Soft-rigid combined circuit board and manufacturing method thereof

Abstract

The present application proposes a method for manufacturing a rigid-flexible circuit board, comprising the following steps: providing a covering film; forming a first peelable adhesive layer on the covering film; forming a first dielectric layer on the covering film having the first peelable adhesive layer; forming a first conductive circuit layer on the first dielectric layer to obtain a first circuit substrate; opening a first groove in the first circuit substrate by laser cutting to a predetermined depth; forming a second peelable adhesive layer on the covering film; forming a second dielectric layer on the first conductive circuit layer; forming a second conductive circuit layer on the second dielectric layer to a second circuit substrate; and opening a second groove in the second circuit substrate by laser cutting to a predetermined depth, thereby obtaining the rigid-flexible circuit board. The present application can reduce the residual dielectric layer after opening the cover. The present application also provides a rigid-flexible circuit board manufactured by the method.

Description

Technical Field

[0001] The present application relates to the field of circuit boards, and in particular to a rigid-flexible circuit board and a manufacturing method thereof. Background Art

[0002] Rigid-flex circuit boards combine the durability of rigid boards with the flexibility of flexible boards. They are lightweight, compact, and resistant to harsh environments, making them particularly suitable for precision electronics applications such as portable electronics, medical electronics, and military equipment. The production of rigid-flex circuit boards typically requires laminating multiple dielectric layers onto a cover film, followed by laser cutting to a predetermined depth. To avoid cutting the cover film, a certain thickness of dielectric layer is typically required, which prevents the innermost dielectric layer from being completely severed, resulting in residual dielectric layer after the cover is opened and peeled off. Summary of the Invention

[0003] In view of this, the present application provides a method for manufacturing a rigid-flexible circuit board that can reduce dielectric layer residue.

[0004] In addition, it is also necessary to provide a rigid-flexible circuit board manufactured by the above method.

[0005] An embodiment of the present application provides a method for manufacturing a rigid-flexible circuit board, comprising the following steps:

[0006] providing a cover film comprising a flexible region and a non-flexible region connected to the flexible region;

[0007] forming a first peelable adhesive layer on the cover film, and making the first peelable adhesive layer correspond to the flexible area;

[0008] forming a first dielectric layer on the cover film having the first peelable adhesive layer, and making the first dielectric layer cover the first peelable adhesive layer;

[0009] forming a first conductive circuit layer on the first dielectric layer, and making the first conductive circuit layer correspond to the non-flexible area, to obtain a first circuit substrate;

[0010] A first groove is formed in the first circuit substrate along the thickness direction of the first circuit substrate by laser cutting to a predetermined depth, so that the first groove passes through the first dielectric layer, the bottom of the first groove corresponds to the cover film, and the flexible area is exposed in the first groove;

[0011] forming a second peelable adhesive layer on the cover film, and positioning the second peelable adhesive layer in the first groove;

[0012] forming a second dielectric layer on the first conductive circuit layer, and making the second dielectric layer cover the first dielectric layer and the second peelable adhesive layer, wherein the material of the second dielectric layer is the same as that of the first dielectric layer;

[0013] forming a second conductive circuit layer on the second dielectric layer, and making the second conductive circuit layer correspond to the non-flexible area to obtain a second circuit substrate; and

[0014] A second groove is opened in the second circuit substrate along the thickness direction of the second circuit substrate by laser depth cutting, so that the second groove passes through the second dielectric layer and corresponds to and communicates with the first groove, thereby obtaining the flexible and rigid circuit board.

[0015] An embodiment of the present application further provides a rigid-flexible circuit board, comprising:

[0016] a cover film comprising a flexible region and a non-flexible region connected to the flexible region;

[0017] a first dielectric layer located on the cover film, wherein a first groove is provided in the first dielectric layer, the first groove penetrates the first dielectric layer, and a bottom of the first groove corresponds to the cover film, and the flexible area is exposed in the first groove;

[0018] a first conductive circuit layer, located on the first dielectric layer, and corresponding to the non-flexible area;

[0019] a second dielectric layer, located on the first conductive circuit layer and the first dielectric layer, wherein the second dielectric layer is made of the same material as the first dielectric layer, and a second groove is provided in the second dielectric layer, the second groove passes through the second dielectric layer, and the second groove corresponds to and is connected to the first groove; and

[0020] The second conductive circuit layer is located on the second dielectric layer, and the second conductive circuit layer corresponds to the non-flexible area.

