode layer 130 is deposited on the at least one mixed layer 120 to form a plurality of bulk acoustic wave filters, wherein the thickness of the second upper electrode layer 130 corresponds to the minimum resonant frequency of the plurality of bulk acoustic wave filters.

[0064] Therefore, unlike the prior art, since the integrated bulk acoustic wave filter in the present application includes multiple bulk acoustic wave filters formed on a first substrate, multiple bulk acoustic wave filters are integrated into one chip, and the multiple bulk acoustic wave filters can be tested at one time.

[0065] Furthermore, when manufacturing an integrated bulk acoustic wave filter, the present application first forms at least one mixed layer on a first substrate, wherein the at least one mixed layer includes a first sacrificial layer etched with multiple first regions and a first upper electrode layer deposited in each first region, so that when the thickness of the first sacrificial layer corresponds to the difference in resonant frequencies of the multiple bulk acoustic wave filters, the thickness of the first upper electrode layer is set to be the same as the thickness of the first sacrificial layer, so that the thickness of the first upper electrode layer can be ensured to correspond to the difference in resonant frequencies of the multiple bulk acoustic wave filters. Thereafter, a second upper electrode layer is deposited on the at least one mixed layer, and multiple bulk acoustic wave filters are formed. The thickness of the second upper electrode layer corresponds to the minimum value of the resonant frequency among the multiple bulk acoustic wave filters. Thus, the integrated bulk acoustic wave filter manufactured by the present application can meet the requirement of having different operating frequencies.

[0066] In addition, since the etching process of two adjacent layer structures made of the same material is more mature and easier to control than that of two adjacent layers made of different materials, compared with generating integrated bulk acoustic wave filters with different operating frequencies by etching the electrodes, the operation disclosed in the present application of first depositing the first sacrificial layer on the first substrate, then etching the first sacrificial layer deposited on the first substrate, and forming multiple first regions for depositing the first upper electrode layer can achieve the technical effect of accurately producing the first upper electrode layer on the first substrate.

[0067] In addition, when the first upper electrode layer is manufactured using the first sacrificial layer including the plurality of first regions, the present application can simultaneously manufacture a semiconductor lead frame structure (ie, a Frame structure), thereby saving a photomask.

[0068] This solves the technical problem in the prior art that the existing integrated BAW filter cannot meet the requirement of having different operating frequencies, which leads to poor frequency band adaptability and waste of resources.

[0069] Example 1

[0070] The following are specific steps for manufacturing an integrated BAW filter (including a first BAW filter and a second BAW filter) provided in an embodiment of the present application:

[0071] refer to Figure 3As shown, first, a first substrate 110 to be removed is prepared. Optionally, the first substrate 110 is made of silicon, silicon carbide or sapphire. Further, a first sacrificial layer 121 is deposited and etched on one side of the first substrate 110, and a plurality of second regions 1212 for exposing the first substrate 110 are formed. The thickness of the first sacrificial layer 121 corresponds to the difference in resonant frequency between the first bulk acoustic wave filter and the second bulk acoustic wave filter. Preferably, the material for making the first sacrificial layer 121 can be undoped silicate glass, phosphate glass or thermal oxide layer, etc., with a uniformity of less than 1%.

[0072] In addition, since the etching process of two adjacent layer structures made of different materials is more mature and easier to control than that of two adjacent layers made of the same material, compared with generating an integrated bulk acoustic wave filter with different operating frequencies by etching the electrodes, the operation disclosed in the present application of first depositing the first sacrificial layer 121 on the first substrate 110 and then etching the first sacrificial layer 121 deposited on the first substrate 110 can greatly reduce the difficulty of the manufacturing process.

[0073] refer to Figure 4 As shown, a first top electrode layer 122 is then deposited on the first substrate 110 and the first sacrificial layer 121. Since the heights of the first top electrode layer 122 deposited in each second region 1212 and the first top electrode layer 122 deposited on the first sacrificial layer 121 are inconsistent, the protruding first top electrode layer 122 is ground flat, and the thickness of the first top electrode layer 122 deposited in each second region 1212 is made the same as that of the first sacrificial layer 121. This allows the thickness of the first top electrode layer 122 to correspond to the difference in resonant frequency between the first BAW filter and the second BAW filter. Preferably, the thickness of the unground first top electrode layer 122 is 1.1 to 3 times the thickness of the first sacrificial layer 121, and the material of the first top electrode layer 122 can be, for example, molybdenum or tungsten, with a uniformity of less than 1%.

