Asymmetric rigid-flex board and processing method

Abstract

The invention provides an asymmetric rigid-flex board and a processing method, and relates to a printed circuit board manufacturing technology, and the method comprises the steps: processing a core board of a flexible board; processing a hard core board; processing the PP layer; processing a gasket layer; the soft board core board, the PP layer, the gasket layer and the hard board core board are sequentially overlapped and pressed, and the soft-hard combined board is obtained through hot pressing; processing an outer-layer circuit of the soft board and an outer-layer circuit of the hard board; quickly pressing an outer layer covering film on the outer side surface of the soft board core board in the soft board area; spraying solder mask on the outer side surface of the soft core board in the hard board area and the outer side surface of the hard core board in the hard board area to form solder mask layers, and exposing and developing the solder mask layers to expose the positions of the bonding pads; and performing depth-controlled groove milling in a soft board area on the outer side of the hard board core board, and removing the gasket layer. According to the invention, the easy bending performance of the soft board area can be ensured, the welding resistance of the hard board area can be ensured, and the practicability is relatively high.

Description

Technical Field

[0001] The present application relates to the field of electronic component processing and manufacturing, and in particular to printed circuit board manufacturing technology, and is specifically related to an asymmetric rigid-flex board and a processing method. Background Art

[0002] The birth and development of FPC and PCB gave birth to a new product, the rigid-flex board; the rigid-flex board refers to a circuit board with the characteristics of FPC and PCB, which is generally formed by combining a flexible circuit board with a rigid circuit board through processes such as pressing and other processes according to relevant process requirements. The rigid-flex board can be used in some products with special requirements. It has both a certain flexible area and a certain rigid area, which is very helpful in saving the internal space of the product, reducing the volume of the finished product, and improving the product performance. Rigid-flex boards are generally designed with a symmetrical structure, with the soft board core located in the inner layer and the hard board core located in the outer layer. During the processing, the hard board part of the soft board area is removed to obtain the rigid-flex board; there are also some rigid-flex boards with an asymmetric structure design, with the soft board core layer located in the outermost layer. This design can meet special application scenarios, and the surface dielectric layer can be made very thin to meet special impedance designs, but this increases the processing difficulty of the outer solder mask layer: since the soft board area needs to be easy to bend, if the solder mask is printed on the entire board, the solder mask will break during the bending process; if the entire board is hot-pressed with a covering film, the covering film has poor anti-soldering performance, and short circuit problems are very likely to occur during the welding of components in the rigid board area. Summary of the invention

[0003] In order to solve the above-mentioned defects of the related prior art, the present application provides an asymmetric hard-flex board and a processing method, which can ensure the bendability of the soft board area and the welding resistance of the hard board area, and has strong practicality.

[0004] In order to achieve the above object, the present invention adopts the following technologies: An asymmetric rigid-flex board having a rigid board area and a flexible board area, comprising: A soft board core board, whose inner surface is provided with a soft board inner layer circuit, whose outer surface is provided with a soft board outer layer circuit, the inner surface of the soft board core board located in the soft board area is hot pressed with an inner layer covering film, the outer surface of the soft board core board located in the soft board area is hot pressed with an outer layer covering film, and the outer surface of the soft board core board located in the hard board area is sprayed with a solder resist layer; A hard board core board is arranged in the hard board area, the inner surface of which is provided with a hard board inner layer circuit, the outer surface of which is provided with a hard board outer layer circuit, and the outer surface of the hard board core board is sprayed with a solder resist layer; The PP layer is arranged in the hard board area, one side surface of which is bonded to the inner surface of the soft board core board in the hard board area, and the other side surface of which is bonded to the outer surface of the hard board core board.