[0021] The present application adopts a single-layer cutting method (i.e., first cutting is performed in the first dielectric layer to form the first groove, then the second dielectric layer is formed, and finally cutting is performed in the second dielectric layer to form the second groove, and the second groove is made to correspond to and connected to the first groove), thereby avoiding the phenomenon that the first dielectric layer cannot be cut off, thereby reducing the residue of the first dielectric layer after the cover is opened. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Schematic diagram of the structure of the covering film provided in one embodiment of the present application.

[0023] Figure 2 is Figure 1 The schematic diagram of the structure after the first peelable adhesive layer is formed on the cover film is shown.

[0024] Figure 3 is Figure 2 The schematic diagram of the structure after the first dielectric layer, the pressing plate and the first conductive circuit layer are sequentially formed on the cover film is shown.

[0025] Figure 4 is Figure 3 The diagram shows a structure diagram after a first groove is formed in the first circuit substrate.

[0026] Figure 5 is Figure 4 The schematic diagram of the structure after the second peelable adhesive layer is formed on the cover film is shown.

[0027] Figure 6 is Figure 5 The diagram shows a structure after a second dielectric layer and a second conductive circuit layer are formed on the first conductive circuit layer.

[0028] Figure 7 is Figure 6 The diagram shows the structure of a rigid-flexible circuit board obtained after a second groove is formed in the second circuit substrate.

[0029] Description of main component symbols

[0030] Rigid-flexible circuit board 100

[0031] Covering film 10

[0032] Flexible Area 101

[0033] Inflexible area 102

[0034] First peelable adhesive layer 20

[0035] First dielectric layer 30

[0036] Glass fiber 31

[0037] Pressed plate 40

[0038] First conductive circuit layer 41

[0039] First circuit substrate 50

[0040] First groove 51

[0041] Second peelable adhesive layer 60

[0042] Second dielectric layer 70

[0043] The second conductive circuit layer 80

[0044] Second circuit substrate 90

[0045] Second groove 91

[0046] The following specific implementation methods will further illustrate the present application in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0047] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0048] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application pertains. The terms used herein in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application.

[0049] In order to further illustrate the technical means and effects adopted by this application to achieve the intended purpose, the following detailed description of this application is made in conjunction with the accompanying drawings and preferred implementation methods.

[0050] An embodiment of the present application provides a method for manufacturing a rigid-flexible circuit board, comprising the following steps:

[0051] Step S11, please refer to Figure 1 , providing a covering film 10.

[0052] The cover film 10 includes a flexible region 101 and a non-flexible region 102 connected to the flexible region 101 .

[0053] In this embodiment, there are two non-flexible regions 102 , and the two non-flexible regions 102 are located on two opposite sides of the flexible region 101 .

[0054] Step S12, see Figure 2 , forming a first peelable adhesive layer 20 on the cover film 10 .

[0055] The first peelable adhesive layer 20 corresponds to the flexible area 101 and can be peeled off from the surface of the cover film 10. The first peelable adhesive layer 20 is used to protect the cover film 10 from being damaged during the subsequent opening process.

[0056] In this embodiment, the material of the first peelable adhesive layer 20 may be polyethylene terephthalate (PET).

[0057] Step S13, please refer to Figure 3 , forming a first dielectric layer 30 on the cover film 10 having the first peelable adhesive layer 20 , and making the first dielectric layer 30 cover the first peelable adhesive layer 20 .

[0058] The material of the first dielectric layer 30 can be selected from epoxy resin, polypropylene (PP), BT resin, polyphenylene oxide (PPO), polyethylene (PE), polyimide (PI), and polyethylene naphthalate (PEN). In this embodiment, the material of the first dielectric layer 30 is polypropylene, and the polypropylene is provided with glass fibers 31.

[0059] In this embodiment, the thickness of the first dielectric layer 30 may be 25 μm.

[0060] In step S14 , a pressing plate 40 and a first conductive circuit layer 41 are formed on the first dielectric layer 30 , and the pressing plate 40 is aligned with the flexible region 101 , and the first conductive circuit layer 41 is aligned with the non-flexible region 102 , thereby obtaining a first circuit substrate 50 .

[0061] In this embodiment, the pressing plate 40 may be a copper foil layer. The pressing plate 40 is used to press the first dielectric layer 30. In other embodiments, the pressing plate 40 may also be omitted.

[0062] Step S15, please refer to Figure 4 A first groove 51 is opened in the first circuit substrate 50 along the thickness direction of the first circuit substrate 50 by laser cutting with a predetermined depth (i.e., a cover opening step), so that the first groove 51 passes through the first dielectric layer 30, and the bottom of the first groove 51 corresponds to the cover film 10, and the flexible area 101 is exposed to the first groove 51.

[0063] It can be understood that the first peelable adhesive layer 20 needs to be removed during the process of forming the first groove 51 .