[0074] refer to Figure 5 As shown, further, a second upper electrode layer 130 is deposited on the first sacrificial layer 121 and the first upper electrode layer 122. The thickness of the second upper electrode layer 130 corresponds to the minimum value of the resonant frequency in the first bulk acoustic wave filter and the second bulk acoustic wave filter. Preferably, the material of the second upper electrode layer 130 can be, for example, molybdenum or tungsten, and the uniformity is less than 1%, and the etching uniformity is less than 5%. Thereafter, a piezoelectric layer 140 is deposited on the second upper electrode layer 130. The thickness of the piezoelectric layer 140 corresponds to the maximum value of the resonant frequency in the first bulk acoustic wave filter and the second bulk acoustic wave filter. Preferably, the material of the piezoelectric layer 140 can be, for example, aluminum nitride or scandium-doped aluminum nitride, and the uniformity is less than 1%.

[0075] Thus, when the thickness of the first upper electrode layer 122 is determined to correspond to the difference in resonant frequencies between the first bulk acoustic wave filter and the second bulk acoustic wave filter, and the thickness of the second upper electrode layer 130 is determined to correspond to the minimum resonant frequency in the first bulk acoustic wave filter and the second bulk acoustic wave filter, the integrated bulk acoustic wave filter generated based on the first upper electrode layer 122 and the second upper electrode layer 130 can meet the requirement of having different operating frequencies.

[0076] In addition, compared with the existing method of generating integrated bulk acoustic wave filters with different operating frequencies by etching the electrodes, the operation of depositing the first upper electrode layer 122 by etching the first sacrificial layer 121 and making the thickness of the first upper electrode layer 122 correspond to the difference in resonant frequency between the first bulk acoustic wave filter and the second bulk acoustic wave filter can achieve the technical effect of precise control.

[0077] refer to Figure 6 As shown, a first lower electrode layer 150 is then deposited and etched on the piezoelectric layer 140, forming a plurality of third regions 151 for exposing the piezoelectric layer 140. The thickness of the first lower electrode layer 150 corresponds to the difference in resonant frequency between the first BAW filter and the second BAW filter. Preferably, the first lower electrode layer 150 can be made of a material such as molybdenum or tungsten, with a uniformity of less than 1% and an etching uniformity of less than 5%.

[0078] refer to Figure 7 As shown, further, a second lower electrode layer 160 is deposited and etched on the first lower electrode layer 150 to form a fourth region 161 for exposing the piezoelectric layer 140. The thickness of the second lower electrode layer 160 corresponds to the minimum resonant frequency of the first and second BAW filters. Preferably, the first lower electrode layer 150 can be made of a material such as molybdenum or tungsten, with a uniformity of less than 1% and an etching uniformity of less than 5%.

[0079] refer to Figures 8 and 9 As shown, first, a second sacrificial layer 170 is deposited on the second lower electrode layer 160 and the piezoelectric layer 140. Then, the second sacrificial layer 170 is etched to form a plurality of fifth regions 171 for exposing the second lower electrode layer 160 and a sixth region 172 for exposing the piezoelectric layer 140. Each fifth region 171 is located on both sides of the sixth region 172. Then, a support layer 180 is deposited on the second lower electrode layer 160, the piezoelectric layer 140, and the second sacrificial layer 170. Further, the first sacrificial layer 121 and the second sacrificial layer 170 are etched to form a first resonant cavity corresponding to the first bulk acoustic wave filter and a second resonant cavity corresponding to the second bulk acoustic wave filter, respectively. Finally, a second substrate 190 is deposited on the support layer 180, the entire structure is flipped over, and the first substrate 110 is removed.

[0080] refer to Figure 10 As shown, finally, the second top electrode layer 130 is etched to form a seventh region 131 for exposing the piezoelectric layer 140. The seventh region 131 corresponds to the fourth region 161. Preferably, the etching uniformity of the second top electrode layer 130 is less than 5%.

