Manufacturing method of integrated bulk acoustic wave filter and integrated bulk acoustic wave filter

Abstract

The invention discloses a manufacturing method of an integrated bulk acoustic wave filter and the integrated bulk acoustic wave filter. The manufacturing method comprises the following steps: manufacturing a first substrate; a plurality of bulk acoustic wave filters are formed on a first substrate, and the specific steps are as follows: at least one mixing layer is formed on the first substrate, and the at least one mixing layer comprises a first sacrificial layer etched with a plurality of first areas and first upper electrode layers deposited in the first areas; the thickness of the first sacrificial layer corresponds to the resonant frequency difference value of the bulk acoustic wave filters, and the thickness of the first upper electrode layer is the same as that 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, in which a thickness of the second upper electrode layer corresponds to a minimum resonant frequency in the plurality of bulk acoustic wave filters, and a sum of the number of the at least one mixed layer and the number of the second upper electrode layers corresponds to the number of the plurality of bulk acoustic wave filters. The technical effect of having different working frequencies is achieved.

Description

Technical Field

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

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

[0003] The BAW filter, namely the bulk acoustic wave filter. Its principle is based on bulk acoustic wave technology. When an alternating electric field is applied across the piezoelectric material, the material generates mechanical vibrations, which propagate inside the material in the form of bulk acoustic waves. By cleverly designing the structure and size of the bulk acoustic wave filter, bulk acoustic waves of a specific frequency can be made to propagate smoothly in the filter while suppressing acoustic waves of other frequencies, thereby achieving the filtering function.

[0004] The D-BAW filter, namely the double-sided patterned process bulk acoustic wave filter. The structure of this bulk acoustic wave filter is fabricated by two bonding processes using a double-sided process. That is, during the manufacturing process, several steps of preparation processes are first implemented on the front side of the wafer, and then the wafer is flipped over through bonding to implement subsequent preparation processes. During packaging, the wafer is flipped again through bonding, and several steps of preparation processes are implemented on the back side, thereby realizing the double-sided process in this way.

[0005] Currently, in order to ensure the reliability of the chip in terms of design, process, and function, and to avoid catastrophic failures during mass production, it is usually necessary to perform wafer-level testing on the chip. The existing methods for wafer-level testing of chips usually involve first manufacturing multiple bulk acoustic wave filters, then separately performing individual wafer-level tests on each bulk acoustic wave filter, and finally packaging together the tested bulk acoustic wave filters. However, there are certain defects in using the above method for wafer-level testing of bulk acoustic wave filters. For example, since individual wafer-level tests are performed on each bulk acoustic wave filter, the development cycle is relatively long. Another example is that when multiple bulk acoustic wave filters are used in combination, it is easy to cause waste of resources.

[0006] To solve the problems mentioned above, the prior art has proposed integrating multiple bulk acoustic wave filters into one chip to generate an integrated bulk acoustic wave filter, thereby completing wafer-level testing on the integrated bulk acoustic wave filter at one time. Although the above method can save manufacturing and testing costs, the individual bulk acoustic wave filters manufactured cannot meet the requirement of having different operating frequencies, which may lead to problems such as poor frequency band adaptability and waste of resources in the integrated bulk acoustic wave filter.

[0007] Publication number: CN119995555A, Title: Bulk acoustic wave filter, preparation method thereof, and radio frequency module. The bulk acoustic wave filter at least includes: a substrate; a first film layer located on one side of the substrate, the first film layer including a first region and a second region surrounding the first region, and a photosensitive dry film disposed around the first region is provided in the second region; a piezoelectric thin film located on the side of the first film layer away from the substrate; wherein the piezoelectric thin film includes a lithium niobate thin film and / or a lithium tantalate thin film; a cavity is jointly formed by the substrate, the photosensitive dry film, and the piezoelectric thin film.

[0008] Publication number: CN222776195U, Title: A bulk acoustic wave filter. It includes a substrate and a plurality of resonators cascaded on the substrate. The plurality of resonators include at least one front-end resonator and one end resonator. The front-end resonator includes a lower electrode, a piezoelectric layer, and an upper electrode sequentially disposed on the substrate. The outer periphery of the upper electrode extends in a direction away from the upper electrode along the hierarchical direction to form a raised portion. An air gap is formed between the raised portion and the piezoelectric layer, and a capacitance compensation structure is formed between the raised portion and the upper electrode or between the raised portion and the lower electrode.