[0005] A method for processing an asymmetric rigid-flexible board comprises the following steps: S100, soft board core board processing, including: cutting the flexible substrate to obtain a soft board sheet, processing the inner surface of the soft board sheet to form an inner conductive circuit pattern of the soft board, etching and browning the inner conductive circuit pattern of the soft board to form an inner layer circuit of the soft board, and quickly pressing an inner layer covering film on the inner surface of the soft board sheet located in the soft board area; S200, hard board core board processing, including: cutting a rigid substrate to obtain a hard board plate, processing the inner surface of the hard board plate to form a hard board inner conductive circuit pattern, etching the hard board inner conductive circuit pattern, controlling the depth of the hard board plate inner surface to form a first controlled depth groove, and browning the hard board inner conductive circuit to form a hard board inner layer circuit; S300, PP layer processing, including: cutting the PP substrate to obtain a PP sheet, drilling and laser cutting the PP sheet, and controlling the depth of the PP sheet in the soft board area to form a second controlled depth groove; S400, gasket layer processing, including: cutting the gasket substrate to obtain a gasket plate, drilling and laser cutting the gasket plate to obtain a gasket layer; S500, pressing, including: stacking the soft board core board, the PP layer, the gasket layer, and the hard board core board in sequence, wherein the gasket layer is located in the first depth-controlled groove and the second depth-controlled groove, and hot pressing to obtain a soft-hard combination board; S600, processing the outer circuit of the soft board and the outer circuit of the hard board, including: drilling holes on the outer surface of the soft board core board and the outer surface of the hard board core board, copper deposition and electroplating on the hole wall, processing the outer side of the soft board core board to form a conductive circuit pattern on the outer side of the soft board, processing the outer side of the hard board core board to form a conductive circuit pattern on the outer side of the hard board, etching the conductive circuit pattern on the outer side of the soft board and the conductive circuit pattern on the outer side of the hard board to obtain the outer circuit of the soft board and the outer circuit of the hard board; S700, quickly pressing an outer covering film on the outer surface of the soft board core board located in the soft board area; S800, spraying a solder resist layer, including: spraying solder resist on the outer surface of the soft board core board located in the hard board area and the outer surface of the hard board core board located in the hard board area to form a solder resist layer, and exposing and developing the solder resist layer to expose the pad position; S900, uncovering, including: controlling the depth of the groove in the soft board area outside the hard board core board and removing the gasket layer.

[0006] Further, the fast pressing of the inner layer covering film in S100 includes: pasting the inner layer covering film on the entire inner surface of the soft board core board, fixing the inner layer covering film with a soldering iron, laser cutting the inner layer covering film, peeling off excess inner layer covering film, and hot pressing the inner layer covering film with a fast pressing machine; The fast pressing of the outer covering film in S700 includes: pasting the outer covering film on the entire outer surface of the soft board core board, fixing the outer covering film with a soldering iron, laser cutting the outer covering film, peeling off excess outer covering film, and hot pressing the outer covering film with a fast pressing machine.

[0007] Furthermore, the size of the first depth-controlling groove in S200 matches the size of the soft board area, and the depth is set to half the thickness of the hard board core board.

[0008] Furthermore, the PP layer in S300 uses non-glue PP, and the PP sheet is drilled to drill positioning holes and rivet holes for pressing. The size of the second depth-controlled groove matches the size of the soft board area, and the depth is equal to the thickness of the PP layer.

[0009] Furthermore, in S400, the size of the gasket layer is smaller than the size of the soft board area, and the thickness of the gasket layer is set to the sum of the depths of the first depth-controlling groove and the second depth-controlling groove.

[0010] Furthermore, the solder resist spraying in S800 adopts an electrostatic spraying method to ensure the uniformity of the solder resist spraying.

[0011] The beneficial effects of the present invention are: The present invention uses two circuit protection methods: covering film and solder resist. The covering film is used in the soft board area to ensure the bending performance of the soft board area, and the covering film will not be broken when bending; the solder resist is used in the hard board area to ensure the anti-welding ability of the hard board area, and short circuit problems will not occur when welding components. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a schematic diagram of the structure of an asymmetric rigid-flex board according to an embodiment of the present application.

[0013] Figure 2 It is a schematic diagram of the asymmetric rigid-flex board processing method during lamination according to an embodiment of the present application.

[0014] Figure 3 It is a schematic diagram of the asymmetric rigid-flex board processing method of an embodiment of the present application when processing the outer layer circuit of the flexible board and the outer layer circuit of the rigid board.

[0015] Markings in the figure: 1-flexible board core, 11-flexible board inner layer circuit, 12-flexible board outer layer circuit, 13-inner layer covering film, 14-outer layer covering film, 2-rigid board core, 21-rigid board inner layer circuit, 22-rigid board outer layer circuit, 3-PP layer, 4-solder mask layer, 5-gasket layer. DETAILED DESCRIPTION

[0016] To make the objectives, technical solutions and advantages of the embodiments of the present invention more clear, the implementation modes of the present invention are described in detail below with reference to the accompanying drawings. However, the embodiments described in the present invention are only part of the embodiments of the present invention, rather than all the embodiments.

