A resonant filter and a manufacturing method thereof

Abstract

Embodiments of the present invention disclose a resonant filter and a manufacturing method thereof. The manufacturing method includes: sequentially laminating and manufacturing a first electrode structure, a piezoelectric structure, and a second electrode structure. A first notch is formed in the second electrode structure. A first support block and a second support block are manufactured on the second electrode structure. The first support block is located on the second electrode, and the second support block is located between two adjacent second electrodes. A resist structure is manufactured on the side of the support block facing away from the piezoelectric structure. The material of the piezoelectric structure is different from that of the resist structure, and the material of the first electrode structure is different from that of the resist structure. The resist structure is a non-metallic material. A second notch is formed in the first electrode structure. A groove penetrating through itself is manufactured in the piezoelectric structure. The groove is located between two adjacent first electrodes. In the lamination direction of the resonant filter, the projection of the groove is located within the interval projection of two adjacent second support blocks, and the resist structure at this interval is exposed in the groove.

Description

Technical Field

[0001] The present invention relates to the technical field of filters, and particularly to a resonant filter and a manufacturing method thereof. Background Art

[0002] A resonator is a device that can generate resonance through a specific physical mechanism and is widely used in multiple fields such as wireless communication, audio equipment, household appliances, consumer electronics, and automotive electronics. Its working principle is to utilize the resonance characteristics of the structure or material at a specific frequency to efficiently concentrate or transfer energy to achieve functions such as signal amplification, filtering, and frequency selection.

[0003] The structure of a traditional resonator usually consists of an upper electrode, a piezoelectric layer, and a lower electrode. One side of the upper electrode facing away from the piezoelectric layer has a deformation space, and one side of the lower electrode facing away from the piezoelectric layer also has a deformation space. The deformation space where the lower electrode is located is usually formed by etching a sacrificial layer. However, due to the physical properties of the piezoelectric material itself and the process factors of deposition or processing during manufacturing, the piezoelectric layer often generates relatively large residual stress. Excessive residual stress may bring various negative impacts. On the one hand, it may cause cracking or peeling of the piezoelectric layer, thus affecting the reliability of the device; on the other hand, the residual stress also changes the physical properties of the piezoelectric layer, such as affecting its piezoelectric constant, thereby reducing the performance of the resonator.

[0004] To solve these problems, in the prior art, a method of etching the piezoelectric layer in the scribe line area is usually adopted to form a stress relief opening to release the residual stress. This method effectively reduces the stress level inside the piezoelectric layer, thereby improving the stability and processing reliability of the device. However, this method also has some obvious limitations. For example, when etching the side of the upper electrode, in order to prevent the etching solution from penetrating to the side of the lower electrode and corroding its structure, a metal barrier structure is usually required at the stress relief opening. And during subsequent wafer dicing, since the metal barrier structure needs to be avoided, the distance between the scribe lines on the wafer will increase accordingly, resulting in a reduction in the available area of a single wafer, thereby increasing the manufacturing cost. Summary of the Invention

[0005] Embodiments of the present invention provide a resonant filter and a manufacturing method thereof to effectively improve the wafer utilization rate when manufacturing a resonator and reduce the manufacturing cost.

[0006] To solve the above technical problems, the embodiments of the present invention disclose the following technical solutions:

[0007] On the one hand, a manufacturing method of a resonant filter is provided, including:

[0008] Sequentially stacking and manufacturing a first electrode structure, a piezoelectric structure, and a second electrode structure;

[0009] A first notch is formed in the second electrode structure, and the first notch divides the second electrode structure into a plurality of second electrodes, and a partial surface of the piezoelectric structure is exposed in the first notch;

[0010] A first support block and a second support block are formed. The first support block is located on the second electrode, and the second support block is located between two adjacent second electrodes and is connected to the piezoelectric structure; wherein, each of the second electrodes is connected to at least two first support blocks arranged at intervals, and there are at least two second support blocks arranged at intervals between two adjacent second electrodes;

[0011] An etching stop structure is formed, and the etching stop structure covers the walls of each of the first support blocks and each of the second support blocks, as well as the piezoelectric structure and the second electrode exposed at the interval between two adjacent support blocks;

[0012] A second notch is formed in the first electrode structure, and the second notch divides the first electrode structure into a plurality of first electrodes, and a partial surface of the piezoelectric structure is exposed in the second notch;

[0013] A groove is formed on a side of the piezoelectric structure facing away from the second electrode structure. The groove is located between two adjacent first electrodes and divides the piezoelectric structure into a plurality of piezoelectric bodies. In the stacking direction, the projection of the groove is located within the projection of the interval between two adjacent second support blocks, and the etching stop structure at this interval is exposed in the groove;

[0014] At least one of the first support blocks is removed for each of the second electrodes, so that at least one cavity is formed on a side of each of the second electrodes facing away from the piezoelectric structure.

[0015] In addition to one or more of the features disclosed above, or as an alternative, the plurality of first electrodes and the plurality of piezoelectric bodies correspond one by one, the plurality of piezoelectric bodies and the plurality of second electrodes correspond one by one, and in the stacking direction of the resonant filter, the projections of the corresponding first electrodes, the projections of the piezoelectric bodies, and the projections of the second electrodes overlap.

