A board-level architecture, a manufacturing method thereof, a system-in-package structure and an electronic device

Abstract

The application provides a board-level architecture, a manufacturing method thereof, a system-in-package structure and an electronic device. The board-level architecture can include a circuit board, at least one filter chip and at least one sealing structure on the circuit board. The filter chip is provided with an electrode structure on a first surface, and the first surface is a surface of the filter chip facing the circuit board. Each sealing structure wraps the filter chip. The sealing structure is in contact with the sidewall of the corresponding filter chip, in contact with the surface of the circuit board, and not in contact with the first surface of the corresponding filter chip. The sealing structure, the first surface of the corresponding filter chip and the circuit board form a cavity, and the projection area of the cavity on the circuit board is greater than the projection area of the corresponding filter chip on the circuit board. In this way, the sealing structure can be prevented from contaminating the first surface of the filter chip, the performance of the filter chip can be improved, and the needs of the electronic device can be met.

Description

Technical Field

[0001] This application relates to the field of chip packaging technology, and in particular to a board-level architecture, its manufacturing method, system-in-package structure, and electronic device. Background Technology

[0002] With the continuous development of electronic technology, electronic devices such as smartphones, smartwatches, and personal digital assistants are gradually moving towards lighter, thinner, smaller, and higher-performance designs. As a key component of communication equipment, filters are increasingly trending towards higher frequencies and smaller sizes. Among these, surface acoustic wave (SAW) filters have been widely used in various electronic devices.

[0003] Although surface acoustic wave (SAW) filters have advantages such as small size, low loss, and good frequency selectivity compared to traditional dielectric filters, the performance of SAW filters in related technologies is poor and difficult to meet the needs of electronic devices. Summary of the Invention

[0004] This application provides a board-level architecture, its manufacturing method, a system-level packaging structure, and an electronic device to solve the problem of poor performance of surface acoustic wave filters in related technologies.

[0005] In a first aspect, embodiments of this application provide a board-level architecture, which may include: a circuit board, and at least one filter chip and at least one sealing structure located on the circuit board. The filter chip has an electrode structure on a first surface, which is the surface of the filter chip facing the circuit board. Each sealing structure encloses the filter chip, and the sealing structure contacts the sidewall of the corresponding filter chip, contacts the surface of the circuit board, and does not contact the first surface of the corresponding filter chip. The sealing structure, the first surface of the corresponding filter chip, and the circuit board constitute a cavity, the projected area of ​​the cavity on the circuit board being larger than the projected area of ​​the corresponding filter chip on the circuit board, where the projected area is the projected area along the thickness direction of the circuit board. It is understood that, in embodiments of this application, the filter chip corresponding to the sealing structure refers to the filter chip enclosed by the sealing structure, and the filter chip corresponding to the cavity refers to the filter chip enclosed by the sealing structure forming the cavity.

[0006] In the board-level architecture provided in this application embodiment, the filter chip can be a surface acoustic wave (SAW) filter chip or a bulk acoustic wave (BAW) filter chip. By setting a sealing structure to enclose the filter chip, the sealing structure, the corresponding first surface of the filter chip, and the circuit board constitute a cavity. This cavity facilitates sound wave transmission and improves the filtering effect of the filter chip. Furthermore, the sealing structure contacts the sidewall of the corresponding filter chip and the surface of the circuit board, but does not contact the first surface of the corresponding filter chip. The projected area of ​​the cavity on the circuit board is larger than the projected area of ​​the corresponding filter chip on the circuit board, allowing for a larger cavity space. This ensures that the sealing structure does not contaminate the first surface of the filter chip, preventing the sealing structure from affecting the function of the filter chip, improving the performance of the filter chip, and enabling the filter chip to meet the requirements of electronic devices.

[0007] Furthermore, in this embodiment, since the sealing structure does not contaminate the first surface of the filter chip, when designing the filter chip structure, components such as electrode structures can be placed close to the edge of the filter chip, increasing the wiring area and facilitating wiring design. During the fabrication of the board-level architecture, after the filter chip is mounted on the surface of the circuit board, a sealing structure is formed around the filter chip. This prevents subsequent formation of structures such as molding compounds from contaminating the first surface of the filter chip, improving the yield rate of the board-level architecture. Moreover, this fabrication process has lower complexity and integration difficulty, saving manufacturing costs.

[0008] In this embodiment, the filter chip can be a surface acoustic wave (SAW) filter chip. The filter chip has an electrode structure on its first surface, which can be an interdigitated comb-shaped electrode. The filter chip can have two electrode structures on its first surface, one of which can serve as a transmitting transducer and the other as a receiving transducer. During operation, the transmitting transducer converts the radio frequency signal into a SAW wave. The SAW wave propagates within a cavity on the circuit board. After reaching the receiving transducer, the receiving transducer converts the SAW wave into an electrical signal for output. In this embodiment, the sealed structure, the corresponding first surface of the filter chip, and the circuit board form a cavity, which allows the SAW wave to propagate within the cavity, improving the transmission efficiency of the SAW wave and enhancing the filtering effect of the filter chip.

[0009] In this embodiment, the filter chip can also be a bulk acoustic wave filter chip. The filter chip has electrode structures on its first and second surfaces, where the second surface is the surface of the filter chip facing away from the circuit board. The electrode structures on the first and second surfaces of the filter chip can excite sound waves, which propagate in a direction perpendicular to the first surface of the filter chip. By forming a cavity with the sealing structure, the corresponding first surface of the filter chip, and the circuit board, the cavity can improve the transmission efficiency of the sound waves and filter the sound waves, thereby improving the filtering effect of the filter chip.

[0010] Optionally, in this embodiment, the circuit board can be a glass substrate, a leadframe substrate, a carrier board, a printed circuit board (PCB), a printed wireboard (PWB) main board, or a package substrate, etc. Metal wiring layers and pads can be disposed on the surface of the circuit board, and at least one pad on the circuit board is grounded. The filter chip can be electrically connected to the pads on the surface of the circuit board via solder balls, thereby electrically connecting the filter chip to the metal wiring layer on the surface of the circuit board.

[0011] In one possible implementation, the filter chip may also have a connection portion on its first surface, with solder balls electrically connected to the connection portion, allowing the solder balls to be fixed to the surface of the filter chip via the connection portion. In this embodiment, since the sealing structure does not contaminate the first surface of the filter chip, the wiring area of ​​the filter chip is relatively large. Therefore, when designing the structure of the filter chip, the connection portion can be placed at any position on the first surface of the filter chip, for example, at a certain distance from the edge of the filter chip. Alternatively, the connection portion can be placed closer to the edge of the filter chip.

[0012] In a specific implementation, an organic film layer can also be disposed on one side of the first surface of the filter chip. The first surface of the filter chip, the connecting portion, and the organic film layer can form a cavity, which can further improve the transmission efficiency of sound waves and enhance the filtering effect of the filter chip. Furthermore, the organic film layer can protect the electrode structure, preventing damage to the electrode structure during subsequent processes. Of course, the filter chip in this embodiment may also omit the organic film layer; this is not a limitation.

[0013] In some embodiments of this application, in the direction from the circuit board to the filter chip, the cross-sectional area of ​​the cavity in the direction parallel to the circuit board exhibits a trend of first increasing and then decreasing, or a gradual decreasing trend. This allows for a larger cavity space, ensuring that the distance between the sealing structure around the cavity and the first surface of the filter chip is greater, guaranteeing that the sealing structure and the first surface of the filter chip do not contact each other, thereby preventing contact between the sealing structure and the electrode structure of the filter chip.

