Integrated bulk acoustic wave filter and method for manufacturing the same

Abstract

The present application discloses an integrated bulk acoustic wave filter and a method for manufacturing the integrated bulk acoustic wave filter, comprising: a second substrate and a plurality of bulk acoustic wave filters, wherein the plurality of bulk acoustic wave filters are formed on the second substrate, and the bulk acoustic wave filters include a first electrode and a plurality of second electrodes, the sum of the number of the first electrode and the plurality of second electrodes corresponds to the number of the plurality of bulk acoustic wave filters, and the thickness of the first upper electrode and the first lower electrode in the first electrode corresponds to the minimum value of the resonant frequency in the bulk acoustic wave filter, and the thickness of the second upper electrode and the second lower electrode in the plurality of second electrodes corresponds to the difference between the resonant frequencies of any two bulk acoustic wave filters in the plurality of bulk acoustic wave filters. The technical effect of being able to adapt to different operating frequencies is achieved.

Description

Technical Field

[0001] The present application relates to the technical field of filter manufacturing, and in particular to an integrated bulk acoustic wave filter and a method for manufacturing 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] The publication number is CN1145131187A, and the name is TSV-based stepped narrow-band piezoelectric thin film bulk acoustic wave filter. It includes a silicon substrate with a silicon dioxide support layer on top, and a plurality of piezoelectric thin film bulk acoustic wave resonators distributed above the silicon dioxide support layer.

[0008] Publication number CN222897242U, titled "A Bulk Acoustic Wave Filter, Multiplexer, and Communication Device," describes the BAW filter as comprising multiple electrically connected resonant branches, each of which includes two opposing resonant cavities. The angle between the opposing arc surfaces of the two resonant cavities in the same resonant branch is a first arc, while the angle between the opposing arc surfaces of the two resonant cavities in different resonant branches is a second arc, with the first arc being smaller than the second arc.

[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 an integrated bulk acoustic wave filter and a method for manufacturing the 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 of the integrated bulk acoustic wave filters.

[0011] According to one 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 plurality of bulk acoustic wave filters are formed on the second substrate, and the bulk acoustic wave filter comprises a first electrode and a plurality of second electrodes, the sum of the number of the first electrodes and the plurality of second electrodes corresponds to the number of the plurality of bulk acoustic wave filters, and the thickness of the first upper electrode and the first lower electrode in the first electrodes corresponds to the minimum value of the resonant frequency in the bulk acoustic wave filter, and the thickness of the second upper electrode and the second lower electrode in the plurality of second electrodes corresponds to the difference between the resonant frequencies of any two bulk acoustic wave filters in the plurality of bulk acoustic wave filters.

[0012] 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 supporting layer and a piezoelectric layer, wherein the supporting layer is formed on a second substrate; a second lower electrode is formed on the supporting layer, the first lower electrode is formed on the second lower electrode, and the second lower electrode corresponding to the first BAW filter is formed with a first area for exposing the first lower electrode, wherein the thickness of the first lower electrode corresponds to the minimum value of the resonant frequency in the first BAW filter and the second BAW filter, and the thickness of the second lower electrode corresponds to the frequency difference between the first BAW filter and the second BAW filter; a piezoelectric layer is formed on the first lower electrode and the supporting layer, and the second lower electrode and the first lower electrode are formed with a second area for exposing the piezoelectric layer, wherein the thickness of the piezoelectric layer corresponds to the maximum value of the 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 supporting layer and the second lower electrode, the first lower electrode and the piezoelectric layer.

[0013] Optionally, a first upper electrode is formed on the piezoelectric layer, wherein the thickness of the first upper electrode corresponds to the minimum value of the resonant frequency in the first bulk acoustic wave filter and the second bulk acoustic wave filter; a second upper electrode is formed on the first upper electrode, and the second upper electrode is formed with a fifth region for exposing the first upper electrode, wherein the thickness of the second upper electrode corresponds to the frequency difference between the first bulk acoustic wave filter and the second bulk acoustic wave filter; and the first upper electrode and the second upper electrode are formed with a seventh region, an eighth region and a ninth region for exposing the piezoelectric layer, wherein the eighth region and the ninth region are respectively formed on both sides of the seventh region.

[0014] Optionally, the first bulk acoustic wave filter and the second bulk acoustic wave filter include: a supporting layer and a piezoelectric layer, wherein the supporting layer is formed on the second substrate; a second lower electrode is formed on the supporting layer, a first lower electrode is formed on the second lower electrode, and the second lower electrode corresponding to the first bulk acoustic wave filter is formed with a tenth region for exposing the first lower electrode, wherein the thickness of the first lower electrode 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 second lower electrode corresponds to the frequency difference between the first bulk acoustic wave filter and the second bulk acoustic wave filter; a piezoelectric layer is formed on the first lower electrode and the supporting layer, and the second lower electrode and the first lower electrode are formed with an eleventh region for exposing the piezoelectric layer, 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; 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 second lower electrode, the first lower electrode and the piezoelectric layer.

[0015] Optionally, the first upper electrode is formed on the piezoelectric layer, wherein the thickness of the first upper electrode corresponds to the minimum value of the resonant frequency in the first bulk acoustic wave filter and the second bulk acoustic wave filter; the second upper electrode is formed on the first upper electrode, and the second upper electrode is formed with a fifteenth region for exposing the first upper electrode, wherein the thickness of the second upper electrode corresponds to the frequency difference between the first bulk acoustic wave filter and the second bulk acoustic wave filter; and the first upper electrode and the second upper electrode are formed with a sixteenth region, a seventeenth region and an eighteenth region, wherein the seventeenth region and the eighteenth region are respectively formed on both sides of the sixteenth region.

