Rigid-flex printed circuit board and manufacturing method thereof

Abstract

The present application relates to the technical field of printed circuit boards, and provides a rigid-flexible printed circuit board and a manufacturing method thereof. The manufacturing method of the rigid-flexible printed circuit board includes: providing a first FPC unit and a second FPC unit; stacking the first FPC unit and the second FPC unit together, and disposing a first thermosetting adhesive between the first FPC unit and the second FPC unit to obtain a product unit. A first space, a second space, and a third space that are connected in sequence and linearly arranged are formed between the first FPC unit and the second FPC unit, and the first thermosetting adhesive is located in the first space; performing a lamination process on the product unit; placing a reinforcing plate and a reinforcing adhesive in the third space, and the reinforcing adhesive is respectively disposed between the reinforcing plate and the first FPC unit, and between the reinforcing plate and the second FPC unit; laminating the first FPC unit, the second FPC unit, and the reinforcing plate together. The manufacturing method of the rigid-flexible printed circuit board in the present application can improve the quality of the rigid-flexible printed circuit board and improve the bending performance of the rigid-flexible printed circuit board.

Description

Technical Field

[0001] This application relates to the technical field of printed circuit boards, and particularly relates to a rigid-flexible printed circuit board and a manufacturing method thereof. Background Art

[0002] With the diversification of electronic devices, in the process of pursuing small size and portability functions, it is found that rigid-flexible printed circuit board products have more advantages. Currently, the materials of rigid-flexible printed circuit boards are mostly glass fiber epoxy resins, and a reinforcing plate needs to be added during the manufacturing process of rigid-flexible printed circuit boards to improve the performance of rigid-flexible printed circuit boards.

[0003] The traditional method is to use the lid-lifting process to embed the reinforcing plate into the rigid-flexible printed circuit board. This method not only has situations such as difficult control of the depth accuracy at the lid-opening position and burrs remaining at the lid-opening edge, which affect the quality of the rigid-flexible printed circuit board, but also the bending performance of the manufactured rigid-flexible printed circuit board is not good. Summary of the Invention

[0004] This application provides a rigid-flexible printed circuit board and a manufacturing method thereof to avoid situations such as difficult control of the depth accuracy at the lid-opening position and burrs remaining at the lid-opening edge when embedding the reinforcing plate into the rigid-flexible printed circuit board, improve the quality of the rigid-flexible printed circuit board, and improve the bending performance of the rigid-flexible printed circuit board.

[0005] An embodiment of the first aspect of this application provides a manufacturing method of a rigid-flexible printed circuit board, including:

[0006] Providing a first FPC unit and a second FPC unit;

[0007] Stacking the first FPC unit and the second FPC unit together, and setting a first thermosetting adhesive between the first FPC unit and the second FPC unit to obtain a product unit. A first space, a second space, and a third space that are connected in sequence and linearly arranged are formed between the first FPC unit and the second FPC unit, and the first thermosetting adhesive is located in the first space;

[0008] Performing a lamination process on the product unit;

[0009] Putting a reinforcing plate and a reinforcing adhesive into the third space, and the reinforcing adhesive is respectively arranged between the reinforcing plate and the first FPC unit, and between the reinforcing plate and the second FPC unit;

[0010] Laminating the first FPC unit, the second FPC unit, and the reinforcing plate together.

[0011] In some of these embodiments, before providing the first FPC unit and the second FPC unit, the rigid-flex printed circuit board manufacturing method further includes: providing a first core board and a second core board, the first core board including a plurality of connected first FPC units, the second core board including a plurality of connected second FPC units, the first FPC units and the second FPC units being arranged in one-to-one correspondence; stacking the first FPC units and the second FPC units together and disposing a first thermosetting adhesive between the first FPC units and the second FPC units to obtain a product unit, specifically including: stacking the first core board and the second core board together and disposing the first thermosetting adhesive between the first core board and the second core board to obtain a first master board, the first master board including a plurality of connected product units.

[0012] In some of these embodiments, after performing a lamination process on the product unit, and before placing a reinforcing board in the third space and placing a reinforcing board and a reinforcing adhesive in the third space, the rigid-flex printed circuit board manufacturing method further includes: performing a punching process on the first master board to obtain a plurality of individual sub-boards, each sub-board including a plurality of connected product units, and the third space of each product unit communicating with the external space.

[0013] In some of these embodiments, after laminating the first FPC unit, the second FPC unit, and the reinforcing board together, a punching process is performed on the sub-board to obtain a plurality of individual product units.

[0014] In some of these embodiments, a first gold finger is provided on a surface of the first FPC unit away from the second FPC unit; a second gold finger is provided on a surface of the second FPC unit away from the second FPC unit; the reinforcing board includes an aluminum plate unit and two BT resin substrates, the aluminum plate unit having opposite first and second surfaces, and the two BT resin substrates being respectively disposed on the first surface and the second surface; after placing the reinforcing board and the reinforcing adhesive in the third space, one of the BT resin substrates is disposed opposite to the first gold finger; the other BT resin substrate is disposed opposite to the second gold finger.

[0015] In some of these embodiments, placing grooves are provided on both the first surface and the second surface, the two placing grooves being disposed opposite to each other, and the two BT resin substrates are respectively placed in the two placing grooves, and a second thermosetting adhesive is disposed between the BT resin substrate and the bottom of the placing groove, and the shape of the BT resin substrate is adapted to the shape of the placing groove.

[0016] In some of these embodiments, after pressing the first FPC unit, the second FPC unit, and the reinforcement plate together, chamfering is performed on both the end of the first gold finger for plugging and unplugging and the end of the second gold finger for plugging and unplugging.

