Surface acoustic wave filter packaging structure and preparation method thereof, and related equipment

Abstract

The invention provides a surface acoustic wave filter packaging structure, a preparation method thereof and related equipment, and relates to the technical field of semiconductors. A spacer region between the interdigital electrode and the bearing substrate in the first direction is a cavity region of the surface acoustic wave filter; the bonding pad structure is in contact with the substrate and the bearing substrate in the first direction, and the interdigital electrode and the bonding pad main body structure are located in the area defined by the first enclosing wall structure, so that the arrangement of at least the Nth enclosing wall structure in the preparation process of the plastic packaging layer can prevent the plastic packaging filler from entering the cavity area. Therefore, the working area of the packaging structure of the surface acoustic wave filter is effectively protected. Compared with the prior art, the technical scheme of the invention does not need additional materials and structures to form a closed cavity, and the bonding pad structure is used as a barrier layer of the plastic package filler, so that the purposes of simplifying the process steps and reducing the production cost are achieved.

Description

Technical Field

[0001] The present application relates to the field of semiconductor technology, and in particular to a surface acoustic wave filter packaging structure and a preparation method thereof, and related equipment. Background Art

[0002] SAW (Surface Acoustic Wave) filter is the abbreviation of surface acoustic wave filter. It is a special filtering device made by using its piezoelectric effect and the physical characteristics of surface acoustic wave propagation. It is widely used in various fields, such as radio frequency. Among them, surface acoustic wave is an elastic wave with energy concentrated near the surface.

[0003] At present, the packaging structure of surface acoustic wave filters is to package the SAW filter into a CSP (Chip Scale Package), but this technology requires additional materials and structures to form a closed cavity, such as using an organic dry film to cover and protect the SAW filter to protect the SAW filter from external contamination, resulting in complex processes and high production costs. Summary of the invention

[0004] In view of the above problems, the present application provides a surface acoustic wave filter packaging structure and a preparation method thereof, and related equipment to simplify the process steps and reduce production costs. The specific scheme is as follows: A first aspect of the present application provides a surface acoustic wave filter packaging structure, the surface acoustic wave filter packaging structure comprising: a surface acoustic wave filter and a carrier substrate; The surface acoustic wave filter comprises a substrate, interdigital electrodes and a pad structure; the substrate and the carrier substrate are arranged opposite to each other in a first direction, and the first direction is perpendicular to the plane where the substrate is located; The interdigitated electrodes and the pad structure are located on the side of the substrate facing the carrier substrate; the pad structure includes a pad main body structure and N wall structures arranged in sequence from the inside to the outside, N ≥ 1, and N is a positive integer; the interdigitated electrodes and the pad main body structure are located inside the area surrounded by the first wall structure; wherein the pad structure is in contact with the substrate and the carrier substrate respectively in the first direction, and there is a gap between the interdigitated electrodes and the carrier substrate in the first direction; The surface acoustic wave filter packaging structure further includes a plastic packaging layer for packaging the surface acoustic wave filter, and the plastic packaging layer is in contact with the outer side wall of the Nth surrounding wall structure.

[0005] Preferably, in the above-mentioned surface acoustic wave filter packaging structure, the wall structure and the pad main body structure are an integrally formed structure.

[0006] Preferably, in the above-mentioned surface acoustic wave filter packaging structure, at least one of the N wall structures is electrically connected to the pad main body structure.

[0007] Preferably, in the above-mentioned surface acoustic wave filter packaging structure, the widths of the N wall structures gradually decrease from the outside to the inside.

[0008] Preferably, in the above-mentioned surface acoustic wave filter packaging structure, the surface acoustic wave filter packaging structure further includes: A bonding layer is located on a side of the carrier substrate facing the surface acoustic wave filter; the pad structure is in contact with the carrier substrate via a groove penetrating the bonding layer.

[0009] Preferably, in the above-mentioned surface acoustic wave filter packaging structure, the surface acoustic wave filter packaging structure further includes: A through hole penetrating the carrier substrate and an external lead structure; The external lead structure is electrically connected to the pad main body structure through the through hole.

[0010] Preferably, in the above-mentioned surface acoustic wave filter packaging structure, the surface acoustic wave filter packaging structure further includes: A protective layer is located on a side of the carrier substrate away from the surface acoustic wave filter; the protective layer exposes a portion of the surface of the external lead structure.