[0016] According to another aspect of the present application, a method for manufacturing an integrated bulk acoustic wave filter is provided, comprising: manufacturing a first substrate; and forming a plurality of bulk acoustic wave filters on the first substrate, wherein the bulk acoustic wave filters include a first electrode and a plurality of second electrodes, the sum of the number of the plurality of first electrodes and the plurality of second electrodes corresponds to the number of the plurality of bulk acoustic wave filters, and the thickness of the first upper electrode and the first lower electrode in the first electrode corresponds to the minimum value of the resonant frequency in the plurality of bulk acoustic wave filters, and the thickness of the second upper electrode and the second lower electrode in the plurality of second electrodes corresponds to the difference between the resonant frequencies of any two bulk acoustic wave filters in the plurality of bulk acoustic wave filters.

[0017] 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.

[0018] Optionally, the operation of forming a first bulk acoustic wave filter and a second bulk acoustic wave filter on a first substrate includes: depositing a first upper electrode on the first substrate, wherein the thickness of the first upper electrode corresponds to the minimum value of the resonant frequency in the first bulk acoustic wave filter and the second bulk acoustic wave filter; depositing a piezoelectric layer on the first upper electrode, 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; depositing a first lower electrode on the piezoelectric layer, wherein the thickness of the first lower electrode 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 second lower electrode on the first lower electrode using a lift-off process and forming a first region for exposing the first lower electrode, wherein the thickness of the second lower electrode corresponds to the frequency difference between 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 on the first substrate also includes: etching the second lower electrode and the first lower electrode to form a second region for exposing the piezoelectric layer; depositing a layer to be corroded on the second lower electrode and the first lower electrode; etching the layer to be corroded to form a third region and a fourth region for exposing the second lower electrode and a fifth region for exposing the piezoelectric layer, wherein the third region and the fourth region are respectively located on both sides of the fifth region; depositing a supporting layer on the second lower electrode, the piezoelectric layer and the layer to be corroded; corroding the layer to be corroded 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 depositing a second substrate on the supporting layer, flipping the entire layer, and removing the first substrate.

[0020] Optionally, the operation of forming a first bulk acoustic wave filter and a second bulk acoustic wave filter on a first substrate includes: depositing a second upper electrode on the first upper electrode using a lift-off process, and forming a sixth region for exposing the first upper electrode, wherein the thickness of the second upper electrode corresponds to the frequency difference between the first bulk acoustic wave filter and the second bulk acoustic wave filter.

[0021] Optionally, the operation of forming the first bulk acoustic wave filter and the second bulk acoustic wave filter on the first substrate includes: etching the second upper electrode and the first upper electrode, and forming a seventh region, an eighth region and a ninth region for exposing the piezoelectric layer, wherein the eighth region and the ninth region are respectively formed on both sides of the seventh region.

[0022] Optionally, the operation of forming a first bulk acoustic wave filter and a second bulk acoustic wave filter on a first substrate includes: depositing a first upper electrode on the first substrate, wherein the thickness of the first upper electrode corresponds to the minimum value of the resonant frequency in the first bulk acoustic wave filter and the second bulk acoustic wave filter; depositing and etching a piezoelectric layer on the first upper electrode, 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; depositing a first lower electrode on the piezoelectric layer, wherein the thickness of the first lower electrode 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 second lower electrode on the first lower electrode using a lift-off process and forming a tenth region for exposing the first lower electrode, wherein the thickness of the second lower electrode corresponds to the frequency difference between the first bulk acoustic wave filter and the second bulk acoustic wave filter.

[0023] Optionally, the operation of forming the first bulk acoustic wave filter and the second bulk acoustic wave filter on the first substrate also includes: etching the second lower electrode and the first lower electrode to form an eleventh region for exposing the piezoelectric layer; depositing a layer to be corroded on the second lower electrode and the first lower electrode; etching the layer to be corroded to form a twelfth region and a thirteenth region for exposing the second lower electrode and a fourteenth region for exposing the piezoelectric layer, wherein the twelfth region and the thirteenth region are respectively located on both sides of the fourteenth region; depositing a supporting layer on the second lower electrode, the piezoelectric layer and the layer to be corroded; depositing a second substrate on the supporting layer, flipping the whole layer over, and removing the first substrate; and etching the layer to be corroded 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.

[0024] Optionally, the operation of forming a first bulk acoustic wave filter and a second bulk acoustic wave filter on a first substrate includes: depositing a second upper electrode on the first upper electrode using a lift-off process, and forming a fifteenth region for exposing the first upper electrode, wherein the thickness of the second upper electrode corresponds to the frequency difference between the first bulk acoustic wave filter and the second bulk acoustic wave filter.

[0025] Optionally, the operation of forming the first bulk acoustic wave filter and the second bulk acoustic wave filter on the first substrate includes: etching the second upper electrode and the first upper electrode, and forming a sixteenth region, a seventeenth region and an eighteenth region for exposing the piezoelectric layer, wherein the seventeenth region and the eighteenth region are respectively formed on both sides of the sixteenth region.

[0026] This application provides an integrated BAW filter and a method for manufacturing the integrated BAW filter. Furthermore, 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 BAW filter, the present application determines the thickness of the first upper electrode and the first lower electrode based on the minimum resonant frequency among the multiple BAW filters. The thickness of the second upper electrode and the second lower electrode is then determined based on the difference in resonant frequencies between any two of the multiple BAW filters. This allows the integrated BAW filters manufactured by the present application to have different operating frequencies. Furthermore, compared to generating integrated BAW filters with different operating frequencies by etching electrodes, generating integrated BAW filters with different operating frequencies by depositing the second electrode can reduce process complexity and lower manufacturing costs.

