Packaging structure of filter

Abstract

The invention relates to the technical field of filter packaging, and discloses a packaging structure of a filter, which is characterized in that a first functional module and a second functional module are respectively arranged on two functional surfaces of a substrate, so that the packaging integration level and the performance of the filter are improved; two through holes are formed in the substrate, and the functional surface on one side is provided with an outer bonding pad for blocking the through holes and balls connected with the outer bonding pad and used for inputting and outputting wireless signals; the first functional module is located between the two outer bonding pads of the functional surface on the side, a first functional cavity is defined by the first cover plate and the substrate, and the outer bonding pads, the first chip bonding pads arranged on the two sides of the first functional layer respectively and the first functional layer are electrically connected in sequence; and similarly, the second cover plate and the substrate enclose to form a second functional cavity, the second chip bonding pad blocks the through hole, the outer bonding pad, the second chip bonding pad and the second functional layer are electrically connected in sequence, the wiring structure is simple, the process cost is reduced, and the packaging efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the field of communication technology, and in particular to a packaging structure of a filter. Background Art

[0002] A filter is a frequency-selective device that allows specific frequency components in a signal to pass through while greatly attenuating other frequency components. The frequency-selective function of the filter can be used to filter out interference noise or perform spectrum analysis. The most important characteristic parameters of a filter include performance indicators such as the frequency selection characteristics, insertion loss, and out-of-band suppression of the filter. The frequency selection characteristics of a filter refer to the response of the filter at different frequencies, that is, the filter can selectively pass or suppress input signals of different frequencies. Insertion loss refers to the attenuation of the original signal in the circuit due to the introduction of the filter, which is characterized by the loss at the center or cutoff frequency, indicating the loss of signal power when the filter is used and before it is used. Stopband suppression is an important indicator to measure the performance of filter selection. The higher the index, the better the suppression of out-of-band interference signals.

[0003] The current wafer-level packaging technology only uses one side of the substrate, which has certain limitations on the miniaturization of the package. With the continuous advancement of 5G communication technology, wireless local area network (WLAN) and other high-frequency communication technologies, the performance requirements of filters are also increasing. This not only includes higher requirements for performance indicators such as frequency selectivity, insertion loss and out-of-band suppression of filters, but also includes the need for miniaturization, lightweight and integration of filter packaging. However, in conventional WLP packaging, in order to form a cavity above the interdigital transducer, it is necessary to construct a complex wiring layer and insulation layer structure to achieve the purpose of fixing the cover plate. The structure is complex, the manufacturing cost is high, and the production efficiency is very low.

[0004] There is an urgent need for a wafer-level packaging technology that can provide an effective solution for filter miniaturization. Summary of the invention

[0005] The object of the present invention is to provide a filter packaging structure with a simple wiring structure and low process cost, thereby improving packaging efficiency and the integration of the packaging structure and further improving the performance of the filter.

[0006] To achieve this object, the present invention adopts the following technical solutions:

[0007] The packaging structure of the filter includes:

[0008] A substrate, wherein two opposite sides of the substrate are set as two functional surfaces, two through holes are provided on the substrate, two ends of the through holes are respectively located on the two functional surfaces, one of the functional surfaces is provided with two external pads and two implant balls, the external pads are arranged in a one-to-one correspondence with the implant balls, the external pads are arranged in a one-to-one correspondence with the through holes, one end of the external pad is connected to the implant ball, and the other end of the external pad blocks the through hole;

[0009] A first functional module, wherein the first functional module is arranged on the same side as the outer pad, and the first functional module is located between the two outer pads; the first functional module comprises a first cover plate, a first functional layer and two first chip pads, the first cover plate and the substrate are arranged to form a first functional cavity, the first functional layer and the two first chip pads are placed in the first functional cavity, the first functional layer is arranged on the functional surface, the two first chip pads are arranged on both sides of the first functional layer, and the outer pad, the first chip pad and the first functional layer are electrically connected in sequence;

[0010] A second functional module, wherein the second functional module is arranged on a side of the substrate away from the external pad; the second functional module comprises a second cover plate, a second functional layer and two second chip pads, the second cover plate and the substrate are arranged to form a second functional cavity, the second functional layer and the two second chip pads are placed in the second functional cavity, the second functional layer is arranged on the functional surface, the two second chip pads are respectively arranged on both sides of the second functional layer, and the second chip pad blocks the through hole, and the external pad, the second chip pad and the second functional layer are electrically connected in sequence.