[0011] Preferably, in the above-mentioned surface acoustic wave filter packaging structure, the interdigitated electrodes include a first bus bar and a second bus bar arranged opposite to each other in the second direction, and a first electrode finger located on the first bus bar and a second electrode finger located on the second bus bar; The first bus bar and the second bus bar have the same length extension direction, both extending along a third direction. The second direction and the third direction are parallel to the plane where the substrate is located, and the second direction and the third direction intersect.

[0012] A second aspect of the present application provides a method for preparing a surface acoustic wave filter packaging structure, the method for preparing a surface acoustic wave filter packaging structure comprising: A surface acoustic wave filter is provided, the surface acoustic wave filter comprising a substrate, an interdigitated electrode and a pad structure; the pad structure comprises a pad main body structure and N wall structures sequentially arranged from the inside to the outside, N ≥ 1, and N is a positive integer; the interdigitated electrode and the pad main body structure are located inside an area surrounded by the first wall structure; The surface acoustic wave filter is fixed on a carrier substrate; the substrate and the carrier substrate are arranged relative to each other in a first direction, and the first direction is perpendicular to the plane where the substrate is located; the interdigitated electrodes and the pad structure are located on the side of the substrate facing the carrier substrate; the pad structure is in contact with the substrate and the carrier substrate respectively in the first direction, and there is a gap between the interdigitated electrodes and the carrier substrate in the first direction; A plastic encapsulation layer is formed for encapsulating the surface acoustic wave filter, and the plastic encapsulation layer is in contact with the outer side wall of the Nth surrounding wall structure.

[0013] Preferably, in the method for preparing the above-mentioned surface acoustic wave filter packaging structure, the wall structure and the pad main body structure are formed in the same process, and the wall structure and the pad main body structure are an integrally formed structure.

[0014] Preferably, in the method for preparing the surface acoustic wave filter packaging structure, before fixing the surface acoustic wave filter on the carrier substrate, the method for preparing the surface acoustic wave filter packaging structure further comprises: A bonding layer is formed on one side surface of the carrier substrate; after the surface acoustic wave filter is fixed on the carrier substrate, the pad structure contacts the carrier substrate through a groove penetrating the bonding layer.

[0015] Preferably, in the above-mentioned method for preparing the surface acoustic wave filter packaging structure, the method for preparing the surface acoustic wave filter packaging structure further comprises: Processing the carrier substrate to form a through hole penetrating the carrier substrate; An external lead structure is formed; the external lead structure is electrically connected to the pad main body structure through the through hole.

[0016] Preferably, in the above-mentioned method for preparing the surface acoustic wave filter packaging structure, the method for preparing the surface acoustic wave filter packaging structure further comprises: A protective layer is formed on a side of the carrier substrate away from the surface acoustic wave filter; the protective layer exposes a portion of the surface of the external lead structure.

[0017] A third aspect of the present application provides a radio frequency device, which includes any one of the above-mentioned surface acoustic wave filter packaging structures.

[0018] A fourth aspect of the present application provides a vehicle-mounted device, which includes any one of the above-mentioned surface acoustic wave filter packaging structures.

[0019] A fifth aspect of the present application provides a vehicle-mounted device, which includes the radio frequency device described above.

[0020] By means of the above technical scheme, the present application provides a surface acoustic wave filter packaging structure and its preparation method, and related equipment, wherein there is a gap between the interdigitated electrode and the carrier substrate in the first direction, and this gap area is the cavity area of ​​the surface acoustic wave filter; the pad structure contacts the substrate and the carrier substrate respectively in the first direction, and the pad structure includes a pad main body structure and N wall structures arranged in sequence from the inside to the outside, and the interdigitated electrode and the pad main body structure are located inside the area surrounded by the first wall structure, so during the preparation of the plastic sealing layer, at least the setting of the Nth wall structure will block the plastic sealing filler from entering the cavity area, thereby achieving effective protection of the working area of ​​the surface acoustic wave filter packaging structure. Compared with the existing technical scheme, the technical scheme of the present application does not require additional materials and structures to form a closed cavity, and uses the pad structure as a barrier layer for the plastic sealing filler, thereby achieving the purpose of simplifying the process steps and reducing production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The above and other features, advantages and aspects of the embodiments of the present disclosure will become more apparent with reference to the following detailed description in conjunction with the accompanying drawings. Throughout the accompanying drawings, the same or similar reference numerals represent the same or similar elements. It should be understood that the drawings are schematic and the originals and elements are not necessarily drawn to scale.