[0028] Furthermore, when the present application utilizes the lift-off process to manufacture the plurality of second electrodes 130 , in addition to being able to realize the requirement that the plurality of BAW filters have different operating frequencies, the semiconductor lead frame structure (ie, Frame structure) can also be manufactured simultaneously, thereby saving photomasks.

[0029] 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.

[0030] 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

[0031] 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:

[0032] 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;

[0033] Figure 2 is a schematic diagram of a first upper electrode, a piezoelectric layer, and a first lower electrode deposited on a first substrate according to Example 1 of the present application;

[0034] Figure 3 is a schematic diagram of the first region according to Example 1 of the present application;

[0035] Figure 4 is a schematic diagram of the second region according to Example 1 of the present application;

[0036] Figure 5 Schematic diagram of the first substrate, the first upper electrode, the piezoelectric layer, the first lower electrode, the second lower electrode, and the layer to be etched according to Example 1 of the present application;

[0037] Figure 6 is a schematic diagram of the third area, the fourth area, and the fifth area according to Example 1 of the present application;

[0038] Figure 7 Schematic diagram of the first substrate, the first upper electrode, the piezoelectric layer, the first lower electrode, the second lower electrode, the layer to be etched, and the support layer according to Example 1 of the present application;

[0039] Figure 8is a schematic diagram of the first resonant cavity and the second resonant cavity according to Example 1 of the present application;

[0040] Figure 9 Schematic diagram of the first substrate, the first upper electrode, the piezoelectric layer, the first lower electrode, the second lower electrode, the support layer, and the second substrate according to Example 1 of the present application;

[0041] Figure 10 is a schematic diagram of the first upper electrode, the piezoelectric layer, the first lower electrode, the second lower electrode, the support layer, and the second substrate after the first substrate is flipped over and removed according to Example 1 of the present application;

[0042] Figure 11 Schematic diagram of the first upper electrode, the piezoelectric layer, the first lower electrode, the second lower electrode, the support layer, the second substrate, and the second upper electrode according to Example 1 of the present application;

[0043] Figure 12 is a schematic diagram of an integrated bulk acoustic wave filter according to Example 1 of the present application;

[0044] Figure 13 is a schematic diagram of a first upper electrode, a piezoelectric layer, and a first lower electrode deposited and etched on a first substrate according to Example 2 of the present application;

[0045] Figure 14 is a schematic diagram of the tenth region according to Example 2 of the present application;

[0046] Figure 15 is a schematic diagram of the eleventh region according to Example 2 of the present application;

[0047] Figure 16 Schematic diagram of the first substrate, the first upper electrode, the piezoelectric layer, the first lower electrode, the second lower electrode, and the layer to be etched according to Example 2 of the present application;

[0048] Figure 17 is a schematic diagram of the twelfth region, the thirteenth region, and the fourteenth region according to Example 2 of the present application;

[0049] Figure 18 Schematic diagram of the first substrate, the first upper electrode, the piezoelectric layer, the first lower electrode, the second lower electrode, the layer to be etched, and the support layer according to Example 2 of the present application;

[0050] Figure 19 is a schematic diagram of the first resonant cavity and the second resonant cavity according to Example 2 of the present application;

[0051] Figure 20Schematic diagram of the first substrate, the first upper electrode, the piezoelectric layer, the first lower electrode, the second lower electrode, the layer to be etched, and the support layer according to Example 2 of the present application;

[0052] Figure 21 is a schematic diagram of the first upper electrode, the piezoelectric layer, the first lower electrode, the second lower electrode, the support layer, and the second substrate after the first substrate is flipped over and removed according to Example 2 of the present application;

[0053] Figure 22 Schematic diagram of the first upper electrode, the piezoelectric layer, the first lower electrode, the second lower electrode, the support layer, the second substrate, and the second upper electrode according to Example 2 of the present application;

[0054] Figure 23 This is a schematic diagram of another integrated bulk acoustic wave filter according to Example 2 of the present application. DETAILED DESCRIPTION

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] 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:

[0061] S101: preparing a first substrate; and

[0062] S102: A plurality of bulk acoustic wave filters are formed on a first substrate, wherein the bulk acoustic wave filters include a first electrode and a plurality of second electrodes, the sum of the number of the plurality of first electrodes and the plurality of second electrodes corresponds to the number of the plurality of bulk acoustic wave filters, and the thickness of the first upper electrode and the first lower electrode in the first electrodes corresponds to the minimum value of the resonant frequency in the plurality of bulk acoustic wave filters, and the thickness of the second upper electrode and the second lower electrode in the plurality of second electrodes corresponds to the difference between the resonant frequencies of any two bulk acoustic wave filters in the plurality of bulk acoustic wave filters.

[0063] The method for manufacturing an integrated bulk acoustic wave filter provided by an embodiment of the present disclosure is adopted, by manufacturing a first substrate and forming a plurality of bulk acoustic wave filters on the first substrate. The bulk acoustic wave filters include a first electrode and a plurality of second electrodes, and the sum of the number of the plurality of first electrodes and the plurality of second electrodes corresponds to the number of the plurality of bulk acoustic wave filters. The thickness of the first upper electrode and the first lower electrode in the first electrode corresponds to the minimum value of the resonant frequency in the plurality of bulk acoustic wave filters, and the thickness of the second upper electrode and the second lower electrode in the plurality of second electrodes corresponds to the difference in resonant frequency between any two bulk acoustic wave filters in 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 the first substrate, the multiple bulk acoustic wave filters are integrated into one chip, and the multiple bulk acoustic wave filters can be tape-out tested at one time.