[0016] In addition to one or more of the features disclosed above, or as an alternative, the forming of the first support block and the second support block includes:

[0017] A support structure is formed on a side of the second electrode structure facing away from the piezoelectric structure, and the support structure covers the second electrode structure and the piezoelectric structure exposed in the first notch;

[0018] The support structure covering the second electrode is etched to form at least two of the first support blocks on each of the second electrodes;

[0019] The support structure covering the piezoelectric structure is etched to form at least two second support blocks between two adjacent second electrodes.

[0020] In addition to or as an alternative to one or more features disclosed above, etching the support structure covering the second electrode to form at least two first support blocks on each second electrode includes:

[0021] For each of the second electrodes, among the first supporting blocks located on the second electrode, at least one of the first supporting blocks also covers a portion of the piezoelectric structure.

[0022] In addition to or as an alternative to one or more of the features disclosed above, the invention further comprises:

[0023] A current-carrying groove is formed on each of the piezoelectric bodies, penetrating the piezoelectric body, and the second electrode corresponding to the piezoelectric body is exposed in the current-carrying groove;

[0024] Manufacturing a plurality of first conductive structures, wherein the first conductive structures correspond to the first electrodes one by one, and the first conductive structures cover a portion of the surface of the corresponding first electrode that is away from the piezoelectric body;

[0025] A plurality of second conductive structures are manufactured, wherein the second conductive structures correspond to the power-carrying slots one by one, and the second conductive structures cover the slot walls of the corresponding power-carrying slots and extend to cover the second electrodes exposed in the power-carrying slots.

[0026] In addition to or as an alternative to one or more of the features disclosed above, before making the second notch on the first electrode structure, the method further includes:

[0027] A bonding structure is made on the side of the etching resistance structure away from the second electrode, and the bonding structure includes a bonding portion and a plurality of protruding portions. The protruding portions fill the gap between two adjacent support blocks, and the bonding portion covers the surface of the side of the etching resistance structure away from the piezoelectric structure, and the bonding portion is connected to the plurality of protruding portions.

[0028] In addition to one or more of the features disclosed above, or as an alternative, in the stacking direction of the resonant filter, the area occupied by the orthographic projection of the groove is the first area, the area occupied by the orthographic projection of the resist structure located in the interval between two adjacent second support blocks is the second area, and the first area is located within the second area.

[0029] In addition to one or more of the features disclosed above, or as an alternative, the piezoelectric structure is made of a material different from that of the etching-resistant structure, the first electrode structure is made of a material different from that of the etching-resistant structure, and the etching-resistant structure is made of a non-metallic material.

[0030] On the other hand, a resonant filter is provided, including:

[0031] A first electrode structure, a piezoelectric structure, and a second electrode structure stacked;

[0032] A second notch is formed in the first electrode structure to form a plurality of first electrodes arranged at intervals;

[0033] A first notch is formed in the second electrode structure to form a plurality of second electrodes arranged at intervals;

[0034] A groove penetrating through itself is formed in the piezoelectric structure to form a plurality of piezoelectric bodies arranged at intervals, and the groove is located between two adjacent first electrodes;

[0035] A support structure is further provided on a surface of the second electrode structure facing away from the piezoelectric structure. The support structure includes a first support block and a second support block. The first support block is connected to the second electrode, and the second support block is located between two adjacent second electrodes and is connected to the piezoelectric structure. Among them, each second electrode is connected to at least two first support blocks arranged at intervals, and there are at least two second support blocks arranged at intervals between two adjacent second electrodes;

[0036] An etching-resistant structure is provided on a surface of the support structure facing away from the second electrode structure. The etching-resistant structure covers the wall surfaces of each first support block and each second support block and covers the piezoelectric structure and the second electrode exposed at the interval between adjacent support blocks. After the etching-resistant structure is formed, at least one of the first support blocks is removed for each second electrode, so that at least one cavity is jointly enclosed between a side of each second electrode facing away from the piezoelectric structure and the etching-resistant structure;

[0037] Among them, the groove is formed between two adjacent first electrodes. In the stacking direction of the resonant filter, the projection of the groove is located within the interval projection of two adjacent second support blocks, and the etching-resistant structure at this interval is exposed in the groove.

[0038] In addition to one or more of the features disclosed above, or as an alternative, the plurality of first electrodes and the plurality of piezoelectric bodies correspond one by one, the plurality of piezoelectric bodies and the plurality of second electrodes correspond one by one. In the stacking direction of the resonant filter, the projections of the corresponding first electrode, the piezoelectric body, and the second electrode overlap.

[0039] In addition to, or as an alternative to, one or more of the features disclosed above, the piezoelectric structure is made of a material different from that of the etching stop structure, the first electrode structure is made of a material different from that of the etching stop structure, and the etching stop structure is made of a non-metallic material.

[0040] In addition to, or as an alternative to, one or more of the features disclosed above, a bonding structure is further connected to the side of the etching stop structure facing away from the second electrode structure. The bonding structure includes a bonding portion and a plurality of protruding portions. The plurality of protruding portions are arranged at intervals on one surface of the bonding portion and are connected to the bonding portion. The protruding portions are used to fill the gaps between two adjacent support blocks, and the bonding portion is used to cover the surface of the etching stop structure facing away from the piezoelectric structure.