[0009] In view of the above technical problem that the existing integrated bulk acoustic wave filter in the prior art cannot meet the requirement of having different operating frequencies, which may lead to poor frequency band adaptability and resource waste of the integrated bulk acoustic wave filter, no effective solution has been proposed yet. Summary of the Invention

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

[0011] According to one aspect of the present application, a manufacturing method of an integrated bulk acoustic wave filter is provided, including: manufacturing a first substrate; forming a plurality of bulk acoustic wave filters on the first substrate. The specific steps include: forming at least one hybrid layer on the first substrate, where at least one hybrid layer includes a first sacrificial layer etched with a plurality of first regions and a first upper electrode layer deposited in each first region, and the thickness of the first sacrificial layer corresponds to the resonant frequency difference 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 at least one hybrid layer and forming a plurality of bulk acoustic wave filters, where the thickness of the second upper electrode layer corresponds to the minimum value of the resonant frequencies in the plurality of bulk acoustic wave filters, and the sum of the number of at least one hybrid 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 a first bulk acoustic wave filter and a 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 planarizing 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 hybrid layer, wherein the thickness of the second upper electrode layer corresponds to the minimum value of the resonance frequencies 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 resonance frequencies 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 the first bulk acoustic wave filter and the 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 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 resonance frequencies 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 further 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 of the fifth regions is located on both sides of the sixth region; depositing a support 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; and depositing a second substrate on the support layer, turning the whole over, 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 operations of forming the first bulk acoustic wave filter and the second bulk acoustic wave filter on the first substrate include: 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 planarizing 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 hybrid layer, wherein the thickness of the second upper electrode layer corresponds to the minimum value of the resonance frequencies 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 the first bulk acoustic wave filter and the 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 resonance frequencies in the first bulk acoustic wave filter and the second bulk acoustic wave filter.

[0018] Optionally, the operations of depositing a piezoelectric layer on the first upper electrode layer and forming the first bulk acoustic wave filter and the second bulk acoustic wave filter include: 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 resonance frequencies in the first bulk acoustic wave filter and the second bulk acoustic wave filter.

[0019] Optionally, the operations of forming the first bulk acoustic wave filter and the second bulk acoustic wave filter further include: 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 a plurality of eleventh regions for exposing the piezoelectric layer, wherein each tenth region is located on both sides of the eleventh region; depositing a support 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 resonance cavity corresponding to the first bulk acoustic wave filter and a second resonance cavity corresponding to the second bulk acoustic wave filter; and depositing a second substrate on the support layer, flipping the whole, and removing the first substrate.

[0020] Optionally, the operations of forming the first bulk acoustic wave filter and the second bulk acoustic wave filter further include: 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, including: a second substrate and a plurality of bulk acoustic wave filters, wherein the bulk acoustic wave filter includes a second upper electrode layer formed on the second substrate, wherein the thickness of the second upper electrode layer corresponds to the minimum resonance 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 resonance frequency difference among 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 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, 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 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, the thickness of the second lower electrode layer corresponds to the minimum resonance frequency among 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 support layer, and the thickness of the piezoelectric layer corresponds to the maximum resonance frequency among the first bulk acoustic wave filter and the second bulk acoustic wave filter; and a first resonance cavity corresponding to the first bulk acoustic wave filter and a second resonance cavity corresponding to the second bulk acoustic wave 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 are formed with 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 resonance frequency among 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 resonance frequency difference 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 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 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 value of the resonance frequencies 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 support 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 value of the resonance frequencies in the first bulk acoustic wave filter and the second bulk acoustic wave filter; and a first resonance cavity corresponding to the first bulk acoustic wave filter and a second resonance cavity corresponding to the second bulk acoustic wave filter are formed between the support 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 are formed with 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 resonance frequencies 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 the resonance frequencies between the first bulk acoustic wave filter and the second bulk acoustic wave filter.

[0026] The present application provides a method for manufacturing an integrated bulk acoustic wave filter and an integrated bulk acoustic wave filter. And since the integrated bulk acoustic wave filter in the present application includes a plurality of bulk acoustic wave filters formed on the first substrate, multiple bulk acoustic wave filters can be integrated on one chip, and the wafer-level testing of multiple bulk acoustic wave filters can be completed at one time.

[0027] Furthermore, when manufacturing the integrated bulk acoustic wave filter in the present application, first, at least one hybrid layer is formed on the first substrate, wherein at least one hybrid layer includes a first sacrificial layer etched with a plurality of first regions and a first upper electrode layer deposited in each first region. Thus, when the thickness of the first sacrificial layer corresponds to the difference in the resonance frequencies of the plurality of 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, then it can be ensured that the thickness of the first upper electrode layer corresponds to the difference in the resonance frequencies of the plurality of bulk acoustic wave filters. Then, a second upper electrode layer is deposited on at least one hybrid layer, and a plurality of bulk acoustic wave filters are formed. The thickness of the second upper electrode layer corresponds to the minimum value of the resonance frequencies in the plurality of bulk acoustic wave filters. Thus, the integrated bulk acoustic wave filter manufactured in the present application can meet the requirement of having different operating frequencies.