[0014] In one possible implementation, the sealing structure may include: a dam located on the circuit board and surrounding the corresponding filter chip, and a filling portion located on the side of the dam facing away from the circuit board. The dam surrounds the corresponding filter chip, i.e., the dam is annular, allowing a certain distance between the portion of the sealing structure near the circuit board and the corresponding filter chip, ensuring that the sealing structure and the first surface of the corresponding filter chip do not contact each other. The filling portion is connected to the dam and fills the gap between the dam and the corresponding filter chip, thus allowing the sealing structure to make tight contact with the sidewall of the corresponding filter chip, forming a cavity with the sealing structure, the corresponding filter chip, and the circuit board.

[0015] In the manufacturing process, inkjet printing can be used to form a dam surrounding the filter chip on the circuit board. Then, printing is performed on the dam towards the filter chip at certain step values ​​to form a filling portion that fills the gap between the dam and the corresponding filter chip. For example, the step value can be about 10 μm. In practical applications, the height of the dam can be greater than the distance between the first surface of the filter chip and the surface of the circuit board, and less than the distance between the second surface of the filter chip and the surface of the circuit board. For example, the height of the dam can be set to be more than 20 μm greater than the distance between the first surface of the filter chip and the surface of the circuit board. Of course, the height of the dam can also be equal to or less than the distance between the first surface of the filter chip and the surface of the circuit board; this is not limited here. Optionally, the width of the dam can be set between 80 μm and 100 μm, and the distance between the dam and the edge of the filter chip can be set between 10 μm and 30 μm. In this embodiment, the use of inkjet printing to fabricate the dam and filling portion is used as an example. In specific implementations, other processes can also be used to fabricate the dam and filling portion; this is not limited here.

[0016] In addition, the sealing structure may also include a top cover connected to the filling portion. The top cover at least covers the edge of the second surface of the corresponding filter chip, which is the surface of the filter chip facing away from the circuit board. This can further improve the tightness between the sealing structure and the filter chip, and enhance the sealing effect of the sealing structure. Optionally, the thickness of the top cover can be set between 20μm and 30μm.

[0017] In one possible implementation, the top cover can be configured to completely cover the second surface of the filter chip. This further improves the tightness between the sealing structure and the filter chip, enhancing the sealing effect. Furthermore, the top cover also protects the filter chip, preventing damage from subsequent processes. In some embodiments of this application, the top cover may only cover the edge portion of the filter chip. This also results in a high degree of tightness between the sealing structure and the filter chip, leading to a better sealing effect. Of course, in other embodiments of this application, the sealing structure may not include a top cover; the choice can be made according to actual needs and is not limited here.

[0018] It should be noted that, in order to clearly illustrate the structure and manufacturing process of the sealing structure, the embodiments of this application take the sealing structure as including a dam and a filling part, or the sealing structure including a dam, a filling part and a top cover as an example. In practical applications, the various parts of the sealing structure can be an integral structure. Of course, provided that the various parts of the sealing structure are firmly connected, the various parts of the sealing structure can also be set separately. This is not limited here.

[0019] In the embodiments of this application, each sealing structure encloses at least one filter chip. That is, each sealing structure may enclose one filter chip, or each sealing structure may enclose two, three or more filter chips arranged adjacently, without limitation.

[0020] In one possible implementation, at least two filter chips are arranged adjacent to each other on the circuit board, and the sealing structures corresponding to the two adjacent filter chips are integral structures. The two sealing structures corresponding to the two adjacent filter chips can share the same side. In specific implementations, in order to facilitate the formation of a sealing structure between the two adjacent filter chips, the gap between the two adjacent filter chips can be set to be greater than 0.1mm. Of course, in order to achieve a high degree of integration in the board-level architecture, the gap between the two adjacent filter chips should not be too large.

[0021] Secondly, this application also provides a system-in-a-package (SIP) structure, which may include any of the aforementioned board-level architectures and a first device located on the circuit board of the board-level architecture. In the aforementioned system architecture, by setting a sealing structure around the filter chip, the sealing structure, the corresponding first surface of the filter chip, and the circuit board can form a cavity. This cavity is beneficial for the transmission of sound waves and can improve the filtering effect of the filter chip. Furthermore, the sealing structure and the corresponding first surface of the filter chip do not contact each other, and the projected area of ​​the cavity on the circuit board is larger than the projected area of ​​the corresponding filter chip on the circuit board, which can make the cavity space larger. Thus, it can be ensured that the sealing structure will not contaminate the first surface of the filter chip, thereby improving the performance of the filter chip. Therefore, the performance of the system-in-a-package structure including this board-level architecture is also better.

[0022] In practical applications, the first device can be an active or passive device. Active devices can be amplifiers, converters, etc., while passive devices can be capacitors, resistors, switches, etc. In specific implementations, the number and type of the first device can be set according to actual needs, as long as it can be circuit-matched with the filter chip. The spacing between the filter chip and the first device can be set to less than 100μm, which can increase the layout density and is beneficial to the trend of high-density layout and miniaturization of system-in-package structures.

[0023] In practical applications, the system-in-package (SIP) structure in this embodiment may further include: a molding compound layer located on the circuit board, which encapsulates each filter chip, each sealing structure, and each first device on the circuit board. By using a molding compound layer to encapsulate each filter chip, the packaging stability of each filter chip can be improved. The molding compound layer can encapsulate each first device on the circuit board; for example, the molding compound layer can encapsulate active and passive devices on the circuit board. In this way, the filter chip and the first device can be packaged into the same SIP structure, which can effectively improve the integration of the SIP structure, save space, and reduce manufacturing costs. Furthermore, it facilitates circuit adaptation between the filter chip and the first device, simplifies the structure of the SIP structure, effectively reduces RF signal loss, and thus improves RF efficiency.

[0024] Optionally, the encapsulation layer material may include: epoxy resin material, acrylic resin material, dielectric material, thermosetting material, thermoplastic material, rubber material or other insulating material.

[0025] In the actual manufacturing process, the filter chip and the first device are mounted on a circuit board, and a sealing structure is formed around the filter chip. Then, an encapsulation layer is formed on the circuit board using an injection molding process. During the injection molding process, the sealing structure prevents the encapsulation material from contacting the first surface of the filter chip. Furthermore, the sealing structure also protects the filter chip, preventing damage from the molding pressure generated by the encapsulation material, thus improving the encapsulation yield. For example, the dams in the sealing structure prevent damage to the first surface and solder balls of the filter chip, the filler in the sealing structure prevents damage to the sidewalls of the filter chip, and the top cap in the sealing structure prevents damage to the second surface of the filter chip.

[0026] Thirdly, embodiments of this application also provide an electronic device, which may include: any of the above-described system-in-package (SiP) structures, and a housing, wherein the housing covers the SiP structure. For example, the electronic device may be any device with radio frequency (RF) functionality, such as a smartphone, smartwatch, personal digital assistant, or base station. Because the SiP structure described above has good performance, the electronic device including the SiP structure also has good performance.