[0041] In addition to, or as an alternative to, one or more of the features disclosed above, it further includes:

[0042] A plurality of first conductive structures, which correspond to the first electrodes one by one, and the first conductive structures are connected to the sides of the corresponding first electrodes facing away from the piezoelectric body;

[0043] A plurality of second conductive structures, which correspond to the second electrodes one by one. An energizing groove penetrating the piezoelectric body is formed on the side of each piezoelectric body facing away from the second electrode, and the second electrode corresponding to the piezoelectric body is exposed in the energizing groove. The second conductive structures cover the groove walls of the corresponding energizing grooves and the second electrodes exposed in the energizing grooves.

[0044] One of the above technical solutions has the following advantages or beneficial effects: In the technical solution disclosed in the present application, the grooves used to divide the piezoelectric structure can not only effectively release the residual stress of the piezoelectric structure, but also directly serve as the cutting channels for subsequent wafer dicing. With this arrangement, the problem of needing to reserve additional space to arrange the cutting channels in the traditional method is avoided, the distance between adjacent resonator filters is reduced, and thus the effective utilization area of the wafer is increased. Specifically, a part of the etching stop structure disclosed in the present application can be arranged directly below the groove and be attached to the piezoelectric structure. Since the material of the etching stop structure is different from that of the piezoelectric structure, the structure on the side of the piezoelectric structure facing away from the first electrode can be protected when the groove is opened. In addition, since the etching stop structure is made of a non-metallic material, it will not damage the cutting tool when dicing the wafer along the groove, because the cutting tool does not need to avoid the groove. This design not only ensures the cutting accuracy, but also further simplifies the cutting operation, improves the processing efficiency and wafer utilization rate. Description of the Drawings

[0045] The following will, with reference to the accompanying drawings and through a detailed description of the specific embodiments of the present invention, make the technical solutions and other beneficial effects of the present invention obvious.

[0046] Figures 1 to 8 It is a cross-sectional view of a resonant filter provided by an embodiment of the present application during the manufacturing process;

[0047] Figure 9 It is a top view of a resonant filter provided by an embodiment of the present application.

[0048] Description of the reference numerals:

[0049] 100, the first electrode structure; 101, the first electrode; 102, the second notch;

[0050] 200, the piezoelectric structure; 201, the piezoelectric body; 2011, the power-on groove; 202, the groove; 203, the release hole;

[0051] 300, the second electrode structure; 301, the second electrode; 302, the first notch;

[0052] 400, the support structure; 401, the first support block; 402, the second support block;

[0053] 500, the resist structure;

[0054] 600, the cavity;

[0055] 700, the first conductive structure; 701, the second conductive structure;

[0056] 800, the bonding structure; 801, the protruding part; 802, the bonding part;

[0057] 900, the first substrate; 901, the second substrate. Specific Embodiments

[0058] In order to make the objectives, technical solutions and beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described in this specification are only for explaining the present invention and not for limiting the present invention.

[0059] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of the said features. In the description of the present invention, "a plurality of" means two or more, unless otherwise specifically defined.

[0060] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "mounted", "connected", and "coupled" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection, a direct connection, or an indirect connection through an intermediate medium, and it may be the internal communication of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0061] In the present invention, unless otherwise clearly specified and limited, the first feature being "on" or "under" the second feature may include the first and second features being in direct contact, or may include the first and second features not being in direct contact but being in contact through additional features therebetween. Moreover, the first feature being "above", "over", and "on top of" the second feature includes the first feature being directly above and obliquely above the second feature, or merely indicating that the first feature has a higher horizontal height than the second feature. The first feature being "under", "beneath", and "underneath" the second feature includes the first feature being directly below and obliquely below the second feature, or merely indicating that the first feature has a lower horizontal height than the second feature.

[0062] The present invention discloses a manufacturing method of a resonant filter, and the manufacturing method of the resonant filter includes:

[0063] S100. Sequentially stack and fabricate a first electrode structure, a piezoelectric structure, and a second electrode structure;

[0064] S200. Fabricate a first notch on the second electrode structure, the first notch separating the second electrode structure into a plurality of second electrodes, and a partial surface of the piezoelectric structure being exposed in the first notch;

[0065] S300. Fabricate a first support block and a second support block. The first support block is located on the second electrode, and the second support block is located between two adjacent second electrodes and is connected to the piezoelectric structure. Each second electrode is connected to at least two spaced-apart first support blocks, and there are at least two spaced-apart second support blocks between two adjacent second electrodes.

[0066] S400. Fabricate a resist etching structure that covers the wall surfaces of each first support block and each second support block, as well as the piezoelectric structure and the second electrode exposed at the intervals between two adjacent support blocks.

[0067] S500. Fabricate a second notch on the first electrode structure. The second notch divides the first electrode structure into multiple first electrodes, and a part of the surface of the piezoelectric structure is exposed in the second notch.

[0068] S600. Fabricate a groove on the side of the piezoelectric structure facing away from the second electrode structure. The groove is located between two adjacent first electrodes and divides the piezoelectric structure into multiple piezoelectric bodies. In the stacking direction, the projection of the groove is located within the projection of the interval between two adjacent second support blocks, and the resist etching structure at this interval is exposed in the groove.

[0069] S700. Remove at least one first support block for each second electrode so that at least one cavity is formed on the side of each second electrode facing away from the piezoelectric structure.