[0011] As an optional technical solution of the packaging structure of the filter, the substrate is provided with a first functional groove between the two external pads, the first functional layer is provided at the bottom of the first functional groove, and the first cover plate is provided at the top of the first functional groove;

[0012] And / or, a second functional groove is provided on a side of the substrate away from the external pad, the second functional layer is provided at the bottom of the second functional groove, and the second cover plate is provided on the top of the second functional groove.

[0013] As an optional technical solution of the packaging structure of the filter, the groove depth of the first functional groove is greater than the thickness of the first functional layer, and the groove depth of the first functional groove is greater than the thickness of the first chip pad;

[0014] And / or, a groove depth of the second functional groove is greater than a thickness of the second functional layer, and a groove depth of the second functional groove is greater than a thickness of the second chip pad.

[0015] As an optional technical solution for the packaging structure of the filter, the substrate is etched to form the first functional groove and / or the second functional groove.

[0016] As an optional technical solution of the packaging structure of the filter, the substrate is provided with an insulating layer, the insulating layer can cover the two first chip pads, and the first cover plate is overlapped on the insulating layer to form the first functional cavity;

[0017] And / or, the insulating layer can cover the two second chip pads, and the second cover plate is overlapped on the insulating layer to form the second functional cavity.

[0018] As an optional technical solution for the packaging structure of the filter, a cavity is provided inside the substrate between the first functional layer and the second functional layer.

[0019] As an optional technical solution for the packaging structure of the filter, the substrate includes a base material and a piezoelectric layer, the piezoelectric layer is arranged on both sides of the base material, and the functional surface is arranged on both sides of the two piezoelectric layers away from each other.

[0020] As an optional technical solution for the packaging structure of the filter, the substrate further includes an intermediate functional layer, and the intermediate functional layer is arranged between the base material and the piezoelectric layer.

[0021] As an optional technical solution of the packaging structure of the filter, a plurality of intermediate functional layers are provided between one side of the substrate and the piezoelectric layer;

[0022] And / or, a plurality of the intermediate functional layers are arranged between the other side of the substrate and the piezoelectric layer.

[0023] As an optional technical solution for the packaging structure of the filter, the through hole is filled with a metal conductive member.

[0024] Beneficial effects of the present invention:

[0025] The packaging structure of the filter provided by the present invention includes a substrate, a first functional module and a second functional module. The two opposite sides of the substrate are set as two functional surfaces, and two through holes are opened on the substrate, and the two ends of the through holes are respectively located on the two functional surfaces; one of the functional surfaces on one side is provided with two external pads and two planting balls, which are arranged one-to-one with the through holes on the same side, one end of the external pad is connected to the planting ball, and the other end of the external pad blocks the through hole, and the two planting balls are used for inputting and outputting wireless signals respectively. The first functional module and the second functional module are respectively arranged on the two functional surfaces of the substrate, which reduces the projection area of ​​a single functional chip on the substrate, improves the integration of the packaging structure of the filter, and can achieve a more compact device size while maintaining and improving the performance of the filter.

[0026] The first functional module is located between the two external pads and is arranged on the same side as the external pads. The first functional module includes a first cover plate, a first functional layer arranged on the functional surface, and two first chip pads respectively arranged on both sides of the first functional layer. The first cover plate and the substrate are arranged to form a first functional cavity. The first functional layer and the two first chip pads are placed in the first functional cavity. The external pads, the first chip pads and the first functional layer are electrically connected in sequence. The second functional module is arranged on a side of the substrate away from the external pads. The second functional module includes a second cover plate, a second functional layer arranged on the functional surface, and two second chip pads respectively arranged on both sides of the second functional layer. The second chip pad blocks the through hole. The second cover plate and the substrate are arranged to form a second functional cavity. The second functional layer and the two second chip pads are placed in the second functional cavity. The external pads, the second chip pads and the second functional layer are electrically connected in sequence. The wiring structure is simple, the complexity of the process is reduced, the cost of the process is reduced, and the packaging efficiency is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a structural cross-sectional view of Example 1 of a packaging structure of a filter provided in a specific embodiment of the present invention;