[0017] like Figure 1 As shown, this embodiment provides an asymmetric hard-flex board having a hard board area and a soft board area, including a soft board core board 1, a hard board core board 2, and a PP layer 3.

[0018] Specifically, Figure 1 As shown, the inner surface of the soft board core board 1 is provided with a soft board inner layer circuit 11, and the outer surface of the soft board core board 1 is provided with a soft board outer layer circuit 12. Since the soft board area of ​​the asymmetric hard-soft board needs to have easy-to-bend performance, the inner surface of the soft board core board 1 located in the soft board area is hot-pressed with an inner layer covering film 13, and the outer surface of the soft board core board 1 located in the soft board area is hot-pressed with an outer layer covering film 14. The inner layer covering film 13 and the outer layer covering film 14 will not break when bent; since the hard board area of ​​the asymmetric hard-soft board needs to weld components, the outer surface of the soft board core board 1 located in the hard board area is sprayed with a solder resist layer 4, and the solder resist layer 4 can ensure that the circuit will not be short-circuited during the welding of components.

[0019] Specifically, Figure 1 As shown, the hard board core board 2 is arranged in the hard board area, and its inner surface is provided with a hard board inner layer circuit 21, and its outer surface is provided with a hard board outer layer circuit 22. The outer surface of the hard board core board 2 is sprayed with a solder resist layer 4, and the solder resist layer 4 can ensure that the circuit will not be short-circuited during the welding process of components.

[0020] Specifically, Figure 1 As shown, the PP layer 3 is arranged in the hard board area, one side surface of which is bonded to the inner surface of the soft board core board 1 in the hard board area, and the other side surface of which is bonded to the outer surface of the hard board core board 2.

[0021] With such a design, the surface of the soft board area of ​​the asymmetric hard-flex board is covered with an inner covering film 13 and an outer covering film 14 respectively, and both the inner covering film 13 and the outer covering film are easy to bend, so that the soft board area of ​​the asymmetric hard-flex board can be bent conveniently under a corresponding working environment; the surface of the hard board area of ​​the asymmetric hard-flex board is sprayed with a solder resist layer 4, so as to ensure the anti-welding ability of the hard board area.

[0022] like Figure 1~Figure 3 As shown, this embodiment provides a method for processing an asymmetric rigid-flexible board, comprising the steps of: S100, processing of a soft board core board 1, including: cutting a flexible substrate to obtain a soft board material, processing the inner surface of the soft board material to form an inner conductive circuit pattern of the soft board, etching and browning the inner conductive circuit pattern of the soft board to form an inner layer circuit 11 of the soft board, and quickly pressing an inner layer covering film 13 on the inner surface of the soft board material located in the soft board area.

[0023] S200, processing of the hard board core board 2, including: cutting the rigid substrate to obtain a hard board board, processing the inner surface of the hard board board to form a conductive circuit pattern on the inner side of the hard board, etching the conductive circuit pattern on the inner side of the hard board, forming a first controlled depth groove on the inner surface of the hard board board located in the soft board area, and browning the conductive circuit on the inner side of the hard board to form a hard board inner layer circuit 21.

[0024] S300, processing the PP layer 3, including: cutting the PP substrate to obtain a PP sheet, drilling and laser cutting the PP sheet, and controlling the depth of the PP sheet in the soft board area to form a second controlled depth groove.

[0025] S400, processing the gasket layer 5, including: cutting the gasket substrate to obtain a gasket plate, drilling and laser cutting the gasket plate.

[0026] S500, pressing, including: stacking the soft board core board 1, the PP layer 3, the gasket layer 5, and the hard board core board 2 in sequence, the gasket layer 5 is located in the first controlled depth groove and the second controlled depth groove, and obtaining a soft-hard combined board through hot pressing.