[0017] In some of these embodiments, a strip portion is further provided on the reinforcement plate; after pressing the first FPC unit, the second FPC unit, and the reinforcement plate together, 3D structural stamping is performed on the strip portion to bend the strip portion.

[0018] In some of these embodiments, before placing the reinforcement plate and the reinforcement adhesive in the third space, the method for manufacturing the rigid-flex printed circuit board further includes:

[0019] Roughening the surface of the reinforcement plate that is in contact with the reinforcement adhesive;

[0020] Attaching the reinforcement adhesive to the two roughened surfaces of the reinforcement plate respectively.

[0021] An embodiment of the second aspect of the present application provides a rigid-flex printed circuit board, including: the rigid-flex printed circuit board is processed by the method for manufacturing the rigid-flex printed circuit board as described in the first aspect.

[0022] The beneficial effect of the method for manufacturing the rigid-flex printed circuit board provided by the embodiments of the present application is that: since the first thermosetting adhesive is only provided in the first space of the product unit, the reinforcement plate can be directly placed in the third space first, and then the first FPC unit, the second FPC unit, and the reinforcement plate can be pressed together through the reinforcement adhesive, so that it is not necessary to perform an opening treatment on the product unit. This not only avoids situations such as difficult control of the depth accuracy at the opening position and burrs remaining at the opening edge when embedding the reinforcement plate into the product unit, improves the quality of the rigid-flex printed circuit board, and moreover, the first FPC unit and the second FPC unit corresponding to the position of the second space are in a layered state, and its flexibility is also better, so that the bending performance of the rigid-flex printed circuit board is also higher.

[0023] The beneficial effect of the rigid-flex printed circuit board provided by the present application compared with the prior art is the same as the beneficial effect of the method for manufacturing the rigid-flex printed circuit board provided by the present application compared with the prior art, which will not be elaborated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0025] Figure 1It is a flowchart of a method for manufacturing a rigid-flex printed circuit board in one embodiment of the present application;

[0026] Figure 2 It is a schematic structural diagram of a product unit in one embodiment of the present application;

[0027] Figure 3 It is to Figure 1 A schematic structural diagram of a rigid-flex printed circuit board after laminating the first FPC unit, the second FPC unit, and the reinforcing plate shown;

[0028] Figure 4 It is Figure 3 A cross-sectional view of part A of the rigid-flex printed circuit board shown;

[0029] Figure 5 It is Figure 3 A cross-sectional view of part B of the rigid-flex printed circuit board shown;

[0030] Figure 6 It is to Figure 3 A schematic structural diagram after performing 3D structural stamping on the strip portion on the reinforcing plate in the rigid-flex printed circuit board shown;

[0031] Figure 7 It is a schematic structural diagram of the first mother board in one embodiment of the present application;

[0032] Figure 8 It is to Figure 7 A schematic structural diagram of a plurality of individual daughter boards obtained after performing punching on the first mother board shown;

[0033] Figure 9 It is Figure 3 A schematic structural diagram of the reinforcing plate in the rigid-flex printed circuit board shown;

[0034] Figure 10 It is Figure 9 A cross-sectional schematic diagram of the reinforcing plate shown;

[0035] Figure 11 It is a schematic structural diagram of a method for manufacturing a reinforcing plate in another embodiment of the present application;

[0036] Figure 12 It is a schematic structural diagram of the reinforcing plate in one embodiment of the present application;

[0037] Figure 13 It is Figure 12 A schematic structural diagram of the BT resin substrate in the reinforcing plate shown;

[0038] Figure 14 It contains Figure 12 A schematic structural diagram of a rigid-flex printed circuit board containing the reinforcing plate shown;

[0039] Figure 15 It is a schematic structural diagram of the second mother board of the aluminum plate unit in the reinforcing plate shown in Figure 12 ;

[0040] Figure 16 It is Figure 12 a schematic structural diagram of the first side and the second side of the reinforcing plate shown in

[0041] The meanings of the marks in the figure are as follows:

[0042] 100, the first mother board; 100a, the daughter board; 10, the product unit; 11, the first FPC unit; 111, the first gold finger; 12, the second FPC unit; 121, the second gold finger; 13, the first thermosetting glue; 14, the first space; 15, the second space; 16, the third space; 200, the second mother board; 20, the reinforcing plate; 21, the aluminum plate unit; 211, the first surface; 2111, the first chamfered part; 212, the second surface; 2121, the second chamfered part; 213, the placement groove; 2131, the mating part; 22, the BT resin substrate; 221, the engaging part; 23, the strip part; 24, the relief groove; 30, the reinforcing glue. Detailed implementation manners

[0043] In order to make the objectives, technical solutions and advantages of the present application clearer and more understandable, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0044] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0045] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present application, "a plurality of" means two or more unless otherwise specifically defined.

[0046] References to "one embodiment", "some embodiments", or "an embodiment" in the specification of this application mean that a particular feature, structure, or characteristic described in connection with that embodiment is included in one or more embodiments of this application. Thus, statements such as "in one embodiment", "in some embodiments", "in other some embodiments", "in still other embodiments", etc., which appear in different places in this specification, do not necessarily refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized. In addition, in one or more embodiments, the particular features, structures, or characteristics may be combined in any suitable manner.

[0047] To illustrate the technical solutions of this application, the following will be described in conjunction with specific drawings and embodiments.

[0048] Please refer to Figure 1 、 Figure 2 and Figure 3 , an embodiment of the first aspect of this application provides a method for manufacturing a rigid-flex printed circuit board, including:

[0049] S100: Provide a first FPC unit 11 and a second FPC unit 12.