[0028] Figure 2 is a structural cross-sectional view of Example 2 of a packaging structure of a filter provided in a specific embodiment of the present invention;

[0029] Figure 3 is a structural cross-sectional view of Example 3 of a packaging structure of a filter provided in a specific embodiment of the present invention;

[0030] Figure 4 is a structural cross-sectional view of a fourth embodiment of a filter packaging structure provided in a specific embodiment of the present invention;

[0031] Figure 5 It is a structural cross-sectional view of Example 5 of the packaging structure of the filter provided in a specific embodiment of the present invention.

[0032] In the figure:

[0033] 100, substrate; 102, external pad; 103, ball planting; 104, first functional groove; 105, second functional groove; 106, insulating layer; 107, cavity; 108, metal conductive part; 109, metal connecting part; 110, base material; 120, piezoelectric layer; 130, intermediate functional layer;

[0034] 200, first functional module; 201, first functional cavity; 210, first cover plate; 220, first functional layer; 230, first chip pad;

[0035] 300, second functional module; 301, second functional cavity; 310, second cover plate; 320, second functional layer; 330, second chip pad. DETAILED DESCRIPTION

[0036] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0037] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0038] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0039] In the description of this embodiment, the terms "upper", "lower", "right", "left" and other directions or positional relationships are based on the directions or positional relationships shown in the drawings, and are only for the convenience of description and simplification of operation, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operate in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.

[0040] like Figures 1 to 5As shown, the present invention discloses a packaging structure of a filter, including a substrate 100, a first functional module 200 and a second functional module 300. The two opposite sides of the substrate 100 are set as two functional surfaces, and two through holes are opened on the substrate 100. The two ends of the through holes are respectively located on the two functional surfaces. One of the functional surfaces is provided with two external pads 102 and two planting balls 103. The external pads 102 and the planting balls 103 are arranged in a one-to-one correspondence. The external pads 102 and the through holes are arranged in a one-to-one correspondence. One end of the external pad 102 is connected to the planting ball 103, and the other end of the external pad 102 blocks the through hole. The two planting balls 103 are respectively used to input and output wireless signals. The first functional module 200 and the second functional module 300 are respectively arranged on the two functional surfaces of the substrate 100. A new packaging method is adopted to reduce the projection area of ​​a single functional chip on the substrate 100, improve the integration of the packaging structure of the filter, and achieve a more compact device size while maintaining and improving the performance of the filter.

[0041] The first functional module 200 is arranged on the same side as the external pad 102, and the first functional module 200 is located between the two external pads 102; the first functional module 200 includes a first cover plate 210, a first functional layer 220 and two first chip pads 230, the first cover plate 210 and the substrate 100 are arranged to form a first functional cavity 201, the first functional layer 220 and the two first chip pads 230 are placed in the first functional cavity 201, the first functional layer 220 is arranged on the functional surface, the two first chip pads 230 are respectively arranged on both sides of the first functional layer 220, and the external pad 102, the first chip pad 230 and the first functional layer 220 are electrically connected in sequence. The second functional module 300 is arranged on the side of the substrate 100 away from the outer pad 102; the second functional module 300 includes a second cover plate 310, a second functional layer 320 and two second chip pads 330, the second cover plate 310 and the substrate 100 are arranged to form a second functional cavity 301, the second functional layer 320 and the two second chip pads 330 are placed in the second functional cavity 301, the second functional layer 320 is arranged on the functional surface, the two second chip pads 330 are respectively arranged on both sides of the second functional layer 320, and the second chip pads 330 block the through hole, and the outer pad 102, the second chip pad 330 and the second functional layer 320 are electrically connected in sequence. The first functional layer 220 and the second functional layer 320 are respectively the core functional areas, which are generally specifically interdigital transducers, and are the main determining parts of product performance. A circuit connection is formed between the first chip pad 230 and the first functional layer 220; similarly, a circuit connection is also formed between the second chip pad 330 and the second functional layer 320.