[0022] Figure 1 A schematic structural diagram of a surface acoustic wave filter packaging structure provided by an embodiment of the present invention; Figure 2 A schematic structural diagram of another surface acoustic wave filter packaging structure provided by an embodiment of the present invention; Figure 3 A schematic diagram of the structure of an interdigital electrode provided by an embodiment of the present invention; Figure 4 A schematic structural diagram of another surface acoustic wave filter packaging structure provided by an embodiment of the present invention; Figure 5 A schematic structural diagram of another surface acoustic wave filter packaging structure provided by an embodiment of the present invention; Figure 6 A schematic flow chart of a method for preparing a surface acoustic wave filter packaging structure provided by an embodiment of the present invention; Figure 7 A method provided by an embodiment of the present invention Figure 6 One of the partial structural schematic diagrams corresponding to the preparation method shown; Figure 8 A method provided by an embodiment of the present invention Figure 6 The second schematic diagram of the partial structure corresponding to the preparation method shown; Fig. 9 A method provided by an embodiment of the present invention Figure 6The third schematic diagram of the partial structure corresponding to the preparation method shown; Fig.10 A method provided by an embodiment of the present invention Figure 6 The fourth schematic diagram of the partial structure corresponding to the preparation method shown; Fig.11 A method provided by an embodiment of the present invention Figure 6 The fifth schematic diagram of the partial structure corresponding to the preparation method shown; Fig.12 A method provided by an embodiment of the present invention Figure 6 The sixth schematic diagram of the partial structure corresponding to the preparation method shown. DETAILED DESCRIPTION

[0023] The embodiments of the present application are described below in conjunction with the drawings in the embodiments of the present application. The terms used in the implementation mode of the present application are only used to explain the specific embodiments of the present application, and are not intended to limit the present application. It is known to those skilled in the art that with the development of technology and the emergence of new scenarios, the technical solutions provided in the embodiments of the present application are also applicable to similar technical problems.

[0024] It should be noted that the directional words appearing in the present invention are based on the relative position relationship shown in the drawings and cannot be used as an absolute limitation to the present application.

[0025] Combined with the content recorded in the background technology, surface acoustic wave resonator and filter are a kind of acoustic device widely used in the radio frequency field. It combines low insertion loss and good suppression performance, and is relatively small in size. It is used to filter out the interference of heterofrequency signals, attenuate some frequency components, and only allow specified frequency components. It is the technical basis for the application of wireless spectrum as a non-renewable scarce resource.

[0026] Its specific principle can be simply understood as based on the piezoelectric properties of piezoelectric materials, using input and output transducer devices such as interdigital transducers to convert electrical signals into mechanical energy, which are then converted back into electrical signals after processing, in order to amplify the required signals, filter out noise signals and improve signal quality. It is widely used in various wireless communication equipment.

[0027] At present, filters are mainly divided into SAW filters and BAW (Bulk Acoustic Wave) filters. Surface acoustic waves are an elastic wave that is generated and propagated on the surface of a piezoelectric substrate with piezoelectric properties, and whose amplitude decreases rapidly as the depth of the piezoelectric substrate increases. For SAW filters, their manufacturing cost is lower than that of BAW filters. They are mainly used in low-frequency bands, have low insertion loss and good suppression, and are highly temperature sensitive.

[0028] For SAW filters, the current SAW filter packaging structure is to package the SAW filter into a CSP, but this technology requires additional materials and structures to form a closed cavity to protect the SAW filter from external contamination, resulting in a complex process and high production cost. For example, an organic dry film is used to cover and protect the SAW filter, and the additional gold ball bonding process also reduces production efficiency.

[0029] Based on this, the embodiment of the present invention provides a surface acoustic wave filter packaging structure and a preparation method thereof, and related equipment, so as to simplify the process steps and reduce the production cost. In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0030] refer to Figure 1 , Figure 1 A schematic diagram of a surface acoustic wave filter packaging structure provided by an embodiment of the present invention, referring to Figure 2 , Figure 2 A schematic diagram of another surface acoustic wave filter packaging structure provided by an embodiment of the present invention. The surface acoustic wave filter packaging structure provided by an embodiment of the present invention comprises: a surface acoustic wave filter 11 and a carrier substrate 12.