[0070] Referring to Figure 1 , in step S100, a first substrate 900 is usually provided to assist in fabricating the first electrode structure 100, the piezoelectric structure 200, and the second electrode structure 300. Specifically, the first electrode structure 100, the piezoelectric structure 200, and the second electrode structure 300 are all thin film structures, with small thickness and low mechanical strength themselves, and are prone to bending, warping, and cracking. Providing the first substrate 900 as a temporary support to fabricate the first electrode structure 100, the piezoelectric structure 200, and the second electrode structure 300 on one side surface of the first substrate 900 can provide sufficient mechanical strength and stability to ensure the smooth progress of subsequent processes.

[0071] In step S200, the second electrode structure 300 is divided into multiple second electrodes 301 by fabricating a first notch 302 that penetrates the second electrode structure 300 on the second electrode structure 300. Referring to Figures 2 to 8 , in the process flow diagram of the manufacturing method of the resonant filter disclosed in the present application, for the sake of simplicity of illustration, only the process of simultaneously fabricating two resonant filters is schematically shown (the two resonant filters will be separated after fabrication). Therefore, in Figure 2In [the figure], only a first notch 302 is formed in the second electrode structure 300, thereby separating the second electrode structure 300 into two independent second electrodes 301, and the two second electrodes 301 belong to two resonant filters respectively. In some embodiments, when manufacturing more than two resonant filters on the same first substrate 900 (or wafer), a plurality of first notches 302 need to be formed to separate the second electrode structure 300 into a plurality of independent second electrodes 301, and these second electrodes 301 respectively correspond to different resonant filters. And after separating the second electrodes 301, a part of the surface of the piezoelectric structure 200 facing away from the first electrode structure 100 will be exposed from the first notch 302.

[0072] Referring to Figure 3 , in step S300, a first support block 401 and a second support block 402 are formed on the side of the second electrode structure 300 facing away from the piezoelectric structure 200. Among them, the first support block 401 is located on the second electrode 301, and the second support block 402 is located between two adjacent second electrodes 301 and is connected to the piezoelectric structure 200.

[0073] Specifically, in some embodiments, the implementation steps of step S300 include: first, forming a support structure 400 on the side of the second electrode structure 300 facing away from the piezoelectric structure 200, and the support structure 400 covers the second electrode structure 300 and the piezoelectric structure 200 exposed in the first notch 302; etching the support structure 400 covering the second electrode 301 to form at least two first support blocks 401 on each second electrode 301; etching the support structure 400 covering the piezoelectric structure 200 to form at least two second support blocks 402 between two adjacent second electrodes 301.

[0074] Referring to Figure 4 , in step S400, an anti-etching structure 500 is formed, and the anti-etching structure 500 is used to isolate adjacent first support blocks 401, adjacent second support blocks 402, and adjacent first support blocks 401 and second support blocks 402. And the materials of the piezoelectric structure and the anti-etching structure are different, the materials of the first electrode structure and the anti-etching structure are different, and the anti-etching structure is made of a non-metallic material.

[0075] Specifically, each second electrode 301 is connected to at least two first support blocks 401 that are spaced apart, which helps to ensure that after the etch stop structure 500 covers the first support block 401 during the production of the etch stop structure 500 in step S400, the first support blocks 401 on each second electrode 301 are isolated from each other. Thus, when subsequently etching the first support block 401 with an etchant to form a deformation space on the side where the second electrode 301 is located, adjacent first support structures 400 can be effectively prevented from being corroded, so as to ensure that there are first support blocks 401 that are not removed on each second electrode 301. The first support blocks 401 that are not removed are used to support the second electrode 301, improving the stability of the resonant sensor structure. Moreover, there are at least two second support blocks 402 that are spaced apart between two adjacent second electrodes 301, which can provide effective support for the piezoelectric structure 200 exposed at the interval between the two adjacent second electrodes 301, enhancing the overall mechanical stability of the piezoelectric structure 200. Especially in step S700, when some of the first support blocks 401 are removed, the second support blocks 402 can prevent the piezoelectric structure 200 from deforming or collapsing. And during the production of the etch stop structure 500 in step S400, the second support blocks 402 help the etch stop material for forming the etch stop structure 500 to deposit along the wall surface of the second support blocks 402 and cover the piezoelectric structure 200 exposed at the interval between the two second support blocks 402.

[0076] The etch stop structure 500 deposited on the surface of the piezoelectric structure 200 on the side facing away from the first electrode structure 100 and located between the two second electrodes 301 can play an effective protective role when opening the trench 202 penetrating the piezoelectric structure 200 in S600, preventing the etchant for etching the piezoelectric structure 200 from penetrating to the side of the piezoelectric structure 200 facing away from the first electrode structure 100 and damaging the structure on that side. It is worth mentioning that the etch stop structure 500 can play a protective role mainly because its material is different from that of the piezoelectric structure 200 and the first electrode structure 100. During step S500 of etching the first electrode structure 100 or step S600 of etching the piezoelectric structure 200, the etch stop structure 500 will not be affected by the etchant, thus effectively protecting the area it covers.

[0077] In some embodiments, the materials of the first electrode structure 100 and the second electrode structure 300 are aluminum (Al), molybdenum (Mo), gold (Au), etc., the material of the piezoelectric structure 200 is aluminum nitride (AlN) or aluminum scandium nitride (AlScN) doped with scandium, the materials of the first support block 401 and the second support block 402 are silicon dioxide (SiO2), and the material of the etch stop structure 500 is an acid-resistant corrosion material such as Poly-Si, AlN, amorphous silicon, etc.