[0050] Specifically, please also refer to Figure 4 , both the first FPC unit 11 and the second FPC unit 12 have undergone the inner layer circuit and inner layer cover film pasting processes. The inner layer circuit is manufactured by a conventional method, and the inner layer cover film is also pasted by a conventional method. The layer structure of the first FPC unit 11 is successively a top cover film, a top double-sided base material CU layer, a top double-sided base material PI layer, a top double-sided base material CU layer, and an upper base material cover film. The layer structure of the second FPC unit 12 is successively a lower base material cover film, a bottom double-sided base material CU layer, a bottom double-sided base material PI layer, a bottom double-sided base material CU layer, and a bottom cover film.

[0051] S200: Stack the first FPC unit 11 and the second FPC unit 12 together, and set a first thermosetting adhesive 13 between the first FPC unit 11 and the second FPC unit 12 to obtain a product unit 10. A first space 14, a second space 15, and a third space 16 that are connected in sequence and linearly arranged are formed between the first FPC unit 11 and the second FPC unit 12, and the first thermosetting adhesive 13 is located in the first space 14.

[0052] Specifically, the first thermosetting adhesive 13 is only located within the first space 14. The first FPC unit 11 and the second FPC unit 12 can be respectively attached to opposite sides of the first thermosetting adhesive 13. The first FPC unit 11 and the second FPC unit 12 at the second space 15 and the third space 16 are in a layered state, and the first thermosetting adhesive 13 at the second space 15 and the third space 16 can be subjected to windowing treatment.

[0053] S300: Perform a lamination process on the product unit 10.

[0054] Specifically, after performing a lamination process on the product unit 10, circuits are fabricated inside the product unit 10, and no circuits are fabricated on the outer layer. The first FPC unit 11 and the second FPC unit 12 at the first space 14 are in a bonded state, and this is the flexible board area. The first FPC unit 11 and the second FPC unit 12 at the second space 15 are in a layered state, and this is the flexure area. And due to the layered state, the bending performance is better. The first FPC unit 11 and the second FPC unit 12 at the third space 16 are in a layered state, and this is the reinforcement area, which is used for later embedding the reinforcement plate 20. Compared with the manufacturing method of traditional rigid-flex boards, the flexure area uncovering process is reduced. It is possible to obtain both a flexure area with rigid-flex combination and a layered effect in the reinforcement area, solving the problems that due to the use of the traditional uncovering process, during the uncovering operation, it is difficult to control the depth accuracy. If the cutting is too deep, the circuit will be cut off and the product will be scrapped. If the cutting is too shallow, the uncovering cannot be completed during uncovering or burrs, burrs, debris and other defects will be generated at the uncovering edge.

[0055] Optionally, after performing a lamination process on the product unit 10, processes such as outer layer circuit, attaching an outer layer cover film, and punching the FPC shape can also be performed on the product unit 10.

[0056] Among them, the outer layer circuit fabrication refers to fabricating the outer layer circuit of the four-layer board of the product unit 10 after lamination. Before circuit fabrication, first drill holes in the product unit 10 (including the embedding positioning holes for the reinforcement plate 20 and the vias between layers), and then electroplate to make the four-layer board of the product unit 10 conduct. After electroplating, the outer layer circuit is fabricated by means of film lamination, exposure, development, and etching.

[0057] Among them, attaching the outer layer cover film means that after completing the outer layer circuit fabrication, the cover film is laminated on the upper and lower outer layers of the product unit 10.

[0058] Among them, punching the FPC shape means punching the shape of the product unit 10 according to the area design of the product unit 10 to obtain the FPC product.

[0059] S400: Place the reinforcement plate 20 and the reinforcement adhesive 30 in the third space 16. The reinforcement adhesive 30 is disposed between the reinforcement plate 20 and the first FPC unit 11, and between the reinforcement plate 20 and the second FPC unit 12.

[0060] Specifically, please refer to Figure 5 simultaneously. Since the first FPC unit 11 and the second FPC unit 12 at the third space 16 are in a layered state, it is convenient to place the reinforcement plate 20 into the third space 16. The reinforcement adhesive 30 can be directly attached to both sides of the reinforcement plate 20 first, and then the reinforcement plate 20 with the reinforcement adhesive 30 attached is placed into the third space 16. The reinforcement adhesive 30 can adopt a thermosetting reinforcement adhesive, such as D3450 acrylic thermosetting reinforcement adhesive, etc.

[0061] S500: Press the first FPC unit 11, the second FPC unit 12 and the reinforcement plate 20 together.

[0062] Specifically, after the reinforcement plate 20 is fixed and inlaid through the inlaid positioning holes, the reinforcement plate 20 can be first inlaid in the third space 16 by using a false press, and then a fast press process is adopted. The press table is padded with silicon-aluminum foil to increase the overall flatness during pressing, so that the reinforcement adhesive 30 is fully dissolved and liquefied and flows to fill the laminated gaps between the reinforcement plate 20 and the first FPC unit 11 and between the reinforcement plate 20 and the second FPC unit 12, so that the reinforcement plate 20 is fully combined with the first FPC unit 11 and the second FPC unit 12.

[0063] It can be understood that after the first FPC unit 11, the second FPC unit 12 and the reinforcement plate 20 are pressed together, the first FPC unit 11 and the second FPC unit 12 at the third space 16 are in a hard board state, and this place becomes a hard board area.

[0064] In the method for manufacturing a rigid-flexible printed circuit board provided by the embodiment of the present application, since the first thermosetting adhesive 13 is only disposed in the first space 14 of the product unit 10, the reinforcement plate 20 can be directly placed into the third space 16 first, and then the first FPC unit 11, the second FPC unit 12 and the reinforcement plate 20 are pressed together through the reinforcement adhesive 30, so that there is no need to open the cover of the product unit 10. This not only avoids the situations such as difficult control of the depth accuracy of the opening position and burrs remaining at the opening edge when the reinforcement plate 20 is embedded in the product unit 10, improves the quality of the rigid-flexible printed circuit board, but also the first FPC unit 11 and the second FPC unit 12 corresponding to the position of the second space 15 are in a layered state, and their flexibility is also better, so that the bending performance of the rigid-flexible printed circuit board is also higher.