[0028] In addition, since the etching process for adjacent two hierarchical structures made of different materials is more mature and easier to control compared to that for adjacent two hierarchical structures made of the same material, compared with the method of generating an integrated bulk acoustic wave filter with different operating frequencies by etching an electrode, the operation disclosed in this application of first depositing a first sacrificial layer on a first substrate, then etching the first sacrificial layer deposited on the first substrate, and forming a plurality of first regions for depositing a first upper electrode layer can achieve the technical effect of precisely fabricating the first upper electrode layer on the first substrate.

[0029] In addition, when fabricating the first upper electrode layer by using the first sacrificial layer including a plurality of first regions in this application, a semiconductor lead frame structure (i.e., Frame structure) can be fabricated simultaneously, thus saving photomasks.

[0030] Furthermore, it solves the technical problem in the prior art that the existing integrated bulk acoustic wave filter cannot meet the requirement of having different operating frequencies, which may lead to poor frequency band adaptability and resource waste of the integrated bulk acoustic wave filter.

[0031] According to the following detailed description of specific embodiments of this application in conjunction with the accompanying drawings, those skilled in the art will become more clear about the above and other objects, advantages and features of this application. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Some specific embodiments of this application will be described in detail hereinafter with reference to the accompanying drawings in an exemplary but not restrictive manner. The same reference numerals in the drawings denote the same or similar components or parts. Those skilled in the art should understand that these drawings are not necessarily drawn to scale. In the drawings: Figure 1 is a flowchart of a method for fabricating an integrated bulk acoustic wave filter according to Embodiment 1 of this application; Figure 2 is a schematic diagram of a first substrate, a plurality of hybrid layers, and a second upper electrode layer according to Embodiment 1 of this application; Figure 3 is a schematic diagram of a first substrate and a first sacrificial layer according to Embodiment 1 of this application; Figure 4 is a schematic diagram of a first substrate, a first sacrificial layer, and a first upper electrode layer according to Embodiment 1 of this application; Figure 5 is a schematic diagram of a first substrate, a first sacrificial layer, a first upper electrode layer, a second upper electrode layer, and a piezoelectric layer according to Embodiment 1 of this application; Figure 6Schematic 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 Embodiment 1 of the present application; 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; 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; Figure 9 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 Embodiment 1 of the present application; Figure 10 Schematic diagram of an integrated bulk acoustic wave filter according to Embodiment 1 of the present application; Figure 11 Schematic diagram of depositing and etching 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 Embodiment 2 of the present application; Figure 12 Schematic diagram of the eighth region according to Embodiment 2 of the present application; Figure 13 Schematic diagram of the ninth region according to Embodiment 2 of the present application; Figure 14 Schematic diagram of the tenth region and the eleventh region according to Embodiment 2 of the present application; Figure 15 Schematic diagram of the first resonant cavity and the second resonant cavity according to Embodiment 2 of the present application; Figure 16 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 Embodiment 2 of the present application; Figure 17 Schematic diagram of another integrated bulk acoustic wave filter according to Embodiment 2 of the present application. Detailed implementation manners

[0033] It should be noted that, without conflict, the embodiments in the present disclosure and the features in the embodiments may be combined with each other. The present disclosure will be described in detail below with reference to the drawings and in combination with the embodiments.

[0034] To enable those skilled in the art to better understand the present disclosure solution, the following will clearly and completely describe the technical solutions in the embodiments of the present disclosure in conjunction with the accompanying drawings in the embodiments of the present disclosure. Obviously, the described embodiments are only a part of the embodiments of the present disclosure, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present disclosure without creative efforts shall fall within the scope of protection of the present disclosure.

[0035] It should be noted that the terms "first", "second", etc. in the specification and claims of the present disclosure and the above-mentioned drawings are used to distinguish similar objects and do not necessarily need to describe a specific order or sequence. It should be understood that such terms can be interchanged under appropriate circumstances for the embodiments of the present disclosure described herein. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0036] 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 "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0037] Secondly, the present application will be described in detail in conjunction with the schematic diagrams. When detailing the embodiments of the present application, for the convenience of explanation, the cross-sectional views showing the device structure will be enlarged locally not in accordance with the general scale, and the schematic diagrams are only examples and should not limit the scope of protection of the present application herein. In addition, in actual production, three-dimensional spatial dimensions of length, width, and depth should be included.