[0078] Refer to Figure 6, Step S500 requires operations on the side where the first electrode structure 100 is located. To facilitate subsequent steps, the side of the piezoelectric structure 200 facing away from the first electrode structure 100 is usually bonded to the second substrate 901. The second substrate 901 is used to support the resonant filter structure and assist in subsequent operations. However, after the resist etching structure 500 is fabricated in step S400, the side of the piezoelectric structure 200 facing away from the first electrode structure 100 is still uneven, making it difficult to stably bond with the second substrate 901. Refer to Figure 5 , in some embodiments, between step S400 and step S500, a bonding structure 800 is further fabricated on the side of the resist etching structure 500 facing away from the second electrode 301. The bonding structure 800 includes a bonding portion 802 and a plurality of protruding portions 801. The protruding portions 801 are filled in the spaces between two adjacent support blocks (the two adjacent support blocks include two adjacent first support blocks 401, two adjacent second support blocks 402, and an adjacent first support block 401 and second support block 402). The bonding portion 802 covers the surface of the resist etching structure 500 facing away from the piezoelectric structure 200, and the bonding portion 802 is connected to the plurality of protruding portions 801 (usually the bonding portion 802 and the plurality of protruding portions 801 are integrally formed). After the bonding structure 800 is fabricated, refer to Figure 6 , in some embodiments, the second substrate 901 is also bonded to the surface of the bonding portion 802 facing away from the resist etching structure 500 to provide stable support for subsequent steps and assist in completing subsequent steps.

[0079] Continue to refer to Figure 6 , after the second substrate 901 is bonded, the first substrate 900 is removed, and the surface of the first electrode structure 100 facing away from the piezoelectric structure 200 is exposed. A second notch 102 penetrating the first electrode structure 100 is formed on the side of the first electrode structure 100 facing away from the piezoelectric structure 200. The second notch 102 divides the first electrode structure 100 into a plurality of first electrodes 101. Similar to the logic of forming the first notch 302, in some embodiments, when fabricating two or more resonant filters on the same second substrate 901 (or wafer), a plurality of second notches 102 need to be formed to divide the first electrode structure 100 into a plurality of independent first electrodes 101. These first electrodes 101 respectively correspond to different resonant filters, and after the division, the first electrodes 101 correspond to the second electrode 301. And after the first electrode structure 100 is divided, a partial surface of the piezoelectric structure 200 facing away from the second electrode structure 300 will be exposed from the first notch 302.

[0080] Further, a groove 202 penetrating the piezoelectric structure 200 is formed on a side of the piezoelectric structure 200 facing away from the second electrode structure 300. The groove 202 is located between two adjacent first electrodes 101, and the piezoelectric structure 200 is divided into a plurality of piezoelectric bodies 201 by the groove 202. With such an arrangement, the groove 202 first divides the piezoelectric structure 200 into a plurality of piezoelectric bodies 201, and releases the stress of the piezoelectric bodies 201 in advance. When the wafer is subsequently cut, the stress impact on the piezoelectric structure 200 during the cutting process can be reduced. The existence of the groove 202 forms a natural stress buffer region, and the large-scale release of stress of the piezoelectric structure 200 during cutting will not affect the device performance, thereby improving the stability of the device. The separated piezoelectric bodies 201 correspond to the first electrodes 101 one by one, and also correspond to the second electrodes 301 one by one. In the stacking direction of the resonant filter, the projections of the corresponding first electrodes 101, the piezoelectric bodies 201, and the second electrodes 301 overlap. The corresponding first electrodes 101, piezoelectric bodies 201, and second electrodes 301 together form a piezoelectric combination of the resonant sensor with the groove 202.

[0081] In the stacking direction of the resonant sensor, the projections of the second notches 102 between two adjacent first electrodes 101, the projections of the first notches 302 between two adjacent second electrodes 301, and the projection of the groove 202 between two adjacent first electrodes 101 overlap. Further, on a side of the piezoelectric structure 200 facing away from the first electrode structure 100, at least two second support blocks 402 are further provided between two adjacent second electrodes 301. In order to avoid damaging other structures on the side of the piezoelectric structure 200 facing away from the first electrode structure 100 by the etching solution when etching the piezoelectric structure 200, in the embodiments disclosed in the present application, the groove 202 is also opened above the interval between two adjacent second support blocks 402, and a resist structure 500 at the interval can block the etching solution from penetrating into the side of the piezoelectric structure 200 facing away from the first electrode structure 100.

[0082] In order to ensure that the resist structure 500 effectively blocks the etching solution, in some embodiments, in the stacking direction of the resonant filter, the area occupied by the orthographic projection of the groove 202 is a first area, and the area occupied by the orthographic projection of the resist structure 500 within the interval between two adjacent second support blocks 402 is a second area. The first area is located within the second area. In other words, the area occupied by the bottom of the groove 202 is between the area where the resist structure 500 within the interval between two adjacent second support blocks 402 contacts the piezoelectric structure 200.

