Rigid-flex board and manufacturing method thereof

Abstract

A manufacturing method of a rigid-flex board comprises the steps that a flexible board is provided, the flexible board is provided with an extending direction, and the flexible board is divided into a first area and a second area connected with the first area in the extending direction; a first protection layer is arranged on the soft board, the first protection layer comprises a first part and a second part connected with the first part, the first part covers the first area, and the second part covers part of the second area. A hard board is arranged in the second area, the hard board and the second part are overlapped, a notch is formed in the hard board corresponding to the second part, and the notch is used for reducing the height difference caused by the second part and pressing the hard board and the soft board, so that the hard board corresponding to the second part is flush with the hard boards of other parts. The manufacturing method of the rigid-flex board provided by the invention has the advantage of high flatness. In addition, the invention also provides a rigid-flex board.

Description

Technical Field

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

[0002] In the design of rigid-flexible printed circuit boards, the selection of circuits and copper surface protective layers is crucial. A rigid-flexible printed circuit board includes a rigid board area and a flexible board area. The rigid board area has high mechanical strength and durability, while the flexible board area has good flexibility and bendability.

[0003] During the production process of the substrate, the circuits of the flexible board need to be protected by a coverlay, and the circuits of the rigid board need to be protected by a soldermask. In order to avoid the risk of peeling of the coverlay of the flexible board, the coverlay usually extends inwards to the rigid-flexible board area by about 0.5 mm. Coupled with the difference in the stacking thickness of each layer of the laminate structure, it is easy to cause the height of the measurement points in this area to be greater than that in other areas, resulting in a reduction in the flatness of the rigid-flexible printed circuit board, which may in turn affect the performance and reliability of electronic devices. Summary of the Invention

[0004] In view of this, it is necessary to provide a manufacturing method of a rigid-flexible printed circuit board to solve the above technical problems.

[0005] In addition, this application also provides a rigid-flexible printed circuit board.

[0006] A manufacturing method of a rigid-flexible printed circuit board includes the steps of: providing a flexible board, the flexible board having an extending direction, along which the flexible board is divided into a first area and a second area connecting the first area; disposing a first protective layer on the flexible board, the first protective layer including a first part and a second part connecting the first part, the first part covering the first area, and the second part covering a part of the second area; disposing a rigid board on the second area, the rigid board having a notch corresponding to the second part, the notch being used to reduce the height difference caused by the second part, and laminating the rigid board and the flexible board so that the rigid board corresponding to the second part is flush with the other parts of the rigid board.

[0007] In some possible embodiments, the rigid board includes a first insulating layer, a first conductive layer, a second insulating layer, and a second conductive layer. The first insulating layer and the second insulating layer are disposed opposite to each other with a gap therebetween. The side of the first insulating layer facing away from the second insulating layer is connected to the second region. The first conductive layer is connected between the first insulating layer and the second insulating layer. The second conductive layer is connected to the side of the second insulating layer facing away from the first conductive layer. The step of "disposing the rigid board in the second region" includes: disposing the notch at the position of the second conductive layer corresponding to the second part; the step of "pressing the rigid board and the flexible board together" includes: partially filling the notch with the second insulating layer.

[0008] In some possible embodiments, the rigid board includes a first insulating layer, a first conductive layer, a second insulating layer, and a second conductive layer. The first insulating layer and the second insulating layer are disposed opposite to each other with a gap therebetween. The side of the first insulating layer facing away from the second insulating layer is connected to the second region. The first conductive layer is connected between the first insulating layer and the second insulating layer. The second conductive layer is connected to the side of the second insulating layer facing away from the first conductive layer. The step of "disposing the rigid board in the second region" includes: disposing the notch at the position of the first conductive layer corresponding to the second part; the step of "pressing the rigid board and the flexible board together" includes: partially filling the notch with the first insulating layer and / or partially filling the notch with the second insulating layer.