[0081] Example 2

[0082] In addition, in order to further increase the operating frequency range of the integrated BAW filter and ensure that the integrated BAW filter can meet the requirement of having different operating frequencies, the present application also provides another integrated BAW filter, the specific manufacturing steps of which include:

[0083] refer to Figures 3 to 5 As shown, first, a first substrate 110 to be removed is prepared. Furthermore, a first sacrificial layer 121 is deposited and etched on one side of the first substrate 110, forming a plurality of second regions 1212 for exposing the first substrate 110. The thickness of the first sacrificial layer 121 corresponds to the difference in resonant frequency between the first BAW filter and the second BAW filter.

[0084] Then, a first top electrode layer 122 is deposited on the first substrate 110 and the first sacrificial layer 121. Since the heights of the first top electrode layer 122 deposited in each first region 1211 are different from those of the first top electrode layer 122 deposited on the first sacrificial layer 121, the protruding first top electrode layer 122 is ground flat, and the thickness of the first top electrode layer 122 deposited in each second region 1212 is made the same as that of the first sacrificial layer 121. This ensures that the thickness of the first top electrode layer 122 corresponds to the difference in resonant frequency between the first and second BAW filters.

[0085] Furthermore, a second upper electrode layer 130 is deposited on the first sacrificial layer 121 and the first upper electrode layer 122. The thickness of the second upper electrode layer 130 corresponds to the minimum resonant frequency of the first BAW filter and the second BAW filter.

[0086] refer to Figure 11 As shown, a piezoelectric layer 140 is then deposited and etched on the second top electrode layer 130. The thickness of the piezoelectric layer 140 corresponding to the second BAW filter is different from the thickness of the piezoelectric layer 140 corresponding to the first BAW filter. Furthermore, in this embodiment, the maximum thickness of the piezoelectric layer 140 corresponds to the maximum resonant frequency of the first and second BAW filters.

[0087] That is to say, when the frequency range requirement of the integrated bulk acoustic wave filter cannot be met by simply changing the thickness of the first upper electrode layer 122, the frequency range of the integrated bulk acoustic wave filter can be further increased by etching the piezoelectric layer 140 to meet the requirement of having different resonant frequencies.

[0088] refer to Figure 12 As shown, a first lower electrode layer 150 is then deposited and etched on the piezoelectric layer 140 to form a plurality of eighth regions 152 for exposing the piezoelectric layer 140. The thickness of the first lower electrode layer 150 corresponds to the difference in resonant frequency between the first BAW filter and the second BAW filter.

[0089] refer to Figure 13 As shown, further, a second lower electrode layer 160 is deposited and etched on the first lower electrode layer 150 to form a ninth region 162 for exposing the piezoelectric layer 140. The thickness of the second lower electrode layer 160 corresponds to the minimum resonant frequency of the first BAW filter and the second BAW filter.

[0090] refer to Figure 14-15 As shown, first, a second sacrificial layer 170 is deposited on the second lower electrode layer 160 and the piezoelectric layer 140. Then, the second sacrificial layer 170 is etched, and a plurality of tenth regions 173 for exposing the second lower electrode layer 160 and an eleventh region 174 for exposing the piezoelectric layer 140 are formed. Among them, each tenth region 173 is located on both sides of the eleventh region 174. Then, a support layer 180 is deposited on the second lower electrode layer 160, the piezoelectric layer 140 and the second sacrificial layer 170. Further, the first sacrificial layer 121 and the second sacrificial layer 170 are corroded, and a first resonant cavity corresponding to the first bulk acoustic wave filter and a second resonant cavity corresponding to the second bulk acoustic wave filter are formed. Finally, a second substrate 190 is deposited on the support layer 180, the whole is flipped over, and the first substrate 110 is removed, thereby generating the following. Figure 16 The structure shown.

[0091] refer to Figure 17 As shown, finally, the second upper electrode layer 130 is etched to form a twelfth region 132 for exposing the piezoelectric layer 140 , wherein the twelfth region 132 corresponds to the ninth region 162 .