[0038] According to the first aspect of this embodiment, a method for manufacturing an integrated bulk acoustic wave filter is provided. Figure 1 The flow schematic diagram of the method is shown. Refer to Figure 1 As shown, the method includes: S101: Fabricate a first substrate; S102: Form a plurality of bulk acoustic wave filters on the first substrate. The specific steps include: Form at least one hybrid layer on a first substrate, where the at least one hybrid layer includes 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 where the thickness of the first sacrificial layer corresponds to the resonant frequency difference of a 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 S103: Deposit a second upper electrode layer on the at least one hybrid layer and form a plurality of bulk acoustic wave filters, where the thickness of the second upper electrode layer corresponds to the minimum resonant frequency among the plurality of bulk acoustic wave filters, and the sum of the number of the at least one hybrid layer and the second upper electrode layer corresponds to the number of the plurality of bulk acoustic wave filters.

[0039] Using the method for manufacturing an integrated bulk acoustic wave filter provided by the embodiments of the present disclosure, a first substrate is manufactured, and at least one hybrid layer is formed on the first substrate. Among them, the at least one hybrid layer includes 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 where the thickness of the first sacrificial layer corresponds to the resonant frequency difference of a 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. Then, a second upper electrode layer is deposited on the at least one hybrid layer and a plurality of bulk acoustic wave filters are formed. Among them, the thickness of the second upper electrode layer corresponds to the minimum resonant frequency among the plurality of bulk acoustic wave filters, and the sum of the number of the at least one hybrid layer and the second upper electrode layer corresponds to the number of the plurality of bulk acoustic wave filters.

[0040] Specifically, referring to Figure 2 As shown, first, manufacture the first substrate 110 to be removed. Then, form at least one hybrid layer 120 on the first substrate 110 (as Figure 2 shows 2 hybrid layers). For example, in the case where the integrated bulk acoustic wave filter that the operator needs to manufacture includes 3 bulk acoustic wave filters, 2 hybrid layers are formed on the first substrate 110. In one solution, the thickness of the first upper electrode layer 122 in the first hybrid layer corresponds to the resonant frequency difference between the bulk acoustic wave filter 1 and the bulk acoustic wave filter 2, and the thickness of the first upper electrode layer 122 in the second hybrid layer corresponds to the resonant frequency difference between the bulk acoustic wave filter 1 and the bulk acoustic wave filter 3. In another solution, the thickness of the first upper electrode layer 122 in the first hybrid layer corresponds to the resonant frequency difference between the bulk acoustic wave filter 1 and the bulk acoustic wave filter 2, and the thickness of the first upper electrode layer 122 in the second hybrid layer corresponds to the resonant frequency difference between the bulk acoustic wave filter 2 and the bulk acoustic wave filter 3. That is, the thicknesses of the first hybrid layer and the second hybrid layer correspond to the resonant frequency differences between any two of the plurality of bulk acoustic wave filters, which will not be elaborated here.

[0041] The specific steps for fabricating at least one hybrid layer include: First, deposit a first sacrificial layer 121 on a first substrate 110, and etch the first sacrificial layer 121 to generate a plurality of first regions 1211. Herein, the thickness of the first sacrificial layer 121 corresponds to the resonance frequency difference of a plurality of bulk acoustic wave filters. After that, an operator deposits a first upper electrode layer 122 on the first sacrificial layer 121 and the first substrate 110, and planarizes the first upper electrode layer 122, so that the thickness of the first upper electrode layer 122 in each of the first regions 1211 is the same as the thickness of the first sacrificial layer 121. Thus, the operator can fabricate other hybrid layers using the same method steps as above, which will not be elaborated herein.

[0042] After that, deposit a second upper electrode layer 130 on at least one hybrid layer 120 and form a plurality of bulk acoustic wave filters. Herein, the thickness of the second upper electrode layer 130 corresponds to the minimum resonance frequency among the plurality of bulk acoustic wave filters.

[0043] Thus, different from the prior art, since the integrated bulk acoustic wave filter in this application includes a plurality of bulk acoustic wave filters formed on a first substrate, multiple bulk acoustic wave filters can be integrated into one chip, and the wafer-level testing of multiple bulk acoustic wave filters can be completed at one time.

[0044] Furthermore, when fabricating the integrated bulk acoustic wave filter in this application, first form at least one hybrid layer on the first substrate. Herein, at least one hybrid layer includes a first sacrificial layer etched with a plurality of first regions and a first upper electrode layer deposited in each of the first regions. Thus, when the thickness of the first sacrificial layer corresponds to the resonance frequency difference of a plurality of bulk acoustic wave filters, set the thickness of the first upper electrode layer to be the same as the thickness of the first sacrificial layer, then it can be ensured that the thickness of the first upper electrode layer corresponds to the resonance frequency difference of a plurality of bulk acoustic wave filters. After that, deposit a second upper electrode layer on at least one hybrid layer and form a plurality of bulk acoustic wave filters. Herein, the thickness of the second upper electrode layer corresponds to the minimum resonance frequency among the plurality of bulk acoustic wave filters. Thus, the integrated bulk acoustic wave filter fabricated in this application can meet the requirement of having different operating frequencies.