[0065] Furthermore, when manufacturing an integrated BAW filter, the present application determines the thickness of the first upper electrode and the first lower electrode based on the minimum resonant frequency among the multiple BAW filters. The thickness of the second upper electrode and the second lower electrode is then determined based on the difference in resonant frequencies between any two of the multiple BAW filters. This allows the integrated BAW filters manufactured by the present application to have different operating frequencies. Furthermore, compared to generating integrated BAW filters with different operating frequencies by etching electrodes, generating integrated BAW filters with different operating frequencies by depositing the second electrode can reduce process complexity and lower manufacturing costs.

[0066] Furthermore, when the present application utilizes the lift-off process to manufacture the plurality of second electrodes 130 , in addition to being able to realize the requirement that the plurality of BAW filters have different operating frequencies, the semiconductor lead frame structure (ie, Frame structure) can also be manufactured simultaneously, thereby saving photomasks.

[0067] 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.

[0068] Example 1

[0069] The following are specific steps for manufacturing an integrated bulk acoustic wave filter provided in an embodiment of the present application:

[0070] refer to Figure 2 As shown, first, a first substrate 110 to be removed is prepared. Optionally, the first substrate 110 is made of silicon, silicon carbide, or sapphire. Furthermore, a first upper electrode 121 is deposited on one side of the first substrate 110. The thickness of the first upper electrode 121 corresponds to the minimum resonant frequency in the first bulk acoustic wave filter and the second bulk acoustic wave filter. Preferably, the material of the first upper electrode 121 can be, for example, molybdenum or tungsten, and the uniformity is less than 1%.

[0071] Then, a piezoelectric layer 140 is deposited on the side of the first upper electrode 121 away from the first substrate 110. The thickness of the piezoelectric layer 140 corresponds to the maximum resonant frequency of the first and second BAW filters. Preferably, the piezoelectric layer 140 is made of, for example, aluminum nitride or scandium-doped aluminum nitride, with a uniformity of less than 1%.

[0072] Furthermore, a first lower electrode 122 is deposited on a side of the piezoelectric layer 140 away from the first upper electrode 121. The thickness of the first lower electrode 122 corresponds to the minimum resonant frequency of the first and second BAW filters. Preferably, the first lower electrode 122 is made of a material such as molybdenum or tungsten, with a uniformity of less than 1%.

[0073] refer to Figure 3 As shown, after the first lower electrode 122 has been deposited, a second lower electrode 132 is further deposited on a side of the first lower electrode 122 away from the piezoelectric layer 140 using a lift-off process, forming a first region 1221 for exposing the first lower electrode 122. The thickness of the second lower electrode 132 corresponds to the frequency difference between the first BAW filter and the second BAW filter. Preferably, the second lower electrode 132 can be made of, for example, molybdenum or tungsten, with a uniformity of less than 1%.

[0074] Therefore, if the thickness of the first lower electrode 122 is determined to correspond to the minimum resonant frequency of the first BAW filter and the second BAW filter, the operator only needs to determine the frequency difference between the first BAW filter and the second BAW filter to determine the thickness of the second lower electrode 132 to be deposited. Furthermore, the integrated BAW filter generated based on the first lower electrode 122 and the second lower electrode 132 can achieve the requirement of having different operating frequencies.

[0075] In addition, compared with the existing method of generating integrated BAW filters with different operating frequencies by etching electrodes, generating integrated BAW filters with different operating frequencies by depositing the second electrode 130 can reduce process complexity and lower production costs.

[0076] In this embodiment, the steps of depositing the second lower electrode 132 using a lift-off process and forming the first region 1221 for exposing the first lower electrode 122 include: first, applying a photoresist on a side of the first lower electrode 122 away from the piezoelectric layer 140 using a lift-off process, exposing and developing the photoresist, and then depositing the second lower electrode 132 using the photoresist having a pattern corresponding to the first region 1221 as a mask. Subsequently, while removing the photoresist, the second lower electrode 132 corresponding to the first region 1221 is also lift-offed, thereby forming the first region 1221 for exposing the first lower electrode 122.

[0077] refer to Figure 4 As shown, when the second lower electrode 132 has been deposited, the second lower electrode 132 and the first lower electrode 122 are etched to form a second region 1401 for exposing the piezoelectric layer 140. Preferably, the etching uniformity is less than 5%.

[0078] refer to Figures 5 to 9 As shown, first, a layer to be etched 150 is deposited on the second lower electrode 132 and the first lower electrode 122. Then, the layer to be etched 150 is etched to form a third region 1222 and a fourth region 1223 for exposing the second lower electrode 132 and a fifth region 1402 for exposing the piezoelectric layer 140. The third region 1222 and the fourth region 1223 are respectively located on both sides of the fifth region 1402. Further, a supporting layer 160 is deposited on the second lower electrode 132, the piezoelectric layer 140 and the layer to be etched 150. Thereafter, the layer to be etched 150 is 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. Finally, a second substrate 170 is deposited on the supporting layer 160, the whole is flipped over, and the first substrate 110 to be removed is removed. Thus, the structure shown in FIG. 1 is finally formed. Figure 10 The structure shown.

