Longitudinal field excitation resonator, filter, manufacturing method of longitudinal field excitation resonator and filter, and electrical product

Abstract

The invention discloses a longitudinal field excitation resonator, a filter, a manufacturing method of the longitudinal field excitation resonator and the filter, and an electrical product, and relates to the technical field of resonators. The longitudinal field excitation resonator includes: a piezoelectric film; the first electrode is arranged on the first surface of the piezoelectric film; the second electrode is arranged on a second surface, opposite to the first surface, of the piezoelectric film; the signal leading-out structure is arranged on the surface of one side, opposite to the piezoelectric film, of the second electrode and the second surface, not covered by the second electrode, of the piezoelectric film; the packaging structure is arranged on the surface of one side, opposite to the piezoelectric film, of the first electrode and the first surface, not covered by the first electrode, of the piezoelectric film; a first cavity is formed among the packaging structure, the piezoelectric film and the first electrode. The signal leading-out structure is not led out from the packaging structure, so that the sealing performance and the reliability of the packaging structure are improved.

Description

Technical Field

[0001] The present application relates to the technical field of resonators, and in particular to a longitudinal field excitation resonator, a filter, a manufacturing method thereof, and an electrical product. Background Art

[0002] The resonator is packaged with polymer / resin / dry film materials, which is lower in cost and smaller in size than other packaging methods. However, the sealing and reliability of the polymer / resin / dry film packaging materials themselves are not as good as those of traditional non-organic materials (such as silicon, etc.), and since it is usually necessary to lead out the signal from the polymer / resin / dry film packaging structure, when the signal lead-out structure is located in the polymer / resin / dry film packaging structure, its packaging sealing and reliability are further reduced; at the same time, since the modulus of the polymer / resin / dry film packaging material itself is low, it is easily deformed by external forces, resulting in failure of the package. Summary of the invention

[0003] In order to solve at least one of the above problems existing in the prior art, the embodiments of the present application provide a longitudinal field excitation resonator, a filter and a manufacturing method thereof, and an electrical product.

[0004] According to a first aspect of an embodiment of the present application, the present application provides a longitudinal field excitation resonator, the resonator comprising:

[0005] Piezoelectric film;

[0006] A first electrode is disposed on a first surface of the piezoelectric film;

[0007] A second electrode is disposed on a second surface of the piezoelectric film facing away from the first surface;

[0008] A signal lead-out structure is arranged on a surface of the second electrode facing away from the piezoelectric film, and on the second surface of the piezoelectric film not covered by the second electrode;

[0009] A sealing structure, arranged on a surface of the first electrode facing away from the piezoelectric film, and on the first surface of the piezoelectric film not covered by the first electrode;

[0010] a covering layer, disposed on the sealing structure, and forming a first cavity with the sealing structure, the piezoelectric film and the first electrode;

[0011] The sealing structure and the covering layer are made of polymer compounds.

[0012] According to a second aspect of the embodiments of the present application, the present application provides a longitudinal field excitation filter, the filter comprising at least two resonators, the resonators being the longitudinal field excitation resonators provided by any embodiment of the present application;

[0013] A packaging structure, arranged on a surface of the first electrode in each of the resonators facing away from the piezoelectric film, and a first surface of the piezoelectric film not covered by the first electrode;

[0014] The packaging structure forms a first cavity with the piezoelectric film in each of the resonators and the first electrode.

[0015] In one embodiment, the filter further comprises:

[0016] A printed circuit board electrically connected to the signal lead-out structure of each resonator in the filter;

[0017] The plastic packaging material covers the top of the packaging structure and the side walls of the filter and fills the gap between the filter and the printed circuit board.

[0018] According to a third aspect of the embodiments of the present application, the present application provides a method for manufacturing a longitudinal field excitation filter, the method comprising:

[0019] Prepare a filter including at least two resonators provided in the second aspect of the embodiment of the present application;

[0020] forming a sealing structure, wherein the sealing structure is arranged on a surface of the first electrode of each resonator facing away from the piezoelectric film, and on a first surface of the piezoelectric film not covered by the first electrode;

[0021] forming a covering layer, wherein the covering layer is formed on the sealing structure and forms the first cavity together with the sealing structure, the piezoelectric film and the first electrode;

[0022] Soldering a printed circuit board, wherein the pads of the printed circuit board are electrically connected to the signal lead-out structures of each resonator in the filter;

[0023] A plastic encapsulation material is formed, wherein the plastic encapsulation material covers the top of the packaging structure and the sidewalls of the filter and fills the gap between the filter and the printed circuit board.

[0024] According to a fourth aspect of the embodiments of the present application, the present application provides an electrical product, which includes the longitudinal field excitation resonator as described in any embodiment of the present application, or the longitudinal field excitation filter as described in any embodiment of the present application.

[0025] In the longitudinal field excitation resonator and longitudinal field excitation filter of the present application, the signal lead-out structure is led out from the bottom of the resonator, and the packaging structure is located above the resonator. Since the signal lead-out structure is not led out from the packaging structure, the sealing and reliability of the packaging structure are improved; secondly, the signal lead-out structure is directly led out through the bottom of the resonator, and the structure is compact. When combined with the small size characteristics of the packaging structure, the size of the package body can be reduced as a whole; finally, the packaging structure is located away from the point of action of the package body and the external connection (such as the lead-out metal layer of the signal lead-out structure used for external electrical connection), which can reduce the possibility of failure of the packaging structure due to the introduction of the external connection point. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the prior art descriptions. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. In the drawings:

[0027] Figure 1 This is a cross-sectional structural diagram of a longitudinal field excitation resonator according to an embodiment of the present application.

