Circuit board assembly and method of manufacturing the same

Abstract

The application provides a circuit board assembly and a preparation method thereof, comprising a flexible circuit board, a component, a reinforcing film and a support structure, wherein the flexible circuit board has a component area, the component is arranged on the component area; the reinforcing film is arranged on the side of the flexible circuit board away from the component, and is arranged correspondingly to the component area; at least part of the support structure is arranged on the side of the reinforcing film away from the flexible circuit board; and extends from at least one side edge of the reinforcing film to the other side edge opposite to it. The circuit board assembly provided by the application can relieve the stress from the edge of the reinforcing film to the central area of the reinforcing film when the component is electrically connected on the flexible circuit board through a process such as high-temperature re-melting welding in the SMT link, thereby avoiding the problem of warping of the component area of the flexible circuit board.

Description

Technical Field

[0001] This application relates to the field of printed circuit boards, and in particular to a printed circuit board assembly and its manufacturing method. Background Technology

[0002] Flexible printed circuit boards (FPCs) are highly reliable and extremely flexible printed circuit boards made with polyimide or polyester film as the substrate. They are characterized by high wiring density, light weight, thinness, and good bending properties.

[0003] The existing preparation process needs to be improved. Summary of the Invention

[0004] This application provides a circuit board assembly and a method for manufacturing the same, which enables the fabrication process.

[0005] To solve the above-mentioned technical problems, the first technical solution provided in this application is: to provide a circuit board assembly, comprising:

[0006] Flexible circuit board with component areas;

[0007] Components are disposed in the device area;

[0008] A reinforcing film is disposed on the side of the flexible circuit board away from the component, and is disposed corresponding to the area of ​​the component;

[0009] A support structure is at least partially disposed on the side of the reinforcing film opposite to the flexible circuit board; and extends from at least one edge of the reinforcing film to the opposite edge; the support structure is used to relieve stress from the edge of the reinforcing film to the central region of the reinforcing film.

[0010] In one embodiment, the support structure includes a plurality of strips, all of which are disposed on the side of the reinforcing film opposite to the flexible circuit board.

[0011] In one embodiment, the plurality of strips are arranged in parallel and spaced apart; and the intersection areas of the intersecting strips are reused.

[0012] In one embodiment, at least a portion of the plurality of strips are arranged in an intersecting manner.

[0013] In one embodiment, the support structure includes an adhesive portion disposed on the side of the reinforcing film opposite to the flexible circuit board, and the adhesive portion is a continuous, seamless sheet or a sheet with multiple cutouts.

[0014] In one embodiment, the bonding portion and the reinforcing film have the same shape and size, and the projection of the bonding portion on the flexible circuit board completely overlaps with the projection of the reinforcing film on the flexible circuit board.

[0015] In one embodiment, an adhesive layer is provided between the flexible circuit board and the reinforcing film, and the adhesive layer has a first thickness;

[0016] The support structure also includes a hook-fitting part connected to the edge of the bonding part, the hook-fitting part extending from the edge of the bonding part to the space between the reinforcing film and the flexible circuit board and disposed in the same layer as the adhesive layer;

[0017] The portion of the coupling extending between the reinforcing film and the flexible circuit board has a second thickness, which is less than or equal to the first thickness.

[0018] In one embodiment, the reinforcing film is rectangular, and the two hook portions extend from the two short sides of the reinforcing film to the space between the reinforcing film and the flexible circuit board.

[0019] In one embodiment, the support structure is detachable from the reinforcing membrane.

[0020] In one embodiment, the material of the strip includes at least one selected from silicone, polyurethane, polyimide, polyester, thermoplastic elastomer, metal, heat-resistant glass, and ceramic.

[0021] To solve the above-mentioned technical problems, the second technical solution provided in this application is: a method for manufacturing a circuit board assembly, comprising:

[0022] Provide flexible circuit boards;

[0023] A reinforcing film is provided on one side of the flexible circuit board; wherein the reinforcing film is provided corresponding to the device area of ​​the flexible circuit board;

[0024] A support structure is provided on the side of the reinforcing film opposite to the flexible circuit board; wherein the support structure extends from at least one edge of the reinforcing film to the opposite edge thereon;

[0025] Components are mounted in the device area of ​​the flexible circuit board; wherein the components are located on the side of the flexible circuit board away from the reinforcing film, thereby forming a circuit board assembly preform.