[0064] Step S16, see Figure 5 , forming a second peelable adhesive layer 60 on the cover film 10 , and positioning the second peelable adhesive layer 60 in the first groove 51 .

[0065] The size of the second peelable adhesive layer 60 is comparable to the size of the first groove 51, so that the second peelable adhesive layer 60 is exactly located in the first groove 51. In one embodiment, the surface of the second peelable adhesive layer 60 away from the cover film 10 may protrude from the surface of the first dielectric layer 30 away from the cover film 10, or may be flush with the surface of the first dielectric layer 30 away from the cover film 10.

[0066] It can be understood that the second peelable adhesive layer 60 corresponds to the flexible area 101, and the second peelable adhesive layer 60 can be peeled off from the surface of the cover film 10. The second peelable adhesive layer 60 is used to protect the cover film 10 from being damaged during the subsequent opening process, and to fill the first groove 51 to prevent the subsequent dielectric layer (see FIG. Figure 6 ) is filled in the first groove 51.

[0067] In this embodiment, the second peelable adhesive layer 60 may also be made of polyethylene terephthalate (PET).

[0068] Step S17, please refer to Figure 6 , forming a second dielectric layer 70 on the first conductive circuit layer 41 , and making the second dielectric layer 70 cover the first dielectric layer 30 and the second peelable adhesive layer 60 .

[0069] The material of the second dielectric layer 70 is the same as that of the first dielectric layer 30. For details, please refer to the material of the first dielectric layer 30 and will not be described in detail here. In this embodiment, the material of the second dielectric layer 70 is polypropylene, and the glass fiber 31 is provided in the polypropylene.

[0070] The thickness of the second dielectric layer 70 is greater than that of the first dielectric layer 30. In this embodiment, the thickness of the second dielectric layer 70 may be 50 μm.

[0071] In step S18 , a second conductive circuit layer 80 is formed on the second dielectric layer 70 , and the second conductive circuit layer 80 is aligned with the non-flexible region 102 , thereby obtaining a second circuit substrate 90 .

[0072] Step S19, please refer to Figure 7 A second groove 91 is formed in the second circuit substrate 90 along the thickness direction of the second circuit substrate 90 by laser cutting to a predetermined depth (i.e., the uncovering step), so that the second groove 91 passes through the second dielectric layer 70 and corresponds to and communicates with the first groove 51, thereby obtaining the rigid-flexible circuit board 100.

[0073] It can be understood that the second peelable adhesive layer 60 needs to be removed during the process of forming the second groove 91 .

[0074] In one embodiment, the inner diameter of the second groove 91 is smaller than or equal to the inner diameter of the first groove 51 .

[0075] See also Figure 7 An embodiment of the present application further provides a rigid-flexible circuit board 100 , which includes a cover film 10 , a first dielectric layer 30 , a first conductive circuit layer 41 , a second dielectric layer 70 , and a second conductive circuit layer 80 .

[0076] The cover film 10 includes a flexible region 101 and a non-flexible region 102 connected to the flexible region 101. In this embodiment, there are two non-flexible regions 102, and the two non-flexible regions 102 are located on opposite sides of the flexible region 101, respectively.

[0077] The first dielectric layer 30 is located on the cover film 10. The material of the first dielectric layer 30 can be selected from a resin such as epoxy resin, polypropylene (PP), BT resin, polyphenylene oxide (PPO), polyethylene (PE), polyimide (PI), and polyethylene naphthalate (PEN). In this embodiment, the first dielectric layer 30 is made of polypropylene, which is provided with glass fibers 31.

[0078] In this embodiment, the thickness of the first dielectric layer 30 may be 25 μm.

[0079] A first groove 51 is defined in the first dielectric layer 30 . The first groove 51 penetrates the first dielectric layer 30 , and the bottom of the first groove 51 corresponds to the cover film 10 . The flexible region 101 is exposed in the first groove 51 .

[0080] The first conductive circuit layer 41 is located on the first dielectric layer 30 , and the first conductive circuit layer 41 corresponds to the non-flexible area 101 .

[0081] The second dielectric layer 70 is positioned above the first conductive circuit layer 41 and the first dielectric layer 30. The material of the second dielectric layer 70 is the same as that of the first dielectric layer 30. For details, please refer to the material of the first dielectric layer 30 and will not be described in detail here. In this embodiment, the second dielectric layer 70 is made of polypropylene, and the glass fibers 31 are disposed within the polypropylene.

[0082] The thickness of the second dielectric layer 70 is greater than that of the first dielectric layer 30. In this embodiment, the thickness of the second dielectric layer 70 may be 50 μm.