[0028] Figure 2 Another schematic diagram of the longitudinal field excitation resonator according to an embodiment of the present application.

[0029] Figure 3 Another schematic diagram of the longitudinal field excitation resonator according to an embodiment of the present application.

[0030] Figure 4 Another schematic diagram of the longitudinal field excitation resonator according to an embodiment of the present application.

[0031] Figure 5 A schematic diagram of a longitudinal field excitation filter according to an embodiment of the present application.

[0032] Figure 6 Another schematic diagram of the longitudinal field excitation filter according to an embodiment of the present application.

[0033] Figure 7 It is a schematic diagram of a method for manufacturing a longitudinal field excitation filter according to an embodiment of the present application.

[0034] FIG. 8A to FIG. 8M Schematic diagram of different process stages of the longitudinal field excitation filter according to an embodiment of the present application. DETAILED DESCRIPTION

[0035] To make the purpose, technical solution and advantages of the embodiments of the present invention more clear, the embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings. Here, the exemplary embodiments of the present invention and their descriptions are used to explain the present invention, but are not intended to limit the present invention.

[0036] Embodiments of the first aspect

[0037] The embodiment of the present application provides a longitudinal field excitation resonator, Figure 1 This is a cross-sectional structural diagram of a longitudinal field excitation resonator according to an embodiment of the present application.

[0038] like Figure 1 As shown, the resonator 100 includes a resonator body and a packaging structure 200 , wherein the resonator body includes a piezoelectric film 110 , a first electrode 190 and a lead-out portion 191 thereof, a second electrode 120 and a lead-out portion 121 thereof, and a signal lead-out structure 3 .

[0039] The piezoelectric film 110 may be a single crystal piezoelectric film or a polycrystalline piezoelectric film, which is not limited in the present application.

[0040] The first electrode 190 (including its lead portion 191) is disposed on the first surface ( Figure 1 The second electrode 120 (including the lead-out portion 121 thereof) is disposed on the second surface (ie, the upper surface) of the piezoelectric film 110 facing away from the first surface. Figure 1 The piezoelectric film 110 and the first electrode 190 (including the lead-out portion 191 thereof) and the second electrode 120 (including the lead-out portion 121 thereof) attached to the two side surfaces of the piezoelectric film 110 may constitute the core functional part of the longitudinal field excitation resonator, for example.

[0041] The packaging structure 200 is disposed on a surface of the first electrode 190 (including the lead-out portion 191 thereof) facing away from the piezoelectric film 110. Figure 1 The upper surface of the first electrode 190 and its lead portion 191 shown in the figure, and the first surface of the piezoelectric film 110 not covered by the first electrode 190 (including its lead portion 191); and a cavity 230 (first cavity) is formed between the packaging structure 200, the piezoelectric film 110 and the first electrode 190 (including its lead portion 191).

[0042] According to the above embodiments, the present application leads the signal lead-out structure from the bottom of the resonator, while the packaging structure is located above the resonator. Since the signal lead-out structure is not led out from the packaging structure, the sealing and reliability of the packaging structure are improved; the signal lead-out structure is directly led out through the bottom of the resonator, and the structure is compact, which, combined with the small size characteristics of the packaging structure, can reduce the size of the package as a whole; the packaging structure is located away from the point of action of the package body and the external connection (such as the lead-out metal layer of the signal lead-out structure used for external electrical connection), reducing the possibility of failure of the packaging structure due to the introduction of the external connection point.

[0043] In one embodiment, the packaging structure is such as Figure 1 As shown, it includes a sealing structure 210 and a covering layer 220 .

[0044] The sealing structure 210 is disposed on a surface of the lead-out portion 191 of the first electrode facing away from the piezoelectric film 110 (eg Figure 1 ), and the first surface of the piezoelectric film 110 not covered by the first electrode 190 (including the lead-out portion 191 thereof) Figure 1 The sealing structure 210 on the left side is shown in FIG.

[0045] The cover layer 220 is disposed on the sealing structure 210 , and forms a cavity 230 with the sealing structure 210 , the piezoelectric film 110 , and the first electrode 190 (including the lead-out portion 191 thereof).

[0046] In one embodiment, the sealing structure 210 and the covering layer 220 are made of a polymer compound (also called a polymer or a high polymer), such as a resin material, and preferably a dry film. The sealing structure 210 and the covering layer 220 can be made by spin coating, or directly attached to the surface of the resonator body; the sealing structure 210 can be formed by photolithography.

[0047] The sealing structure 210 supports the cover layer 220 , which helps to enhance the stability of the cover layer 220 as a packaging structure.

[0048] In the present application, the longitudinal field excitation resonator can have different structures. Figures 2 to 4 Longitudinal field excited resonators with different signal extraction structures are demonstrated respectively.

[0049] Figure 2 Another schematic diagram of a longitudinal field excitation resonator is provided for the embodiment of the present application, such as Figure 2 As shown, the longitudinal field excitation resonator includes: a first electrode 190 (including a lead portion 191), a piezoelectric film 110, a second electrode 120 (including a lead portion 121), a dielectric layer 150 and a substrate 160 arranged in sequence along a first direction. Figure 2 See, the first direction is from top to bottom.