[0065] Please refer to Figure 2 and Figure 7, in some embodiments, before providing the first FPC unit 11 and the second FPC unit 12, the rigid-flex printed circuit board manufacturing method further includes: providing a first core board and a second core board, the first core board includes a plurality of connected first FPC units 11, the second core board includes a plurality of connected second FPC units 12, and the first FPC units 11 and the second FPC units 12 are arranged in one-to-one correspondence.

[0066] Stack the first FPC unit 11 and the second FPC unit 12 together, and dispose a first thermosetting adhesive 13 between the first FPC unit 11 and the second FPC unit 12 to obtain a product unit 10, specifically including: stacking the first core board and the second core board together, and disposing a first thermosetting adhesive 13 between the first core board and the second core board to obtain a first mother board 100, the first mother board 100 includes a plurality of connected product units 10, and the flexible board regions, flexure regions, and reinforcing regions of the plurality of connected product units 10 are all in a connected state.

[0067] By adopting the above solution, multiple product units 10 can be simultaneously pressed in the subsequent process, improving production efficiency.

[0068] Please refer to Figure 2 and Figure 8 , in some embodiments, after performing a pressing process on the product unit 10, and before placing a reinforcing plate 20 in the third space 16 and placing a reinforcing plate 20 and a reinforcing adhesive 30 in the third space 16, the rigid-flex printed circuit board manufacturing method further includes: performing a punching process on the first mother board 100 to obtain a plurality of individual daughter boards 100a, each daughter board 100a includes a plurality of connected product units 10, and the third space 16 of each product unit 10 communicates with the external space.

[0069] By adopting the above solution, multiple product units 10 can be simultaneously pressed, improving production efficiency, and it is also convenient to place the reinforcing plate 20 into the third space 16.

[0070] Optionally, after pressing the first FPC unit 11, the second FPC unit 12, and the reinforcing plate 20 together, perform a punching process on the daughter board 100a to obtain a plurality of individual product units 10. In this way, it is convenient to press the first FPC unit 11, the second FPC unit 12, and the reinforcing plate 20 together, improving production efficiency.

[0071] Please refer to Figure 3 , Figure 9 and Figure 10 , in some embodiments, a first gold finger 111 is provided on a surface of the first FPC unit 11 away from the second FPC unit 12; a second gold finger 121 is provided on a surface of the second FPC unit 12 away from the second FPC unit 12.

[0072] The reinforcing plate 20 includes an aluminum plate unit 21 and two BT resin substrates 22. The aluminum plate unit 21 has opposite first and second surfaces 211 and 212, and the two BT resin substrates 22 are respectively disposed on the first surface 211 and the second surface 212. After the reinforcing plate 20 is placed in the third space 16, and after the reinforcing plate 20 and the reinforcing adhesive 30 are placed in the third space 16, one of the BT resin substrates 22 is disposed opposite to the first gold finger 111; the other BT resin substrate 22 is disposed opposite to the second gold finger 121.

[0073] By adopting the above solution, the heat dissipation performance of the product can be improved, the signal transmission jamming and loss caused by the heating of the gold fingers due to long-term power-on can be improved, the signal transmission stability is enhanced, and the risk of short-circuit burning of the product caused by the top pin piercing the gold fingers during use can also be reduced by virtue of the good insulation performance of the BT resin substrate 22.

[0074] It can be understood that the aluminum plate unit 21 can adopt AL7075 alloy aluminum with good mechanical properties, high temperature resistance and corrosion resistance. The BT resin substrate 22 can be polymerized from bismaleimide resin and triazine. The BT resin substrate 22 has advantages such as good heat resistance, low dielectric constant (DK) and low dissipation factor (DF). Due to its excellent low dielectric loss, the influence on the transmission loss of high-speed signals is extremely small.

[0075] It can be understood that a graphics card with a rigid-flexible printed circuit board processed by using the manufacturing method of the rigid-flexible printed circuit board in this embodiment has a complete set of functions. Under the same working time and power, no problems occur, and the CPU temperature is relatively low, bringing a better user experience.

[0076] It can be understood that for the rigid-flexible printed circuit board processed by using the manufacturing method of the rigid-flexible printed circuit board in this embodiment, materials are only used in the reinforcing area. In terms of material utilization rate, compared with the traditional rigid-flexible printed circuit board, its glass fiber epoxy resin substrate is used in a whole-piece lamination. The reinforcing plate 20 described in this embodiment saves more materials, and the material utilization rate is increased by 30% to 50%, and the material usage rate is higher.

[0077] Optionally, after the first FPC unit 11, the second FPC unit 12 and the reinforcing plate 20 are pressed together, the front end of the gold finger area (i.e., the edge corresponding to the BT resin substrate 22) is milled. After milling, the buried BT resin substrate 22 and the aluminum plate unit 21 of the reinforcing plate 20 corresponding to the gold finger are exposed.

[0078] Please refer to Figure 3 、 Figure 9 and Figure 10, in some embodiments, for facilitating subsequent plugging and unplugging processing, after the first FPC unit 11, the second FPC unit 12 and the reinforcing plate 20 are pressed together, chamfering is performed on the ends of the first gold finger 111 and the second gold finger 121 for plugging and unplugging, so that the front ends of the first gold finger 111 and the second gold finger 121 both present a slope shape.