[0045] In addition, since the etching process for two adjacent hierarchical structures made of the same material is more mature and easier to control than that for two adjacent hierarchical structures made of different materials, compared with generating an integrated bulk acoustic wave filter with different operating frequencies by etching the electrodes, the operation of first depositing the first sacrificial layer on the first substrate, then etching the first sacrificial layer deposited on the first substrate, and forming a plurality of first regions for depositing the first upper electrode layer disclosed in this application can achieve the technical effect of precisely fabricating the first upper electrode layer on the first substrate.

[0046] In addition, when fabricating the first upper electrode layer by using a first sacrificial layer including a plurality of first regions in the present application, a semiconductor lead frame structure (i.e., Frame structure) can be fabricated simultaneously, thereby saving photomasks.

[0047] Furthermore, it solves the technical problem in the prior art that the existing integrated bulk acoustic wave filter cannot meet the requirement of having different operating frequencies, which may lead to poor frequency band adaptability and resource waste of the integrated bulk acoustic wave filter.

[0048] Embodiment 1 The following are the specific fabrication steps of an integrated bulk acoustic wave filter (including a first bulk acoustic wave filter and a second bulk acoustic wave filter) provided by an embodiment of the present application: Refer to Figure 3 As shown, first, a first substrate 110 to be removed is fabricated. 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. Among them, the thickness of the first sacrificial layer 121 corresponds to the resonance frequency difference between the first bulk acoustic wave filter and the second bulk acoustic wave filter. Preferably, the fabrication material of the first sacrificial layer 121 can be undoped silicate glass, phosphate glass, or a thermal oxide layer, etc., with a uniformity of less than 1%.

[0049] In addition, since the etching process for adjacent two hierarchical structures made of different materials is more mature and easier to control than that for adjacent two hierarchical structures made of the same material, compared with fabricating an integrated bulk acoustic wave filter with different operating frequencies by etching the electrodes, the operation 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 disclosed in the present application can greatly reduce the fabrication process difficulty.

[0050] Refer to Figure 4 As shown, then, a first upper electrode layer 122 is deposited on the first substrate 110 and the first sacrificial layer 121. Since the heights of the first upper electrode layer 122 deposited in each of the second regions 1212 and the first upper electrode layer 122 deposited on the first sacrificial layer 121 are inconsistent, the protruding first upper electrode layer 122 is ground flat, and the first upper electrode layer 122 deposited in each of the second regions 1212 is made to have the same thickness as the first sacrificial layer 121, so that the thickness of the first upper electrode layer 122 corresponds to the resonance frequency difference between the first bulk acoustic wave filter and the second bulk acoustic wave filter. Preferably, the thickness of the unground first upper electrode layer 122 is 1.1 to 3 times the thickness of the first sacrificial layer 121, and the fabrication material of the first upper electrode layer 122 can be, for example, molybdenum or tungsten, with a uniformity of less than 1%.

[0051] Reference 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. Among them, the thickness of the second upper electrode layer 130 corresponds to the minimum value of the resonance frequencies in the first bulk acoustic wave filter and the second bulk acoustic wave filter. Preferably, the material for fabricating 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%. Then, a piezoelectric layer 140 is deposited on the second upper electrode layer 130. Among them, the thickness of the piezoelectric layer 140 corresponds to the maximum value of the resonance frequencies in the first bulk acoustic wave filter and the second bulk acoustic wave filter. Preferably, the material for fabricating the piezoelectric layer 140 can be, for example, aluminum nitride or scandium-doped aluminum nitride, and the uniformity is less than 1%.

[0052] Thus, in the case where the thickness of the first upper electrode layer 122 is determined to correspond to the difference in resonance 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 value of the resonance frequencies 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.

[0053] In addition, compared with the existing method of generating an integrated bulk acoustic wave filter 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 resonance frequencies between the first bulk acoustic wave filter and the second bulk acoustic wave filter can achieve the technical effect of precise control.

[0054] Reference Figure 6 As shown, then, a first lower electrode layer 150 is deposited and etched on the piezoelectric layer 140, and a plurality of third regions 151 for exposing the piezoelectric layer 140 are formed. Among them, the thickness of the first lower electrode layer 150 corresponds to the difference in resonance frequencies between the first bulk acoustic wave filter and the second bulk acoustic wave filter. Preferably, the material for fabricating the first lower electrode layer 150 can be, for example, molybdenum or tungsten, the uniformity is less than 1%, and the etching uniformity is less than 5%.