[0031] The surface acoustic wave filter includes a substrate 13 , interdigital electrodes 14 and a pad structure 15 ; the substrate 13 and the carrier substrate 12 are arranged opposite to each other in a first direction X, and the first direction X is perpendicular to the plane where the substrate 13 is located.

[0032] The interdigitated electrodes 14 and the pad structure 15 are located on the side of the substrate 13 facing the carrier substrate 12; the pad structure 15 includes a pad main body structure 151 and N wall structures 152 arranged in sequence from the inside to the outside, N ≥ 1, and N is a positive integer; the interdigitated electrodes 14 and the pad main body structure 151 are located inside the area surrounded by the first wall structure 152; wherein the pad structure 15 is in contact with the substrate 13 and the carrier substrate 12 in the first direction X, respectively, and there is a gap between the interdigitated electrodes 14 and the carrier substrate 12 in the first direction X. It should be noted that, Figure 1 In the following, N=2 is taken as an example for explanation.

[0033] The surface acoustic wave filter packaging structure further includes a plastic packaging layer 16 for packaging the surface acoustic wave filter 11 . The plastic packaging layer 16 is in contact with the outer side wall of the Nth surrounding wall structure 152 .

[0034] Specifically, in the embodiment of the present invention, the substrate 13 is a piezoelectric substrate, and the material of the substrate 13 includes but is not limited to lithium niobium oxide, niobium tantalate, etc. The material of the carrier substrate 12 is an insulating material, including but not limited to ceramic, glass, silicon, or other organic materials, such as resin, Polymid, etc. Figure 3 , Figure 3 A schematic diagram of the structure of an interdigitated electrode provided in an embodiment of the present invention. The interdigitated electrode 14 includes a first bus bar 141 and a second bus bar 142 arranged opposite to each other in a second direction Y, and a first electrode finger 143 located on the first bus bar 141 and a second electrode finger 144 located on the second bus bar 142. The first bus bar 141 and the second bus bar 142 have the same length extension direction, both extending along a third direction Z, the second direction Y and the third direction Z are parallel to the plane where the substrate 13 is located, and the second direction Y and the third direction Z intersect.

[0035] In the embodiment of the present invention, the second direction Y and the third direction Z are perpendicular to each other. The first electrode fingers 143 and the second electrode fingers 144 have the same length extension direction, which are parallel to the second direction Y respectively. The multiple first electrode fingers 143 on the first bus bar 141 are arranged at intervals in the third direction Z, and the multiple second electrode fingers 144 on the second bus bar 142 are arranged at intervals in the third direction Z. The multiple first electrode fingers 143 on the first bus bar 141 and the multiple second electrode fingers 144 on the second bus bar 142 are arranged crosswise in sequence in the third direction Z, and there is a gap between the multiple first electrode fingers 143 on the first bus bar 141 and the second bus bar 142, and there is a gap between the multiple second electrode fingers 144 on the second bus bar 142 and the first bus bar 141. At this time, the bus bars and the electrode fingers are distributed in a manner similar to crossing fingers, forming a so-called interdigitated electrode. When the first bus bar 141 and the first electrode fingers 143 thereon are used as the transmitting end, the second bus bar 142 and the second electrode fingers 144 thereon are used as the receiving end. Conversely, when the first bus bar 141 and the first electrode fingers 143 thereon are used as the receiving end, the second bus bar 142 and the second electrode fingers 144 thereon are used as the transmitting end. The transmitting end part is used to convert the electrical signal into an acoustic wave, and the acoustic wave mainly propagates on the surface of the substrate, and the receiving end part is used to convert the received acoustic wave into an electrical signal output, thereby realizing filtering.