[0092] According to another aspect of the present application, an integrated bulk acoustic wave filter is also provided, including: a second substrate 190 and a plurality of bulk acoustic wave filters, wherein the bulk acoustic wave filter includes a second upper electrode layer 130 formed on the second substrate 190, wherein the thickness of the second upper electrode layer 130 corresponds to the minimum value of the resonant frequency among the plurality of bulk acoustic wave filters; and at least one first upper electrode layer 122 formed on the second upper electrode layer 130, wherein the first upper electrode layer 122 is formed with a plurality of thirteenth regions 1221 for exposing the second upper electrode layer 130, wherein the plurality of thirteenth regions 1221 correspond to the pre-etched first sacrificial layer 121, the thickness of the first sacrificial layer 121 corresponds to the difference in the resonant frequencies of the plurality of bulk acoustic wave filters, the thickness of the first upper electrode layer 122 is the same as the thickness of the first sacrificial layer 121, and the sum of the number of at least one first upper electrode layer 122 and the second upper electrode layer 130 corresponds to the number of the plurality of bulk acoustic wave filters.

[0093] Optionally, the plurality of BAW filters include: a first BAW filter and a second BAW filter, and the first BAW filter and the second BAW filter include: a support layer 180, a second lower electrode layer 160, a first lower electrode layer 150 and a piezoelectric layer 140, wherein the support layer 180 is deposited on the second substrate 190; the second lower electrode layer 160 is deposited and etched on the support layer 180, the first lower electrode layer 150 is deposited and etched on the second lower electrode layer 160, and the second lower electrode layer 160 and the first lower electrode layer 150 are formed with a fourth region 161 for exposing the piezoelectric layer 140, wherein the thickness of the first lower electrode layer 150 is the same as that of the second lower electrode layer 160. The difference between the integrated acoustic wave filter and the second bulk acoustic wave filter corresponds to the thickness of the second lower electrode layer 160, which corresponds to the minimum resonant frequency in the first bulk acoustic wave filter and the second bulk acoustic wave filter; the piezoelectric layer 140 is deposited on the first lower electrode layer 150, the second lower electrode layer 160 and the support layer 180, and the thickness of the piezoelectric layer 140 corresponds to the maximum resonant frequency in the first bulk acoustic wave filter and the second bulk acoustic wave filter; and a first resonant cavity corresponding to the first bulk acoustic wave filter and a second resonant cavity corresponding to the second bulk acoustic wave filter are formed between the support layer 180 and the first lower electrode layer 150, the second lower electrode layer 160 and the piezoelectric layer 140.

[0094] Optionally, the second upper electrode layer 130 is deposited on the piezoelectric layer 140; the first upper electrode layer 122 is deposited on the second upper electrode layer 130, and the second upper electrode layer 130 and the first upper electrode layer 122 form a seventh region 131 for exposing the piezoelectric layer 140, wherein the seventh region 131 corresponds to the fourth region 161, and the thickness of the second upper electrode layer 130 corresponds to the minimum value of the resonant frequency in the first bulk acoustic wave filter and the second bulk acoustic wave filter, and the thickness of the first upper electrode layer 122 corresponds to the difference in resonant frequency between the first bulk acoustic wave filter and the second bulk acoustic wave filter.

[0095] Optionally, the first bulk acoustic wave filter and the second bulk acoustic wave filter include: a support layer 180, a second lower electrode layer 160, a first lower electrode layer 150 and a piezoelectric layer 140, wherein the support layer 180 is formed on the second substrate 190; the second lower electrode layer 160 is formed on the support layer 180, the first lower electrode layer 150 is formed on the second lower electrode layer 160, and the second lower electrode layer 160 and the first lower electrode layer 150 are formed with a ninth region 162 for exposing the piezoelectric layer 140, wherein the thickness of the first lower electrode layer 150 corresponds to the difference between the first bulk acoustic wave filter and the second bulk acoustic wave filter, and the thickness of the second lower electrode layer 160 corresponds to the thickness of the first bulk acoustic wave filter. Corresponding to the minimum value of the resonant frequency in the second bulk acoustic wave filter; the piezoelectric layer 140 is deposited on the first lower electrode layer 150, the second lower electrode layer 160 and the support layer 180, and the thickness of the piezoelectric layer 140 corresponding to the second bulk acoustic wave filter is different from the thickness of the piezoelectric layer 140 corresponding to the first bulk acoustic wave filter, wherein the maximum thickness of the piezoelectric layer 140 corresponds to the maximum value of the resonant frequency in the first bulk acoustic wave filter and the second bulk acoustic wave filter; and a first resonant cavity corresponding to the first bulk acoustic wave filter and a second resonant cavity corresponding to the second bulk acoustic wave filter are formed between the support layer 180 and the first lower electrode layer 150, the second lower electrode layer 160 and the piezoelectric layer 140.