[0079] By adopting the above solution, since the BT resin substrate 22 is provided in the area of the reinforcing plate 20 corresponding to the first gold finger 111 and the second gold finger 121, and the BT resin substrate 22 is a resin polymer material, when chamfering, it is only necessary to chamfer the first FPC unit 11, the second FPC unit 12 and the BT resin substrate 22. When chamfering, the milling cutter does not need to chamfer the aluminum plate unit 21 anymore. Since the BT resin substrate 22 is a resin polymer and its hardness is lower than that of the aluminum plate unit 21, the wear of the milling cutter can be greatly reduced, thereby reducing the loss of the milling cutter and the cost. At the same time, when chamfering, the milling cutter does not need to chamfer the aluminum plate unit 21 anymore, and problems such as burrs and flash generated during chamfering can also be reduced, improving the product yield.

[0080] Please refer to Figure 3 and Figure 6 , in some embodiments, for facilitating product assembly, a strip portion 23 is further provided on the reinforcing plate 20. After the first FPC unit 11, the second FPC unit 12 and the reinforcing plate 20 are pressed together, the strip portion 23 extends to the outside of the first FPC unit 11 and the second FPC unit 12.

[0081] After the first FPC unit 11, the second FPC unit 12 and the reinforcing plate 20 are pressed together, 3D structure stamping processing is performed on the strip portion 23 to bend the strip portion 23. In this way, the strip portion 23 can present a 3D structure, facilitating the assembly of the pressed first FPC unit 11, second FPC unit 12 and reinforcing plate 20 with other components together, and further realizing diversified assembly scenarios, such as side wall assembly, suspension assembly and other methods.

[0082] Optionally, when performing 3D structure stamping processing on the strip portion 23, it is fixed using the positioning holes on the strip portion 23, and die stamping operation is adopted. The bottom die of the die makes a bending structure slot for the strip portion 23, and through the operation of the punching press, the upper die of the die presses down to press the strip portion 23 into the bending structure slot of the bottom die of the die.

[0083] Optionally, after performing 3D structure stamping processing on the strip portion 23, the rigid-flexible printed circuit board is subjected to processes such as SMT component mounting, finished product function testing, finished product appearance inspection and product packaging, etc., which can all be carried out in a conventional manner.

[0084] In some of these embodiments, in order to improve the bonding strength between the reinforcement plate 20 and the reinforcement adhesive 30, before placing the reinforcement plate 20 and the reinforcement adhesive 30 in the third space 16, the rigid-flex printed circuit board manufacturing method further includes: first roughening the surface of the reinforcement plate 20 that comes into contact with the reinforcement adhesive 30, and then attaching the reinforcement adhesive 30 to the two roughened surfaces of the reinforcement plate 20 respectively. In this way, the bonding between the reinforcement plate 20 and the reinforcement adhesive 30 can be made closer.

[0085] Optionally, after roughening the surface of the reinforcement plate 20 by micro-etching with an alkaline solution and then performing plasma cleaning, the bonding strength between the reinforcement plate 20 and the reinforcement adhesive 30 can be increased, and this method can also be used to roughen the oxide layer on the surface of the reinforcement plate 20.

[0086] In some of these embodiments, placing grooves 213 are provided on both the first surface 211 and the second surface 212, the two placing grooves 213 are arranged back to back, the two BT resin substrates 22 are respectively placed in the two placing grooves 213, a second thermosetting adhesive is provided between the BT resin substrate 22 and the bottom of the placing groove 213, and the shape of the BT resin substrate 22 is adapted to the shape of the placing groove 213.

[0087] Please refer to Figure 11 、 Figure 2 and Figure 14 , in this embodiment, the reinforcement plate 20 is manufactured through the following steps:

[0088] S10: Provide an aluminum plate unit 21, the aluminum plate unit 21 has opposite first surface 211 and second surface 212, placing grooves 213 are provided on both the first surface 211 and the second surface 212, and the two placing grooves 213 are arranged back to back.

[0089] Specifically, the material of the aluminum plate unit 21 is aluminum, such as T - specification aluminum with high hardness and high strength can be selected to prevent the deformation of the aluminum plate unit 21. The aluminum plate unit 21 may have already undergone a drilling process, that is, peripheral holes, part number holes, and other positioning holes have been drilled on the aluminum plate unit 21.

[0090] S20: Place the two BT resin substrates 22 in the two placing grooves 213 respectively, and provide a second thermosetting adhesive between the BT resin substrate 22 and the bottom of the placing groove 213. The shape of the BT resin substrate 22 is adapted to the shape of the placing groove 213.

[0091] Specifically, a BT board with a copper thickness of 1 / 3OZ can be selected to minimize the material cost. After cutting, the copper foils on both sides of the BT board are etched off first to obtain the BT resin substrate 22, and then the BT resin substrate 22 is subjected to a drilling process, that is, the peripheral holes on the board edge and the anti - reflection holes for forming the routing board are drilled. The aperture of the peripheral holes can be designed to be 3.0 mm for pin - positioning during the false bonding with the second thermosetting adhesive.

[0092] Optionally, each BT resin substrate 22 can be temporarily attached with two pieces of second thermosetting adhesives with a thickness of 0.025 mm. When temporarily attaching, use pin nails to align with the peripheral holes of the BT resin substrate 22 and then position them, and use a vacuum temporary attachment machine for temporary attachment.

[0093] Optionally, after temporarily attaching the second thermosetting adhesive, the BT resin substrate 22 is drilled twice. There are two sets of drilling data for the front and back. Since anti-reverse holes have been drilled during the first drilling, it can avoid the situation of using the wrong data for production. When drilling for the second time, form milling positioning holes with a depth of 1.45 mm inside the BT resin substrate 22. These positioning holes need to be designed in the waste area of the final product to avoid depressions after pressing with the rigid-flexible board.

[0094] Optionally, the BT resin substrate 22 is cleaned of dust to facilitate better bonding of the BT resin substrate 22 with the second thermosetting adhesive in the later stage.