[0050] Below the core functional part of the resonator, a cavity 130 (second cavity) is defined on the side of the dielectric layer 150 facing the second electrode 120 , and a through hole 151 (first through hole) is defined at the bottom of the cavity 130 .

[0051] A through hole 161 (second through hole) is provided on the substrate 160, and the through hole 161 is connected and aligned (substantially coaxial) with the through hole 151. The through hole 151 and the through hole 161 aligned and connected therewith partially or completely overlap with the cavity 130 in the first direction mentioned above, that is, the positions of the through hole 151 and the corresponding through hole 161 can vary within the bottom surface of the cavity 130.

[0052] At the same time, the through hole 151 and the through hole 161 aligned and connected thereto also overlap with the cavity 230 in the first direction mentioned above, that is, the extension line of the central axis of the through hole 151 and the corresponding through hole 161 passes through the cavity 230 (first cavity) but not through the sealing structure 210. This can further reduce the possibility of failure of the polymer packaging structure due to the introduction of electrical or mechanical coupling at the external connection points (through holes 151 and through holes 161).

[0053] The metal layer 140 covers the bottom surface and sidewalls of the cavity 130, and the metal layer 140 extends between the dielectric layer 150 and the second electrode 120, and is attached to the edge of the second electrode 120 and its lead-out portion 121. That is, the portion of the metal layer 140 located below the core functional portion and the second electrode 120 together form the cavity 130.

[0054] The first part 170w of the metal layer 170 is covered on the sidewalls of the through hole 151, the sidewalls of the through hole 161, and the surface of the metal layer 140 exposed through the through hole 151, and the second part 170p of the metal layer 170 extends outside the through hole 161 and is attached to the surface of the substrate 160 facing away from the dielectric layer 150. The first part 170w and the second part 170p constitute the entire metal layer 170, so that the electrical signal on the second electrode 120 of the resonator (including its lead-out portion 121) can be transmitted to the back side of the substrate 160 through the metal layer 140 and the metal layer 170, so as to transmit the electrical signal to other functional devices.

[0055] from Figure 2In the present embodiment, the signal lead-out structure composed of the metal layer 140, the through hole 151, the through hole 161 and the metal layer 170 is located below the core functional part of the resonator, and the packaging structure composed of the sealing structure 210 and the covering layer 220 is located above the resonator body. The signal lead-out structure is not led out from the packaging structure, and the sealing and reliability of the packaging structure are improved. At the same time, the signal lead-out structure is directly led out from the bottom of the resonator, and the structure is compact. When combined with the small size of the packaging structure, the size of the package body can be reduced as a whole, which is conducive to increasing the number of devices per unit wafer area and reducing costs. In addition, the packaging structure is located away from the resonator and the packaging body composed of the packaging structure and the external connection point (such as the lead-out metal layer 170 for external electrical connection), and the possibility of failure of the packaging structure due to the introduction of the external connection point is reduced.

[0056] Figure 3 Another schematic diagram of a longitudinal field excitation resonator is provided for the embodiment of the present application, such as Figure 3 As shown, the longitudinal field excitation resonator includes: a first electrode 190, a piezoelectric film 110, a second electrode 120, a dielectric layer 150 and a substrate 160 arranged in sequence along a first direction. Figure 3 See, the first direction is from top to bottom.

[0057] Below the core functional part of the resonator, a cavity 130 (second cavity) and a through hole 151 (first through hole) are provided on the side of the dielectric layer 150 facing the second electrode 120. The through hole 151 is provided at a position of the dielectric layer 150 corresponding to the lead-out portion 121 of the second electrode 120, that is, on the dielectric layer region below the lead-out portion 121 of the second electrode 120, and a portion of the surface of the lead-out portion 121 is exposed in the through hole 151. The cavity 130 is opened at a position corresponding to the area outside the dielectric layer 150 and the lead-out portion 121 of the second electrode 20. The upper bottom surface of the cavity 130 exposes a part of the surface of the second electrode 120 facing away from the piezoelectric film 110, and the lower bottom surface of the cavity 130 exposes a part of the surface of the side where the substrate 160 and the dielectric layer 150 are bonded. The lateral periphery of the cavity 130 is the dielectric layer 150, that is, the cavity 130 is surrounded by the second electrode 120 (excluding the lead-out portion 121) (corresponding to the upper bottom surface of the cavity 130), the substrate 160 (corresponding to the lower bottom surface of the cavity 130) and the dielectric layer 150 (corresponding to the side wall of the cavity 130).

[0058] A through hole 161 (second through hole) is provided on the substrate 160, and the through hole 161 is connected and aligned with the through hole 151 (substantially coaxial). At the same time, the through hole 151 and the through hole 161 aligned and connected therewith overlap with the cavity 230 in the first direction mentioned above, that is, the extension line of the central axis of the through hole 151 and the through hole 161 corresponding thereto passes through the cavity 230 (first cavity) but not through the sealing structure 210. This can further reduce the possibility of failure of the polymer packaging structure due to the introduction of electrical or mechanical coupling at the external connection points (through holes 151 and through holes 161).