[0042] Specifically, the signal path of the first functional module 200 is: the external circuit inputs the wireless signal through the ball 103 at one end, the external pad 102 connected to the ball 103 at the end receives the signal, and then the external pad 102 transmits it to the first chip pad 230 close to one side, then the first functional layer 220 converts the wireless signal input by the first chip pad 230 into an acoustic signal that propagates on the surface or inside of the substrate 100, and then converts it into a wireless signal through the inverse piezoelectric effect and outputs it to the first chip pad 230 on the other side, and finally transmits it to the external pad 102 on the other side and outputs it to the external circuit through the ball 103 at the other end.

[0043] Similarly, the signal path of the second functional module 300 is: the external circuit inputs a wireless signal through the ball 103 at one end, the external pad 102 connected to the ball 103 at this end receives the signal, and transmits it to the corresponding second chip pad 330 through the through hole at this end. Then, the second functional layer 320 converts the wireless signal input from the second chip pad 330 into an acoustic signal that propagates on the surface or inside of the substrate 100, and then converts it into a wireless signal through the inverse piezoelectric effect and outputs it to the second chip pad 330 on the other side, and then passes through the through hole at the other end, and finally transmits it to the external pad 102 on the other side and outputs it to the external circuit through the ball 103 at the other end.

[0044] The packaging structure and wiring structure of the filter are simple, which reduces the complexity of the process, reduces the cost of the process, and improves the packaging efficiency.

[0045] Exemplarily, the through hole is filled with a metal conductive member 108 , and copper is usually selected as the material of the metal conductive member 108 to better conduct and connect the second chip pad 330 and the external pad 102 .

[0046] Embodiment 1

[0047] Specific as Figure 1 As shown in , the substrate 100 is provided with a first functional groove 104 between two external pads 102, the first functional layer 220 is provided at the bottom of the first functional groove 104, and the first cover plate 210 is provided on the top of the first functional groove 104; similarly, the substrate 100 is provided with a second functional groove 105 on the side away from the external pad 102, the second functional layer 320 is provided at the bottom of the second functional groove 105, and the second cover plate 310 is provided on the top of the second functional groove 105. The first functional layer 220 and the second functional layer 320 are provided inside the first functional groove 104 and the second functional groove 105, respectively, and there is no need to construct an additional cavity 107 on the surface of the substrate 100, which reduces the thickness of about two functional cavities compared with the existing filter. The first functional groove 104 and the second functional groove 105 are provided at the upper and lower ends of the substrate 100, which reduces the height after packaging, reduces the plane size of the filter, improves the integration of the product, and can reduce the packaging volume of the filter.

[0048] It can be understood that the groove depth of the first functional groove 104 is greater than the thickness of the first functional layer 220, and the groove depth of the first functional groove 104 is greater than the thickness of the first chip pad 230; similarly, the groove depth of the second functional groove 105 is greater than the thickness of the second functional layer 320, and the groove depth of the second functional groove 105 is greater than the thickness of the second chip pad 330. The first chip pad 230 and the second chip pad 330 can be placed in the first functional groove 104 and the second functional groove 105 respectively. The groove depth of the first functional groove 104 is the depth of the first functional cavity 201, and the groove depth of the second functional groove 105 is the depth of the second functional cavity 301. The first chip pad 230 and the first functional layer 220 can be selectively prepared in the same layer, or prepared in batches to form different thicknesses, and maintain electrical connection, and the second chip pad 330 and the second functional layer 320 are also the same. Specifically, a metal connector 109 is provided between the outer pad 102 and the first chip pad 230 to better conduct and connect the first chip pad 230 and the outer pad 102 in the first functional slot 104. Exemplarily, the ball 103, the outer pad 102, the first chip pad 230 and the second chip pad 330 are all made of metal, which plays the role of circuit connection, and the corresponding metal can be selected according to different functions.

[0049] Specifically, an etching process may be used to form the first functional groove 104 and / or the second functional groove 105 on the substrate 100 , which can better control the required groove depth.