[0095] Optionally, the overall outer dimension of the placement groove 213 is at least 0.1 mm larger than the outer dimension of the BT resin substrate 22 to facilitate placing the BT resin substrate 22 into the placement groove 213.

[0096] Optionally, the depth of the placement groove 213 is 0.35 mm - 0.45 mm, such as 0.35 mm, 0.37 mm, 0.39 mm, 0.41 mm, 0.43 mm, and 0.45 mm, etc. The sum of the thicknesses of the BT resin substrate 22 and the second thermosetting adhesive is 0.36 mm - 0.44 mm, such as 0.36 mm, 0.38 mm, 0.40 mm, 0.42 mm, and 0.44 mm, etc. In this way, the overall flatness of the aluminum plate unit 21 and the BT resin substrate 22 can be improved, and finally the flatness of the surface of the finished rigid-flexible board after pressing the reinforcing plate 20 and the flexible board can be improved.

[0097] S30: Press the aluminum plate unit 21 and two BT resin substrates 22 together.

[0098] Specifically, put the aluminum plate unit 21 and two BT resin substrates 22 into a fast press for rapid pressing. The fast press lamination method is: 2.0 mm silica gel pad + silicone-free release film + aluminum plate unit 21 and two BT resin substrates 22 + silicone-free release film + 2.0 silica gel pad. Among them, using a 2.0 mm silica gel pad can fully fill the height difference between the BT resin substrate 22 and the aluminum plate unit 21 due to the controlled depth tolerance, ensuring that the BT resin substrate 22 can be completely attached to the aluminum plate unit 21, thereby improving the bonding rate between the two and further improving the product reliability. Using a silicone-free release film can avoid the precipitation of silicone oil substances due to high temperature during the fast press process, resulting in the residual silicone oil substances on the surface of the aluminum plate unit 21 after fast pressing, and finally affecting the pressing reliability of the reinforcing plate 20 and the rigid-flexible board.

[0099] S40: curing the second thermosetting adhesive.

[0100] Specifically, the pressed aluminum plate unit 21 and the two BT resin substrates 22 may be subjected to a curing baking process at 150°+2 hours to completely cure the second thermosetting adhesive.

[0101] The manufacturing method of the reinforcement plate 20 provided in the embodiment of the present application has placement grooves 213 on both the first surface 211 and the second surface 212 opposite to each other of the aluminum plate unit 21, and a BT resin substrate 22 is arranged in the placement groove 213. The aluminum plate unit 21 and the BT resin substrate 22 are fixed together by pressing together with a second thermosetting adhesive. Therefore, when the reinforcement plate 20 is embedded in the rigid-flexible board, the BT resin substrate 22 can be made to correspond to the signal transmission intensive area on the rigid-flexible board, such as the gold finger area on the rigid-flexible board. In this way, the excellent heat resistance, excellent low dielectric properties, low thermal expansion rate and good mechanical characteristics of the BT resin substrate 22 can be utilized to reduce the transmission loss of high-speed signals, avoid signal transmission jams and losses caused by long-term power-on heating of the gold fingers, and improve the signal transmission performance in the signal transmission intensive area on the rigid-flexible board to better meet the requirements of the rigid-flexible board for high-frequency and high-speed performance, and provide better rigidity and fixed support for the rigid-flexible board.

[0102] Please refer to Figure 14 In some embodiments, before providing an aluminum plate unit 21, the method for manufacturing the reinforcing plate 20 further includes: processing placement grooves 213 on the first surface 211 and the second surface 212. For example, the placement grooves 213 can be processed on the first surface 211 and the second surface 212 using a controlled gong machine.

[0103] Please refer to Figure 12 , Figure 13 and Figure 15 In some embodiments, in order to improve production efficiency, placement grooves 213 are processed on the first surface 211 and the second surface 212 respectively, specifically including:

[0104] First, a second motherboard 200 is provided, and the second motherboard 200 has a plurality of connected aluminum plate units 21 .

[0105] Specifically, the second motherboard 200 has a front side and a back side opposite to each other, the front side and the first side 211 of all the aluminum plate units 21 are located on the same plane, and the back side and the second side 212 of all the aluminum plate units 21 are located on the same plane. In this embodiment, the size of the second motherboard 200 is 500mm*600mm, and the second motherboard 200 is drilled with peripheral holes, material number holes, and post-process gong plate positioning holes.

[0106] Secondly, the placement grooves 213 on the first surface 211 of all the aluminum plate units 21 are machined.

[0107] Specifically, a medium-viscosity protective film can be first pasted on the reverse side of the second master plate 200 for vacuum adsorption on the depth-controlled milling machine. The protective film needs to cover all the hole positions on the surface of the second master plate 200 to avoid vacuum leakage during vacuum adsorption. Then, the depth-controlled milling machine is used to machine the placement grooves 213 on the first surface 211 of all the aluminum plate units 21. After machining, the protective film on the back is torn off.

[0108] Next, the placement grooves 213 on the second surface 212 of all the aluminum plate units 21 are machined.

[0109] Specifically, a medium-viscosity protective film can be first pasted on the front surface of the second master plate 200 for vacuum adsorption on the depth-controlled milling machine. The protective film needs to cover all the hole positions on the surface of the second master plate 200 to avoid vacuum leakage during vacuum adsorption. Then, the depth-controlled milling machine is used to machine the placement grooves 213 on the second surface 212 of all the aluminum plate units 21. After machining, the protective film on the front is torn off.

[0110] Finally, the multiple aluminum plate units 21 are separated.

[0111] Specifically, the second master plate 200 can be separated into multiple individual aluminum plate units 21 by stamping.