[0036] like Figure 1As shown, there is a gap between the interdigitated electrode 14 and the carrier substrate 12 in the first direction X, and this gap area is the cavity area of ​​the surface acoustic wave filter 11; the pad structure 15 includes a pad main body structure 151 and N wall structures 152 arranged in sequence from the inside to the outside, and the wall structure 152 forms a closed figure. The interdigitated electrode 14 and the pad main body structure 151 are located inside the area surrounded by the first wall structure 152. Since the pad structure 15 is in contact with the substrate 13 and the carrier substrate 12 respectively in the first direction X, the setting of at least the Nth wall structure 152 during the preparation of the plastic encapsulation layer 16 will prevent the plastic encapsulation filler from entering the cavity area, and the setting of N wall structures 152 can also achieve N-fold protection of the working area of ​​the surface acoustic wave filter packaging structure, thereby achieving effective protection of the working area of ​​the surface acoustic wave filter packaging structure. Compared with the prior art solutions, the technical solution of the present application does not require additional materials and structures to form a closed cavity, and utilizes the pad structure 15 as a barrier layer for the plastic encapsulation filler, thereby simplifying the process steps and reducing the production cost.

[0037] Optionally, the material of the pad structure 15 includes but is not limited to Al material, that is, the material of the pad main body structure 151 includes but is not limited to Al material, and the material of the wall structure 152 includes but is not limited to Al material.

[0038] In an optional embodiment of the present invention, reference Figure 4 , Figure 4 The schematic diagram of another surface acoustic wave filter packaging structure provided by an embodiment of the present invention is as follows: The wall structure 152 and the pad main body structure 151 are integrally formed.

[0039] Specifically, in the embodiment of the present invention, the wall structure 152 and the pad main structure 151 are configured as an integrally formed structure to improve the overall stability of the pad structure 15 and avoid the problem of the wall structure 152 and / or the pad main structure 151 tilting.

[0040] In an optional embodiment of the present invention, at least one of the N wall structures 152 is electrically connected to the pad main body structure 151 .

[0041] Specifically, in the embodiment of the present invention, at least one of the N wall structures 152 is electrically connected to the pad main structure 151. Obviously, the wall structure 152 electrically connected to the pad main structure 151 can also serve as an electrical connection point between the surface acoustic wave filter 11 and external components, thereby reducing the difficulty of electrical connection between the surface acoustic wave filter 11 and external components, and can be applicable to various layout designs.

[0042] It should be noted that if Figure 2As shown, four pad main structures 151 are illustrated, wherein the pad main structures 151 at the upper left corner and the lower right corner are not connected to the wall structure 152 and are independent of each other, and the pad main structures 151 at the lower left corner and the upper right corner are an integrated structure with the wall structure 152, so Figure 2 The pad main body structure 151 at the lower left corner and the upper right corner is not illustrated.

[0043] It should be further explained that the layout of the pad main structure 151 and the wall structure 152 may also include other variations. Figure 2 As for the orientation shown, the two pad main structures 151 on the left are not connected to the wall structure 152 and are independent of each other, and the two pad main structures 151 on the right are an integral structure with the wall structure 152; or, the two pad main structures 151 on the top are not connected to the wall structure 152 and are independent of each other, and the two pad main structures 151 on the bottom are an integral structure with the wall structure 152; or, one of the four pad main structures 151 is not connected to the wall structure 152 and is independent of each other, and the remaining three pad main structures 151 are an integral structure with the wall structure 152; or, three of the four pad main structures 151 are not connected to the wall structure 152 and are independent of each other, and the remaining one pad main structure 151 is an integral structure with the wall structure 152; and so on.

[0044] In an optional embodiment of the present invention, reference Figure 5 , Figure 5 A schematic diagram of another surface acoustic wave filter packaging structure provided by an embodiment of the present invention. The width of the N wall structures 152 gradually decreases from the outside to the inside. Figure 5 As shown, there is a relationship of L1>L2.

[0045] Specifically, in the embodiment of the present invention, the width of the wall structure 152 ranges from 10 μm to 15 μm; for example, the width of the wall structure 152 is 10 μm, 13.5 μm or 15 μm, etc. Since the plastic encapsulation filler will first impact the Nth wall structure 152, in order to avoid the Nth wall structure 152 from tilting or collapsing, the width of the Nth wall structure 152 is set wider, forming a structure in which the widths of the N wall structures 152 gradually decrease from the outside to the inside, thereby improving the stability of the Nth wall structure 152, thereby achieving effective protection of the working area of ​​the surface acoustic wave filter packaging structure to the greatest extent.