[0027] Fourthly, embodiments of this application also provide a method for manufacturing a board-level architecture, which may include:

[0028] A circuit board and at least one filter chip are provided; wherein the filter chip has an electrode structure on its first surface;

[0029] At least one filter chip is mounted on the surface of the circuit board with its first surface facing the circuit board.

[0030] A sealing structure is formed around at least one filter chip, which contacts the sidewall of the filter chip, the surface of the circuit board, and does not contact the first surface of the filter chip, so that the sealing structure, the corresponding first surface of the filter chip, and the circuit board constitute a cavity; wherein each sealing structure encloses the filter chip, and the projected area of ​​the cavity on the circuit board is larger than the projected area of ​​the corresponding filter chip on the circuit board, and the projected area is the projected area along the thickness direction of the circuit board.

[0031] In the board-level architecture manufacturing method provided in this application embodiment, after the filter chip is mounted on the surface of the circuit board, a sealing structure is formed around at least one filter chip. This sealing structure contacts the sidewall of the filter chip, contacts the surface of the circuit board, and does not contact the first surface of the filter chip. This prevents the subsequent formation of structures such as molding layers from contaminating the first surface of the filter chip, avoids the sealing structure from affecting the function of the filter chip, improves the performance of the filter chip, and increases the yield of the board-level architecture. Furthermore, this manufacturing process has low complexity and integration difficulty, saving manufacturing costs.

[0032] Furthermore, the sealed structure, the corresponding first surface of the filter chip, and the circuit board form a cavity, which facilitates sound wave transmission and improves the filtering effect of the filter chip. In addition, the projected area of ​​the cavity on the circuit board is larger than that of the corresponding filter chip, allowing for a larger cavity space. This ensures that the sealed structure does not contaminate the first surface of the filter chip, preventing it from affecting the filter chip's function, improving its performance, and enabling the filter chip to meet the requirements of electronic devices.

[0033] In one possible implementation, the circuit board can be a glass circuit board, a leadframe circuit board, a carrier board, a printed circuit board (PCB), a printed wireboard (PWB) main board, or a package substrate, etc. Metal wiring layers and pads can be disposed on the surface of the circuit board, and at least one pad on the circuit board is grounded. The filter chip can be a surface acoustic wave (SAW) filter chip or a bulk acoustic wave (BAW) filter chip. The SAW filter chip can have two electrode structures on its first surface, one of which can serve as a transmitting transducer, and the other as a receiving transducer. The BAW filter chip has electrode structures on its first surface, and also on its second surface.

[0034] In one possible implementation, the filter chip is mounted on the surface of a circuit board, with the first surface of the filter chip facing the circuit board. The filter chip is electrically connected to pads on the surface of the circuit board via solder balls, thereby electrically connecting the filter chip to the metal circuit layer on the surface of the circuit board.

[0035] In the manufacturing method provided in this application embodiment, the sealing structure can be manufactured in the following manner:

[0036] A dam is formed around the filter chip, for example, using inkjet printing. The height of the dam can be less than the distance between the second surface of the filter chip and the surface of the circuit board; the second surface is the side of the filter chip facing away from the circuit board. In practical applications, the height of the dam can be greater than the distance between the first surface of the filter chip and the surface of the circuit board. For example, the height of the dam can be set to be at least 20 μm greater than the distance between the first surface of the filter chip and the surface of the circuit board. Of course, the height of the dam can also be equal to or less than the distance between the first surface of the filter chip and the surface of the circuit board; this is not limited here. Optionally, the width of the dam can be set between 80 μm and 100 μm, and the distance between the dam and the edge of the filter chip can be set between 10 μm and 30 μm.

[0037] In the process of fabricating the dam, a certain degree of process error is permissible. For example, the dam material may flow to the area below the filter chip on the circuit board surface, or it may come into contact with the solder balls below the filter chip, as long as the dam material does not come into contact with the first surface of the filter chip. This expands the process window and reduces the process difficulty.

[0038] Then, a filling portion is formed on top of the dam to fill the gap between the dam and the filter chip and to contact the sidewall of the filter chip. The dam and the corresponding filling portion can constitute the aforementioned sealing structure. In the actual process, inkjet printing can be used to print on the dam towards the filter chip at a certain step value to form the filling portion that fills the gap between the dam and the corresponding filter chip. For example, the step value can be about 10 μm.

[0039] In one possible implementation, after forming the filling portion, it may further include:

[0040] A top cover connected to the filling portion is formed on the second surface of the filter chip. In actual manufacturing, the top cover can be fabricated using inkjet printing. By forming a top cover connected to the filling portion, the tightness between the sealing structure and the filter chip can be further improved, enhancing the sealing effect of the sealing structure. Optionally, the thickness of the top cover can be set between 20 μm and 30 μm.

[0041] The top cover at least covers the edge of the second surface of the filter chip. The top cover can completely cover the second surface of the filter chip; or, the top cover can only cover the edge portion of the filter chip. Of course, in some other embodiments of this application, the sealing structure may not have a top cover. It can be set according to actual needs, and there is no limitation here.

[0042] In this embodiment, the use of inkjet printing technology to manufacture the dam, filling part and top cover is taken as an example. In actual implementation, other processes can also be used to manufacture the dam, filling part and top cover, which is not limited here.

[0043] In this embodiment, the fabrication method of the system-in-package (SIP) structure is similar to the fabrication method of the board-level architecture described above. The difference lies in that, during the fabrication of the SIP structure, before forming the sealing structure encapsulating the filter chip, a first device needs to be mounted on the circuit board. This first device can be an active or passive device. Furthermore, after forming the sealing structure, a molding compound is formed to encapsulate each filter chip, each sealing structure, and each first device on the circuit board. The process of forming the sealing structure in the SIP structure is similar to the process of forming the sealing structure in the board-level architecture described above, and the repetitions will not be repeated.

[0044] In this embodiment of the application, the method for fabricating a system-level encapsulation structure may include:

[0045] The filter chip and the first device are mounted on the surface of the circuit board. The first device can be an active or passive device. Active devices can be amplifiers, converters, etc., while passive devices can be capacitors, resistors, etc. In practice, the number and type of the first device can be set according to actual needs, as long as it can be circuit-matched with the filter chip. The spacing between the filter chip and the first device can be set to less than 100μm, which can increase the layout density and is beneficial to the trend of high-density layout and miniaturization of system-in-package structures.

[0046] A dam is formed around the filter chip, and a filler portion is formed on top of the dam to fill the gap between the dam and the filter chip and to contact the sidewall of the filter chip. After forming the filler portion, a top cover connected to the filler portion can be formed on the second surface of the filter chip. During the dam fabrication process, certain process errors are permissible. For example, the dam material may flow to the area below the filter chip on the circuit board surface, or it may come into contact with the solder balls below the filter chip, as long as the dam material does not contact the first surface of the filter chip. This expands the process window and reduces process complexity. Furthermore, the dam material can also flow to the area below adjacent first devices, filling the gap between the first devices and the circuit board, thus achieving an underfill function and improving the reliability of the first devices.

[0047] After forming the sealed structure, a molding compound is formed to encapsulate each filter chip, each sealed structure, and each first device on the circuit board. For example, the first device can be an active device or a passive device. By using a molding compound to encapsulate each filter chip, the packaging stability of each filter chip can be improved. In this embodiment, encapsulating the filter chip and the first device in the same system-in-package (SIP) structure can effectively improve the integration of the SIP structure, save space, and reduce manufacturing costs. Furthermore, it facilitates circuit adaptation between the filter chip and the first device, simplifies the structure of the SIP structure, effectively reduces RF signal loss, and thus improves RF efficiency.