[0059] The first part 170w of the metal layer 170 is covered on the sidewalls of the through hole 151, the sidewalls of the through hole 161, and the surface of the lead-out portion 121 of the second electrode 120 exposed through the through hole 151, and the second part 170p of the metal layer 170 extends outside the through hole 161 and is attached to the surface of the side of the substrate 160 that is away from the dielectric layer 150. The first part 170w and the second part 170p constitute the entire metal layer 170, so that the electrical signal on the resonator second electrode 120 (including its lead-out portion 121) can be transmitted to the back side of the substrate 160 through the metal layer 170, so as to transmit the electrical signal to other functional devices.

[0060] and Figure 2 The signal extraction structure of the resonator shown is first compared to, Figure 3 In the signal extraction structure shown, the metal layer 170 is located outside the cavity 130, and Figure 3 The cavity and signal lead-out are realized by metal layer bonding.

[0061] use Figure 3 The resonator structure described can effectively reduce the space occupied by the device in the horizontal direction by controlling the distance between the central axis of the through hole in the resonator and the upper bottom surface of the cavity, thereby reducing the device size, increasing the number of devices per unit wafer area, and reducing costs. Since no bonding alignment process is required, the distance between the central axis of the through hole and the upper bottom surface of the cavity can be controlled to be between 1 micron and 100 microns. In addition, since the cavity of the present application is formed by a bonding process, compared to the method of forming the cavity by a sacrificial layer release process, the present application eliminates the hidden danger of the etchant in the release process damaging the device structure, and improves the process reliability and yield rate.

[0062] Figure 4 Another schematic diagram of a longitudinal field excitation resonator is provided for the embodiment of the present application, such as Figure 4As shown, the longitudinal field excitation resonator includes: a first electrode 190 (including a lead portion 191), a piezoelectric film 110, a second electrode 120 (including a lead portion 121), a bonding layer 180-1, a bonding layer 180-2, a metal layer 140 and a substrate 160 arranged in sequence along a first direction. The bonding layer 180-1 is attached to the inner side of the edge of the lower surface of the second electrode 120, and the bonding layer 180-2 is attached to the upper surface of the metal layer 140, and the bonding layer 180-1 and the bonding layer 180-2 form a bonding relationship. Figure 4 See, the first direction is from top to bottom.

[0063] Below the core functional part, there is a cavity 130 (second cavity). Figure 4 It can be seen that the cavity 130 is surrounded by the second electrode 120, the bonding layer 180-1, the bonding layer 180-2 and the metal layer 140, wherein a portion of the lower surface of the second electrode 120 is the upper bottom surface of the cavity 130, the inner walls of the bonding layer 180-1 and the bonding layer 180-2 are the side walls of the cavity 130, and a portion of the upper surface of the metal layer 140 is the lower bottom surface of the cavity 130.

[0064] The substrate 160 is provided with a through hole 161, wherein the through hole 161 overlaps with the cavity 230 in the first direction mentioned above, that is, the extension line of the central axis of the through hole 161 passes through the cavity 230 (first cavity) but not through the sealing structure 210. This can further reduce the possibility of failure of the polymer packaging structure due to the introduction of electrical or mechanical coupling at the external connection point (through hole 161).

[0065] The through hole 161 has a metal layer 170, and the metal layer 170 is electrically connected to the metal layer 140. For example, Figure 4 As shown, the sidewall of the through hole 161 and the partial surface of the metal layer 140 exposed by the through hole 161 have a second metal layer 170, more specifically a first portion 170w of the second metal layer 170, and the second metal layer 170 also has a second portion, namely Figure 4 The first portion 170w and the second portion 170p extend out of the second through hole and are attached to the surface of the substrate 160 facing away from the metal layer 140. The first portion 170w and the second portion 170p constitute the entire metal layer 170, so that the electrical signal on the resonator second electrode 120 (including its lead-out portion 121) can be transmitted to the back side of the substrate 160 through the metal layer 140 and the metal layer 170, so as to transmit the electrical signal to other functional devices.

[0066] Figure 4The number of bonding layers shown is two, namely bonding layer 180-1 and bonding layer 180-2. In actual applications, the number of bonding layers and the corresponding bonding relationship can also be changed according to needs. For example, a single bonding layer implementation method can be adopted, such as retaining only bonding layer 180-1 and attaching it to the second electrode 120 and then directly bonding it to the metal layer 140, or retaining only bonding layer 180-2 and attaching it to the metal layer 140 and then directly bonding it to the second electrode 120, etc.

[0067] In one embodiment, the resonator further comprises a supporting layer. Figure 4 As shown, the support layer includes:

[0068] The metal layer 141 is disposed on a surface of the substrate 160 facing the second electrode 120 and is not electrically connected to the metal layer 140 ;

[0069] The metal layer 122 is disposed on the second surface of the piezoelectric film 110 and is not electrically connected to the second electrode 120 (including the lead portion 121 thereof);

[0070] The bonding layer 180 - 3 and the bonding layer 180 - 4 for bonding are provided between the metal layer 141 and the second electrode 120 (including the lead portion 121 ), and between the metal layer 141 and the metal layer 122 .

[0071] The above embodiment improves the stability of the longitudinal field excitation resonator structure in the packaging process by providing a support layer.

[0072] In one embodiment, the material of the piezoelectric film 110 includes but is not limited to at least one of the following: lithium niobate (LiNbO3), lithium tantalate (LiTaO3), aluminum nitride (AlN), scandium-doped aluminum nitride (AlScN), barium strontium titanate (BST), etc.

[0073] In one embodiment, the material of the substrate 160 includes but is not limited to silicon, sapphire, gallium arsenide, etc.