[0096] Optionally, the second upper electrode layer 130 is deposited on the piezoelectric layer 140; the first upper electrode layer 122 is deposited on the second upper electrode layer 130, and the second upper electrode layer 130 and the first upper electrode layer 122 form a twelfth region 132 for exposing the piezoelectric layer 140, wherein the twelfth region 132 corresponds to the ninth region 162, and the thickness of the second upper electrode layer 130 corresponds to the minimum value of the resonant frequency in the first bulk acoustic wave filter and the second bulk acoustic wave filter, and the thickness of the first upper electrode layer 122 corresponds to the difference in resonant frequency between the first bulk acoustic wave filter and the second bulk acoustic wave filter.

[0097] Unless otherwise specifically stated, the relative arrangement of the parts and steps, the numerical expressions and the numerical values ​​set forth in these embodiments do not limit the scope of the present disclosure. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the drawings are not drawn according to actual proportional relationships. The techniques, methods and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the techniques, methods and equipment should be considered as part of the authorization specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as being merely exemplary and not as limitations. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that similar numbers and letters represent similar items in the following figures, and therefore, once an item is defined in one figure, it does not need to be further discussed in subsequent figures.

[0098] For ease of description, spatially relative terms such as "above," "above," "on the upper surface of," and "upper" may be used herein to describe the spatial positional relationship of a device or feature to other devices or features as shown in the figures. It should be understood that spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if a device in a drawing is inverted, a device described as "above" or "on top of" another device or structure would then be positioned as "below" or "below" the other device or structure. Thus, the exemplary term "above" can include both the "above" and "below" orientations. The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used herein should be interpreted accordingly.

[0099] In the description of the present disclosure, it should be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "horizontal, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present disclosure and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of the present disclosure; the directional words "inside and outside" refer to the inside and outside relative to the outline of each component itself.

[0100] The above description is merely a preferred embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A method for manufacturing an integrated bulk acoustic wave filter, characterized in that: include: Producing a first substrate (110); A plurality of bulk acoustic wave filters are formed on the first substrate (110), and the specific steps include: At least one mixed layer (120) is formed on the first substrate (110), wherein the mixed layer (120) comprises a first sacrificial layer (121) etched with a plurality of first regions (1211) and a first upper electrode layer (122) deposited in each of the first regions (1211), wherein the first sacrificial layer (121) and the first upper electrode layer (122) are arranged horizontally, and wherein the thickness of the first sacrificial layer (121) corresponds to the difference in resonant frequencies of the plurality of bulk acoustic wave filters, and the thickness of the first upper electrode layer (122) is the same as the thickness of the first sacrificial layer (121); as well as A second upper electrode layer (130) is deposited on the at least one mixed layer (120) to form the plurality of bulk acoustic wave filters, wherein the thickness of the second upper electrode layer (130) corresponds to a minimum value of a resonant frequency in the plurality of bulk acoustic wave filters, and the sum of the number of the at least one mixed layer (120) and the second upper electrode layer (130) corresponds to the number of the plurality of bulk acoustic wave filters.

2. The production method according to claim 1, characterized in that The operation of forming a plurality of bulk acoustic wave filters on the first substrate (110) comprises: A first bulk acoustic wave filter and a second bulk acoustic wave filter are formed on the first substrate (110).