[0046] In an optional embodiment of the present invention, Figure 1 , Figure 4 as well as Figure 5As shown, the surface acoustic wave filter packaging structure provided by the embodiment of the present invention also includes: A bonding layer 17 is located on a side of the carrier substrate 12 facing the surface acoustic wave filter 11 ; the pad structure 15 is in contact with the carrier substrate 12 via a groove penetrating the bonding layer 17 .

[0047] The surface acoustic wave filter packaging structure provided by the embodiment of the present invention further includes: a through hole penetrating the carrier substrate 12, and an external lead structure 18. The external lead structure 18 is electrically connected to the pad main body structure 151 through the through hole.

[0048] The SAW filter packaging structure provided by the embodiment of the present invention further includes: a protection layer 19 located on a side of the carrier substrate 12 away from the SAW filter 11 ; the protection layer 19 exposes a portion of the surface of the external lead structure 18 .

[0049] It should be noted that the external lead structure 18 is also referred to as an RDL (Re Distribution Layer) structure in the field.

[0050] Specifically, in the embodiment of the present invention, a bonding layer 17 is provided to achieve bonding between the surface acoustic wave filter 11 and the carrier substrate 12, and the pad structure 15 is contacted with the carrier substrate 12 through a groove penetrating the bonding layer 17, so that the contact area between the pad structure 15 and the bonding layer 17 can be increased, thereby improving the bonding stability of the surface acoustic wave filter packaging structure, and directly using a through-hole process to form an electrical connection of the RDL. Compared with the gold ball bonding process of the prior art, the process steps are simplified, the production cost is reduced, and the production efficiency is improved.

[0051] The protection layer 19 is mainly used to protect the exposed surface area of ​​the external lead structure 18 and a partial area of ​​the carrier substrate 12 , and a few electrical connection points can be exposed according to actual needs.

[0052] Optionally, the material of the external lead structure 18 includes but is not limited to Cu material.

[0053] Based on the above embodiment of the present invention, another embodiment of the present invention further provides a method for preparing a surface acoustic wave filter packaging structure, referring to Figure 6 , Figure 6 A schematic flow chart of a method for preparing a surface acoustic wave filter packaging structure provided by an embodiment of the present invention. The method for preparing a surface acoustic wave filter packaging structure provided by an embodiment of the present invention comprises: S101: Figure 7As shown, a surface acoustic wave filter 11 is provided, which includes a substrate 13, a forked electrode 14 and a pad structure 15; the pad structure 15 includes a pad main structure 151 and N wall structures 152 arranged in sequence from the inside to the outside, N ≥ 1, and N is a positive integer; the forked electrode 14 and the pad main structure 151 are located inside the area enclosed by the first wall structure 152.

[0054] Specifically, in the embodiment of the present invention, the wall structure 152 and the pad main body structure 151 are formed in the same process, and optionally the wall structure 152 and the pad main body structure 151 are an integrally formed structure.

[0055] S102: Figure 8 and Fig. 9 As shown, the surface acoustic wave filter 11 is fixed on a carrier substrate 12; the substrate 13 and the carrier substrate 12 are arranged relative to each other in a first direction X, and the first direction X is perpendicular to the plane where the substrate 13 is located; the interdigitated electrodes 14 and the pad structure 15 are located on the side of the substrate 13 facing the carrier substrate 12; the pad structure 15 is in contact with the substrate 13 and the carrier substrate 12 respectively in the first direction X, and there is a gap between the interdigitated electrodes 14 and the carrier substrate 12 in the first direction X.

[0056] Specifically, in the embodiments of the present invention, Figure 8 As shown, before fixing the surface acoustic wave filter 11 on the carrier substrate 12, the method for preparing the surface acoustic wave filter packaging structure further includes: A bonding layer 17 is formed on one side surface of the carrier substrate 12. Fig. 9 As shown, after the surface acoustic wave filter 11 is fixed on the carrier substrate 12 , the pad structure 15 contacts the carrier substrate 12 through the groove penetrating the bonding layer 17 .

[0057] S103: Fig.10 As shown, a plastic encapsulation layer 16 is formed to encapsulate the surface acoustic wave filter 11 , and the plastic encapsulation layer 16 is in contact with the outer side wall of the Nth surrounding wall structure 152 .