[0055] Reference Figure 7 As shown, further, a second lower electrode layer 160 is deposited and etched on the first lower electrode layer 150, and a fourth region 161 for exposing the piezoelectric layer 140 is formed. And the thickness of the second lower electrode layer 160 corresponds to the minimum value of the resonance frequencies in the first bulk acoustic wave filter and the second bulk acoustic wave filter. Preferably, the material for fabricating the first lower electrode layer 150 can be, for example, molybdenum or tungsten, the uniformity is less than 1%, and the etching uniformity is less than 5%.

[0056] ReferenceFigures 8 - 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, and 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 are formed. Among them, each of the fifth regions 171 is located on both sides of the sixth region 172. After that, 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, 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, and the first substrate 110 is removed.

[0057] Reference Figure 10 As shown, finally, the second upper electrode layer 130 is etched, and a seventh region 131 for exposing the piezoelectric layer 140 is formed. Among them, the seventh region 131 corresponds to the fourth region 161. Preferably, the etching uniformity of the second upper electrode layer 130 is less than 5%.

[0058] Embodiment 2 In addition, in order to further increase the working frequency range of the integrated bulk acoustic wave filter and ensure that the integrated bulk acoustic wave filter can meet the requirement of having different working frequencies, the present application also provides another integrated bulk acoustic wave filter. The specific manufacturing steps include: Reference Figures 3 - 5 As shown, first, a first substrate 110 to be removed is fabricated. 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. Among them, the thickness of the first sacrificial layer 121 corresponds to the difference in resonant frequencies between the first bulk acoustic wave filter and the second bulk acoustic wave filter.

[0059] Then, a first upper electrode layer 122 is deposited on the first substrate 110 and the first sacrificial layer 121. Since the heights of the first upper electrode layer 122 deposited in each of the first regions 1211 and the first upper electrode layer 122 deposited on the first sacrificial layer 121 are inconsistent, the protruding first upper electrode layer 122 is ground flat, and the first upper electrode layer 122 deposited in each of the second regions 1212 is made to have the same thickness as the first sacrificial layer 121, so that the thickness of the first upper electrode layer 122 corresponds to the difference in resonant frequencies between the first bulk acoustic wave filter and the second bulk acoustic wave filter.

[0060] Further, a second upper electrode layer 130 is deposited on the first sacrificial layer 121 and the first upper electrode layer 122. Among them, the thickness of the second upper electrode layer 130 corresponds to the minimum value of the resonance frequencies in the first bulk acoustic wave filter and the second bulk acoustic wave filter.

[0061] Reference Figure 11 As shown, after that, a piezoelectric layer 140 is deposited and etched on the second upper electrode layer 130. Among them, 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 in this embodiment, the maximum thickness of the piezoelectric layer 140 corresponds to the maximum value of the resonance frequencies in the first bulk acoustic wave filter and the second bulk acoustic wave filter.

[0062] That is to say, when the requirement of the frequency range of the integrated bulk acoustic wave filter cannot be met only by 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 resonance frequencies.

[0063] Reference Figure 12 As shown, after that, a first lower electrode layer 150 is deposited and etched on the piezoelectric layer 140, and a plurality of eighth regions 152 for exposing the piezoelectric layer 140 are formed. Among them, the thickness of the first lower electrode layer 150 corresponds to the resonance frequency difference between the first bulk acoustic wave filter and the second bulk acoustic wave filter.

[0064] Reference Figure 13 As shown, further, a second lower electrode layer 160 is deposited and etched on the first lower electrode layer 150, and a ninth region 162 for exposing the piezoelectric layer 140 is formed. And the thickness of the second lower electrode layer 160 corresponds to the minimum value of the resonance frequencies in the first bulk acoustic wave filter and the second bulk acoustic wave filter.

[0065] Reference Figures 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. After that, 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, and a first resonance cavity corresponding to the first bulk acoustic wave filter and a second resonance 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, and the first substrate 110 is removed, thereby generating a structure as Figure 16 shown.

[0066] Reference 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. Among them, the twelfth region 132 corresponds to the ninth region 162.

[0067] According to another aspect of the present application, an integrated bulk acoustic wave filter is further provided, including: a second substrate 190 and a plurality of bulk acoustic wave filters. The bulk acoustic wave filter includes a second upper electrode layer 130 formed on the second substrate 190, where the thickness of the second upper electrode layer 130 corresponds to the minimum resonance 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, where the first upper electrode layer 122 is formed with a plurality of thirteenth regions 1221 for exposing the second upper electrode layer 130. Among them, 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 resonance frequency difference among 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.