[0083] A second groove 91 is defined in the second dielectric layer 70. The second groove 91 penetrates the second dielectric layer 70 and corresponds to and communicates with the first groove 51. In one embodiment, the inner diameter of the second groove 91 is smaller than or equal to the inner diameter of the first groove 51.

[0084] The second conductive circuit layer 80 is located on the second dielectric layer 70 , and the second conductive circuit layer 80 corresponds to the non-flexible area 102 .

[0085] The present application adopts a single-layer cutting method (i.e., first cutting is performed in the first dielectric layer 30 to form the first groove 51, then the second dielectric layer 70 is formed, and finally cutting is performed in the second dielectric layer 70 to form the second groove 91, and the second groove 91 is made to correspond to and communicate with the first groove 51), thereby avoiding the phenomenon that the first dielectric layer 30 cannot be cut off, thereby reducing the residue of the first dielectric layer 30 after the cover is opened.

[0086] The above description is merely an optimized specific implementation of the present application, but in actual application, it cannot be limited to this implementation.

Claims

1. A method for manufacturing a rigid-flexible circuit board, characterized in that: The following steps are involved: providing a cover film comprising a flexible region and a non-flexible region connected to the flexible region; forming a first peelable adhesive layer on the cover film, and making the first peelable adhesive layer correspond to the flexible area; forming a first dielectric layer on the cover film having the first peelable adhesive layer, and making the first dielectric layer cover the first peelable adhesive layer; forming a first conductive circuit layer on the first dielectric layer, and making the first conductive circuit layer correspond to the non-flexible area, to obtain a first circuit substrate; A first groove is formed in the first circuit substrate along the thickness direction of the first circuit substrate by laser cutting to a predetermined depth, so that the first groove passes through the first dielectric layer, the bottom of the first groove corresponds to the cover film, and the flexible area is exposed in the first groove; forming a second peelable adhesive layer on the cover film, and positioning the second peelable adhesive layer in the first groove; forming a second dielectric layer on the first conductive circuit layer, and making the second dielectric layer cover the first dielectric layer and the second peelable adhesive layer, wherein the material of the second dielectric layer is the same as that of the first dielectric layer; forming a second conductive circuit layer on the second dielectric layer, and making the second conductive circuit layer correspond to the non-flexible area to obtain a second circuit substrate; and A second groove is opened in the second circuit substrate along the thickness direction of the second circuit substrate by laser depth cutting, so that the second groove passes through the second dielectric layer and corresponds to and communicates with the first groove, thereby obtaining the flexible and rigid circuit board.

2. The method for manufacturing a rigid-flexible circuit board according to claim 1, wherein: The thickness of the second dielectric layer is greater than that of the first dielectric layer.

3. The method for manufacturing a rigid-flexible circuit board according to claim 1, wherein: The size of the second peelable adhesive layer is adapted to the size of the first groove.

4. The method for manufacturing a rigid-flexible circuit board according to claim 1, wherein: An inner diameter of the first groove is greater than or equal to an inner diameter of the second groove.

5. The method for manufacturing a rigid-flexible circuit board according to claim 1, wherein: The first dielectric layer and the second dielectric layer are both made of polypropylene, epoxy resin, polyphenylene ether, polyimide, or polyethylene.

6. A rigid-flexible circuit board, characterized in that: include: a cover film comprising a flexible region and a non-flexible region connected to the flexible region; a first dielectric layer located on the cover film, wherein a first groove is provided in the first dielectric layer, the first groove penetrates the first dielectric layer, and a bottom of the first groove corresponds to the cover film, and the flexible area is exposed in the first groove; a first conductive circuit layer, located on the first dielectric layer, and corresponding to the non-flexible area; a second dielectric layer, located on the first conductive circuit layer and the first dielectric layer, wherein the second dielectric layer is made of the same material as the first dielectric layer, and a second groove is provided in the second dielectric layer, the second groove passes through the second dielectric layer, and the second groove corresponds to and is connected to the first groove; as well as The second conductive circuit layer is located on the second dielectric layer, and the second conductive circuit layer corresponds to the non-flexible area.

7. The rigid-flex circuit board according to claim 6, wherein: The thickness of the second dielectric layer is greater than that of the first dielectric layer.

8. The rigid-flex circuit board according to claim 6, wherein: An inner diameter of the first groove is greater than or equal to an inner diameter of the second groove.

9. The rigid-flex circuit board according to claim 6, wherein: The first dielectric layer and the second dielectric layer are both made of polypropylene, epoxy resin, polyphenylene ether, polyimide, or polyethylene.

10. The rigid-flex circuit board according to claim 6, wherein: There are two non-flexible areas, and the two non-flexible areas are located on two opposite sides of the flexible area.

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