3. The production method according to claim 2, characterized in that: The operation of forming a first bulk acoustic wave filter and a second bulk acoustic wave filter on the first substrate (110) comprises: Depositing and etching the first sacrificial layer (121) on the first substrate (110) to form a plurality of second regions (1212) for exposing the first substrate (110), wherein the thickness of the first sacrificial layer (121) corresponds to the difference in resonant frequency between the first bulk acoustic wave filter and the second bulk acoustic wave filter; Depositing and smoothing the first upper electrode layer (122) on the first substrate (110) and the first sacrificial layer (121), and ensuring that the thickness of the first upper electrode layer (122) in the plurality of second regions (1212) is the same as the thickness of the first sacrificial layer (121); Depositing the second upper electrode layer (130) on the first sacrificial layer (121) and the first upper electrode layer (122), wherein the thickness of the second upper electrode layer (130) corresponds to the minimum value of the resonant frequency in the first bulk acoustic wave filter and the second bulk acoustic wave filter; and A piezoelectric layer (140) is deposited on the second upper electrode layer (130) to form the first bulk acoustic wave filter and the second bulk acoustic wave filter, wherein the thickness of the piezoelectric layer (140) corresponds to a maximum value of a resonant frequency in the first bulk acoustic wave filter and the second bulk acoustic wave filter.

4. The production method according to claim 3, characterized in that: The operation of depositing a piezoelectric layer (140) on the second upper electrode layer (130) and forming the first bulk acoustic wave filter and the second bulk acoustic wave filter comprises: Depositing and etching a first lower electrode layer (150) on the piezoelectric layer (140) to form a plurality of third regions (151) for exposing the piezoelectric layer (140), wherein the thickness of the first lower electrode layer (150) corresponds to the difference in resonant frequency between the first bulk acoustic wave filter and the second bulk acoustic wave filter; and A second lower electrode layer (160) is deposited and etched on the first lower electrode layer (150), and a fourth region (161) is formed for exposing the piezoelectric layer (140), wherein the thickness of the second lower electrode layer (160) corresponds to a minimum value of a resonant frequency in the first bulk acoustic wave filter and the second bulk acoustic wave filter.

5. The production method according to claim 4, characterized in that: The operation of forming the first bulk acoustic wave filter and the second bulk acoustic wave filter further includes: depositing a second sacrificial layer (170) on the second lower electrode layer (160) and the piezoelectric layer (140); Etching the second sacrificial layer (170) to form a plurality of fifth regions (171) for exposing the second lower electrode layer (160) and a sixth region (172) for exposing the piezoelectric layer (140), wherein each fifth region (171) is located on both sides of the sixth region (172); depositing a support layer (180) on the second lower electrode layer (160), the piezoelectric layer (140), and the second sacrificial layer (170); etching the first sacrificial layer (121) and the second sacrificial layer (170) to form a first resonant cavity corresponding to the first bulk acoustic wave filter and a second resonant cavity corresponding to the second bulk acoustic wave filter; and A second substrate (190) is deposited on the support layer (180), the entire layer is flipped over, and the first substrate (110) is removed.

6. The manufacturing method according to claim 5, characterized in that: The operation of forming the first bulk acoustic wave filter and the second bulk acoustic wave filter further includes: The second upper electrode layer (130) is etched to form a seventh region (131) for exposing the piezoelectric layer (140), wherein the seventh region (131) corresponds to the fourth region (161).

7. The production method according to claim 2, characterized in that: The operation of forming a first bulk acoustic wave filter and a second bulk acoustic wave filter on the first substrate (110) comprises: Depositing and etching the first sacrificial layer (121) on the first substrate (110) to form a plurality of second regions (1212) for exposing the first substrate (110), wherein the thickness of the first sacrificial layer (121) corresponds to the difference in resonant frequency between the first bulk acoustic wave filter and the second bulk acoustic wave filter; Depositing and smoothing the first upper electrode layer (122) on the first substrate (110) and the first sacrificial layer (121), and ensuring that the thickness of the first upper electrode layer (122) within the plurality of second regions (1212) corresponds to the thickness of the first sacrificial layer (121); Depositing the second upper electrode layer (130) on the first sacrificial layer (121) and the first upper electrode layer (122), wherein the thickness of the second upper electrode layer (130) corresponds to the minimum value of the resonant frequency in the first bulk acoustic wave filter and the second bulk acoustic wave filter; and A piezoelectric layer (140) is deposited and etched on the second upper electrode layer (130), and the first bulk acoustic wave filter and the second bulk acoustic wave filter are formed, wherein the thickness of the piezoelectric layer (140) corresponding to the second bulk acoustic wave filter is different from the thickness of the piezoelectric layer (140) corresponding to the first bulk acoustic wave filter, and the maximum thickness of the piezoelectric layer (140) corresponds to the maximum value of the resonant frequency in the first bulk acoustic wave filter and the second bulk acoustic wave filter.