[0068] Optionally, 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. 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. Among them, 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, the thickness of the second lower electrode layer 160 corresponds to the minimum resonance frequency among 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 resonance frequency among the first bulk acoustic wave filter and the second bulk acoustic wave filter; and a first resonance cavity corresponding to the first bulk acoustic wave filter and a second resonance 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.

[0069] Optionally, a second upper electrode layer 130 is deposited on the piezoelectric layer 140; a 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, where 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 resonance frequencies 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 the resonance frequencies of the first bulk acoustic wave filter and the second bulk acoustic wave filter.

[0070] 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, where 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 form a ninth region 162 for exposing the piezoelectric layer 140, where 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 resonance frequencies 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, where the maximum thickness of the piezoelectric layer 140 corresponds to the maximum value of the resonance frequencies in the first bulk acoustic wave filter and the second bulk acoustic wave filter; and a first resonance cavity corresponding to the first bulk acoustic wave filter and a second resonance 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.

[0071] Optionally, a second upper electrode layer 130 is deposited on the piezoelectric layer 140; a 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, where 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 resonance frequencies 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 the resonance frequencies of the first bulk acoustic wave filter and the second bulk acoustic wave filter.

[0072] Unless otherwise specifically stated, the relative arrangements, numerical expressions, and numerical values of the components and steps 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 dimensions of the various parts shown in the drawings are not drawn in actual proportional relationships. Technologies, methods, and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, such technologies, methods, and devices should be regarded as part of the authorization specification. In all the examples shown and discussed here, any specific values should be construed as merely exemplary and not as a limitation. Thus, other examples of the exemplary embodiments may have different values. It should be noted that like reference numerals and letters denote like items in the following drawings, and thus, once an item is defined in one drawing, it need not be further discussed in subsequent drawings.

[0073] For ease of description, spatial relative terms such as "above", "over", "on the upper surface", "upper", etc. may be used herein to describe the spatial positional relationship of one device or feature to other devices or features as shown in the figures. It should be understood that the spatial relative terms are intended to encompass different orientations in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is inverted, a device described as "above" or "over" other devices or structures will then be positioned "below" or "beneath" the other devices or structures. Thus, the exemplary term "above" can include both the orientations of "above" and "below". The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the corresponding interpretations of the spatial relative descriptions used herein will be made.

[0074] In the description of the present disclosure, it should be understood that the orientation or positional relationships indicated by orientation terms such as "front, rear, upper, lower, left, right", "lateral, vertical, perpendicular, horizontal", and "top, bottom" are generally based on the orientation or positional relationships shown in the drawings, and are only for ease of describing the present disclosure and simplifying the description. Without contrary description, these orientation terms do not indicate and imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and thus should not be construed as limiting the protection scope of the present disclosure; the orientation terms "inside, outside" refer to the inside and outside relative to the contour of each component itself.

[0075] As described above, the above are only the preferred specific embodiments of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the technical field of the present application within the technical scope disclosed by the present application should be covered by the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A manufacturing method of an integrated bulk acoustic wave filter, characterized in that Including: Fabricating a first substrate (110); Forming a plurality of bulk acoustic wave filters on the first substrate (110), the specific steps including: Forming at least one hybrid layer (120) on the first substrate (110), wherein the hybrid layer (120) includes 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), and wherein the thickness of the first sacrificial layer (121) corresponds to the resonant frequency difference 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); And Depositing a second upper electrode layer (130) on the at least one hybrid layer (120) and forming the plurality of bulk acoustic wave filters, wherein the thickness of the second upper electrode layer (130) corresponds to the minimum resonant frequency among the plurality of bulk acoustic wave filters, and the sum of the number of the at least one hybrid layer (120) and the second upper electrode layer (130) corresponds to the number of the plurality of bulk acoustic wave filters.

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

3. The manufacturing 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) includes: Depositing and etching the first sacrificial layer (121) on the first substrate (110) and forming a plurality of second regions (1212) for exposing the first substrate (110), wherein the thickness of the first sacrificial layer (121) corresponds to the resonant frequency difference between the first bulk acoustic wave filter and the second bulk acoustic wave filter; Depositing and planarizing the first upper electrode layer (122) on the first substrate (110) and the first sacrificial layer (121), and making the thickness of the first upper electrode layer (122) in the plurality of second regions (1212) 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 resonant frequency between the first bulk acoustic wave filter and the second bulk acoustic wave filter; and 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, wherein the thickness of the piezoelectric layer (140) corresponds to the maximum resonant frequency between the first bulk acoustic wave filter and the second bulk acoustic wave filter.