[0048] Optionally, the encapsulation layer material may include: epoxy resin material, acrylic resin material, dielectric material, thermosetting material, thermoplastic material, rubber material or other insulating material.

[0049] In actual manufacturing processes, an injection molding process can be used to form a molding compound layer on the circuit board. During this process, the sealing structure prevents the molding compound from contacting the first surface of the filter chip. Furthermore, the sealing structure also protects the filter chip, preventing damage from the molding flow pressure generated by the molding compound and improving molding yield. For example, the dams in the sealing structure prevent damage to the first surface and solder balls of the filter chip, the filler portion prevents damage to the sidewalls of the filter chip, and the top cap prevents damage to the second surface of the filter chip. Attached Figure Description

[0050] Figure 1 This is a schematic diagram of the board-level architecture provided in the embodiments of this application;

[0051] Figure 2 This is a schematic diagram of the planar structure of the surface acoustic wave filter chip in the embodiments of this application;

[0052] Figure 3 This is a schematic diagram of the structure of the bulk acoustic wave filter chip in the embodiments of this application;

[0053] Figure 4 This is another schematic diagram of the board-level architecture provided in the embodiments of this application;

[0054] Figure 5 This is another schematic diagram of the board-level architecture provided in the embodiments of this application;

[0055] Figure 6 This is another schematic diagram of the board-level architecture provided in the embodiments of this application;

[0056] Figure 7 This is another schematic diagram of the board-level architecture provided in the embodiments of this application;

[0057] Figure 8 This is another schematic diagram of the board-level architecture provided in the embodiments of this application;

[0058] Figure 9 This is another schematic diagram of the board-level architecture provided in the embodiments of this application;

[0059] Figure 10 This is another schematic diagram of the board-level architecture provided in the embodiments of this application;

[0060] Figure 11 This is a schematic diagram of the system-level packaging structure provided in the embodiments of this application;

[0061] Figure 12 A flowchart illustrating the method for fabricating a board-level architecture as provided in this application embodiment;

[0062] Figures 13 to 16 This is a schematic diagram of the structure corresponding to each step in the board-level architecture fabrication method in the embodiments of this application;

[0063] Figures 17 to 20 This is a schematic diagram of the structure corresponding to each step in the method for fabricating the system-level encapsulation structure in the embodiments of this application.

[0064] Figure label:

[0065] 100 - Board-level architecture; 10 - Circuit board; 11 - Filter chip; 111 - Electrode structure; 112 - Connection part; 113 - Organic film layer; 12 - Sealing structure; 121 - Dam; 122 - Filling part; 123 - Top cover; 13 - Solder ball; 14 - Active device; 15 - Passive device; 16 - Molding layer; S1 - First surface; S2 - Second surface; Q - Cavity; W - Cavity body. Detailed Implementation

[0066] To make the objectives, technical solutions, and advantages of this application clearer, the application will now be described in further detail with reference to the accompanying drawings.

[0067] It should be noted that the same reference numerals in the accompanying drawings of this application denote the same or similar structures, and therefore repeated descriptions of them will be omitted. Terms expressing position and direction described in this application are illustrative based on the accompanying drawings, but may be modified as needed, and all such modifications are included within the scope of protection of this application. The accompanying drawings of this application are for illustrating relative positional relationships only and do not represent actual scale.

[0068] To address the poor performance of surface acoustic wave (SAW) filters in related technologies, this application provides a board-level architecture, its fabrication method, a system-in-package (SIP) structure, and an electronic device. This board-level architecture can be used to package SAW filter chips or bulk acoustic wave (BAW) filter chips; of course, it can also be used to package other types of chips, and is not limited here. The SIP structure in this application can be applied to various types of electronic devices, such as smartphones, smartwatches, personal digital assistants, base stations, and any device with radio frequency (RF) functionality.

[0069] Figure 1 This is a schematic diagram of the board-level architecture provided in the embodiments of this application, such as... Figure 1 As shown, the board-level architecture provided in this application embodiment may include: a circuit board 10, and at least one filter chip 11 and at least one sealing structure 12 located on the circuit board 10. The filter chip 11 has an electrode structure on its first surface S1. Figure 1 (Not shown in the diagram), the first surface S1 is the surface of the filter chip 11 facing the circuit board 10. Each sealing structure 12 encloses the filter chip 11, and the sealing structure 12 contacts the sidewall of the corresponding filter chip 11, contacts the surface of the circuit board 10, and does not contact the first surface S1 of the corresponding filter chip 11. The sealing structure 12, the first surface S1 of the corresponding filter chip 11, and the circuit board 10 constitute a cavity Q. The projected area of ​​the cavity Q on the circuit board 10 is larger than the projected area of ​​the corresponding filter chip 11 on the circuit board 10, and this projected area is the projected area along the thickness direction of the circuit board 10. It can be understood that, in the embodiments of this application, the filter chip 11 corresponding to the sealing structure 12 refers to the filter chip 11 enclosed by the sealing structure 12, and the filter chip 11 corresponding to the cavity Q refers to the filter chip 11 enclosed by the sealing structure 12 forming the cavity Q.

[0070] In the board-level architecture provided in this application embodiment, the filter chip can be a surface acoustic wave (SAW) filter chip or a bulk acoustic wave (BAW) filter chip. By setting a sealing structure to enclose the filter chip, the sealing structure, the corresponding first surface of the filter chip, and the circuit board constitute a cavity. This cavity facilitates sound wave transmission and improves the filtering effect of the filter chip. Furthermore, the sealing structure contacts the sidewall of the corresponding filter chip and the surface of the circuit board, but does not contact the first surface of the corresponding filter chip. The projected area of ​​the cavity on the circuit board is larger than the projected area of ​​the corresponding filter chip on the circuit board, allowing for a larger cavity space. This ensures that the sealing structure does not contaminate the first surface of the filter chip, preventing the sealing structure from affecting the function of the filter chip, improving the performance of the filter chip, and enabling the filter chip to meet the requirements of electronic devices.

[0071] Furthermore, in this embodiment, since the sealing structure does not contaminate the first surface of the filter chip, when designing the filter chip structure, components such as electrode structures can be placed close to the edge of the filter chip, increasing the wiring area and facilitating wiring design. During the fabrication of the board-level architecture, after the filter chip is mounted on the surface of the circuit board, a sealing structure is formed around the filter chip. This prevents subsequent formation of structures such as molding compounds from contaminating the first surface of the filter chip, improving the yield rate of the board-level architecture. Moreover, this fabrication process has lower complexity and integration difficulty, saving manufacturing costs.

[0072] Figure 2 This is a schematic diagram of the planar structure of the surface acoustic wave filter chip in the embodiments of this application, combined with... Figure 1 and Figure 2 In this embodiment, the filter chip 11 can be a surface acoustic wave (SAW) filter chip. The filter chip 11 has an electrode structure 111 on its first surface S1, which can be an interdigitated comb-shaped electrode. The filter chip 11 can have two electrode structures 111 on its first surface S1, one of which can function as a transmitting transducer, and the other as a receiving transducer. During operation, the transmitting transducer converts the radio frequency signal into a SAW wave. The SAW wave propagates within the cavity Q on the circuit board 10. After reaching the receiving transducer, the receiving transducer converts the SAW wave into an electrical signal for output. In this embodiment, the sealing structure 12, the corresponding first surface S1 of the filter chip 11, and the circuit board 10 constitute the cavity Q, which allows the SAW wave to propagate within the cavity Q, improving the transmission efficiency of the SAW wave and enhancing the filtering effect of the filter chip 11.