[0083] When manufacturing the resonant filter, each first electrode 101 and each second electrode 301 need to lead out electrical signals through conductive structures. Specifically, referring to Figure 7The conductive structure for leading out the electrical signal of the first electrode 101 is the first conductive structure 700, and the conductive structure for leading out the electrical signal of the second electrode 301 is the second conductive structure 701. The specific steps for fabricating the first conductive structure 700 and the second conductive structure 701 are as follows: First, a through-hole 2011 that penetrates the piezoelectric body 201 is fabricated on each piezoelectric body 201, and the second electrode 301 corresponding to the piezoelectric body 201 is exposed in the through-hole 2011. Then, a conductive material is deposited on one side of each through-hole 2011 and each first electrode 101 facing away from the piezoelectric body 201, so as to form the first conductive structure 700 on a partial surface of one side of each first electrode 101 facing away from the piezoelectric body 201, and form the second conductive structure 701 that covers the sidewall of the through-hole 2011 and extends to cover the second electrode 301 exposed in the through-hole 2011 for each through-hole 2011.

[0084] It should be noted that etching the trench 202 and etching the through-hole 2011 on the piezoelectric structure 200 are usually completed by one-time patterning etching. With such a setting, synchronous etching can reduce the number of mask plates used, reduce the time and cost of the photolithography and etching processes, and help save materials and resources. At the same time, multiple etchings may introduce additional thermal stress or residual stress to the piezoelectric structure 200, affecting the performance of the piezoelectric layer, while synchronous etching can avoid stress accumulation caused by repeated processing and maintain the stability of the piezoelectric structure 200.

[0085] It is worth mentioning that a cavity 600 for the deformation of the second electrode 301 needs to be provided on one side where each second electrode 301 is located. When the details of fabricating the first support block 401 and the second support block 402 in the foregoing public step S300 were mentioned, it was stated that "each second electrode 301 is at least connected to two spaced-apart first support blocks 401, which helps to ensure that there are first support blocks 401 that are not removed on each second electrode 301 when etching the first support block 401 with etching solution to form a deformation space on one side where the second electrode 301 is located, so as to support the second electrode 301 and improve the stability of the resonant sensor structure." That is, in this application, when fabricating the deformation cavity 600 for each second electrode 301, it is achieved by selectively removing one of the first support blocks 401 connected thereto. Specifically, referring to Figure 7, in some embodiments, when manufacturing the first support block 401, for each of the second electrodes 301, in the first support block 401 located on the second electrode 301, at least one of the first support blocks 401 also covers a part of the piezoelectric structure 200. With this arrangement, after the resist etching structure 500 is formed, there is a release gap between the second electrode 301 connected to the first support block 401 and the resist etching structure 500 covering the first support block 401. By opening a release hole 203 penetrating the piezoelectric body 201 on the surface of the piezoelectric body 201 facing away from the second electrode 301, the first support block 401 at the release gap is exposed in the release hole 203, and the first support block 401 can be removed by injecting an etching solution into the release hole 203. It should be noted that referring to Figure 9 , the corresponding first electrode 101 and second electrode 301 are partially overlapped. When the release hole 203 is opened, it avoids the first electrode 101 and the second electrode 301 and only penetrates the piezoelectric body 201. For the convenience of subsequent plugging of the release hole 203, the aperture of the release hole 203 is relatively small. To improve the manufacturing efficiency of the cavity 600, multiple release holes 203 can be opened on one piezoelectric body 201. When the power supply groove 2011 is opened, it needs to avoid the first electrode 101 and also only penetrates the piezoelectric body 201. It should be noted that the second substrate 901 can be selected to be removed after all the manufacturing steps of the resonant filter are completed.

[0086] The groove 202 for dividing the piezoelectric structure 200 in the technical solution disclosed in the present application can not only effectively release the residual stress of the piezoelectric structure 200, but also directly serve as a dicing lane for subsequent wafer dicing. Referring to Figure 9 , Figure 9 is a top view of a resonant filter provided by an embodiment of the present application, taking the example of simultaneously manufacturing four resonant filters on one wafer in this top view. The grooves 202 between two adjacent first electrodes 101 communicate with each other and jointly form the dicing lane of the wafer. With this arrangement, the problem of needing to additionally reserve space to arrange the dicing lane in the traditional method is avoided, the distance between adjacent resonant filters is reduced, and thus the effective utilization area of the wafer is improved. Specifically, a part of the resist etching structure 500 in the present application can be arranged directly below the groove 202 and fit the piezoelectric structure 200. The material of the resist etching structure 500 is different from that of the piezoelectric structure 200, so the structure on the side of the piezoelectric structure 200 facing away from the first electrode 101 can be protected when the groove 202 is opened. In addition, the resist etching structure 500 is made of a non-metallic material, and when the wafer is diced along the groove 202, it will not damage the cutting tool. This feature not only eliminates the limitation that the cutting tool needs to avoid the groove 202, but also makes it possible to perform precise cutting along the groove 202.