[0027] S600, processing the outer layer circuit 12 of the soft board and the outer layer circuit 22 of the hard board, including: drilling holes on the outer surface of the soft board core board 1 and the outer surface of the hard board core board 2, copper plating and electroplating the hole walls, processing the outer side of the soft board core board 1 to form a conductive circuit pattern on the outer side of the soft board, processing the outer side of the hard board core board 2 to form a conductive circuit pattern on the outer side of the hard board, etching the conductive circuit pattern on the outer side of the soft board and the conductive circuit pattern on the outer side of the hard board to obtain the outer layer circuit 12 of the soft board and the outer layer circuit 22 of the hard board.

[0028] S700 , quickly pressing the outer covering film 14 on the outer surface of the soft board core board 1 located in the soft board area.

[0029] S800, spraying solder resist layer 4, including: spraying solder resist on the outer surface of the soft board core board 1 located in the hard board area and the outer surface of the hard board core board 2 located in the hard board area to form solder resist layer 4, exposing and developing the solder resist layer 4 to expose the pad position.

[0030] S900, uncovering, including: controlling the depth of the groove on the outer surface of the hard board core board 2 located in the soft board area, and removing the gasket layer 5.

[0031] Preferably, Figure 1 and Figure 2As shown, the quick pressing of the inner layer covering film 13 in S100 includes: sticking the inner layer covering film 13 on the entire inner surface of the soft board core board 1, fixing the inner layer covering film 13 with a soldering iron, laser cutting the inner layer covering film 13, peeling off the excess inner layer covering film 13, and hot pressing the inner layer covering film 13 with a quick pressing machine; further preferably, the excess inner layer covering film 13 here refers to the inner layer covering film 13 located in the hard board area.

[0032] The quick pressing of the outer covering film 14 in S700 includes: sticking the outer covering film 14 on the entire outer surface of the soft board core board 1, fixing the outer covering film 14 with a soldering iron, laser cutting the outer covering film 14, peeling off the excess outer covering film 14, and hot pressing the outer covering film 14 with a quick pressing machine; further preferably, the excess outer covering film 14 here refers to the outer covering film 14 located in the hard board area.

[0033] Preferably, Figure 2 As shown, the size of the first depth control groove in S200 matches the size of the soft board area, and the matching here means that the size of the first depth control groove is equal to that of the soft board area; the depth of the first depth control groove is set to half the thickness of the hard board core board 2.

[0034] Preferably, Figure 2 As shown, the PP layer 3 in S300 uses non-glue PP, and the PP plate is drilled to drill positioning holes and rivet holes for pressing. The size of the second depth control groove matches the size of the soft board area. The matching here means that the size of the second depth control groove is equal to the size of the soft board area; the depth of the second depth control groove is equal to the thickness of the PP layer 3.

[0035] Preferably, Figure 2 As shown, the size of the gasket layer 5 in S400 is smaller than the size of the soft board area. Further preferably, the size difference between the gasket layer 5 and the soft board area is set to 1 mm, so as to facilitate the gasket to be embedded in the first depth control groove and the second depth control groove; the thickness of the gasket layer 5 is set to the sum of the depths of the first depth control groove and the second depth control groove.

[0036] Preferably, Figure 1 As shown, the solder resist spraying in S800 is performed by electrostatic spraying, so as to ensure the uniformity of the solder resist layer 4 spraying.

[0037] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Obviously, those skilled in the art can make various modifications and variations to the present application without departing from the spirit and scope of the present application.

Claims

1. An asymmetric rigid-flex board having a rigid board area and a flexible board area, characterized in that: include: A soft board core board (1), whose inner surface is provided with a soft board inner layer circuit (11), whose outer surface is provided with a soft board outer layer circuit (12), an inner layer covering film (13) is hot pressed on the inner surface of the soft board core board (1) located in the soft board area, an outer layer covering film (14) is hot pressed on the outer surface of the soft board core board (1) located in the soft board area, and a solder resist layer (4) is sprayed on the outer surface of the soft board core board (1) located in the hard board area; A hard board core board (2) is arranged in the hard board area, its inner surface is provided with a hard board inner layer circuit (21), its outer surface is provided with a hard board outer layer circuit (22), and the outer surface of the hard board core board (2) is sprayed with a solder resist layer (4); The PP layer (3) is arranged in the hard board area, with one side surface bonded to the inner surface of the soft board core board (1) in the hard board area, and the other side surface bonded to the outer surface of the hard board core board (2).