[0009] In some possible embodiments, the rigid board includes a first insulating layer, a first conductive layer, a second insulating layer, and a second conductive layer. The first insulating layer and the second insulating layer are disposed opposite to each other with a gap therebetween. The side of the first insulating layer facing away from the second insulating layer is connected to the second region. The first conductive layer is connected between the first insulating layer and the second insulating layer. The second conductive layer is connected to the side of the second insulating layer facing away from the first conductive layer. The step of "disposing the rigid board in the second region" includes: disposing the notch at the position of the first insulating layer corresponding to the second part; the step of "pressing the rigid board and the flexible board together" includes: partially filling the notch with the first insulating layer.

[0010] In some possible embodiments, it further includes the step of: disposing a second protective layer on the side of the rigid board facing away from the flexible board.

[0011] A flexible-rigid printed circuit board includes a flexible board, a first protective layer, and a rigid board. The flexible board has an extending direction. Along the extending direction, the flexible board is divided into a first region and a second region connecting the first region. The first protective layer includes a first part and a second part connecting the first part. The first part covers the first region, and the second part covers a part of the second region. The rigid board is disposed in the second region. The rigid board is provided with a notch corresponding to the second part. The notch is used to reduce the height difference caused by the second part, so that the rigid board corresponding to the second part is flush with the other parts of the rigid board.

[0012] In some possible embodiments, the rigid board includes a first insulating layer, a first conductive layer, a second insulating layer, and a second conductive layer. The first insulating layer and the second insulating layer are relatively spaced apart. One side of the first insulating layer facing away from the second insulating layer is connected to the second region. The first conductive layer is connected between the first insulating layer and the second insulating layer. The second conductive layer is connected to one side of the second insulating layer facing away from the first conductive layer.

[0013] In some possible embodiments, the notch is provided at the second conductive layer corresponding to the second part, and a part of the second insulating layer is filled into the notch.

[0014] In some possible embodiments, the notch is provided at the first conductive layer corresponding to the second part, and a part of the first insulating layer and / or a part of the second insulating layer is filled into the notch.

[0015] In some possible embodiments, the notch is provided at the first insulating layer corresponding to the second part, and a part of the first insulating layer is filled into the notch.

[0016] Compared with the prior art, the manufacturing method of the flexible-rigid printed circuit board provided by the present application reduces the manifestation of the misalignment and deformation on the surface of the rigid board by providing a notch in the rigid board and filling a part of the rigid board into the notch during the process of laminating the rigid board and the flexible board, thereby facilitating the improvement of the flatness of the rigid board after lamination. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic cross-sectional view of the flexible board provided by the first embodiment of the present application.

[0018] Figure 2 is Figure 1 a schematic cross-sectional view of the flexible board shown after the first protective layer is provided.

[0019] Figure 3 is Figure 2 a schematic cross-sectional view of the flexible board shown after the rigid board is provided.

[0020] Figure 4 As shown in Figure 3 the cross-sectional schematic diagram after pressing the flexible board and the rigid board.

[0021] Figure 5 As shown in Figure 4 the cross-sectional schematic diagram of the rigid board after setting the second protective layer.

[0022] Figure 6 This is the cross-sectional schematic diagram of the flexible board provided in the second embodiment of the present application after setting the rigid board.

[0023] Figure 7 As shown in Figure 6 the cross-sectional schematic diagram after pressing the flexible board and the rigid board.

[0024] Figure 8 This is the cross-sectional schematic diagram of the flexible board provided in the third embodiment of the present application after setting the rigid board.

[0025] Figure 9 As shown in Figure 8 the cross-sectional schematic diagram after pressing the flexible board and the rigid board.

[0026] Main component symbol description

[0027] Rigid-flex board 100

[0028] Flexible board 10

[0029] Inner conductive layer 101

[0030] Inner insulating layer 102

[0031] First area 11

[0032] Second area 12

[0033] First protective layer 20

[0034] First part 21

[0035] Second part 22

[0036] Rigid board 30

[0037] First insulating layer 31

[0038] First conductive layer 32

[0039] Second insulating layer 33

[0040] Second conductive layer 34

[0041] Notch 35

[0042] First notch 351

[0043] Second notch 352

[0044] Third notch 353

[0045] Second protective layer 40

[0046] Extension direction A

[0047] Thickness direction B

[0048] The following specific embodiments will further illustrate the present application in conjunction with the above drawings. Specific embodiments

[0049] The technical solutions in the embodiments of the present application will be described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments.