[0079] refer to Figure 11 As shown, a second upper electrode 131 is deposited on a side of the first upper electrode 121 away from the piezoelectric layer 140 using a lift-off process, forming a sixth region 1211 for exposing the first upper electrode 121. The thickness of the second upper electrode 131 corresponds to the frequency difference between the first BAW filter and the second BAW filter. Preferably, the second upper electrode 131 can be made of, for example, molybdenum or tungsten, with a uniformity of less than 1%.

[0080] Therefore, if the thickness of the first upper electrode 121 is determined to correspond to the minimum resonant frequency of the first and second BAW filters, the operator can determine the thickness of the second upper electrode 131 to be deposited by simply determining the frequency difference between the first and second BAW filters. Furthermore, the integrated BAW filter generated based on the first and second upper electrodes 121 and 131 can achieve the requirement of having different operating frequencies.

[0081] In addition, compared with the existing method of generating integrated BAW filters with different operating frequencies by etching electrodes, generating integrated BAW filters with different operating frequencies by depositing the second electrode 130 can reduce process complexity and lower production costs.

[0082] In this embodiment, the steps of depositing the second upper electrode 131 using a lift-off process and forming the sixth region 1211 for exposing the first upper electrode 121 include: first, applying a photoresist on a side of the first upper electrode 121 away from the piezoelectric layer 140 using a lift-off process, exposing and developing the photoresist, and then using the photoresist having a pattern corresponding to the sixth region 1211 as a mask to deposit the second upper electrode 131. Subsequently, while removing the photoresist, the second upper electrode 131 corresponding to the sixth region 1211 is also lift-off, thereby forming the sixth region 1211 for exposing the first upper electrode 121.

[0083] refer to Figure 12 As shown, after the second upper electrode 131 has been deposited, the second upper electrode 131 and the first upper electrode 121 are etched to form a seventh region 1403, an eighth region 1404, and a ninth region 1405 for exposing the piezoelectric layer 140. The eighth region 1404 and the ninth region 1405 are respectively formed on both sides of the seventh region 1403. Preferably, the etching uniformity is less than 5%.

[0084] Example 2

[0085] 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:

[0086] refer to Figure 13 As shown, first, a first substrate 110 to be removed is prepared. Optionally, the first substrate 110 is made of silicon, silicon carbide, or sapphire. Furthermore, a first upper electrode 121 is deposited on one side of the first substrate 110. The thickness of the first upper electrode 121 corresponds to the minimum resonant frequency in the first bulk acoustic wave filter and the second bulk acoustic wave filter. Preferably, the material of the first upper electrode 121 can be, for example, molybdenum or tungsten, and the uniformity is less than 1%.

[0087] Then, a piezoelectric layer 140 is deposited and etched on the side of the first upper electrode 121 facing away from the first substrate 110. The thickness of the piezoelectric layer corresponding to the second BAW filter is different from the thickness of the piezoelectric layer corresponding to the first BAW filter. In this embodiment, the maximum thickness of the piezoelectric layer 140 corresponds to the maximum resonant frequency of the first and second BAW filters.

[0088] That is, when the frequency range requirement of the integrated BAW filter cannot be met by depositing the second electrode 130 alone, the frequency range of the integrated BAW filter can be further increased by etching the piezoelectric layer 140 to meet requirements with different power frequencies.

[0089] Furthermore, a first lower electrode 122 is deposited on a side of the piezoelectric layer 140 away from the first upper electrode 121. The thickness of the first lower electrode 122 corresponds to the minimum resonant frequency of the first and second BAW filters. Preferably, the first lower electrode 122 is made of a material such as molybdenum or tungsten, with a uniformity of less than 1%.

[0090] Then, refer to Figure 14 As shown, after the first lower electrode 122 has been deposited, a second lower electrode 132 is further deposited on a side of the first lower electrode 122 away from the piezoelectric layer 140 using a lift-off process, forming a tenth region 1224 for exposing the first lower electrode 122. The thickness of the second lower electrode 132 corresponds to the frequency difference between the first BAW filter and the second BAW filter. Preferably, the second lower electrode 132 can be made of, for example, molybdenum or tungsten, with a uniformity of less than 1%.

[0091] refer to Figure 15 As shown, when the second lower electrode 132 has been deposited, the second lower electrode 132 and the first lower electrode 122 are etched to form an eleventh region 1406 for exposing the piezoelectric layer 140. Preferably, the etching uniformity is less than 5%.

[0092] refer to Figures 16 to 20 As shown, first, a layer to be etched 150 is deposited on the second lower electrode 132 and the first lower electrode 122. Then, the layer to be etched 150 is etched to form a twelfth region 1225 and a thirteenth region 1226 for exposing the second lower electrode 132 and a fourteenth region 1407 for exposing the piezoelectric layer 140. The twelfth region 1225 and the thirteenth region 1226 are located on both sides of the fourteenth region 1407, respectively. Further, a support layer 160 is deposited on the second lower electrode 132, the piezoelectric layer 140 and the layer to be etched 150. Thereafter, the layer to be etched 150 is 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 170 is deposited on the support layer 160, the whole is flipped over, and the first substrate 110 to be removed is removed. Thus, the structure shown in FIG. 1 is finally formed. Figure 21 The structure shown.

[0093] refer to Figure 22 As shown, a second upper electrode 131 is deposited on a side of the first upper electrode 121 away from the piezoelectric layer 140 using a lift-off process, forming a fifteenth region 1212 for exposing the first upper electrode 121. The thickness of the second upper electrode 131 corresponds to the frequency difference between the first BAW filter and the second BAW filter. Preferably, the second upper electrode 131 can be made of, for example, molybdenum or tungsten, with a uniformity of less than 1%.