[0073] Figure 3 This is a schematic diagram of the structure of the bulk acoustic wave filter chip in the embodiments of this application, combined with... Figure 1 and Figure 3 In this embodiment, the filter chip 11 can also be a bulk acoustic wave filter chip. The filter chip 11 has an electrode structure 111 on its first surface S1, and also has an electrode structure 111 on its second surface S2, wherein the second surface S2 is the surface of the filter chip 11 facing away from the circuit board 10. Because in Figure 3 The electrode structure 111 in the second surface S2 cannot be seen from the shown perspective; therefore, the electrode structure 111 in the second surface S2 is represented by a dashed line. The electrode structure 111 on the first surface S1 and the second surface S2 of the filter chip 11 can excite sound waves. The sound waves propagate in a direction perpendicular to the first surface S1 of the filter chip 11. By forming a cavity Q through the sealing structure 12, the corresponding first surface S1 of the filter chip 11, and the circuit board 10, the cavity Q can improve the transmission efficiency of the sound waves and filter the sound waves, thereby improving the filtering effect of the filter chip 11.

[0074] Optionally, in the embodiments of this application, the aforementioned circuit board can be a glass circuit board, a leadframe circuit board, a carrier board, a printed circuit board (PCB), a printed wire board (PWB) main board, or a packaging substrate, etc. Metal wiring layers and pads can be disposed on the surface of the circuit board, and at least one pad on the circuit board is grounded. (Refer to...) Figure 1 The filter chip 11 can be electrically connected to the pads on the surface of the circuit board 10 via solder balls 13, so that the filter chip 11 is electrically connected to the metal line layer on the surface of the circuit board 10.

[0075] Figure 4 Another schematic diagram of the board-level architecture provided in the embodiments of this application is shown below. Figure 4 As shown, the filter chip 11 may also have a connecting portion 112 on its first surface S1. Solder balls 13 are electrically connected to the connecting portion 112, allowing the solder balls 13 to be fixed to the surface of the filter chip 11 via the connecting portion 112. In this embodiment, since the sealing structure 12 does not contaminate the first surface S1 of the filter chip 11, the wiring area of ​​the filter chip is relatively large. Therefore, when designing the structure of the filter chip, the connecting portion 112 can be placed at any position on the first surface S1 of the filter chip 11. For example, the connecting portion 112 can be placed at a position a certain distance from the edge of the filter chip 11. Figure 5 Another schematic diagram of the board-level architecture provided in the embodiments of this application is shown below. Figure 5As shown in the embodiment of this application, the connecting part 112 may also be located at a position close to the edge of the filter chip 11.

[0076] Figure 6 This is another schematic diagram of the board-level architecture in the embodiments of this application, such as... Figure 6 As shown, an organic film layer 113 can also be disposed on one side of the first surface S1 of the filter chip 11. The first surface S1, the connecting portion 112, and the organic film layer 113 of the filter chip 11 can form a cavity W, which can further improve the transmission efficiency of sound waves and improve the filtering effect of the filter chip 11. In addition, the organic film layer 113 can protect the electrode structure 111 and prevent damage to the electrode structure 111 by subsequent processes. Of course, the filter chip 11 in this embodiment may not have the organic film layer 113, and this is not limited here.

[0077] In some embodiments of this application, such as Figure 1 As shown, in the direction from the bottom to the top of the circuit board 10 toward the filter chip 11 (i.e., the direction from bottom to top in the figure), the cross-sectional area of ​​the cavity Q in the direction parallel to the circuit board 10 shows a trend of first increasing and then decreasing. Figure 7 Another schematic diagram of the board-level architecture provided in the embodiments of this application is shown below. Figure 7 As shown, in the direction from the circuit board 10 to the filter chip 11 (i.e., from bottom to top in the figure), the cross-sectional area of ​​the cavity Q in the direction parallel to the circuit board 10 can also gradually decrease. This allows for a larger cavity Q, increasing the distance between the sealing structure 12 surrounding the cavity Q and the first surface S1 of the filter chip 11, ensuring that the sealing structure 12 and the first surface S1 of the filter chip 11 do not contact each other, thereby preventing the sealing structure 12 from contacting the electrode structure of the filter chip 11.

[0078] In specific implementation, such as Figure 1 As shown, the sealing structure 12 may include: a dam 121 located on the circuit board 10 and surrounding the corresponding filter chip 11, and a filling portion 122 located on the side of the dam 121 facing away from the circuit board 10. The dam 121 surrounds the corresponding filter chip 11, that is, the dam 121 is annular, which allows a certain distance between the portion of the sealing structure 12 near the circuit board 10 and the corresponding filter chip 11, ensuring that the sealing structure 12 and the first surface S1 of the corresponding filter chip 11 do not contact each other. The filling portion 122 is connected to the dam 121, and the filling portion 122 fills the gap between the dam 121 and the corresponding filter chip 11. In this way, the sealing structure 12 can be in close contact with the sidewall of the corresponding filter chip 11, so that the sealing structure 12, the corresponding filter chip 11, and the circuit board 10 form a cavity Q.

[0079] In the manufacturing process, inkjet printing can be used to form a dam 121 surrounding the filter chip 11 on the circuit board 10. Then, printing is performed on the dam 121 towards the filter chip 11 at certain step values ​​to form a filling portion 122 that fills the gap between the dam 121 and the corresponding filter chip 11. For example, the step value can be about 10 μm. In practical applications, the height of the dam 121 can be greater than the distance between the first surface S1 of the filter chip 11 and the surface of the circuit board 10, and less than the distance between the second surface S2 of the filter chip 11 and the surface of the circuit board 10. For example, the height of the dam 121 can be set to be more than 20 μm greater than the distance between the first surface S1 of the filter chip 11 and the surface of the circuit board 10. Of course, the height of the dam 121 can also be equal to or less than the distance between the first surface S1 of the filter chip 11 and the surface of the circuit board 10, which is not limited here. Optionally, the width of the dam 121 can be set to between 80μm and 100μm, and the distance between the dam 121 and the edge of the filter chip 11 can be set to between 10μm and 30μm. In this embodiment, the dam 121 and the filling part 122 are fabricated using inkjet printing technology as an example. In actual implementation, other processes can also be used to fabricate the dam 121 and the filling part 122, and no limitation is made here.

[0080] In addition, continue to refer to Figure 1 The sealing structure 12 may further include a top cover 123 connected to the filling portion 122, the top cover 123 at least covering the edge of the second surface S2 of the corresponding filter chip 11, the second surface S2 being the surface of the filter chip 11 facing away from the circuit board 10. This further improves the tightness between the sealing structure 12 and the filter chip 11, enhancing the sealing effect of the sealing structure 12. Optionally, the thickness of the top cover 123 may be set between 20 μm and 30 μm.