[0074] In one embodiment, the shape of the cavity 130 is not limited to Figures 2 to 4 The cavity 130 is shown as an inverted trapezoid or a rectangle, but it can be changed into other shapes according to the process conditions.

[0075] In one embodiment, the shapes and numbers of the through holes 151 and 161 are not limited to Figures 2 to 4 As shown, in actual applications, the number of through holes 151 is one or more, and the number and position of through holes 161 also correspond to the through holes 151 one by one; at the same time, the shapes of through holes 151 and through holes 161 are not limited to Figures 2 to 4 Shape shown.

[0076] use Figure 4The resonator structure shown has a signal lead structure located below the core working part of the device, which can effectively reduce the space occupied by the device in the horizontal direction, thereby reducing the device size, increasing the number of devices per unit wafer area, and reducing costs. In addition, since the cavity is formed by a bonding process, it replaces the sacrificial layer release process, thereby eliminating the hidden danger of the etchant in the release process damaging the device structure, and improving the process reliability and yield rate.

[0077] Embodiments of the second aspect

[0078] An embodiment of the present application provides a longitudinal field excitation filter, the filter comprising at least two resonators, and the resonator is any longitudinal field excitation resonator provided in the embodiment of the first aspect of the present application.

[0079] A packaging structure, arranged on a surface of the first electrode in each of the resonators facing away from the piezoelectric film, and a first surface of the piezoelectric film not covered by the first electrode;

[0080] The packaging structure forms a cavity with the piezoelectric film in each of the resonators and the first electrode.

[0081] Figure 5 A schematic diagram of the longitudinal field excitation filter provided in this application, Figure 5 The filter consists of two Figure 2 The longitudinal field excited resonator shown is taken as an example for explanation.

[0082] like Figure 5 As mentioned above, the first resonator ( Figure 5 The resonator on the left side includes, from top to bottom, a first electrode 190 (including its lead-out portion 191), a piezoelectric film 110, a second electrode 120 (including its lead-out portion 121), a metal layer 140, a dielectric layer 150 and a substrate 160, wherein the metal layer 140 and the second electrode 120 form a cavity 130, a through hole 151 is provided on the dielectric layer 150, a through hole 161 is provided on the substrate, and the through holes 151 are connected and aligned with the through holes 161, a first portion 170w of the metal layer 170 covers the side walls of the through hole 151, the side walls of the through hole 161 and the surface of the metal layer 140 exposed through the through hole 151, and a second portion 170p of the metal layer 170 extends to the surface of the substrate 160 facing away from the dielectric layer 150.

[0083] Similarly, the second resonator ( Figure 5The resonator on the right side includes, from top to bottom, a first electrode 190-1 (including its lead-out portion 191-1), a piezoelectric film 110, a second electrode 120-1 (including its lead-out portion 121-1), a metal layer 140-1, a dielectric layer 150 and a substrate 160, wherein the metal layer 140-1 and the second electrode 120-1 form a cavity 130-1, a through hole 151-1 is opened on the dielectric layer 150, a through hole 161-1 is opened on the substrate, and the through holes 151-1 are connected and aligned with the through holes 161-1, a first portion 170w-1 of the metal layer 170-1 covers the side walls of the through hole 151-1, the side walls of the through hole 161-1 and the surface of the metal layer 140-1 exposed through the through hole 151-1, and a second portion 170p-1 of the metal layer 170-1 extends to the surface of the substrate 160 facing away from the dielectric layer 150.

[0084] from Figure 5 As can be seen, the lead portion 191 of the first electrode of the first resonator is electrically connected to the lead portion 191 - 1 of the first electrode of the second resonator, and the first resonator and the second resonator share a piezoelectric film 110 , a dielectric layer 150 and a substrate 160 .

[0085] The packaging structure includes three sealing structures 210 and a covering layer 220. The first sealing structure 210 is located on the first surface of the piezoelectric film on the first resonator side, the second sealing structure 210 is located on the first surface of the piezoelectric film on the second resonator side, and the third sealing structure 210 is located on the lead-out surface of the first electrode electrically connected to the two resonators.

[0086] A cavity is formed between the packaging structure and the two resonators. Figure 5 It can be seen that, for example, the first sealing structure 210, the second sealing structure 210, the covering layer 220 in the packaging structure, the piezoelectric film 110 on the first resonator side, and the first electrode 190 (including its lead-out portion 191) form a cavity 230; the second sealing structure 210, the third sealing structure 210, the covering layer 220 in the packaging structure, the piezoelectric film 110 on the second resonator side, and the first electrode 190-1 (including its lead-out portion 191-1) form a cavity 230-1.

[0087] The covering layer 220 is disposed on the three sealing structures 210 , and under the support of the sealing structures 210 , the stability of the covering layer 220 is enhanced.

[0088] Figure 5 The filter only includes two resonators. In practical applications, the number of resonators included in the filter can be more than two, and the structure of the resonator can be Figure 2 , Figure 3 , Figure 4The longitudinal field excitation resonator shown or the resonator of other structures is not limited in this application.

[0089] In one embodiment, the longitudinal field excitation filter further comprises:

[0090] A printed circuit board electrically connected to a signal lead-out structure of each resonator included in the longitudinal field excitation filter;

[0091] The plastic packaging material covers the top of the packaging structure of the longitudinal field excitation filter and the side wall of the longitudinal field excitation filter, and fills the gap between the longitudinal field excitation filter and the printed circuit board.