[0026] The pre-formed circuit board assembly is placed in a high-temperature reactor and processed at a first preset temperature for a first preset time to weld the components together with the flexible circuit board.

[0027] In one embodiment, the first preset temperature ranges from 150 to 260 degrees Celsius;

[0028] The first preset time range is 3-8 minutes.

[0029] In one embodiment, the step of soldering the components to the flexible circuit board further includes:

[0030] The support structure is disassembled.

[0031] The beneficial effects of this application, unlike the prior art, are as follows: the circuit board assembly provided in this application includes a flexible circuit board, a reinforcing film, and a support structure. The flexible circuit board has a device area where components are disposed. The reinforcing film is disposed on one side of the flexible circuit board and corresponds to the device area, serving to structurally reinforce the flexible circuit board. At least a portion of the support structure is disposed on the side of the reinforcing film away from the flexible circuit board and extends from at least one edge of the reinforcing film to the opposite edge. Specifically, the circuit board assembly provided in this application, by providing a support structure that extends from at least one edge of the reinforcing film to the opposite edge, allows for better control of the expansion and contraction of the reinforcing film caused by high temperatures during the SMT process, when components are electrically connected to the flexible circuit board through processes such as high-temperature reflow soldering. This reduces stress on the reinforcing film from its edge to its center, thereby preventing warping of the device area of ​​the flexible circuit board. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort, wherein:

[0033] Figure 1 A partial structural schematic diagram of an embodiment of the circuit board assembly provided in this application from one perspective;

[0034] Figure 2 A partial structural schematic diagram of one embodiment of the circuit board assembly provided in this application from a certain perspective;

[0035] Figure 3 A partial structural schematic diagram of one embodiment of the circuit board assembly provided in this application from a certain perspective;

[0036] Figure 4 A partial structural schematic diagram of one embodiment of the circuit board assembly provided in this application from a certain perspective;

[0037] Figure 5 A partial structural schematic diagram of one embodiment of the circuit board assembly provided in this application from a certain perspective;

[0038] Figure 6 A partial structural schematic diagram of one embodiment of the circuit board assembly provided in this application from a certain perspective;

[0039] Figure 7 A partial structural schematic diagram of one embodiment of the circuit board assembly provided in this application from a certain perspective;

[0040] Figure 8 A partial structural schematic diagram of one embodiment of the circuit board assembly provided in this application from a certain perspective;

[0041] Figure 9 A partial structural schematic diagram of one embodiment of the circuit board assembly provided in this application from a certain perspective;

[0042] Figure 10 A partial structural schematic diagram of one embodiment of the circuit board assembly provided in this application from a certain perspective;

[0043] Figure 11 A schematic diagram of the structure of the circuit board assembly provided in this application after removing the flexible circuit board and components;

[0044] Figure 12 A schematic diagram of the structure of an embodiment of the fitting portion provided in this application;

[0045] Figure 13 A schematic diagram of another embodiment of the fitting portion provided in this application;

[0046] Figure 14 A schematic flowchart of the first embodiment of the method for manufacturing the circuit board assembly provided in this application;

[0047] Figure 15 This is a schematic flowchart of a second embodiment of the method for fabricating a circuit board assembly provided in this application. Specific implementation methods

[0048] The terms "first," "second," and "third" in this application are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first," "second," or "third" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified. All directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of this application are only used to explain the relative positional relationships and movements between components in a specific orientation (as shown in the figures). If the specific orientation changes, the directional indications also change accordingly. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or devices.

[0049] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0050] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0051] See Figure 1 , Figure 1 A partial structural schematic diagram of an embodiment of the circuit board assembly provided in this application from one perspective.

[0052] This application provides a circuit board assembly, including a flexible circuit board 10, components 101, a reinforcing film 20, and a support structure 30.

[0053] The flexible circuit board 10 has a device area S, in which a component 101 with a specific function is disposed. The flexible circuit board 10 also has a conductive pattern (not shown) for electrically connecting the component 101 disposed on the same layer or on different layers, and for electrically connecting with external devices.