[0094] refer to Figure 23 As shown, after the second upper electrode 131 has been deposited, the second upper electrode 131 and the first upper electrode 121 are etched to form a sixteenth region 1408, a seventeenth region 1409, and an eighteenth region 1410 for exposing the piezoelectric layer 140. The seventeenth region 1409 and the eighteenth region 1410 are respectively formed on both sides of the sixteenth region 1408. Preferably, the etching uniformity is less than 5%.

[0095] According to another aspect of the present application, an integrated bulk acoustic wave filter is also provided, including: a second substrate 170 and a plurality of bulk acoustic wave filters, wherein the plurality of bulk acoustic wave filters are formed on the second substrate 170, and the bulk acoustic wave filter includes a first electrode 120 and a plurality of second electrodes 130, the sum of the number of the first electrodes 120 and the plurality of second electrodes 130 corresponds to the number of the plurality of bulk acoustic wave filters, and the thickness of the first upper electrode 121 and the first lower electrode 122 in the first electrode 120 corresponds to the minimum value of the resonant frequency in the bulk acoustic wave filter, and the thickness of the second upper electrode 131 and the second lower electrode 132 in the plurality of second electrodes 130 corresponds to the difference in the resonant frequency of any two bulk acoustic wave filters in the plurality of bulk acoustic wave filters.

[0096] 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 160 and a piezoelectric layer 140, wherein the support layer 160 is formed on a second substrate 170; a second lower electrode 132 is formed on the support layer 160, a first lower electrode 122 is formed on the second lower electrode 132, and the second lower electrode 132 corresponding to the first BAW filter is formed with a first region 1221 for exposing the first lower electrode 122, wherein the thickness of the first lower electrode 122 corresponds to a second region 1221 corresponding to a minimum value of a resonant frequency in the first BAW filter and the second BAW filter. The thickness of the lower electrode 132 corresponds to the frequency difference between the first bulk acoustic wave filter and the second bulk acoustic wave filter; the piezoelectric layer 140 is formed on the first lower electrode 122 and the support layer 160, and the second lower electrode 132 and the first lower electrode 122 are formed with a second area 1401 for exposing the piezoelectric layer 140, wherein 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 160 and the second lower electrode 132, the first lower electrode 122 and the piezoelectric layer 140.

[0097] Optionally, a first upper electrode 121 is formed on the piezoelectric layer 140, wherein the thickness of the first upper electrode 121 corresponds to the minimum value of the resonant frequency in the first bulk acoustic wave filter and the second bulk acoustic wave filter; a second upper electrode 131 is formed on the first upper electrode 121, and the second upper electrode 131 is formed with a sixth region 1211 for exposing the first upper electrode 121, wherein the thickness of the second upper electrode 131 corresponds to the frequency difference between the first bulk acoustic wave filter and the second bulk acoustic wave filter; and the first upper electrode 121 and the second upper electrode 131 are formed with a seventh region 1403, an eighth region 1404 and a ninth region 1405 for exposing the piezoelectric layer 140, wherein the eighth region 1404 and the ninth region 1405 are respectively formed on both sides of the seventh region 1403.

[0098] Optionally, the first bulk acoustic wave filter and the second bulk acoustic wave filter include: a supporting layer 160 and a piezoelectric layer 140, wherein the supporting layer 160 is formed on the second substrate 170; the second lower electrode 132 is formed on the supporting layer 160, the first lower electrode 122 is formed on the second lower electrode 132, and the second lower electrode 132 corresponding to the first bulk acoustic wave filter is formed with a tenth region 1224 for exposing the first lower electrode 122, wherein the thickness of the first lower electrode 122 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 second lower electrode 132 corresponds to the frequency difference between the first bulk acoustic wave filter and the second bulk acoustic wave filter; The piezoelectric layer 140 is formed on the first lower electrode 122 and the supporting layer 160, and the second lower electrode 132 and the first lower electrode 122 are formed with an eleventh region 1406 for exposing the piezoelectric layer 140, 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 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 supporting layer 160 and the second lower electrode 132, the first lower electrode 122 and the piezoelectric layer 140.

[0099] Optionally, a first upper electrode 121 is formed on the piezoelectric layer 140, wherein the thickness of the first upper electrode 121 corresponds to the minimum value of the resonant frequency in the first bulk acoustic wave filter and the second bulk acoustic wave filter; a second upper electrode 131 is formed on the first upper electrode 121, and the second upper electrode 131 is formed with a fifteenth region 1212 for exposing the first upper electrode 121, wherein the thickness of the second upper electrode 131 corresponds to the frequency difference between the first bulk acoustic wave filter and the second bulk acoustic wave filter; and the first upper electrode 121 and the second upper electrode 131 are formed with a sixteenth region 1408, a seventeenth region 1409 and an eighteenth region 1410 for exposing the piezoelectric layer 140, wherein the seventeenth region 1409 and the eighteenth region 1410 are respectively formed on both sides of the sixteenth region 1408.

[0100] Since the integrated BAW filter in the present application includes a plurality of BAW filters formed on a first substrate, the plurality of BAW filters are integrated into one chip, and wafer testing of the plurality of BAW filters can be completed at one time.