[0092] Figure 6 Another schematic diagram of the longitudinal field excitation filter provided in this application, which Figure 5 The longitudinal field excitation filter shown is soldered to a printed circuit board (PCB) and covered with a plastic packaging material to form a higher level packaging structure, wherein the PCB is connected to the printed circuit board (PCB) through different connection structures. Figure 5 The resonators shown in are connected separately.

[0093] like Figure 6 As shown, the PCB includes a structure layer 410 , a structure layer 420 , and at least two connection structures penetrating the structure layer 410 and the structure layer 420 .

[0094] Specifically, with the first resonator ( Figure 6 The connection structure corresponding to the first resonator on the left side includes metal connection pillars 320, 330 and 340 connected in sequence inside the PCB board, a pad 310 disposed on the surface of the PCB board and connected to the metal connection pillar 320, an adhesive layer 311 disposed on the surface of the pad 310, and a solder ball 176 disposed on the adhesive layer 311. The first resonator with the packaging structure is fixed on the PCB board by connecting the solder ball 176 to the metal layer 170 of the first resonator, and an electrical connection is formed between the first resonator and the PCB board.

[0095] Similarly, with the second resonator ( Figure 6 The connection structure corresponding to the second resonator on the right side includes metal connection pillars 320-1, 330-1 and 340-1 connected in sequence inside the PCB board, a pad 310-1 disposed on the surface of the PCB board and connected to the metal connection pillar 320-1, an adhesive layer 311-1 disposed on the surface of the pad 310-1, and a solder ball 176-1 disposed on the adhesive layer 311-1. The second resonator with the packaging structure is fixed on the PCB board by connecting the solder ball 176-1 to the metal layer 170-1 of the second resonator, and an electrical connection is formed between the second resonator and the PCB board.

[0096] pass Figure 6 The connection structure fixes the filter including the first resonator and the second resonator on the PCB board, and forms an electrical connection between the filter and the PCB board.

[0097] In this embodiment, the packaging structure, the resonator structure and the materials used are similar to those of the embodiment of the first aspect, and the above contents are incorporated herein and will not be repeated here.

[0098] In one embodiment, the through holes of the resonators included in the filter are filled with metal material.

[0099] For example, Figure 6 As shown, the filter consists of a first resonator ( Figure 6 The through hole 151 and the through hole 161 of the resonator on the left side of the filter are filled with metal material 175, and the second resonator ( Figure 6 The metal material 175-1 is filled in the through hole 151-1 and the through hole 161-1 of the resonator on the right side.

[0100] In this embodiment, metal material is filled in the resonator through hole, so that the structural connection and electrical connection between the resonator and the solder ball of the PCB board can be more reliable.

[0101] In one embodiment, if Figure 6 As shown, the plastic encapsulation material 500 covers the top of the packaging structure and the side walls of the filter, and fills the gap between the bottom surface of the filter and the printed circuit board.

[0102] The material of the plastic packaging material 500 is, for example, epoxy resin molding compound.

[0103] According to the above embodiments, the present application leads the signal lead-out structure out from the bottom of the resonator, while the packaging structure is located above the resonator. Since the signal lead-out structure is not led out from the packaging structure, the sealing and reliability of the packaging structure are improved; secondly, the signal lead-out structure is directly led out through the bottom of the resonator, and the structure is compact. When combined with the small size characteristics of the packaging structure, the size of the package body can be reduced as a whole; finally, the packaging structure is located on the side away from the PCB board, and the possibility of failure of the polymer / resin / dry film packaging structure caused by force conduction after the PCB board is bent is reduced.

[0104] Embodiments of the third aspect

[0105] The present application provides a method for manufacturing a longitudinal field excitation filter, the method comprising:

[0106] Prepare a filter comprising at least two resonators; wherein the resonator is any resonator provided in the embodiment of the first aspect of the present application;

[0107] Forming a sealing structure, the sealing structure is arranged on a surface of the first electrode of each resonator in the filter facing away from the piezoelectric film, and on a first surface of the piezoelectric film not covered by the first electrode;

[0108] forming a covering layer, wherein the covering layer is formed on the sealing structure and forms a cavity with the sealing structure, the piezoelectric film and the first electrode;

[0109] Soldering a printed circuit board, wherein the pads of the printed circuit board are electrically connected to the signal lead-out structures of each resonator in the filter;

[0110] A plastic encapsulation material is formed, which covers the top of the packaging structure and the sidewalls of the filter and fills the gap between the filter and the printed circuit board.

[0111] Figure 7 is a schematic diagram of a method for manufacturing a longitudinal field excitation filter according to an embodiment of the present application, wherein Figure 6 The manufacture of the longitudinal field excitation filter shown in FIG. Figure 7 As shown, the method includes:

[0112] S1, preparing a structure covered with a piezoelectric film 110 on a substrate 100, and depositing a metal layer 120M on the surface of the piezoelectric film 110 facing away from the substrate 100, see Fig. 8A ;

[0113] S2, a sacrificial layer 131 and a sacrificial layer 131-1 are fabricated on the surface of the metal layer 120M by deposition, grinding, and patterning processes, see Figure 8B ;

[0114] S3, depositing a metal layer 140M on the surfaces of the sacrificial layer 131, the sacrificial layer 131-1 and the metal layer 120M, see Figure 8C ;