[0054] In some embodiments, the components 101 include, but are not limited to, at least one or more of capacitors, inductors, resistors, diodes, transistors, power supplies, antennas, and IC chips. Any component 101 can be used to make the circuit have a specific function, and no limitation is made here.

[0055] In some embodiments, the flexible circuit board 10 can be a single-layer structure or a multi-layer stacked structure. The single-layer flexible circuit board 10 is simple to fabricate, while the multi-layer stacked flexible circuit board 10 can have more complex circuit structures and richer circuit functions. The specific design is based on actual needs.

[0056] The reinforcing film 20 is disposed on the side of the flexible circuit board 10 away from the component 101 and is disposed in the corresponding component area S, and is used to reinforce the structure of the flexible circuit board 10.

[0057] Specifically, the reinforcing film 20 is used to enhance the mechanical stability of the circuit board assembly. For example, the reinforcing film 20 can increase the mechanical stability of the flexible circuit board 10 in specific areas (such as the device area S, the bending area); the reinforcing film 20 is also used to help maintain the shape of the flexible circuit board 10 in places where a fixed shape or support is required, ensuring reliable electrical connections; the reinforcing film 20 is also used as a support in areas of the flexible circuit board 10 where precise alignment or welding is required, facilitating precise positioning during automated assembly processes, etc.

[0058] In some embodiments, the reinforcing film 20 is made of composite materials or specially designed plastic sheets. Specifically, the selection of materials for the reinforcing film 20 primarily considers its hardness, temperature resistance, cost, and compatibility with other film layers in the circuit board assembly. During the design process, the size, position, and shape of the reinforcing film 20 are carefully planned according to the needs of the actual application to ensure that the reinforcement effect is achieved without affecting the overall flexibility of the circuit board assembly.

[0059] In this embodiment, the reinforcing membrane 20 is made of a flexible material, for example, a polyimide membrane (PI membrane).

[0060] At least a portion of the support structure 30 is disposed on the side of the reinforcing film 20 away from the flexible circuit board 10; and extends from at least one edge of the reinforcing film 20 to the opposite edge thereon.

[0061] Understandably, during the SMT (Surface Mount Technology) process, when components 101 are electrically connected to the flexible circuit board 10 through high-temperature reflow soldering or other processes, the high temperature causes the reinforcing film 20 to expand and contract (generally, it contracts from the edge of the reinforcing film 20 towards the center, or expands from the center of the reinforcing film 20 towards the edge). The expanded and contracted reinforcing film 20 can then cause the corresponding device area S of the flexible circuit board 10 to warp. The circuit board assembly provided in this application, by setting a support structure 30, has certain stress parameters and extends from at least one edge of the reinforcing film 20 to the opposite edge, can prevent the reinforcing film 20 from expanding and contracting due to high temperature when components 101 are electrically connected to the flexible circuit board 10 through high-temperature reflow soldering or other processes during the SMT process. This alleviates the stress in the area from the edge of the reinforcing film 20 to the center of the reinforcing film 20, thereby preventing the device area S of the flexible circuit board 10 from warping.

[0062] In some embodiments, the material of the support structure 30 includes rigid materials or flexible materials. Rigid materials include, but are not limited to, at least one of heat-resistant glass, ceramics, and metals; flexible materials include, but are not limited to, at least one of silicone, polyurethane, polyimide, polyester, and thermoplastic elastomers.

[0063] It should be noted that the material of the support structure 30 is different from that of the reinforcing film 20. In some embodiments, the stress parameter of the support structure 30 is greater than that of the reinforcing film 20, which improves the effect of the reinforcing film 20 on expansion and contraction caused by high temperature, thereby alleviating the stress in the area from the edge to the center of the reinforcing film 20, and thus avoiding warping of the device area S of the flexible circuit board 10 due to the expansion and contraction of the reinforcing film 20.