4. The manufacturing 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 includes: Deposit and etch a first lower electrode layer (150) on the piezoelectric layer (140), and 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 resonance frequencies between the first bulk acoustic wave filter and the second bulk acoustic wave filter; and Deposit and etch a second lower electrode layer (160) on the first lower electrode layer (150), and form a fourth region (161) for exposing the piezoelectric layer (140), wherein the thickness of the second lower electrode layer (160) corresponds to the minimum resonance frequency among the first bulk acoustic wave filter and the second bulk acoustic wave filter.

5. The manufacturing method according to claim 4, wherein The operations of forming the first bulk acoustic wave filter and the second bulk acoustic wave filter further include: Deposit a second sacrificial layer (170) on the second lower electrode layer (160) and the piezoelectric layer (140); Etch the second sacrificial layer (170), and 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 of the fifth regions (171) is located on both sides of the sixth region (172); Deposit a support layer (180) on the second lower electrode layer (160), the piezoelectric layer (140), and the second sacrificial layer (170); Corrode the first sacrificial layer (121) and the second sacrificial layer (170), and form a first resonance cavity corresponding to the first bulk acoustic wave filter and a second resonance cavity corresponding to the second bulk acoustic wave filter; and Deposit a second substrate (190) on the support layer (180), flip the whole, and remove the first substrate (110).

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

7. The manufacturing method according to claim 2, characterized in that, The operations of forming a first bulk acoustic wave filter and a second bulk acoustic wave filter on the first substrate (110) include: Deposit and etch the first sacrificial layer (121) on the first substrate (110), and 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 resonance frequencies between the first bulk acoustic wave filter and the second bulk acoustic wave filter; Deposit and planarize the first upper electrode layer (122) on the first substrate (110) and the first sacrificial layer (121), and make the thickness of the first upper electrode layer (122) in the plurality of second regions (1212) correspond to the thickness of the first sacrificial layer (121); Deposit 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 resonance frequency in the first bulk acoustic wave filter and the second bulk acoustic wave filter; and Deposit and etch the piezoelectric layer (140) on the second upper electrode layer (130), and form the first bulk acoustic wave filter and the second bulk acoustic wave filter, 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 resonance frequency in the first bulk acoustic wave filter and the second bulk acoustic wave filter.

8. The manufacturing 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 includes:[[]] Deposit and etch the first lower electrode layer (150) on the piezoelectric layer (140), and 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 resonance frequency difference between the first bulk acoustic wave filter and the second bulk acoustic wave filter; Deposit and etch the second lower electrode layer (160) on the first lower electrode layer (150), and form a ninth region (162) for exposing the piezoelectric layer (140), wherein the thickness of the second lower electrode layer (160) corresponds to the minimum resonance frequency in the first bulk acoustic wave filter and the second bulk acoustic wave filter.

9. The manufacturing method according to claim 8, wherein The operation of forming the first bulk acoustic wave filter and the second bulk acoustic wave filter further includes:[[]] Deposit a second sacrificial layer (170) on the second lower electrode layer (160) and the piezoelectric layer (140); Etch the second sacrificial layer (170), and 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); Deposit a support layer (180) on the second lower electrode layer (160), the piezoelectric layer (140), and the second sacrificial layer (170); Corrode the first sacrificial layer (121) and the second sacrificial layer (170), and form a first resonance cavity corresponding to the first bulk acoustic wave filter and a second resonance cavity corresponding to the second bulk acoustic wave filter; and Deposit a second substrate (190) on the support layer (180), turn it over as a whole, and remove the first substrate (110).

10. The manufacturing method according to claim 9, wherein, The operation of forming the first bulk acoustic wave filter and the second bulk acoustic wave filter further includes:[[]] Etch the second upper electrode layer (130) and 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, Comprising: 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 the minimum resonance 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 a pre-etched first sacrificial layer (121), the thickness of the first sacrificial layer (121) corresponds to the resonance frequency difference 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 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) are formed with 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 resonance frequency among 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 resonance frequency among the first bulk acoustic wave filter and the second bulk acoustic wave filter; and A first resonance cavity corresponding to the first bulk acoustic wave filter and a second resonance 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).

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) are formed with a seventh region (131) for exposing the piezoelectric layer (140), where the seventh region (131) corresponds to the fourth region (161), and the thickness of the second upper electrode layer (130) corresponds to the minimum resonance frequency among 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 resonance frequency difference 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 include: a support layer (180), a second lower electrode layer (160), a first lower electrode layer (150), and a piezoelectric layer (140), where 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), where 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 resonance frequency among 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 resonance frequency among the first bulk acoustic wave filter and the second bulk acoustic wave filter; and a first resonance cavity corresponding to the first bulk acoustic wave filter and a second resonance 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).

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) are formed with a twelfth region (132) for exposing the piezoelectric layer (140), where 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 resonance frequencies 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 the resonance frequencies between the first bulk acoustic wave filter and the second bulk acoustic wave filter.

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