[0115] S4, the metal layer 120M is patterned to form the second electrode 120 (including the lead-out portion 121 thereof) and the second electrode 120-1 (including the lead-out portion 121-1 thereof), and the metal layer 140M is patterned to form the metal connection layer 140 and the metal connection layer 140-1, see Fig.8D ;

[0116] S5, a dielectric layer 150 is formed on the metal connection layer 140, the metal connection layer 140-1 and the surface of the piezoelectric film 110 by deposition and grinding processes, and a through hole 151 and a through hole 151-1 are formed in 150 by a patterning process, see Fig. 8E ;

[0117] S6, bonding the substrate 160 to the surface of the medium 150, see Figure 8F ;

[0118] S7, Flip Figure 8F The substrate 100 is removed, and the first electrode 190 (including the lead-out portion 191 thereof) and the first electrode 190-1 (including the lead-out portion 191-1 thereof) are formed on the surface of the piezoelectric film 110 facing away from the second electrode by deposition and patterning processes, see Figure 8G ;

[0119] S8, by deposition and grinding processes, the first electrode 190 (including the lead portion 191 thereof), the first electrode 190-1 (including the lead portion 191-1 thereof) and the piezoelectric film 110 are covered with a protective layer 180, see Figure 8H ;

[0120] S9, Flip Figure 8H The structure is as follows: a through hole 161 and a through hole 161-1 are formed in the substrate 160 by an imaging process; a metal layer 170 is made to cover the side walls of the through hole 161 and the through hole 151, the surface of the metal connection layer 140 exposed at the bottom of the through hole 151, and a part of the surface of the substrate 160 by deposition and patterning processes; and a metal layer 170-1 is made to cover the side walls of the through hole 161-1 and the through hole 151-1, the surface of the metal connection layer 140-1 exposed at the bottom of the through hole 151-1, and a part of the surface of the substrate 160; optionally, the through hole covered with the metal layer 170 may be further filled with metal 175, and the through hole covered with the metal layer 170-1 may be further filled with metal 175-1, see Figure 8I ;

[0121] S10, using an etchant to release the sacrificial material 131 and the sacrificial layer 131-1, forming the cavity 130 and the cavity 130-1 and removing the protective layer 180; using a spin coating and patterning process to form a sealing structure 210 on the surface of the piezoelectric film 110 on both sides of the two resonators and on the surface of the lead-out portion 191 and the lead-out portion 191-1 connected between the two resonators, see Figure 8J ;

[0122] S11, covering the sealing structure 210 with the covering layer 220 by a film laminating process, and forming a cavity 230 and a cavity 230-1 between the covering layer 220, the sealing structure 210 and the upper surface of the resonator, see Figure 8K ; Here, the wafer covering the package structure should usually be diced to separate the individual chips;

[0123] S12, fix the chip covering the package structure to the pad 310 (including the adhesive layer 311) and the pad 310-1 (including the adhesive layer 311-1) of the PCB board through the solder ball 176 and the solder ball 176-1, wherein the upper parts of the solder ball 176 and the solder ball 176-1 are respectively connected to the metal layer 170 (including the filling part 175) and the metal layer 170-1 (including the filling part 175-1) of the resonator, and the lower parts of the solder ball 176 and the solder ball 176-1 are respectively connected to the pad 310 (including the adhesive layer 311) and the pad 310-1 (including the adhesive layer 311-1) of the PCB board, so as to realize the electrical connection and structural fixation of the chip and the PCB, see Figure 8L ;

[0124] S13, a plastic encapsulation material 500, usually epoxy molding compound (EMC), is applied to cover Figure 8L The package structure surface and filter side wall in the structure are filled in the gap between the filter and the PCB board to form a complete package structure. Figure 8M .

[0125] The longitudinal field excitation filter obtained by the manufacturing method of this embodiment includes a resonator whose signal lead-out structure is led out from the bottom of the resonator, while the packaging structure is located above the resonator. Since the signal lead-out structure is not led out from the packaging structure, the sealing and reliability of the packaging structure are improved; secondly, the signal lead-out structure is directly led out from the bottom of the resonator, and the structure is compact. When combined with the small size characteristics of the packaging structure, the size of the package body can be reduced as a whole; finally, the packaging structure is located on the side away from the PCB board, and the possibility of failure of the polymer / resin / dry film packaging structure caused by force conduction after the PCB board is bent is reduced.

[0126] In one embodiment, the present application provides an electrical product, the electrical product comprising: a longitudinal field excitation resonator as described in any embodiment of the present application, or a longitudinal field excitation filter as described in any embodiment of the present application. For example, the electrical product comprises: (1) RF filters, duplexers, multiplexers, especially broadband RF filters applied to 5G communication frequency bands, such as: N77, N78, N79, WiFi filters applied to 3GHz to 5GHz frequency bands; (2) RF front-end modules, communication modules, and communication devices containing the above filters, duplexers, and multiplexers; (3) oscillators and clock signal generators; (4) biological, chemical, and physical sensors using the resonator as a sensitive element; (5) IoT sensor nodes containing the above resonators, or filters, or oscillators, or sensors.

[0127] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A longitudinal field excitation resonator, characterized in that: The resonator comprises: Piezoelectric film; A first electrode is disposed on a first surface of the piezoelectric film; A second electrode is disposed on a second surface of the piezoelectric film facing away from the first surface; A signal lead-out structure is arranged on a surface of the second electrode facing away from the piezoelectric film, and on the second surface of the piezoelectric film not covered by the second electrode; A sealing structure, arranged on a surface of the first electrode facing away from the piezoelectric film, and on the first surface of the piezoelectric film not covered by the first electrode; a covering layer, disposed on the sealing structure, and forming a first cavity with the sealing structure, the piezoelectric film and the first electrode; The sealing structure and the covering layer are made of polymer compounds.