[0112] Optionally, after separating the multiple aluminum plate units 21, the multiple individual aluminum plate units 21 can be subjected to high-pressure water washing to wash away the residual aluminum powder and aluminum chips on the aluminum plate units 21 and clean the plate surface.

[0113] By adopting the above solution, the placement grooves 213 on the first surface 211 and the second surface 212 of multiple aluminum plate units 21 can be machined with only two processes, with high processing efficiency and reduced production costs.

[0114] Please refer to Figure 12 、 Figure 14 and Figure 16 , in some embodiments, in order to prevent the right-angle edge of the reinforcing plate 20 from causing the circuit across the right-angle edge on the rigid-flex board to break during subsequent lamination with the rigid-flex board, resulting in batch scrapping anomalies, one side edge of the first surface 211 has a first chamfer portion 2111, and one side edge of the second surface 212 has a second chamfer portion 2121 opposite to the first chamfer portion 2111. Both the first chamfer portion 2111 and the second chamfer portion 2121 can be in the form of an inclined chamfer or a rounded corner. In this way, the sharp edges of the first side and the second side can be prevented from directly contacting the circuit on the rigid-flex board and causing it to break.

[0115] It can be understood that multiple first chamfered portions 2111 and second chamfered portions 2121 can be provided.

[0116] In this embodiment, both the first chamfered portion 2111 and the second chamfered portion 2121 are chamfered obliquely, and the angle α of the chamfered oblique angle is 18° - 22°, such as 18°, 20° and 22°, etc., and the width D is 0.8 mm - 1.0 mm, such as 0.8 mm, 0.9 mm and 1.0 mm, etc. The chamfered oblique angle can be machined with a 70° bevel tool of diamond. In this way, it can be further avoided that the edges and corners of the first side and the second side directly contact the circuit on the rigid-flex printed circuit board, resulting in its fracture.

[0117] Please refer to Figure 12 、 Figure 13 and Figure 15 , in some of these embodiments, before providing an aluminum plate unit 21, the manufacturing method of the reinforcing plate 20 further includes:

[0118] First, provide a second master board 200, and there are multiple connected aluminum plate units 21 on the second master board 200.

[0119] Specifically, the second master board 200 has opposite front and back surfaces. The front surface is in the same plane as the first surface 211 of all the aluminum plate units 21, and the back surface is in the same plane as the second surface 212 of all the aluminum plate units 21.

[0120] Secondly, process multiple avoidance grooves 24 on the second master board 200. The avoidance grooves 24 are arranged in one-to-one correspondence with the aluminum plate units 21. The avoidance grooves 24 penetrate through the second master board 200, and both ends of the avoidance grooves 24 have a first groove edge and a second groove edge respectively.

[0121] Specifically, the avoidance grooves 24 penetrate through the front and back surfaces of the second master board 200. Both the first groove edge and the second groove edge are right-angle edges. The first groove edge and the second groove surface are respectively located on the front surface and the back surface of the second master board 200. When pressing with the rigid-flex printed circuit board subsequently, the first groove edge and the second groove edge will cause the circuit across the first groove edge and the second groove edge on the rigid-flex printed circuit board to break, resulting in a batch of abnormal scrapping.

[0122] Then, chamfer the first groove edge of all the avoidance grooves 24 so that a first chamfered portion 2111 is formed on the first groove edge.

[0123] Specifically, a medium-viscosity protective film can be pasted on the back surface of the second master board 200 first for vacuum adsorption on the depth-controlled milling machine. The protective film needs to cover all the hole positions on the surface of the second master board 200 to avoid vacuum leakage during vacuum adsorption. Then, use a diamond bevel tool to chamfer the first groove edge of all the avoidance grooves 24 to form the first chamfered portion 2111.

[0124] Then, chamfer all the second groove edges of the relief grooves 24 so that a second chamfered portion 2121 is formed on the second groove edges.

[0125] Specifically, a medium-viscosity protective film can be first pasted on the front surface of the second mother board 200 for vacuum adsorption on a depth-controlled routing machine. The protective film needs to cover all the hole positions on the board surface of the second mother board 200 to avoid vacuum leakage during vacuum adsorption. Then, a diamond bevel tool is used to chamfer all the second groove edges of the relief grooves 24 to form the second chamfered portion 2121.

[0126] Finally, separate the multiple aluminum plate units 21.

[0127] Specifically, the second mother board 200 can be separated into multiple individual aluminum plate units 21 by stamping.

[0128] Through the above technical solution, the processing efficiency of the first side edge and the second side edge can be improved.

[0129] Optionally, when chamfering all the first groove edges of the relief grooves 24, the placement grooves 213 on the first surface 211 of all the aluminum plate units 21 can be processed at the same time; when chamfering all the second groove edges of the relief grooves 24, the placement grooves 213 on the second surface 212 of all the aluminum plate units 21 can be processed at the same time.

[0130] In some embodiments, before providing an aluminum plate unit 21, the manufacturing method of the reinforcing plate 20 further includes: performing an anodic oxidation treatment on the aluminum plate unit 21. In this way, the surface hardness of the aluminum plate unit 21 can be further improved and the board surface can be prevented from being scratched.

[0131] Optionally, an anodic oxidation treatment can be performed on the second mother board 200.

[0132] In this embodiment, a black anodic oxidation treatment is performed on the aluminum plate unit 21.

[0133] Please refer to Figure 12 、 Figure 13 and Figure 14 , in some embodiments, a mating portion 2131 is provided on one side wall of the placement groove 213, and a engaging portion 221 is provided at one end of the BT resin substrate 22. The mating portion 2131 is engaged with the engaging portion 221.

[0134] By adopting the above solution, when the two BT resin substrates 22 are respectively placed in the two placement grooves 213, the mating portion 2131 can be engaged with the engaging portion 221 to prevent the BT resin substrates 22 from being placed in the wrong direction.