[0087] The present application also provides a resonant filter, referring to Figure 8, the resonant filter includes: a first electrode structure 100, a piezoelectric structure 200, and a second electrode structure 300 which are stacked. A second notch 102 is formed on the first electrode structure 100 to form a plurality of first electrodes 101 arranged at intervals. A first notch 302 is formed on the second electrode structure 300 to form a plurality of second electrodes 301 arranged at intervals. A groove 202 penetrating through itself is formed on the side of the piezoelectric structure 200 facing away from the second electrode structure 300 to form a plurality of piezoelectric bodies 201 arranged at intervals. The groove 202 is located between two adjacent first electrodes 101. A support structure 400 is further provided on the surface of the second electrode structure 300 facing away from the piezoelectric structure 200. The support structure 400 includes a first support block 401 and a second support block 402. The first support block 401 is connected to the second electrode 301. The second support block 402 is located between two adjacent second electrodes 301 and is connected to the piezoelectric structure 200. Each second electrode 301 is connected to at least two first support blocks 401 arranged at intervals, and there are at least two second support blocks 402 arranged at intervals between two adjacent second electrodes 301. A resist etching structure 500 is provided on the surface of the support structure 400 facing away from the second electrode structure 300. The resist etching structure 500 covers the wall surfaces of each first support block 401 and each second support block 402, and the piezoelectric structure 200 and the second electrode 301 exposed at the intervals between adjacent support blocks. The material of the piezoelectric structure 200 is different from that of the resist etching structure 500, and the material of the first electrode structure 100 is different from that of the resist etching structure 500. After the resist etching structure 500 is formed, at least one first support block 401 is removed for each second electrode 301, so that at least one cavity 600 is jointly enclosed between the side of each second electrode 301 facing away from the piezoelectric structure 200 and the resist etching structure 500. The groove 202 is formed between two adjacent first electrodes 101. In the stacking direction of the resonant filter, the projection of the groove 202 is located within the interval projection of two adjacent second support blocks 402, and the resist etching structure 500 at this interval is exposed in the groove 202.

[0088] Specifically, a plurality of first electrodes 101 and a plurality of piezoelectric bodies 201 correspond one by one, and a plurality of piezoelectric bodies 201 and a plurality of second electrodes 301 correspond one by one. In the stacking direction of the resonant filter, the projections of the corresponding first electrodes 101, piezoelectric bodies 201, and second electrodes 301 overlap. And after the combined resonant filter is manufactured, it can be divided along the groove 202 to form a plurality of independent resonant filters.

[0089] In some embodiments, a bonding structure 800 is further connected to a side of the etching stop structure 500 facing away from the second electrode structure 300. The bonding structure 800 includes a bonding portion 802 and a plurality of protruding portions 801. The plurality of protruding portions 801 are arranged at intervals on one surface of the bonding portion 802 and are connected to the bonding portion 802. The protruding portions 801 are used to fill the gaps between two adjacent support blocks, and the bonding portion 802 is used to cover the surfaces of the first support block 401 and the second support block 402 facing away from the second electrode structure 300.

[0090] In some embodiments, the resonant filter further includes a plurality of first conductive structures 700 and a plurality of second conductive structures 701. The first conductive structures 700 correspond to the first electrodes 101 one by one, and the first conductive structures 700 are connected to the sides of the corresponding first electrodes 101 facing away from the piezoelectric body 201. The second conductive structures 701 correspond to the second electrodes 301 one by one. An energization groove 2011 penetrating through the piezoelectric body 201 is formed on a side of each piezoelectric body 201 facing away from the second electrode 301. The second electrode 301 corresponding to the piezoelectric body 201 is exposed in the energization groove 2011, and the second conductive structures 701 cover the groove walls of the corresponding energization grooves 2011 and the second electrodes 301 exposed in the energization grooves 2011.

[0091] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in this specification.

[0092] The above embodiments only represent several implementation manners of the present application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the patent application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several deformations and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A manufacturing method of a resonant filter, characterized in that, Including: Successively laminating and fabricating a first electrode structure, a piezoelectric structure, and a second electrode structure; Fabricating a first notch on the second electrode structure, the first notch separating the second electrode structure into a plurality of second electrodes, and a partial surface of the piezoelectric structure being exposed in the first notch; Fabricating a first support block and a second support block, the first support block being located on the second electrode, the second support block being located between two adjacent second electrodes and connected to the piezoelectric structure; wherein, each of the second electrodes is connected to at least two first support blocks arranged at intervals, and there are at least two second support blocks arranged at intervals between two adjacent second electrodes; Fabricating an etching stop structure, the etching stop structure covering the wall surfaces of each of the first support blocks and each of the second support blocks, and covering the piezoelectric structure and the second electrode exposed at the interval between two adjacent support blocks; Fabricating a second notch on the first electrode structure, the second notch separating the first electrode structure into a plurality of first electrodes, and a partial surface of the piezoelectric structure being exposed in the second notch; Fabricating a groove on a side of the piezoelectric structure facing away from the second electrode structure, the groove being located between two adjacent first electrodes, separating the piezoelectric structure into a plurality of piezoelectric bodies, in the lamination direction, the projection of the groove being located within the projection of the interval between two adjacent second support blocks, and the etching stop structure at this interval being exposed in the groove; Removing at least one of the first support blocks for each of the second electrodes, so that at least one cavity is formed on a side of each of the second electrodes facing away from the piezoelectric structure.

2. The manufacturing method of the resonant filter according to claim 1, characterized in that, The plurality of first electrodes and the plurality of piezoelectric bodies correspond one by one, the plurality of piezoelectric bodies and the plurality of second electrodes correspond one by one, and in the lamination direction of the resonant filter, the projections of the corresponding first electrode, the piezoelectric body, and the second electrode overlap.

3. The manufacturing method of the resonant filter according to claim 1, characterized in that, The fabricating the first support block and the second support block includes: Fabricating a support structure on a side of the second electrode structure facing away from the piezoelectric structure, the support structure covering the second electrode structure and the piezoelectric structure exposed in the first notch; Etching the support structure covering the second electrode to form at least two of the first support blocks on each of the second electrodes; Etching the support structure covering the piezoelectric structure to form at least two of the second support blocks between two adjacent second electrodes.