2. The longitudinal field excitation resonator according to claim 1, characterized in that: The signal extraction structure comprises: A dielectric layer is arranged on a side of the second electrode facing away from the piezoelectric film; a side of the dielectric layer facing the second electrode has a second cavity, and a bottom of the second cavity has a first through hole; A substrate is disposed on a surface of the dielectric layer facing away from the second electrode; the substrate has a second through hole, the second through hole is aligned and connected with the first through hole, and an extension line of the central axis of the aligned and connected first through hole and the second through hole passes through the first cavity; The bottom surface and sidewalls of the second cavity have a first metal layer, and the first metal layer extends between the dielectric layer and the second electrode; The sidewall of the first through hole, the sidewall of the second through hole, and the surface of the first metal layer exposed through the first through hole have a second metal layer, and the second metal layer extends to the surface of the substrate facing away from the dielectric layer.

3. The longitudinal field excitation resonator according to claim 1, characterized in that: The signal extraction structure comprises: A dielectric layer is arranged on a side of the second electrode facing away from the piezoelectric film; a first through hole is provided at a position of the dielectric layer corresponding to the lead-out portion of the second electrode; a second cavity is provided at a position of the dielectric layer corresponding to an area outside the lead-out portion of the second electrode; A substrate is disposed on a surface of the dielectric layer facing away from the second electrode; the substrate has a second through hole, the second through hole is aligned and connected with the first through hole, and an extension line of the central axis of the aligned and connected first through hole and the second through hole passes through the first cavity; The upper bottom surface of the second cavity exposes a part of the surface of the second electrode facing away from the piezoelectric film, and the lower bottom surface of the second cavity exposes a part of the surface of the substrate and the dielectric layer in contact with each other; A metal layer is provided on the sidewall of the first through hole, the sidewall of the second through hole and the second electrode exposed through the first through hole, and the metal layer extends to the surface of the substrate facing away from the dielectric layer.

4. The longitudinal field excitation resonator according to claim 1, characterized in that: The signal extraction structure comprises: A first bonding layer is arranged on a side of the second electrode facing away from the piezoelectric film; A first metal layer, disposed on a side of the first bonding layer facing away from the second electrode; A substrate, disposed on a side of the first metal layer facing away from the first bonding layer; The second electrode, the first bonding layer and the first metal layer form a second cavity; The substrate has at least one through hole, and an extension line of a central axis of the through hole passes through the first cavity; The through hole has a second metal layer therein, and the second metal layer is electrically connected to the first metal layer.

5. The longitudinal field excitation resonator according to claim 4, characterized in that: The resonator further comprises a support layer, the support layer comprising: a third metal layer, disposed on a surface of the substrate facing the second electrode and not electrically connected to the first metal layer; a fourth metal layer, disposed on the second surface of the piezoelectric film and not electrically connected to the second electrode; a second bonding layer, disposed between the third metal layer and the second electrode; The third bonding layer is arranged between the third metal layer and the fourth metal layer.

6. The longitudinal field excited resonator according to any one of claims 1 to 5, characterized in that: The piezoelectric film is a single crystal piezoelectric film or a polycrystalline piezoelectric film.

7. The longitudinal field excited resonator according to any one of claims 1 to 5, characterized in that: The polymer compound is a resin or a dry film.

8. A longitudinal field excitation filter, characterized in that: The filter comprises at least two resonators, wherein the resonators are longitudinal field excitation resonators as described in any one of claims 1 to 7; A packaging structure, arranged on a surface of the first electrode in each of the resonators facing away from the piezoelectric film, and a first surface of the piezoelectric film not covered by the first electrode; The packaging structure forms a first cavity with the piezoelectric film in each of the resonators and the first electrode.

9. The longitudinal field excitation filter according to claim 8, characterized in that: The lead-out portions of the first electrodes in the resonators are electrically connected.

10. The longitudinal field excitation filter according to claim 8 or 9, characterized in that: The filter further comprises: A printed circuit board electrically connected to the signal lead-out structure of each resonator in the filter; The plastic packaging material covers the top of the packaging structure and the side walls of the filter and fills the gap between the filter and the printed circuit board.

11. A method for manufacturing a longitudinal field excitation filter, characterized in that: The method comprises: Prepare the filter comprising at least two resonators as claimed in claim 8; forming a sealing structure, wherein the sealing structure is arranged on a surface of the first electrode of each resonator facing away from the piezoelectric film, and on a first surface of the piezoelectric film not covered by the first electrode; forming a covering layer, wherein the covering layer is formed on the sealing structure and forms a first cavity with the sealing structure, the piezoelectric film and the first electrode; Soldering a printed circuit board, wherein the pads of the printed circuit board are electrically connected to the signal lead-out structures of each resonator in the filter; A plastic encapsulation material is formed, wherein the plastic encapsulation material covers the top of the packaging structure and the sidewalls of the filter and fills the gap between the filter and the printed circuit board.

12. An electrical product, characterized in that: The electrical product comprises: the longitudinal field excitation resonator according to any one of claims 1 to 7, or the longitudinal field excitation filter according to any one of claims 8 to 10.

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