[0050] Embodiment 2

[0051] Specific as Figure 2 As shown in, on the basis of the first embodiment, in order to prevent the mutual influence of the signals at both ends, a cavity 107 is added inside the substrate 100, that is, between the first functional layer 220 and the second functional layer 320. The cavity 107 is provided by utilizing the acoustic isolation characteristics of the piezoelectric material and the air or vacuum, which can effectively prevent the mutual influence between the first functional module 200 and the second functional module 300, and improve the electromechanical coupling coefficient; and the cavity 107 in the substrate 100 can improve the heat dissipation effect.

[0052] Embodiment 3

[0053] Specific as Figure 3As shown in , on the basis of the first embodiment, in order to prevent the signals at both ends from influencing each other, the substrate 100 can also be divided into a base material 110 and a piezoelectric layer 120, the piezoelectric layer 120 is arranged on both sides of the base material 110, and the functional surface is arranged on both sides of the two piezoelectric layers 120 away from each other. Among them, the base material 110 plays a supporting role, and silicon, sapphire, spinel, etc. can be selected as the base material 110; the piezoelectric layer 120 can be selected from materials such as lithium niobate and lithium tantalate. The composite substrate 100 has good reflectivity and can prevent the signals at both ends from influencing each other.

[0054] Furthermore, the composite substrate 100 also includes an intermediate functional layer 130, which is arranged between the substrate 110 and the piezoelectric layer 120. The intermediate functional layer 130 is an intermediate layer with a specific function. Any number of intermediate functional layers 130 can be arranged between the substrate 110 and the piezoelectric layer 120 according to actual conditions to meet the specific functional requirements of the filter packaging structure; or the intermediate functional layer 130 is not arranged to meet the reflectivity required by the composite substrate 100, which can prevent the first functional module 200 and the second functional module 300 from affecting each other, while improving the performance of the product.

[0055] For example, the interlayer structure of the composite substrate 100 can be selectively configured to be vertically symmetrical or asymmetrical, as long as the thickness and functionality required for the packaging structure of the filter are met.

[0056] Embodiment 4

[0057] Specific as Figure 4 As shown in , different from the grooves provided on both sides of the substrate 100 in the first embodiment, in the embodiment, the first functional module 200 and the second functional module 300 are directly provided on the surface of the substrate 100, and the substrate 100 is not grooved, and an insulating layer 106 is provided on the substrate 100, and the insulating layer 106 can cover the two first chip pads 230 and the two second chip pads 330, and the first cover plate 210 is overlapped on the insulating layer 106 to form the first functional cavity 201, and the second cover plate 310 is overlapped on the insulating layer 106 to form the second functional cavity 301. Although the thickness of the packaging structure of the filter is not further reduced by technical means, the packaging structure wiring structure of the filter is further simplified, the difficulty and cost of the process are reduced, and the packaging efficiency can be greatly improved without affecting the performance of the filter.

[0058] For example, the internal structure of the substrate 100 may also refer to and adopt the cavity 107 design or the composite multilayer design in the second or third embodiment.

[0059] Embodiment 5

[0060] Specific as Figure 5As shown in , based on the fourth embodiment, the first functional module 200 is still arranged on the surface of the substrate 100, and no groove processing is performed, but a second functional groove 105 is arranged on the other side of the substrate 100 where the second functional module 300 is arranged, and the second functional module 300 is located in the second functional groove 105. Similarly, the second functional module 300 may be arranged on the surface of the substrate 100, and the first functional module 200 may be placed in the first functional groove 104, which can be specifically designed according to actual conditions to achieve the appropriate size required for the packaging structure of the filter.