4. The manufacturing method of the resonant filter according to claim 3, characterized in that, The etching the support structure covering the second electrode to form at least two of the first support blocks on each of the second electrodes includes: For each of the second electrodes, among the first support blocks located on the second electrode, at least one of the first support blocks also covers a partial piezoelectric structure.

5. The manufacturing method of the resonant filter according to claim 2, characterized in that, Further including: Fabricating a through-hole groove penetrating each of the piezoelectric bodies on each of the piezoelectric bodies, and the second electrode corresponding to the piezoelectric body being exposed in the through-hole groove; Fabricating a plurality of first conductive structures, the first conductive structures corresponding to the first electrodes one by one, and the first conductive structures covering a partial surface of the corresponding first electrode on a side facing away from the piezoelectric body; Form a plurality of second conductive structures, where the second conductive structures correspond to the power supply grooves one by one, and the second conductive structures cover the groove walls of the corresponding power supply grooves and extend to cover the second electrodes exposed in the power supply grooves.

6. The manufacturing method of the resonant filter according to claim 1, wherein, Before forming the second notch on the first electrode structure, the manufacturing method of the resonant filter further includes: Form a bonding structure on a side of the etching stop structure facing away from the second electrode. The bonding structure includes a bonding portion and a plurality of protruding portions. The protruding portions are filled in the spaces between two adjacent support blocks. The bonding portion covers a surface of the etching stop structure facing away from the piezoelectric structure, and the bonding portion is connected to the plurality of protruding portions.

7. The manufacturing method of the resonant filter according to claim 1, characterized in that In the stacking direction of the resonant filter, the region occupied by the orthographic projection of the groove is a first region, and the region occupied by the orthographic projection of the etching stop structure within the space between two adjacent second support blocks is a second region. The first region is located within the second region.

8. The manufacturing method of the resonant filter according to claim 1, characterized in that, The piezoelectric structure and the etching stop structure are made of different materials. The first electrode structure and the etching stop structure are made of different materials. The etching stop structure is made of a non-metallic material.

9. A resonant filter, characterized in that, Comprising: A first electrode structure, a piezoelectric structure, and a second electrode structure stacked; A second notch is formed on the first electrode structure to form a plurality of first electrodes arranged at intervals; A first notch is formed on the second electrode structure to form a plurality of second electrodes arranged at intervals; A groove penetrating through itself is formed on the piezoelectric structure to form a plurality of piezoelectric bodies arranged at intervals. The groove is located between two adjacent first electrodes; A support structure is further provided on a surface of the second electrode structure facing away from the piezoelectric structure. The support structure includes a first support block and a second support block. The first support block is connected to the second electrode. The second support block is located between two adjacent second electrodes and is connected to the piezoelectric structure. Each of the second electrodes is connected to at least two first support blocks arranged at intervals, and there are at least two second support blocks arranged at intervals between two adjacent second electrodes; An etching stop structure is provided on a surface of the support structure facing away from the second electrode structure. The etching stop structure covers the wall surfaces of each first support block and each second support block and covers the piezoelectric structure and the second electrode exposed at the intervals between adjacent support blocks. After the etching stop structure is formed, at least one of the first support blocks is removed for each of the second electrodes, so that at least one cavity is jointly enclosed between a side of each second electrode facing away from the piezoelectric structure and the etching stop structure; Among them, the groove is formed between two adjacent first electrodes. In the stacking direction of the resonant filter, the projection of the groove is located within the projection of the space between two adjacent second support blocks, and the etching stop structure at this interval is exposed in the groove.

10. The resonant filter according to claim 9, wherein, The plurality of first electrodes and the plurality of piezoelectric bodies correspond to each other one by one, and the plurality of piezoelectric bodies and the plurality of second electrodes correspond to each other one by one. In the stacking direction of the resonant filter, the projections of the corresponding first electrode, the piezoelectric body, and the second electrode overlap.

11. The resonant filter according to claim 9, wherein The piezoelectric structure and the resistive etching structure are made of different materials, the first electrode structure and the resistive etching structure are made of different materials, and the resistive etching structure is made of a non-metallic material.

12. The resonant filter according to claim 9, characterized in that, A bonding structure is further connected to the side of the resistive etching structure facing away from the second electrode structure. The bonding structure includes a bonding portion and a plurality of protruding portions. The plurality of protruding portions are arranged at intervals on one surface of the bonding portion and are connected to the bonding portion. The protruding portions are used to fill the gaps between two adjacent support blocks, and the bonding portion is used to cover the surface of the resistive etching structure facing away from the piezoelectric structure.

13. The resonant filter according to claim 10, wherein Further included are: A plurality of first conductive structures, which correspond to the first electrodes one by one, and the first conductive structures are connected to the sides of the corresponding first electrodes facing away from the piezoelectric body; A plurality of second conductive structures, which correspond to the second electrodes one by one. An energization groove penetrating the piezoelectric body is formed on the side of each piezoelectric body facing away from the second electrode, and the second electrode corresponding to the piezoelectric body is exposed in the energization groove. The second conductive structure covers the groove wall of the corresponding energization groove and the second electrode exposed in the energization groove.

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