[0064] See Figures 2-11 , Figure 2 A partial structural schematic diagram of one embodiment of the circuit board assembly provided in this application from a certain perspective; Figure 3 A partial structural schematic diagram of one embodiment of the circuit board assembly provided in this application from a certain perspective; Figure 4 A partial structural schematic diagram of one embodiment of the circuit board assembly provided in this application from a certain perspective; Figure 5 A partial structural schematic diagram of one embodiment of the circuit board assembly provided in this application from a certain perspective; Figure 6 A partial structural schematic diagram of one embodiment of the circuit board assembly provided in this application from a certain perspective; Figure 7 A partial structural schematic diagram of one embodiment of the circuit board assembly provided in this application from a certain perspective; Figure 8 A partial structural schematic diagram of one embodiment of the circuit board assembly provided in this application from a certain perspective; Figure 9 A partial structural schematic diagram of one embodiment of the circuit board assembly provided in this application from a certain perspective; Figure 10 A partial structural schematic diagram of one embodiment of the circuit board assembly provided in this application from a certain perspective; Figure 11 A schematic diagram of the structure of the circuit board assembly provided in this application after removing the flexible circuit board and components; Figure 12 A schematic diagram of the structure of an embodiment of the fitting portion provided in this application; Figure 13 This is a schematic diagram of another embodiment of the fitting part provided in this application.

[0065] See Figures 2-9 In the first embodiment of this application, the support structure 30 includes a plurality of strips 31, all of which are disposed on the side of the reinforcing film 20 away from the flexible circuit board 10.

[0066] See Figures 10-13 In the second embodiment of this application, the support structure 30 includes a bonding portion 32, which is disposed on the side of the reinforcing film 20 away from the flexible circuit board 10, and the bonding portion 32 is a continuous seamless sheet or a sheet with multiple hollow portions B.

[0067] Specifically, by providing multiple strips 31 or bonding portions 32 on the side of the reinforcing film 20 away from the flexible circuit board 10, the multiple strips 31 or bonding portions 32 can alleviate the stress in the area from the edge to the center of the reinforcing film 20, prevent the reinforcing film 20 from expanding and contracting due to high temperature, and thus avoid the problem of warping of the device area S of the flexible circuit board 10.

[0068] Compared to the second embodiment, the support structure 30 provided in the first embodiment of this application can save the cost of the support structure 30.

[0069] Compared to the first embodiment, the support structure 30 provided in the second embodiment of this application has a larger contact area between the bonding portion 32 and the reinforcing film 20, thus providing better improvement for the expansion and contraction of the reinforcing film 20 caused by high temperature. The specific choice can be made according to actual needs.

[0070] in addition, Figure 13 Compared to the shown bonding portion 32 Figure 13 The fitting part 32 shown can save the cost of the support structure 30.

[0071] See Figures 2-4 In some embodiments, the multiple strips 31 are arranged in parallel and spaced apart.

[0072] For example, refer to Figure 2 , a plurality of strip-shaped bodies 31 are arranged in parallel and at intervals along the first direction X. Specifically, by arranging a plurality of strip-shaped bodies 31 in parallel and at intervals along the first direction X, the plurality of strip-shaped bodies 31 can improve the expansion and contraction of the reinforcing film 20 caused by high temperature in the first direction X, thereby alleviating the stress from the edge of the reinforcing film 20 to the central region of the reinforcing film 20, and further avoiding the problem of warping of the device area S of the flexible printed circuit board 10 in the first direction X.

[0073] For example, refer to Figure 3 , a plurality of strip-shaped bodies 31 are arranged in parallel and at intervals along the second direction Y. Specifically, by arranging a plurality of strip-shaped bodies 31 in parallel and at intervals along the second direction Y, the plurality of strip-shaped bodies 31 can improve the expansion and contraction of the reinforcing film 20 caused by high temperature in the second direction Y, thereby alleviating the stress from the edge of the reinforcing film 20 to the central region of the reinforcing film 20, and further avoiding the problem of warping of the device area S of the flexible printed circuit board 10 in the second direction Y.

[0074] For example, refer to Figure 4 , a plurality of strip-shaped bodies 31 are arranged in parallel and at intervals along the third direction. Specifically, by arranging a plurality of strip-shaped bodies 31 in parallel and at intervals along the third direction, the plurality of strip-shaped bodies 31 can improve the expansion and contraction of the reinforcing film 20 caused by high temperature in the third direction, thereby alleviating the stress from the edge of the reinforcing film 20 to the central region of the reinforcing film 20, and further avoiding the problem of warping of the device area S of the flexible printed circuit board 10 in the third direction.