[0135] Optionally, the mating portion 2131 is provided as a bump, and the engaging portion 221 is provided as a groove adapted to the bump; or, the mating portion 2131 is provided as a groove, and the engaging portion 221 is provided as a bump adapted to the groove.

[0136] In this embodiment, the mating portion 2131 is provided as a groove, and the engaging portion 221 is provided as a bump adapted to the groove.

[0137] An embodiment of the second aspect of the present application provides a rigid-flexible printed circuit board, including: The rigid-flexible printed circuit board is processed by the manufacturing method of the rigid-flexible printed circuit board as in the first aspect.

[0138] For the rigid-flexible printed circuit board provided in the embodiment of the present application, since the first thermosetting adhesive 13 is only provided in the first space 14 of the product unit 10, the reinforcing plate 20 can be directly placed into the third space 16 first, and then the first FPC unit 11, the second FPC unit 12, and the reinforcing plate 20 can be pressed together through the reinforcing adhesive 30, so that there is no need to perform an opening treatment on the product unit 10. This not only avoids the situations such as difficult control of the depth accuracy of the opening position and burrs remaining at the opening edge when the reinforcing plate 20 is embedded in the product unit 10, improves the quality of the rigid-flexible printed circuit board, but also the first FPC unit 11 and the second FPC unit 12 corresponding to the position of the second space 15 are in a layered state, and their flexibility is also better, so that the bending performance of the rigid-flexible printed circuit board is also higher.

[0139] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A method for manufacturing a rigid-flex printed circuit board, characterized in that, Including: Providing a first FPC unit and a second FPC unit, wherein a first gold finger is provided on a surface of the first FPC unit away from the second FPC unit, and a second gold finger is provided on a surface of the second FPC unit away from the first FPC unit; Stacking the first FPC unit and the second FPC unit together, and disposing a first thermosetting adhesive between the first FPC unit and the second FPC unit to obtain a product unit. A first space, a second space and a third space which are connected in sequence and linearly arranged are formed between the first FPC unit and the second FPC unit, and the first thermosetting adhesive is located in the first space; Performing a lamination process on the product unit; Placing a reinforcing plate and a reinforcing adhesive in the third space, the reinforcing adhesive being respectively disposed between the reinforcing plate and the first FPC unit and between the reinforcing plate and the second FPC unit. The reinforcing plate includes an aluminum plate unit and two BT resin substrates. The aluminum plate unit has opposite first and second surfaces, and the two BT resin substrates are respectively disposed on the first surface and the second surface, and one of the BT resin substrates is disposed opposite to the first gold finger; the other BT resin substrate is disposed opposite to the second gold finger; Pressing the first FPC unit, the second FPC unit and the reinforcing plate together; Using a routing tool to perform chamfering on the ends of the first gold finger for plugging and unplugging and the ends of the second gold finger for plugging and unplugging, so that the front ends of the first gold finger and the second gold finger both present a slope shape, and the routing tool does not perform chamfering on the aluminum plate unit.

2. The method for manufacturing a rigid-flex printed circuit board according to claim 1, wherein, Before providing the first FPC unit and the second FPC unit, the method for manufacturing the rigid-flexible printed circuit board further includes: providing a first core board and a second core board, the first core board including a plurality of connected first FPC units, the second core board including a plurality of connected second FPC units, and the first FPC units and the second FPC units being arranged in one-to-one correspondence; stacking the first FPC unit and the second FPC unit together, and disposing a first thermosetting adhesive between the first FPC unit and the second FPC unit to obtain a product unit, specifically including: stacking the first core board and the second core board together, and disposing the first thermosetting adhesive between the first core board and the second core board to obtain a first master board, the first master board including a plurality of connected product units.

3. The method for manufacturing a rigid-flex printed circuit board according to claim 2, wherein After performing the lamination process on the product unit, and before placing the reinforcing plate in the third space and placing the reinforcing plate and the reinforcing adhesive in the third space, the method for manufacturing the rigid-flexible printed circuit board further includes: performing a punching process on the first master board to obtain a plurality of individual sub-boards, each sub-board including a plurality of connected product units, and the third spaces of each product unit communicating with the external space.

4. The method for manufacturing a rigid-flex printed circuit board according to claim 3, wherein After pressing the first FPC unit, the second FPC unit and the reinforcing plate together, performing a punching process on the sub-board to obtain a plurality of individual product units.

5. The method for manufacturing a rigid-flex printed circuit board according to claim 1, wherein Placement grooves are provided on both the first surface and the second surface, the two placement grooves are arranged back to back, the two BT resin substrates are respectively placed in the two placement grooves, a second thermosetting adhesive is provided between the BT resin substrate and the bottom of the placement groove, and the shape of the BT resin substrate is adapted to the shape of the placement groove.

6. The method for manufacturing a rigid-flex printed circuit board according to claim 1, wherein, A strip portion is further provided on the reinforcing plate; after the first FPC unit, the second FPC unit and the reinforcing plate are pressed together, 3D structural stamping is performed on the strip portion to bend the strip portion.

7. The method for manufacturing a rigid-flex printed circuit board according to any one of claims 1 to 6, characterized in that, Before placing the reinforcing plate and the reinforcing adhesive in the third space, the method for manufacturing the rigid-flexible printed circuit board further includes: Roughening the surface of the reinforcing plate for contacting the reinforcing adhesive; Attaching the reinforcing adhesives to the two roughened surfaces of the reinforcing plate respectively.

8. A rigid-flex printed circuit board, characterized in that, including: The rigid-flexible printed circuit board is processed by the method for manufacturing a rigid-flexible printed circuit board according to any one of claims 1 to 7.

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