[0058] Optionally, the method for preparing the surface acoustic wave filter packaging structure provided by the embodiment of the present invention further includes: like Fig.11 As shown, the carrier substrate 12 is processed to form a through hole 20 penetrating the carrier substrate 12 .

[0059] like Fig.12As shown, an external lead structure 18 is formed; the external lead structure 18 is electrically connected to the pad main body structure 151 through the through hole 20.

[0060] like Figure 1 As shown, a protection layer 19 is formed on the side of the carrier substrate 12 away from the surface acoustic wave filter 11 ; the protection layer 19 exposes a portion of the surface of the external lead structure 18 .

[0061] It can be seen from the above description that in the surface acoustic wave filter packaging structure prepared in the embodiment of the present invention, there is a gap between the interdigitated electrode 14 and the carrier substrate 12 in the first direction X, and this gap area is the cavity area of ​​the surface acoustic wave filter 11; the pad structure 15 includes a pad main body structure 151 and N wall structures 152 arranged in sequence from the inside to the outside, and the wall structure 152 forms a closed figure. The interdigitated electrodes 14 and the pad main body structure 151 are located inside the area surrounded by the first wall structure 152. Since the pad structure 15 is in contact with the substrate 13 and the carrier substrate 12 respectively in the first direction X, the setting of at least the Nth wall structure 152 during the preparation of the plastic sealing layer 16 will prevent the plastic sealing filler from entering the cavity area, and the setting of N wall structures 152 can also achieve N-fold protection of the working area of ​​the surface acoustic wave filter packaging structure, thereby achieving effective protection of the working area of ​​the surface acoustic wave filter packaging structure. Compared with the existing technical solutions, the technical solution of the present application does not require additional materials and structures to form a closed cavity, and uses the pad structure as a barrier layer for the plastic encapsulation filler, thereby simplifying the process steps and reducing the production cost.

[0062] Based on the above embodiment of the present invention, a radio frequency device is provided in another embodiment of the present invention. The radio frequency device includes the surface acoustic wave filter packaging structure described in the above embodiment.

[0063] Based on the above embodiments of the present invention, another embodiment of the present invention further provides a vehicle-mounted device, which includes the surface acoustic wave filter packaging structure described in the above embodiments.

[0064] Alternatively, the vehicle-mounted device includes the radio frequency device described in the above embodiment.

[0065] The above is a detailed introduction to a surface acoustic wave filter packaging structure and a preparation method thereof, and related equipment provided by the present invention. Specific examples are used in this article to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for a person skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as a limitation on the present invention.

[0066] It should be noted that each embodiment in this specification is described in a progressive manner, and each embodiment focuses on the differences from other embodiments, and the same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part description.

[0067] It should also be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device that includes a series of elements is inherent to the elements, or also includes elements inherent to these processes, methods, articles or devices. In the absence of further restrictions, the elements defined by the sentence "including a..." do not exclude the presence of other identical elements in the process, method, article or device that includes the elements.

[0068] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A surface acoustic wave filter packaging structure, characterized in that: The surface acoustic wave filter packaging structure comprises: a surface acoustic wave filter and a carrier substrate; The surface acoustic wave filter comprises a substrate, interdigital electrodes and a pad structure; the substrate and the carrier substrate are arranged opposite to each other in a first direction, and the first direction is perpendicular to the plane where the substrate is located; The interdigitated electrodes and the pad structure are located on the side of the substrate facing the carrier substrate; the pad structure includes a pad main body structure and N wall structures arranged in sequence from the inside to the outside, N ≥ 1, and N is a positive integer; the interdigitated electrodes and the pad main body structure are located inside the area surrounded by the first wall structure; wherein the pad structure is in contact with the substrate and the carrier substrate respectively in the first direction, and there is a gap between the interdigitated electrodes and the carrier substrate in the first direction; The surface acoustic wave filter packaging structure further includes a plastic packaging layer for packaging the surface acoustic wave filter, and the plastic packaging layer is in contact with the outer side wall of the Nth surrounding wall structure.

2. The surface acoustic wave filter packaging structure according to claim 1, characterized in that: The wall structure and the pad main body structure are an integrally formed structure.

3. The surface acoustic wave filter packaging structure according to claim 1, characterized in that: At least one of the N wall structures is electrically connected to the pad main body structure.