8. The production method according to claim 7, characterized in that: The operation of depositing and etching the piezoelectric layer (140) on the second upper electrode layer (130) and forming the first bulk acoustic wave filter and the second bulk acoustic wave filter comprises: Depositing and etching a first lower electrode layer (150) on the piezoelectric layer (140) to form a plurality of eighth regions (152) for exposing the piezoelectric layer (140), wherein the plurality of eighth regions (152) correspond to the plurality of second regions (1212), and the thickness of the first lower electrode layer (150) corresponds to the difference in resonant frequency between the first bulk acoustic wave filter and the second bulk acoustic wave filter; A second lower electrode layer (160) is deposited and etched on the first lower electrode layer (150) to form a ninth region (162) for exposing the piezoelectric layer (140), wherein the thickness of the second lower electrode layer (160) corresponds to a minimum value of a resonant frequency in the first bulk acoustic wave filter and the second bulk acoustic wave filter.

9. The production method according to claim 8, characterized in that: The operation of forming the first bulk acoustic wave filter and the second bulk acoustic wave filter further includes: depositing a second sacrificial layer (170) on the second lower electrode layer (160) and the piezoelectric layer (140); Etching the second sacrificial layer (170) to form a plurality of tenth regions (173) for exposing the second lower electrode layer (160) and an eleventh region (174) for exposing the piezoelectric layer (140), wherein each tenth region (173) is located on both sides of the eleventh region (174); depositing a support layer (180) on the second lower electrode layer (160), the piezoelectric layer (140), and the second sacrificial layer (170); etching the first sacrificial layer (121) and the second sacrificial layer (170) to form a first resonant cavity corresponding to the first bulk acoustic wave filter and a second resonant cavity corresponding to the second bulk acoustic wave filter; and A second substrate (190) is deposited on the support layer (180), the entire layer is flipped over, and the first substrate (110) is removed.

10. The manufacturing method according to claim 9, characterized in that: The operation of forming the first bulk acoustic wave filter and the second bulk acoustic wave filter further includes: The second upper electrode layer (130) is etched to form a twelfth region (132) for exposing the piezoelectric layer (140), wherein the twelfth region (132) corresponds to the ninth region (162).

11. An integrated bulk acoustic wave filter, characterized in that: include: A second substrate (190) and a plurality of bulk acoustic wave filters, wherein the bulk acoustic wave filters include a second upper electrode layer (130) formed on the second substrate (190), wherein the thickness of the second upper electrode layer (130) corresponds to a minimum value of a resonant frequency in the plurality of bulk acoustic wave filters; and At least one first upper electrode layer (122) is formed on the second upper electrode layer (130), wherein the first upper electrode layer (122) is formed with a plurality of thirteenth regions (1221) for exposing the second upper electrode layer (130), wherein the plurality of thirteenth regions (1221) correspond to a pre-etched first sacrificial layer (121), the thickness of the first sacrificial layer (121) corresponds to the difference in resonant frequencies of the plurality of bulk acoustic wave filters, the thickness of the first upper electrode layer (122) is the same as the thickness of the first sacrificial layer (121), and the first sacrificial layer (121) and the first upper electrode layer (122) are arranged horizontally, and The sum of the number of the at least one first upper electrode layer (122) and the second upper electrode layer (130) corresponds to the number of the plurality of bulk acoustic wave filters.