[0081] like Figure 1 As shown, the top cover 123 can be configured to completely cover the second surface S2 of the filter chip 11. On the one hand, this can further improve the tightness between the sealing structure 12 and the filter chip 11 and enhance the sealing effect of the sealing structure 12. On the other hand, the top cover 123 can also protect the filter chip 11 and prevent subsequent processes from damaging the filter chip 11. Figure 8 Another schematic diagram of the board-level architecture provided in the embodiments of this application is shown below. Figure 8As shown, in some embodiments of this application, the top cover 123 may only cover the edge portion of the filter chip 11. This allows for a higher degree of tightness between the sealing structure 12 and the filter chip 11, resulting in a better sealing effect of the sealing structure 12. Of course, in other embodiments of this application, the top cover 123 may not be provided in the sealing structure 12. It can be set according to actual needs, and no limitation is made here.

[0082] It should be noted that, in order to clearly illustrate the structure and manufacturing process of the sealing structure, the embodiments of this application take the sealing structure as including a dam and a filling part, or the sealing structure including a dam, a filling part and a top cover as an example. In practical applications, the various parts of the sealing structure can be an integral structure. Of course, provided that the various parts of the sealing structure are firmly connected, the various parts of the sealing structure can also be set separately. This is not limited here.

[0083] In this embodiment, each sealing structure encloses at least one filter chip. Figure 1 The illustration is based on the example of each sealed structure 12 enclosing a filter chip 11. Figure 9 Another schematic diagram of the board-level architecture provided in the embodiments of this application is shown below. Figure 9 As shown, each sealing structure 12 can also enclose two adjacent filter chips 11. Of course, each sealing structure can also enclose three or more adjacent filter chips, which is not limited here.

[0084] Figure 10 Another schematic diagram of the board-level architecture provided in the embodiments of this application is shown below. Figure 10 As shown, at least two filter chips 11 are arranged adjacent to each other on the circuit board 10. Figure 10 Taking a circuit board 10 with two adjacent filter chips 11 as an example, the sealing structures 12 corresponding to the two adjacent filter chips 11 are integral structures. The two sealing structures 12 corresponding to the two adjacent filter chips 11 can share the same side. In specific implementations, in order to facilitate the formation of sealing structures 12 between the two adjacent filter chips 11, the gap between the two adjacent filter chips 11 can be set to be greater than 0.1mm. Of course, in order to achieve a high degree of integration of the board-level architecture, the gap between the two adjacent filter chips 11 should not be too large.

[0085] Based on the same technical concept, embodiments of this application also provide a system-in-a-package (SIP) structure. Figure 11 This is a schematic diagram of the system-level packaging structure provided in the embodiments of this application, such as... Figure 11As shown, the system-level packaging structure may include any of the board-level architectures 100 described above, and a first device (e.g., Figure 11 As shown in 14 or 15, the first device is located on the circuit board 10 of the board architecture 100.

[0086] In the aforementioned system architecture, by setting a sealing structure around the filter chip, the sealing structure, the corresponding first surface of the filter chip, and the circuit board can form a cavity. This cavity facilitates sound wave transmission and improves the filtering effect of the filter chip. Furthermore, the sealing structure and the corresponding first surface of the filter chip do not contact each other, and the projected area of ​​the cavity on the circuit board is larger than the projected area of ​​the corresponding filter chip on the circuit board. This allows for a larger cavity space, ensuring that the sealing structure does not contaminate the first surface of the filter chip, thus improving the performance of the filter chip. Consequently, the system-in-package structure including this board-level architecture also exhibits good performance.

[0087] like Figure 11 As shown, the first device can be an active device 14 or a passive device 15. The active device 14 can be an amplifier, converter, or other similar device, while the passive device 15 can be a capacitor, resistor, switch, or other similar device. In specific implementations, the number and type of the first device can be set according to actual needs, as long as it can be circuit-matched with the filter chip 11. The spacing between the filter chip 11 and the first device can be set to less than 100μm, which can improve the layout density and is beneficial to the trend of high-density layout and miniaturization of system-in-package structures.

[0088] In practical applications, such as Figure 11 As shown, the system-in-package (SIP) structure in this embodiment may further include a molding compound 16 located on the circuit board 10. The molding compound 16 encapsulates each filter chip 11, each sealing structure 12, and each first device on the circuit board 10. By encapsulating each filter chip 11 with the molding compound 16, the packaging stability of each filter chip 11 can be improved. The molding compound 16 can encapsulate each first device on the circuit board 10. For example, the molding compound 16 can encapsulate the active device 14 and the passive device 15 on the circuit board 10. In this way, the filter chip 11 and the first device can be packaged into the same SIP structure, which can effectively improve the integration of the SIP structure, save space, and reduce manufacturing costs. Furthermore, it facilitates circuit adaptation between the filter chip 11 and the first device, making the structure of the SIP structure simple, effectively reducing the loss of radio frequency signals, and thus improving the efficiency of radio frequency.

[0089] Optionally, the material of the molding layer 16 may include: epoxy resin, acrylic resin, dielectric material, thermosetting material, thermoplastic material, rubber material, or other insulating material.

[0090] In the actual manufacturing process, the filter chip 11 and the first device are mounted on the circuit board 10, and a sealing structure 12 is formed around the filter chip 11. Then, an encapsulation layer 16 is formed on the circuit board 10 using an injection process. During the injection process, the sealing structure 12 prevents the encapsulation material from contacting the first surface S1 of the filter chip 11. Furthermore, the sealing structure 12 also protects the filter chip 11, preventing damage from the molding pressure generated by the encapsulation material and improving the encapsulation yield. For example, the dam 121 in the sealing structure 12 prevents damage to the first surface S1 and solder balls 13 of the filter chip 11, the filler portion 122 in the sealing structure 12 prevents damage to the sidewalls of the filter chip 11, and the top cover 123 in the sealing structure 12 prevents damage to the second surface S2 of the filter chip 11.

[0091] Based on the same technical concept, this application also provides an electronic device, which may include: any of the above-described system-in-package (SiP) structures, and a housing, with the housing covering the SiP structure. For example, the electronic device may be any device with radio frequency (RF) functionality, such as a smartphone, smartwatch, personal digital assistant, or base station. Because the above-described SiP structures have good performance, the electronic device including the above-described SiP structures also has good performance.

[0092] Based on the same technical concept, embodiments of this application also provide a method for manufacturing a board-level architecture. Figure 12 A flowchart illustrating the method for fabricating a board-level architecture as provided in an embodiment of this application. Figures 13 to 16 This is a schematic diagram of the structure corresponding to each step in the board-level architecture fabrication method in the embodiments of this application. For example... Figure 12 As shown, the manufacturing method provided in this application embodiment may include:

[0093] S201. A circuit board and at least one filter chip are provided; wherein the filter chip has an electrode structure on its first surface;

[0094] S202. At least one filter chip is mounted on the surface of the circuit board with its first surface facing the circuit board.

[0095] S203. A sealing structure is formed around at least one filter chip, which contacts the sidewall of the filter chip, contacts the surface of the circuit board, and does not contact the first surface of the filter chip, so that the sealing structure, the corresponding first surface of the filter chip, and the circuit board constitute a cavity; wherein each sealing structure encloses the filter chip, and the projected area of ​​the cavity on the circuit board is greater than the projected area of ​​the corresponding filter chip on the circuit board, and the projected area is the projected area along the thickness direction of the circuit board.