[0101] Furthermore, when manufacturing an integrated BAW filter, the present application determines the thickness of the first upper electrode and the first lower electrode based on the minimum resonant frequency among the multiple BAW filters. The thickness of the second upper electrode and the second lower electrode is then determined based on the difference in resonant frequencies between any two of the multiple BAW filters. This allows the integrated BAW filters manufactured by the present application to have different operating frequencies. Furthermore, compared to generating integrated BAW filters with different operating frequencies by etching electrodes, generating integrated BAW filters with different operating frequencies by depositing the second electrode can reduce process complexity and lower manufacturing costs.

[0102] 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.

[0103] Furthermore, when the present application utilizes the lift-off process to manufacture the plurality of second electrodes 130 , in addition to being able to realize the requirement that the plurality of BAW filters have different operating frequencies, the semiconductor lead frame structure (ie, Frame structure) can also be manufactured simultaneously, thereby saving photomasks.

[0104] 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.

[0105] 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.

[0106] 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.

[0107] 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. An integrated bulk acoustic wave filter, characterized in that: include: A second substrate (170) and a plurality of bulk acoustic wave filters, wherein the plurality of bulk acoustic wave filters are formed on the second substrate (170), and the bulk acoustic wave filters include a first electrode (120) and a plurality of second electrodes (130), the sum of the number of the first electrode (120) and the number of the plurality of second electrodes (130) corresponds to the number of the plurality of bulk acoustic wave filters, and the thickness of the first upper electrode (121) and the first lower electrode (122) in the first electrode (120) corresponds to the minimum value of the resonant frequency in the bulk acoustic wave filters, and the thickness of the second upper electrode (131) and the second lower electrode (132) in the plurality of second electrodes (130) corresponds to the difference between the resonant frequencies of any two bulk acoustic wave filters in the plurality of bulk acoustic wave filters.

2. The integrated bulk acoustic wave filter according to claim 1, wherein: 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 (160) and a piezoelectric layer (140), wherein The support layer (160) is formed on the second substrate (170); The second lower electrode (132) is formed on the supporting layer (160), the first lower electrode (122) is formed on the second lower electrode (132), and the second lower electrode (132) corresponding to the first bulk acoustic wave filter is formed with a first region (1221) for exposing the first lower electrode (122), wherein the thickness of the first lower electrode (122) corresponds to a 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 second lower electrode (132) corresponds to a frequency difference between the first bulk acoustic wave filter and the second bulk acoustic wave filter; The piezoelectric layer (140) is formed on the first lower electrode (122) and the support layer (160), and the second lower electrode (132) and the first lower electrode (122) are formed with a second region (1401) for exposing the piezoelectric layer (140), 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; 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 (160), the second lower electrode (132), the first lower electrode (122), and the piezoelectric layer (140).

3. The integrated bulk acoustic wave filter according to claim 2, wherein: The first upper electrode (121) is formed on the piezoelectric layer (140), wherein the thickness of the first upper electrode (121) corresponds to the minimum value of the resonant frequency in the first bulk acoustic wave filter and the second bulk acoustic wave filter; The second upper electrode (131) is formed on the first upper electrode (121), and the second upper electrode (131) is formed with a sixth region (1211) for exposing the first upper electrode (121), wherein the thickness of the second upper electrode (131) corresponds to the frequency difference between the first bulk acoustic wave filter and the second bulk acoustic wave filter; and The first upper electrode (121) and the second upper electrode (131) are formed with a seventh region (1403), an eighth region (1404) and a ninth region (1405) for exposing the piezoelectric layer (140), wherein the eighth region (1404) and the ninth region (1405) are respectively formed on both sides of the seventh region (1403).

4. The integrated bulk acoustic wave filter according to claim 3, wherein: The first bulk acoustic wave filter and the second bulk acoustic wave filter include: a support layer (160) and a piezoelectric layer (140), wherein The support layer (160) is formed on the second substrate (170); The second lower electrode (132) is formed on the supporting layer (160), the first lower electrode (122) is formed on the second lower electrode (132), and the second lower electrode (132) corresponding to the first bulk acoustic wave filter is formed with a tenth region (1224) for exposing the first lower electrode (122), wherein the thickness of the first lower electrode (122) 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 second lower electrode (132) corresponds to the frequency difference between the first bulk acoustic wave filter and the second bulk acoustic wave filter; The piezoelectric layer (140) is formed on the first lower electrode (122) and the support layer (160), and the second lower electrode (132) and the first lower electrode (122) are formed with an eleventh region (1406) for exposing the piezoelectric layer (140), 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 (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 (160), the second lower electrode (132), the first lower electrode (122), and the piezoelectric layer (140).

5. The integrated bulk acoustic wave filter according to claim 4, wherein: The first upper electrode (121) is formed on the piezoelectric layer (140), wherein the thickness of the first upper electrode (121) corresponds to the minimum value of the resonant frequency in the first bulk acoustic wave filter and the second bulk acoustic wave filter; The second upper electrode (131) is formed on the first upper electrode (121), and the second upper electrode (131) is formed with a fifteenth region (1212) for exposing the first upper electrode (121), wherein the thickness of the second upper electrode (131) corresponds to the frequency difference between the first bulk acoustic wave filter and the second bulk acoustic wave filter; and The first upper electrode (121) and the second upper electrode (131) are formed with a sixteenth region (1408), a seventeenth region (1409) and an eighteenth region (1410) for exposing the piezoelectric layer (140), wherein the seventeenth region (1409) and the eighteenth region (1410) are respectively formed on both sides of the sixteenth region (1408).