[0061] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, various obvious changes, readjustments and substitutions can be made without departing from the protection scope of the present invention. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. Filter packaging structure, It is characterized in that include: A substrate (100), wherein two opposite sides of the substrate (100) are arranged as two functional surfaces, and two through holes are provided on the substrate (100), and two ends of the through holes are respectively located on the two functional surfaces, and one of the functional surfaces is provided with two external pads (102) and two implant balls (103), and the external pads (102) and the implant balls (103) are arranged in a one-to-one correspondence, and the external pads (102) and the through holes are arranged in a one-to-one correspondence, one end of the external pad (102) is connected to the implant ball (103), and the other end of the external pad (102) blocks the through hole; A first functional module (200), wherein the first functional module (200) and the outer solder pad (102) are arranged on the same side, and the first functional module (200) is located between the two outer solder pads (102); the first functional module (200) comprises a first cover plate (210), a first functional layer (220) and two first chip solder pads (230); the first cover plate (210) and the substrate (100) are arranged to form a first functional cavity (201); the first functional layer (220) and the two first chip solder pads (230) are arranged on the first functional cavity (201); the first functional layer (220) is arranged on the functional surface; the two first chip solder pads (230) are respectively arranged on both sides of the first functional layer (220); the outer solder pad (102), the first chip solder pad (230) and the first functional layer (220) are electrically connected in sequence; A second functional module (300), wherein the second functional module (300) is arranged on a side of the substrate (100) away from the external solder pad (102); the second functional module (300) comprises a second cover plate (310), a second functional layer (320) and two second chip solder pads (330); the second cover plate (310) and the substrate (100) are arranged to form a second functional cavity (301); the second functional layer (320) and the two second chip solder pads (330) are placed on the second functional cavity (301); the second functional layer (320) is arranged on the functional surface; the two second chip solder pads (330) are respectively arranged on both sides of the second functional layer (320); and the second chip solder pad (330) blocks the through hole; the external solder pad (102), the second chip solder pad (330) and the second functional layer (320) are electrically connected in sequence.

2. The packaging structure of the filter according to claim 1, It is characterized in that The substrate (100) is provided with a first functional groove (104) between the two external pads (102); the first functional layer (220) is provided at the bottom of the first functional groove (104); and the first cover plate (210) is provided on the top of the first functional groove (104); And / or, the substrate (100) is provided with a second functional groove (105) on a side away from the external pad (102), the second functional layer (320) is provided at the bottom of the second functional groove (105), and the second cover plate (310) is covered on the top of the second functional groove (105).

3. The packaging structure of the filter according to claim 2, It is characterized in that The groove depth of the first functional groove (104) is greater than the thickness of the first functional layer (220), and the groove depth of the first functional groove (104) is greater than the thickness of the first chip pad (230); And / or, the groove depth of the second functional groove (105) is greater than the thickness of the second functional layer (320), and the groove depth of the second functional groove (105) is greater than the thickness of the second chip pad (330).

4. The packaging structure of the filter according to claim 2, It is characterized in that The substrate (100) is etched to form the first functional groove (104) and / or the second functional groove (105).

5. The packaging structure of the filter according to claim 1, It is characterized in that The substrate (100) is provided with an insulating layer (106), the insulating layer (106) can cover the two first chip pads (230), and the first cover plate (210) is overlapped on the insulating layer (106) to form the first functional cavity (201); And / or, the insulating layer (106) can cover the two second chip pads (330), and the second cover plate (310) is overlapped on the insulating layer (106) to form the second functional cavity (301).

6. The packaging structure of the filter according to claim 1, It is characterized in that A cavity (107) is provided inside the substrate (100) between the first functional layer (220) and the second functional layer (320).

7. The packaging structure of the filter according to claim 1, It is characterized in that The substrate (100) comprises a base material (110) and a piezoelectric layer (120), wherein the piezoelectric layer (120) is arranged on two sides of the base material (110), and the functional surface is arranged on two sides of the two piezoelectric layers (120) that are away from each other.

8. The packaging structure of the filter according to claim 7, It is characterized in that The substrate (100) further comprises an intermediate functional layer (130), wherein the intermediate functional layer (130) is arranged between the base material (110) and the piezoelectric layer (120).

9. The packaging structure of the filter according to claim 8, It is characterized in that A plurality of intermediate functional layers (130) are disposed between one side of the substrate (110) and the piezoelectric layer (120); And / or, a plurality of the intermediate functional layers (130) are arranged between the other side of the substrate (110) and the piezoelectric layer (120).

10. The packaging structure of the filter according to any one of claims 1 to 9, It is characterized in that The through hole is filled with a metal conductive member (108).

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