[0075] 6]Among them, the first direction X is perpendicular to the second direction Y; the third direction intersects both the first direction X and the second direction Y, and the included angle between the third direction and the first direction X and the second direction Y is not 90 degrees.

[0076] Refer to Figures 5-9 , in some embodiments, at least some of the plurality of strip-shaped bodies 31 are arranged in a cross manner, and the cross regions of the strip-shaped bodies 31 arranged in a cross manner are reused.

[0077] For example, refer to Figure 5 , a plurality of strip-shaped bodies 31 are arranged in a "square" shape. Specifically, by arranging a plurality of strip-shaped bodies 31 in a "square" shape, the plurality of strip-shaped bodies 31 arranged in a "square" shape respectively support the four edges of the reinforcing film 20, which is beneficial to improving the expansion and contraction of the edges of the reinforcing film 20 caused by high temperature, thereby alleviating the stress from the edge of the reinforcing film 20 to the central region of the reinforcing film 20, and further avoiding the problem of warping of the device area S of the flexible printed circuit board 10 in the third direction.

[0078] For example, refer to Figure 6 and Figure 7, a plurality of strip-shaped bodies 31 are arranged in a "day" character shape. Specifically, compared with the "square" character arrangement, the plurality of strip-shaped bodies 31 arranged in a "day" character shape add a strip-shaped body 31 extending along the first direction X or the second direction inside the "square" character, so as to further improve the improvement effect on the expansion and contraction of the reinforcing film 20 caused by high temperature in the first direction X or the second direction.

[0079] For example, see Figure 8 , a plurality of strip-shaped bodies 31 are arranged in a "field" character shape. Specifically, compared with the "square" character arrangement, the plurality of strip-shaped bodies 31 arranged in a "field" character shape add a strip-shaped body 31 extending along the first direction X and a strip-shaped body 31 extending along the second direction Y inside the "square" character, so as to improve the improvement effect on the expansion and contraction of the reinforcing film 20 caused by high temperature in the first direction X and the second direction Y at the same time.

[0080] For example, see Figure 9 , a plurality of strip-shaped bodies 31 are arranged in a "rice" character shape. The plurality of strip-shaped bodies 31 arranged in a "rice" character shape support different positions on the four edges of the reinforcing film 20 respectively, which is beneficial to improving the expansion and contraction of the edges of the reinforcing film 20 caused by high temperature, thereby relieving the stress from the edges of the reinforcing film 20 to the central area of the reinforcing film 20, and further avoiding the problem of warping of the device area S of the flexible printed circuit board 10 in the third direction.

[0081] In some embodiments, the material of the plurality of strip-shaped bodies 31 is also a flexible material. Thus, after the SMT process, the plurality of strip-shaped bodies 31 do not need to be peeled off from the reinforcing film 20, and can also play a dual reinforcing effect on the flexible printed circuit board 10.

[0082] In other embodiments, if the reinforcing film 20 and the support structure 30 are arranged corresponding to the non-bending part of the flexible printed circuit board 10, the material of the plurality of strip-shaped bodies 31 can also be a rigid material.

[0083] See Figure 10 and Figure 11 [[ID=二十三]], in the second embodiment of the present application, the shape and size of the fitting part 32 are the same as those of the reinforcing film 20, and the projection of the fitting part 32 on the flexible printed circuit board 10 completely overlaps with the projection of the reinforcing film 20 on the flexible printed circuit board 10.

[0084] Specifically, by setting the projections of the fitting part 32 and the reinforcing film 20 to completely overlap, the fitting part 32 can improve the expansion and contraction of any area of the reinforcing film under high temperature, enhance the blocking ability against the thermal deformation of the reinforcing film 20, and further avoid the problem of warping of the device area S of the flexible printed circuit board 10. [[ID=二十七]]

[0085] See Figure 10 or Figure 11In some embodiments, an adhesive layer 40 for bonding the flexible circuit board 10 and the reinforcing film 20 is provided between them, wherein the adhesive layer 40 has a first thickness. The support structure 30 also includes a hook portion 33 connected to the edge of the bonding portion 32, extending from the edge of the bonding portion 32 to the space between the reinforcing film 20 and the flexible circuit board 10 and disposed in the same layer as the adhesive layer 40. The portion of the hook portion 33 extending between the reinforcing film 20 and the flexible circuit board 10 has a second thickness, which is less than or equal to the first thickness.