4. The surface acoustic wave filter packaging structure according to any one of claims 1 to 3, characterized in that: The widths of the N wall structures gradually decrease from the outside to the inside.

5. The surface acoustic wave filter packaging structure according to claim 1, characterized in that: The surface acoustic wave filter packaging structure also includes: A bonding layer is located on a side of the carrier substrate facing the surface acoustic wave filter; the pad structure is in contact with the carrier substrate via a groove penetrating the bonding layer.

6. The surface acoustic wave filter packaging structure according to claim 1, characterized in that: The surface acoustic wave filter packaging structure also includes: A through hole penetrating the carrier substrate and an external lead structure; The external lead structure is electrically connected to the pad main body structure through the through hole.

7. The surface acoustic wave filter packaging structure according to claim 6, characterized in that: The surface acoustic wave filter packaging structure also includes: A protective layer is located on a side of the carrier substrate away from the surface acoustic wave filter; the protective layer exposes a portion of the surface of the external lead structure.

8. The surface acoustic wave filter packaging structure according to claim 1, characterized in that: The interdigitated electrodes include a first bus bar and a second bus bar disposed opposite to each other in a second direction, and a first electrode finger located on the first bus bar and a second electrode finger located on the second bus bar; The first bus bar and the second bus bar have the same length extension direction, both extending along a third direction. The second direction and the third direction are parallel to the plane where the substrate is located, and the second direction and the third direction intersect.

9. A method for preparing a surface acoustic wave filter packaging structure, characterized in that: The preparation method of the surface acoustic wave filter packaging structure comprises: A surface acoustic wave filter is provided, the surface acoustic wave filter comprising a substrate, an interdigitated electrode and a pad structure; the pad structure comprises a pad main body structure and N wall structures sequentially arranged from the inside to the outside, N ≥ 1, and N is a positive integer; the interdigitated electrode and the pad main body structure are located inside an area surrounded by the first wall structure; The surface acoustic wave filter is fixed on a carrier substrate; the substrate and the carrier substrate are arranged relative to each other in a first direction, and the first direction is perpendicular to the plane where the substrate is located; the interdigitated electrodes and the pad structure are located on the side of the substrate facing the carrier substrate; the pad structure is in contact with the substrate and the carrier substrate respectively in the first direction, and there is a gap between the interdigitated electrodes and the carrier substrate in the first direction; A plastic encapsulation layer is formed for encapsulating the surface acoustic wave filter, and the plastic encapsulation layer is in contact with the outer side wall of the Nth surrounding wall structure.

10. The method for preparing a surface acoustic wave filter packaging structure according to claim 9, characterized in that: The surrounding wall structure and the pad main body structure are formed in the same process, and the surrounding wall structure and the pad main body structure are an integrally formed structure.

11. The method for preparing a surface acoustic wave filter packaging structure according to claim 9, characterized in that: Before fixing the surface acoustic wave filter on the carrier substrate, the method for preparing the surface acoustic wave filter packaging structure further includes: A bonding layer is formed on one side surface of the carrier substrate; after the surface acoustic wave filter is fixed on the carrier substrate, the pad structure contacts the carrier substrate through a groove penetrating the bonding layer.

12. The method for preparing a surface acoustic wave filter packaging structure according to any one of claims 9 to 11, characterized in that: The method for preparing the surface acoustic wave filter packaging structure further comprises: Processing the carrier substrate to form a through hole penetrating the carrier substrate; An external lead structure is formed; the external lead structure is electrically connected to the pad main body structure through the through hole.

13. The method for preparing a surface acoustic wave filter packaging structure according to claim 12, characterized in that: The method for preparing the surface acoustic wave filter packaging structure further comprises: A protective layer is formed on a side of the carrier substrate away from the surface acoustic wave filter; the protective layer exposes a portion of the surface of the external lead structure.

14. A radio frequency device, characterized in that: The radio frequency device comprises the surface acoustic wave filter packaging structure according to any one of claims 1 to 8.

15. A vehicle-mounted device, characterized in that: The vehicle-mounted equipment includes the surface acoustic wave filter packaging structure according to any one of claims 1 to 8.

16. A vehicle-mounted device, characterized in that: The vehicle-mounted device includes the radio frequency device according to claim 14.

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