[0096] In the board-level architecture manufacturing method provided in this application embodiment, after the filter chip is mounted on the surface of the circuit board, a sealing structure is formed around at least one filter chip. This sealing structure contacts the sidewall of the filter chip, contacts the surface of the circuit board, and does not contact the first surface of the filter chip. This prevents the subsequent formation of structures such as molding layers from contaminating the first surface of the filter chip, avoids the sealing structure from affecting the function of the filter chip, improves the performance of the filter chip, and increases the yield of the board-level architecture. Furthermore, this manufacturing process has low complexity and integration difficulty, saving manufacturing costs.

[0097] Furthermore, the sealed structure, the corresponding first surface of the filter chip, and the circuit board form a cavity, which facilitates sound wave transmission and improves the filtering effect of the filter chip. In addition, the projected area of ​​the cavity on the circuit board is larger than that of the corresponding filter chip, allowing for a larger cavity space. This ensures that the sealed structure does not contaminate the first surface of the filter chip, preventing it from affecting the filter chip's function, improving its performance, and enabling the filter chip to meet the requirements of electronic devices.

[0098] In step S201 above, the circuit board can be a glass circuit board, a leadframe circuit board, a carrier board, a printed circuit board (PCB), a printed wire board (PWB) main board, or a package substrate, etc. Metal wiring layers and pads can be disposed on the surface of the circuit board, and at least one pad on the circuit board is grounded. The filter chip can be a surface acoustic wave (SAW) filter chip or a bulk acoustic wave (SAW) filter chip. The structure of the SAW filter chip can be as follows: Figure 2 As shown, the surface acoustic wave (SAW) filter chip has an electrode structure 111 on its first surface S1. This electrode structure 111 can be an interdigitated comb-shaped electrode. The SAW filter chip can have two electrode structures 111 on its first surface S1, one of which can serve as a transmitting transducer, and the other as a receiving transducer. The structure of the bulk acoustic wave filter chip can be as follows: Figure 3 As shown, the bulk acoustic wave filter chip has an electrode structure 111 on the first surface S1, and the filter chip 11 also has an electrode structure 111 on the second surface S2.

[0099] In step S202 above, as Figure 13As shown, the filter chip 11 is mounted on the surface of the circuit board 10, with the first surface S1 of the filter chip 11 facing the circuit board 10. The filter chip 11 is electrically connected to the pads on the surface of the circuit board 10 via solder balls 13, so that the filter chip 11 is electrically connected to the metal circuit layer on the surface of the circuit board 10.

[0100] In step S203 above, the sealing structure can be made in the following way:

[0101] like Figure 14 As shown, a dam 121 is formed around the filter chip 11. For example, the dam 121 can be fabricated using an inkjet printing process. The height h1 of the dam 121 is less than the distance h2 between the second surface S2 of the filter chip 11 and the surface of the circuit board 10. The second surface S2 is the surface of the filter chip 11 facing away from the circuit board 10. In practical applications, the height h1 of the dam 121 can be greater than the distance h3 between the first surface S1 of the filter chip 11 and the surface of the circuit board 10. For example, the height h1 of the dam 121 can be set to be at least 20 μm greater than the distance h3 between the first surface S1 of the filter chip 11 and the surface of the circuit board 10. Of course, the height h1 of the dam 121 can also be equal to or less than the distance h3 between the first surface S1 of the filter chip 11 and the surface of the circuit board 10; this is not limited here. Optionally, the width of the dam 121 can be set between 80 μm and 100 μm, and the distance between the dam 121 and the edge of the filter chip 11 can be set between 10 μm and 30 μm.

[0102] Reference Figure 14 In the process of manufacturing the dam 121, a certain degree of process error is allowed. For example, the material of the dam 121 may flow to the position below the filter chip 11 on the surface of the circuit board 10, or it may come into contact with the solder balls 13 below the filter chip 11, as long as the material of the dam 121 does not come into contact with the first surface S1 of the filter chip 11. In this way, the process window can be expanded and the process difficulty can be reduced.

[0103] Then, as Figure 15 As shown, a filling portion 122 is formed on the dam 121 to fill the gap between the dam 121 and the filter chip 11 and to contact the sidewall of the filter chip 11. The dam 121 and the corresponding filling portion 122 can constitute the aforementioned sealing structure. In the actual process, inkjet printing can be used to print on the dam 121 towards the filter chip 11 at a certain step value to form the filling portion 122 that fills the gap between the dam 121 and the corresponding filter chip 11. For example, the step value can be about 10 μm.

[0104] like Figure 16As shown, in step S203 above, after forming the filling portion, the following may also be included:

[0105] A top cover 123, connected to the filling portion 122, is formed on the second surface S2 of the filter chip 11. In actual manufacturing, the top cover 123 can be fabricated using inkjet printing. By forming the top cover 123 connected to the filling portion 122, the tightness between the sealing structure 12 and the filter chip 11 can be further improved, enhancing the sealing effect of the sealing structure 12. Optionally, the thickness of the top cover 123 can be set between 20 μm and 30 μm.

[0106] The top cover 123 at least covers the edge of the second surface S2 of the filter chip 11. For example... Figure 16 As shown, a top cover 123 can be formed to completely cover the second surface S2 of the filter chip 11. On the one hand, this can further improve the tightness between the sealing structure 12 and the filter chip 11, enhancing the sealing effect of the sealing structure 12. On the other hand, the top cover 123 can also protect the filter chip 11, preventing damage to the filter chip 11 from subsequent processes. (Refer to...) Figure 8 The top cover 123 formed can also only cover the edge portion of the filter chip 11, thus ensuring a high degree of tightness between the sealing structure 12 and the filter chip 11, resulting in a better sealing effect of the sealing structure 12. Of course, in some other embodiments of this application, the top cover 123 may not be provided in the sealing structure 12, and can be provided according to actual needs, without limitation here.

[0107] In this embodiment, the dam 121, filling part 122 and top cover 123 are manufactured using inkjet printing technology as an example. In actual implementation, other processes can also be used to manufacture the dam 121, filling part 122 and top cover 123, which is not limited here.

[0108] In this embodiment, the fabrication method of the system-in-package (SIP) structure is similar to the fabrication method of the board-level architecture described above. The difference lies in that, during the fabrication of the SIP structure, before forming the sealing structure encapsulating the filter chip, a first device needs to be mounted on the circuit board. This first device can be an active or passive device. Furthermore, after forming the sealing structure, a molding compound is formed to encapsulate each filter chip, each sealing structure, and each first device on the circuit board. The process of forming the sealing structure in the SIP structure is similar to the process of forming the sealing structure in the board-level architecture described above, and the repetitions will not be repeated. Figures 17 to 20 The accompanying drawings are schematic diagrams of the steps in the method for fabricating the system-in-package structure in this application embodiment. The following is a brief description of the method for fabricating the system-in-package structure in this application embodiment, in conjunction with the accompanying drawings.

[0109] like Figure 17 As shown, the filter chip 11 and the first device (such as...) Figure 17 The first device (shown as 14 and 15 in the diagram) is mounted on the surface of the circuit board 10. For example, the first device can be an active device 14, or it can be a passive device 15. The active device 14 can be an amplifier, converter, or other device, while the passive device 15 can be a capacitor, resistor, or other device. In specific implementations, the number and type of the first device can be set according to actual needs, as long as it can be circuit-matched with the filter chip 11. The spacing between the filter chip 11 and the first device can be set to less than 100μm, which can improve the layout density and is beneficial to the high-density layout and miniaturization trend of system-in-package structures.