[0086] Specifically, the hook-and-loop portion 33 extends between the reinforcing film 20 and the flexible circuit board 10, the support structure 30 is located at the adhesive portion 32 on the side of the reinforcing film 20 away from the flexible circuit board 10, and the hook-and-loop portion 33 on the side of the reinforcing film 20 close to the flexible circuit board 10 can improve the expansion and contraction of the reinforcing film 20 caused by high temperature, alleviate the stress in the area from the edge of the reinforcing film 20 to the center of the reinforcing film 20, and thus avoid the problem of warping of the device area S of the flexible circuit board 10.

[0087] In addition, setting the second thickness to be less than or equal to the first thickness can prevent the part of the hook 33 extending between the reinforcing film 20 and the flexible circuit board 10 from being too thick, which would cause the flexible circuit board 10 and the reinforcing film 20 to peel off and affect the stability of the device.

[0088] In some embodiments, the bonding portion 32 and the hooking portion 33 are made of the same material. When the flexible circuit board 10 is a flexible circuit board, the bonding portion 32 and the hooking portion 33 are also made of flexible material. In this way, after the SMT process, the bonding portion 32 and the hooking portion 33 do not need to be peeled off from the reinforcing film 20, and can also play a dual reinforcing role for the flexible circuit board 10.

[0089] In other embodiments, if the reinforcing film 20 and the support structure 30 are provided for the non-bending portion of the flexible circuit board 10, the materials of the bonding portion 32 and the hooking portion 33 can also be rigid materials.

[0090] See Figure 11 In some embodiments, the reinforcing film 20 is rectangular, and two hook portions 33 extend from the two short sides of the reinforcing film 20 to the space between the reinforcing film 20 and the flexible circuit board 10. It is understood that when the reinforcing film 20 is rectangular, the opposite two short sides of the reinforcing film 20 experience greater expansion and contraction deformation due to high temperatures. Therefore, in this embodiment, the hook portions 33 extend from the short sides of the reinforcing film 20 to the space between the reinforcing film 20 and the flexible circuit board 10. This can improve the expansion and contraction of the short sides of the reinforcing film 20 due to high temperatures, thereby alleviating the stress in the area from the edge to the center of the reinforcing film 20, and thus avoiding the problem of warping in the device area S of the flexible circuit board 10.

[0091] Furthermore, when the material of the support structure 30 is a rigid material, the support structure 30 and the reinforcing film 20 are made detachable. For example, the support structure 30 can be pulled out along one long side of the reinforcing film 20 towards the other long side. In this way, the support structure 30 can be prevented from affecting the bending of the flexible circuit board 10. In addition, the disassembled support structure 30 can be reused, saving costs.

[0092] Specifically, the circuit board assembly provided in this application, by setting a support structure 30, the support material having certain stress parameters, and the support structure 30 extending from at least one edge of the reinforcing film 20 to the opposite edge, can mitigate the expansion and contraction of the reinforcing film 20 caused by high temperature when the components 101 are electrically connected to the flexible circuit board 10 through processes such as high-temperature reflow soldering in the SMT process. This alleviates the stress in the area from the edge of the reinforcing film 20 to the center of the reinforcing film 20, thereby avoiding the problem of warping of the device area S of the flexible circuit board 10.

[0093] See Figure 14 , Figure 14 This is a flowchart illustrating the first embodiment of the method for fabricating a circuit board assembly provided in this application. Specifically, this application also provides a method for fabricating a circuit board assembly, including:

[0094] Step S1: Provide a flexible circuit board.

[0095] Flexible circuit boards can be single-layer or multi-layer stacked structures. Single-layer flexible circuit boards are simpler to fabricate, while multi-layer stacked flexible circuit boards allow for more complex circuit structures and richer circuit functions. The specific design depends on the actual needs.

[0096] The flexible circuit board is defined with a device area, which is used to mount and solder components.

[0097] Step S2: Set a reinforcing film on one side of the flexible circuit board.