12. The integrated bulk acoustic wave filter according to claim 11, wherein: The plurality of bulk acoustic wave filters include: a first bulk acoustic wave filter and a second bulk acoustic wave filter, and the first bulk acoustic wave filter and the second bulk acoustic wave filter include: a support layer (180), a second lower electrode layer (160), a first lower electrode layer (150) and a piezoelectric layer (140), wherein The support layer (180) is deposited on the second substrate (190); The second lower electrode layer (160) is deposited and etched on the support layer (180), the first lower electrode layer (150) is deposited and etched on the second lower electrode layer (160), and the second lower electrode layer (160) and the first lower electrode layer (150) form a fourth region (161) for exposing the piezoelectric layer (140), wherein the thickness of the first lower electrode layer (150) corresponds to the difference between the first bulk acoustic wave filter and the second bulk acoustic wave filter, and the thickness of the second lower electrode layer (160) corresponds to the minimum value of the resonant frequency in the first bulk acoustic wave filter and the second bulk acoustic wave filter; The piezoelectric layer (140) is deposited on the first lower electrode layer (150), the second lower electrode layer (160), and the support layer (180), and the thickness of the piezoelectric layer (140) corresponds to the maximum value of the resonant frequency in the first bulk acoustic wave filter and the second bulk acoustic wave filter; and A first resonant cavity corresponding to the first bulk acoustic wave filter and a second resonant cavity corresponding to the second bulk acoustic wave filter are formed between the support layer (180), the first lower electrode layer (150), the second lower electrode layer (160) and the piezoelectric layer (140).

13. The integrated bulk acoustic wave filter according to claim 12, wherein: The second upper electrode layer (130) is deposited on the piezoelectric layer (140); The first upper electrode layer (122) is deposited on the second upper electrode layer (130), and the second upper electrode layer (130) and the first upper electrode layer (122) form a seventh region (131) for exposing the piezoelectric layer (140), wherein the seventh region (131) corresponds to the fourth region (161), and The thickness of the second upper electrode layer (130) corresponds to the minimum value of the resonant frequency in the first bulk acoustic wave filter and the second bulk acoustic wave filter, and the thickness of the first upper electrode layer (122) corresponds to the difference in resonant frequency between the first bulk acoustic wave filter and the second bulk acoustic wave filter.

14. The integrated bulk acoustic wave filter according to claim 12, wherein: The first bulk acoustic wave filter and the second bulk acoustic wave filter comprise: a support layer (180), a second lower electrode layer (160), a first lower electrode layer (150), and a piezoelectric layer (140), wherein The support layer (180) is formed on the second substrate (190); The second lower electrode layer (160) is formed on the support layer (180), the first lower electrode layer (150) is formed on the second lower electrode layer (160), and the second lower electrode layer (160) and the first lower electrode layer (150) are formed with a ninth region (162) for exposing the piezoelectric layer (140), wherein the thickness of the first lower electrode layer (150) corresponds to the difference between the first bulk acoustic wave filter and the second bulk acoustic wave filter, and the thickness of the second lower electrode layer (160) corresponds to the minimum value of the resonant frequency in the first bulk acoustic wave filter and the second bulk acoustic wave filter; The piezoelectric layer (140) is deposited on the first lower electrode layer (150), the second lower electrode layer (160), and the support layer (180), and the thickness of the piezoelectric layer (140) corresponding to the second bulk acoustic wave filter is different from the thickness of the piezoelectric layer (140) corresponding to the first bulk acoustic wave filter, and the maximum thickness of the piezoelectric layer (140) corresponds to the maximum value of the resonant frequency in the first bulk acoustic wave filter and the second bulk acoustic wave filter; and A first resonant cavity corresponding to the first bulk acoustic wave filter and a second resonant cavity corresponding to the second bulk acoustic wave filter are formed between the support layer (180), the first lower electrode layer (150), the second lower electrode layer (160) and the piezoelectric layer (140).

15. The integrated bulk acoustic wave filter according to claim 14, wherein: The second upper electrode layer (130) is deposited on the piezoelectric layer (140); The first upper electrode layer (122) is deposited on the second upper electrode layer (130), and the second upper electrode layer (130) and the first upper electrode layer (122) form a twelfth region (132) for exposing the piezoelectric layer (140), wherein the twelfth region (132) corresponds to the ninth region (162), and The thickness of the second upper electrode layer (130) corresponds to the minimum value of the resonant frequency in the first bulk acoustic wave filter and the second bulk acoustic wave filter, and the thickness of the first upper electrode layer (122) corresponds to the difference in resonant frequency between the first bulk acoustic wave filter and the second bulk acoustic wave filter.

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