2. A method for processing an asymmetric rigid-flex board, characterized in that: Includes steps: S100, processing of a soft board core board (1), comprising: cutting a flexible substrate to obtain a soft board sheet, processing the inner surface of the soft board sheet to form a conductive circuit pattern on the inner side of the soft board, etching and browning the conductive circuit pattern on the inner side of the soft board to form a soft board inner layer circuit (11), and quickly pressing an inner layer covering film (13) on the inner surface of the soft board sheet located in the soft board area; S200, processing a hard board core board (2), including: cutting a rigid substrate to obtain a hard board board, processing the inner surface of the hard board board to form a hard board inner conductive circuit pattern, etching the hard board inner conductive circuit pattern, controlling the depth of a groove on the inner surface of the hard board board in the soft board area to form a first controlled depth groove, and browning the hard board inner conductive circuit to form a hard board inner layer circuit (21); S300, processing the PP layer (3), including: cutting the PP substrate to obtain a PP sheet, drilling and laser cutting the PP sheet, and controlling the depth of the PP sheet in the soft board area to form a second controlled depth groove; S400, processing the gasket layer (5), including: cutting the gasket substrate to obtain a gasket plate, drilling and laser cutting the gasket plate to obtain the gasket layer (5); S500, pressing, comprising: stacking the soft board core board (1), the PP layer (3), the gasket layer (5), and the hard board core board (2) in sequence, wherein the gasket layer (5) is located in the first depth-controlled groove and the second depth-controlled groove, and hot pressing to obtain a soft-hard combined board; S600, processing the outer layer circuit (12) of the soft board and the outer layer circuit (22) of the hard board, including: drilling holes on the outer surface of the soft board core board (1) and the outer surface of the hard board core board (2), copper deposition and electroplating on the hole wall, processing the outer side of the soft board core board (1) to form a conductive circuit pattern on the outer side of the soft board, processing the outer side of the hard board core board (2) to form a conductive circuit pattern on the outer side of the hard board, etching the conductive circuit pattern on the outer side of the soft board and the conductive circuit pattern on the outer side of the hard board to obtain the outer layer circuit (12) of the soft board and the outer layer circuit (22) of the hard board; S700, quickly pressing an outer covering film (14) on the outer surface of the soft board core board (1) located in the soft board area; S800, spraying a solder resist layer (4), comprising: spraying solder resist on the outer surface of the soft board core board (1) located in the hard board area and the outer surface of the hard board core board (2) located in the hard board area to form a solder resist layer (4), and exposing and developing the solder resist layer (4) to expose the pad position; S900, uncovering, including: controlling the depth of the groove in the soft board area outside the hard board core board (2) and removing the gasket layer (5).

3. The method for processing an asymmetric rigid-flexible board according to claim 2, characterized in that: The quick pressing of the inner layer covering film (13) in S100 includes: attaching the inner layer covering film (13) to the entire inner surface of the soft board core board (1), fixing the inner layer covering film (13) with a soldering iron, laser cutting the inner layer covering film (13), peeling off excess inner layer covering film (13), and hot pressing the inner layer covering film (13) with a quick pressing machine; The fast pressing of the outer covering film (14) in S700 includes: attaching the outer covering film (14) to the entire outer surface of the soft board core board (1), fixing the outer covering film (14) with a soldering iron, laser cutting the outer covering film (14), peeling off excess outer covering film (14), and hot pressing the outer covering film (14) with a fast pressing machine.

4. The method for processing an asymmetric rigid-flex board according to claim 2, characterized in that: The size of the first depth-controlling groove in S200 matches the size of the soft board area, and the depth is set to be half the thickness of the hard board core board (2).

5. The method for processing an asymmetric rigid-flex board according to claim 2, characterized in that: The PP layer (3) in S300 is made of non-glue PP, and the PP plate is drilled to drill positioning holes and rivet holes for pressing. The size of the second depth-controlled groove matches the size of the soft board area, and the depth is equal to the thickness of the PP layer (3).

6. The method for processing an asymmetric rigid-flex board according to claim 2, characterized in that: In S400, the size of the gasket layer (5) is smaller than the size of the soft board area, and the thickness of the gasket layer (5) is set to the sum of the depths of the first depth-controlling groove and the second depth-controlling groove.

7. The method for processing an asymmetric rigid-flex board according to claim 2, characterized in that: The solder mask spraying in S800 adopts electrostatic spraying method to ensure the uniformity of solder mask spraying.

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