[0098] The reinforcing film is positioned in the device area of ​​the flexible circuit board. Specifically, the reinforcing film enhances the mechanical stability of the circuit board assembly. For example, it can increase the mechanical stability of the flexible circuit board in specific areas (such as device area S, bending area); it also helps maintain the shape of the flexible circuit board in places where a fixed form or support is required, ensuring reliable electrical connections; and it serves as a support in areas of the flexible circuit board that require precise alignment or welding, facilitating precise positioning during automated assembly processes.

[0099] In some embodiments, the reinforcing film is made of composite materials or specially designed plastic sheets. Specifically, the selection of materials for the reinforcing film primarily considers its hardness, temperature resistance, cost, and compatibility with other films in the circuit board assembly. During the design process, the size, location, and shape of the reinforcing film are carefully planned according to the needs of the actual application to ensure that the reinforcement effect is achieved without affecting the overall flexibility of the circuit board assembly.

[0100] In this embodiment, the reinforcing film is made of a flexible material, such as a polyimide film (PI film).

[0101] Step S3: Set up a support structure on the side of the reinforcing film away from the flexible circuit board.

[0102] The support structure is at least partially disposed on the side of the reinforcing film away from the flexible circuit board; and extends from at least one edge of the reinforcing film to the opposite edge.

[0103] In some embodiments, the material of the support structure includes rigid materials or flexible materials. Rigid materials include, but are not limited to, at least one of heat-resistant glass, ceramics, and metals; flexible materials include, but are not limited to, at least one of silicone, polyurethane, polyimide, polyester, and thermoplastic elastomers.

[0104] It should be noted that the material of the support structure is different from that of the reinforcing film. In some embodiments, the stress parameter of the support structure is greater than that of the reinforcing film. This results in a better improvement in the expansion and contraction of the reinforcing film caused by high temperatures during subsequent SMT processes, thereby alleviating the stress in the area from the edge to the center of the reinforcing film and preventing warping of the device area of ​​the flexible circuit board due to the expansion and contraction of the reinforcing film.

[0105] Among them, the supporting structure can be Figures 2 to 13 The support structure 30 provided in any embodiment.

[0106] Step S4: Components are mounted in the device area of ​​the flexible circuit board; wherein the components are located on the side of the flexible circuit board away from the reinforcing film, thereby forming a circuit board assembly preform.

[0107] In some embodiments, the components include, but are not limited to, at least one or more of capacitors, inductors, resistors, diodes, transistors, power supplies, antennas, and IC chips, as long as the circuit composed of the above components has a specific function, and are not limited herein.

[0108] Step S5: Place the pre-made circuit board assembly in a high-temperature reaction furnace and process it at a first preset temperature for a first preset time to weld the components together with the flexible circuit board.

[0109] The first preset temperature can be in the range of 150-260 degrees Celsius. For example, the first preset temperature can be 150 degrees Celsius, 180 degrees Celsius, 210 degrees Celsius, 240 degrees Celsius, or 260 degrees Celsius, etc., and is not limited here. The first preset temperature can be different or the same at different welding stages of the circuit board assembly preform in the high-temperature reactor.

[0110] The first preset time can be in the range of 3-8 minutes. For example, the first preset time can be 3 minutes, 5 minutes, 7 minutes or 8 minutes, etc., without any restrictions.

[0111] Understandably, during the SMT process, when components are electrically connected to a flexible circuit board using high-temperature reflow soldering or similar processes, the high temperature causes the reinforcing film to expand and contract. This expansion and contraction can lead to warping of the corresponding device area on the flexible circuit board. The circuit board assembly provided in this application, by setting a support structure with certain stress parameters and extending from at least one edge of the reinforcing film to the opposite edge, can prevent the reinforcing film from expanding and contracting due to high temperature during the SMT process. This alleviates the stress in the area from the edge to the center of the reinforcing film, thereby preventing warping of the device area on the flexible circuit board.

[0112] See Figure 15 , Figure 15 This is a schematic flowchart of a second embodiment of the method for fabricating a circuit board assembly provided in this application.

[0113] In one embodiment, after step S5, the method further includes:

[0114] Step S6: Disassemble the support structure.