[0110] like Figure 18 As shown, a dam 121 is formed around the filter chip 11. For example, the dam 121 can be fabricated using an inkjet printing process. During the fabrication of the dam 121, certain process errors are permissible. For example, the material of the dam 121 may flow to a position below the filter chip 11 on the surface of the circuit board 10, or it may come into contact with the solder balls 13 below the filter chip 11, as long as the material of the dam 121 does not contact the first surface S1 of the filter chip 11. This expands the process window and reduces the process difficulty. Furthermore, the material of the dam 121 can also flow to the area below adjacent first devices, filling the gap between the first devices and the circuit board 10, thus achieving an underfill function and improving the reliability of the first devices.

[0111] like Figure 19 As shown, a filling portion 122 is formed on the dam 121 to fill the gap between the dam 121 and the filter chip 11 and to contact the sidewall of the filter chip 11. The dam 121 and the corresponding filling portion 122 can constitute the aforementioned sealing structure. In the actual process, inkjet printing can be used to print on the dam 121 in the direction of the filter chip 11 at a certain step value to form the filling portion 122 that fills the gap between the dam 121 and the corresponding filter chip 11.

[0112] like Figure 20 As shown, after forming the filling portion 122, a top cover 123 connected to the filling portion 122 can be formed on the second surface S2 of the filter chip 11. In actual manufacturing, the top cover 123 can be fabricated using inkjet printing. The top cover 123 at least covers the edge of the second surface S2 of the filter chip 11.

[0113] Reference Figure 11A molding compound 16 is formed to encapsulate each filter chip 11, each sealing structure 12, and each first device on the circuit board 10. For example, the first device can be an active device 14 or a passive device 15. By encapsulating each filter chip 11 with the molding compound 16, the packaging stability of each filter chip 11 can be improved. In this embodiment, encapsulating the filter chip 11 and the first device in the same system-in-package (SIP) structure can effectively improve the integration of the SIP structure, save space, and reduce manufacturing costs. Furthermore, it facilitates circuit adaptation between the filter chip 11 and the first device, simplifies the structure of the SIP structure, effectively reduces RF signal loss, and thus improves RF efficiency.

[0114] Optionally, the material of the molding layer 16 may include: epoxy resin, acrylic resin, dielectric material, thermosetting material, thermoplastic material, rubber material, or other insulating material.

[0115] In the actual manufacturing process, an injection molding process can be used to form a molding compound 16 on the circuit board 10. During the injection molding process, the sealing structure 12 can prevent the molding compound from contacting the first surface S1 of the filter chip 11. Furthermore, the sealing structure 12 can also protect the filter chip 11, preventing damage from the molding flow pressure generated by the molding compound and improving the molding yield. For example, the dam 121 in the sealing structure 12 can prevent damage to the first surface S1 and solder balls 13 of the filter chip 11, the filler portion 122 in the sealing structure 12 can prevent damage to the sidewalls of the filter chip 11, and the top cover 123 in the sealing structure 12 can prevent damage to the second surface S2 of the filter chip 11.

[0116] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this application.

[0117] Obviously, those skilled in the art can make various modifications and variations to the embodiments of this application without departing from the spirit and scope of the embodiments of this application. Therefore, if these modifications and variations to the embodiments of this application fall within the scope of the claims of this application and their equivalents, this application also intends to include these modifications and variations.

Claims

1. A board-level architecture, characterized in that, include: A circuit board, and at least one filter chip and at least one sealing structure located on the circuit board; The filter chip has an electrode structure on its first surface, which is the surface of the filter chip facing the circuit board. Each of the aforementioned sealing structures encloses the filter chip; The sealing structure is in contact with the sidewall of the corresponding filter chip, the sealing structure is in contact with the surface of the circuit board, and the sealing structure is not in contact with the first surface of the corresponding filter chip. The sealing structure, the first surface of the corresponding filter chip, and the circuit board form a cavity, and the projected area of ​​the cavity on the circuit board is larger than the projected area of ​​the corresponding filter chip on the circuit board. The projected area is the projected area along the thickness direction of the circuit board; The sealing structure includes: a dam located on the circuit board and surrounding the corresponding filter chip, and a filling portion located on the side of the dam facing away from the circuit board; The filling part is connected to the dam, and the filling part fills the gap between the dam and the corresponding filter chip; In the direction from the circuit board to the filter chip, the cross-sectional area of ​​the cavity in the direction parallel to the circuit board first increases and then decreases.

2. The board-level architecture as described in claim 1, characterized in that, The sealing structure further includes a top cover connected to the filling portion; The top cover at least covers the edge of the second surface of the corresponding filter chip, the second surface being the surface of the filter chip facing away from the circuit board.

3. The board-level architecture as described in claim 2, characterized in that, The top cover completely covers the second surface of the filter chip.

4. The board-level architecture as described in any one of claims 1 to 3, characterized in that, At least two filter chips are arranged adjacent to each other on the circuit board, and the sealing structure corresponding to each of the at least two adjacent filter chips is an integral structure.

5. A system-level packaging structure, characterized in that, include: The board-level architecture as described in any one of claims 1 to 4, and the first device; the first device is located on the circuit board of the board-level architecture.

6. The system-in-package structure as described in claim 5, characterized in that, Also includes: A molding compound layer located on top of the circuit board; The molding compound encapsulates each filter chip, each sealing structure, and each of the first devices on the circuit board.

7. An electronic device, characterized in that, include: The system-in-package structure as described in claim 5 or 6, and a housing, wherein the housing encloses the system-in-package structure.

8. A method for fabricating a board-level architecture, characterized in that, include: A circuit board and at least one filter chip are provided; wherein the filter chip has an electrode structure on its first surface; The at least one filter chip is mounted on the surface of the circuit board with the first surface facing the circuit board. Around at least one of the filter chips, a sealing structure is formed that contacts the sidewall of the filter chip, the surface of the circuit board, and does not contact the first surface of the filter chip, such that the sealing structure, the corresponding first surface of the filter chip, and the circuit board constitute a cavity; wherein each of the sealing structures encloses the filter chip, and the projected area of ​​the cavity on the circuit board is larger than the projected area of ​​the corresponding filter chip on the circuit board, wherein the projected area is the projected area along the thickness direction of the circuit board; in the direction from the circuit board to the filter chip, the cross-sectional area of ​​the cavity in the direction parallel to the circuit board shows a trend of first increasing and then decreasing; The sealing structure is manufactured in the following manner: A dam is formed around the filter chip; wherein the height of the dam is less than the distance between the second surface of the filter chip and the surface of the circuit board, and the second surface is the surface of the filter chip facing away from the circuit board; A filling portion is formed on the dam to fill the gap between the dam and the filter chip and to contact the sidewall of the filter chip; the dam and the corresponding filling portion constitute the sealing structure.

9. The manufacturing method as described in claim 8, characterized in that, After forming the filling portion, the method further includes: A top cover connected to the filling portion is formed on the second surface of the filter chip; wherein the top cover at least covers the edge of the second surface of the filter chip.

10. The manufacturing method as described in claim 8 or 9, characterized in that, After forming the sealing structure, the method further includes: A plastic encapsulation layer is formed to encapsulate each of the filter chips and each of the sealing structures on the circuit board.

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