6. A method for manufacturing an integrated bulk acoustic wave filter, characterized in that: include: Producing a first substrate (110); as well as A plurality of bulk acoustic wave filters are formed on the first substrate (110), wherein the bulk acoustic wave filters include a first electrode (120) and a plurality of second electrodes (130), the sum of the number of the first electrode (120) and the number of the second electrodes (130) corresponds to the number of the plurality of bulk acoustic wave filters, and the thickness of the first upper electrode (121) and the first lower electrode (122) in the first electrode (120) corresponds to the minimum value of the resonant frequency in the plurality of bulk acoustic wave filters, and the thickness of the second upper electrode (131) and the second lower electrode (132) in the plurality of second electrodes (130) corresponds to the difference between the resonant frequencies of any two bulk acoustic wave filters in the plurality of bulk acoustic wave filters.

7. The production method according to claim 6, 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).

8. The production method according to claim 7, 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 the first upper electrode (121) on the first substrate (110), wherein the thickness of the first upper electrode (121) corresponds to the minimum value of the resonant frequency in the first bulk acoustic wave filter and the second bulk acoustic wave filter; depositing a piezoelectric layer (140) on the first upper electrode (121), wherein 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; depositing the first lower electrode (122) on the piezoelectric layer (140), wherein the thickness of the first lower electrode (122) corresponds to a minimum value of the resonant frequency in the first bulk acoustic wave filter and the second bulk acoustic wave filter; and The second lower electrode (132) is deposited on the first lower electrode (122) by a lift-off process, and a first region (1221) for exposing the first lower electrode (122) is formed, wherein the thickness of the second lower electrode (132) corresponds to the frequency difference between 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 a first bulk acoustic wave filter and a second bulk acoustic wave filter on the first substrate (110) further includes: Etching the second lower electrode (132) and the first lower electrode (122) to form a second region (1401) for exposing the piezoelectric layer (140); Depositing a layer to be etched (150) on the second lower electrode (132) and the first lower electrode (122); Etching the layer to be etched (150) to form a third region (1222) and a fourth region (1223) for exposing the second lower electrode (132), and a fifth region (1402) for exposing the piezoelectric layer (140), wherein the third region (1222) and the fourth region (1223) are respectively located on both sides of the fifth region (1402); depositing a support layer (160) on the second lower electrode (132), the piezoelectric layer (140), and the layer to be etched (150); Etching the to-be-etched layer (150) 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 (170) is deposited on the support layer (160), 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 a first bulk acoustic wave filter and a second bulk acoustic wave filter on the first substrate (110) comprises: The second upper electrode (131) is deposited on the first upper electrode (121) by a lift-off process, and a sixth region (1211) is formed for exposing the first upper electrode (121), wherein the thickness of the second upper electrode (131) corresponds to the frequency difference between the first bulk acoustic wave filter and the second bulk acoustic wave filter.

11. The manufacturing method according to claim 10, 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: The second upper electrode (131) and the first upper electrode (121) are etched to form a seventh region (1403), an eighth region (1404), and a ninth region (1405) for exposing the piezoelectric layer (140), wherein the eighth region (1404) and the ninth region (1405) are respectively formed on both sides of the seventh region (1403).

12. The manufacturing method according to claim 7, 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 the first upper electrode (121) on the first substrate (110), wherein the thickness of the first upper electrode (121) corresponds to the minimum value of the resonant frequency in the first bulk acoustic wave filter and the second bulk acoustic wave filter; Depositing and etching a piezoelectric layer (140) on the first upper electrode (121), 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 (140) corresponds to the maximum value of the resonant frequency in the first bulk acoustic wave filter and the second bulk acoustic wave filter; depositing the first lower electrode (122) on the piezoelectric layer (140), wherein the thickness of the first lower electrode (122) corresponds to a minimum value of the resonant frequency in the first bulk acoustic wave filter and the second bulk acoustic wave filter; and A second lower electrode (132) is deposited on the first lower electrode (122) using a lift-off process, and a tenth region (1224) is formed for exposing the first lower electrode (122), wherein the thickness of the second lower electrode (132) corresponds to the frequency difference between the first bulk acoustic wave filter and the second bulk acoustic wave filter.

13. The manufacturing method according to claim 12, 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) further includes: Etching the second lower electrode (132) and the first lower electrode (122) to form an eleventh region (1406) for exposing the piezoelectric layer (140); Depositing a layer to be etched (150) on the second lower electrode (132) and the first lower electrode (122); Etching the layer to be etched (150) to form a twelfth region (1225) and a thirteenth region (1226) for exposing the second lower electrode (132), and a fourteenth region (1407) for exposing the piezoelectric layer (140), wherein the twelfth region (1225) and the thirteenth region (1226) are respectively located on both sides of the fourteenth region (1407); depositing a support layer (160) on the second lower electrode (132), the piezoelectric layer (140), and the layer to be etched (150); Depositing a second substrate (170) on the support layer (160), flipping the entire layer over, and removing the first substrate (110); and The layer to be etched (150) is 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.

14. The manufacturing method according to claim 13, 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: A second upper electrode (131) is deposited on the first upper electrode (121) using a lift-off process, and a fifteenth region (1212) is formed for exposing the first upper electrode (121), wherein the thickness of the second upper electrode (131) corresponds to the frequency difference between the first bulk acoustic wave filter and the second bulk acoustic wave filter.

15. The manufacturing method according to claim 14, 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: The second upper electrode (131) and the first upper electrode (121) are etched to form a sixteenth region (1408), a seventeenth region (1409) and an eighteenth region (1410) for exposing the piezoelectric layer (140), wherein the seventeenth region (1409) and the eighteenth region (1410) are respectively formed on both sides of the sixteenth region (1408).

Images