[0115] Specifically, in this embodiment, the material of the supporting structure is a rigid material.

[0116] Among them, such as Figure 11 As shown, the support structure can be pulled away along one long side of the reinforcing film towards the other long side, thereby avoiding the support structure from affecting the bending of the flexible circuit board; in addition, the disassembled support structure can be reused, saving costs.

[0117] The above are merely implementation methods of this application and do not limit the patent scope of this application. Any equivalent structural or procedural changes made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A circuit board assembly, characterized in that, include: Flexible circuit board with component areas; Components are disposed in the device area; A reinforcing film is disposed on the side of the flexible circuit board away from the component, and is disposed corresponding to the area of ​​the component; A support structure is at least partially disposed on the side of the reinforcing film opposite to the flexible circuit board; and extends from at least one edge of the reinforcing film to the opposite edge thereon; The supporting structure is used to prevent the reinforcing membrane from expanding and contracting due to high temperature, thereby relieving the stress in the area from the edge of the reinforcing membrane to the center of the reinforcing membrane.

2. The circuit board assembly according to claim 1, characterized in that, The support structure includes multiple strips, all of which are disposed on the side of the reinforcing film away from the flexible circuit board.

3. The circuit board assembly according to claim 2, characterized in that, The multiple strip-shaped bodies are arranged in parallel and at intervals.

4. The circuit board assembly according to claim 2, characterized in that, Some of the strips are arranged in an intersecting manner; and the intersection areas of the intersecting strips are reused.

5. The circuit board assembly according to claim 1, characterized in that, The support structure includes an adhesive portion disposed on the side of the reinforcing film away from the flexible circuit board, and the adhesive portion is a continuous seamless sheet or a sheet with multiple hollow portions.

6. The circuit board assembly according to claim 5, characterized in that, The bonding portion has the same shape and size as the reinforcing film, and the projection of the bonding portion on the flexible circuit board completely overlaps with the projection of the reinforcing film on the flexible circuit board.

7. The circuit board assembly according to claim 6, characterized in that, An adhesive layer is provided between the flexible circuit board and the reinforcing film, and the adhesive layer has a first thickness; The support structure also includes a hook-fitting part connected to the edge of the bonding part, the hook-fitting part extending from the edge of the bonding part to the space between the reinforcing film and the flexible circuit board and disposed in the same layer as the adhesive layer; The portion of the coupling extending between the reinforcing film and the flexible circuit board has a second thickness, which is less than or equal to the first thickness.

8. The circuit board assembly according to claim 7, characterized in that, The reinforcing film is rectangular, and the two hook-fitting portions extend from the two short sides of the reinforcing film to the space between the reinforcing film and the flexible circuit board.

9. The circuit board assembly according to claim 7 or 8, characterized in that, The support structure and the reinforcing membrane are detachable.

10. The circuit board assembly according to claim 1, characterized in that, The material of the support structure includes at least one of silicone, polyurethane, polyimide, polyester, thermoplastic elastomer, metal, heat-resistant glass, or ceramic.

11. A method for manufacturing a circuit board assembly, characterized in that, include: Provide flexible circuit boards; A reinforcing film is provided on one side of the flexible circuit board; wherein the reinforcing film is provided corresponding to the device area of ​​the flexible circuit board; A support structure is provided on the side of the reinforcing film opposite to the flexible circuit board; wherein the support structure extends from at least one edge of the reinforcing film to the opposite edge thereon; Components are mounted in the device area of ​​the flexible circuit board; wherein the components are located on the side of the flexible circuit board away from the reinforcing film, thereby forming a circuit board assembly preform. The pre-formed circuit board assembly is placed in a high-temperature reaction furnace and treated at a first preset temperature for a first preset time to weld the components together with the flexible circuit board. The supporting structure is used to prevent the reinforcing membrane from expanding and contracting due to high temperature, thereby relieving the stress in the area from the edge of the reinforcing membrane to the center of the reinforcing membrane.

12. The preparation method according to claim 11, characterized in that, The first preset temperature range is 150-260 degrees Celsius; The first preset time range is 3-8 minutes.

13. The preparation method according to claim 11, characterized in that, The process of welding the components to the flexible circuit board further includes: Disassemble the support structure.

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