[0050] It should be noted that when a component is considered to be "disposed on" another component, it can be directly disposed on the other component or there may be an intermediate component present at the same time.

[0051] Please refer to Figures 1 to 5 , the first embodiment of the present application provides a manufacturing method of a flexible-rigid printed circuit board 100, including the steps:

[0052] S1: Please refer to Figure 1 , provide a flexible board 10, the flexible board 10 has an extension direction A, along the extension direction A, the flexible board 10 is divided into a first area 11 and a second area 12 connecting the first area 11.

[0053] In this embodiment, the flexible board 10 is a printed circuit board made of a flexible insulating substrate, which can be freely bent, wound, and folded, can withstand millions of dynamic bends without damaging the wires, and can be arbitrarily wired according to the requirements of the spatial layout. The flexible board 10 also has a thickness direction B, along the thickness direction B, the flexible board 10 includes a plurality of inner conductive layers 101 and a plurality of inner insulating layers 102 arranged at intervals, and each inner insulating layer 102 is disposed between two adjacent inner conductive layers 101. Among them, the material of the inner insulating layer 102 includes one of polyimide (PI), polyester (PET), and polytetrafluoroethylene (PTFE).

[0054] S2: Please refer to Figure 2, a first protective layer 20 is provided on the flexible printed circuit board 10. The first protective layer 20 includes a first portion 21 and a second portion 22 connecting the first portion 21. The first portion 21 covers the first region 11, and the second portion 22 covers a part of the second region 12. Among them, the material of the first protective layer 20 includes one of polyimide (PI), polyester (PET), liquid photo-imageable coverlay (LPIC), and polytetrafluoroethylene (PTFE). The first protective layer 20 is used to protect the inner conductive layer 101 on the flexible printed circuit board 10, prevent physical damage and chemical corrosion, and provide electrical insulation at the same time.

[0055] In this embodiment, the first protective layers 20 are provided on both opposite outer sides of the flexible printed circuit board 10. The second portions 22 of the two first protective layers 20 both cover a part of the second region 12.

[0056] S3: Please refer to Figure 3 , a rigid board 30 is attached to the second region 12. The rigid board 30 is provided with a notch (not labeled) corresponding to the second portion 22, and the notch is used to reduce the height difference caused by the second portion 22.

[0057] In this embodiment, the rigid board 30 includes a first insulating layer 31, a first conductive layer 32, a second insulating layer 33, and a second conductive layer 34. The first insulating layer 31 and the second insulating layer 33 are relatively spaced apart. One side of the first insulating layer 31 facing away from the second insulating layer 33 is connected to the second region 12. The first conductive layer 32 is connected between the first insulating layer 31 and the second insulating layer 33, and the second conductive layer 34 is connected to one side of the second insulating layer 33 facing away from the first conductive layer 32. Among them, the first conductive layer 32 and the second conductive layer 34 are circuit layers, and the first insulating layer 31 and the second insulating layer 33 are made of rigid insulating materials. Specifically, it includes one of glass fiber epoxy resin boards, polytetrafluoroethylene boards, and ceramic substrates.

[0058] In this embodiment, a rigid board 30 is attached to both opposite outer sides of the second region 12 of the flexible printed circuit board 10. The two rigid boards 30 are symmetrically arranged with respect to the flexible printed circuit board 10.

[0059] In this embodiment, the notch includes a first notch 351, and step S3 further includes:

[0060] S31: Provide the first notch 351 at a position on the first conductive layer 32 corresponding to the second portion 22. The first notch 351 penetrates through the first conductive layer 32, and the first insulating layer 31 and the second insulating layer 33 are exposed at the first notch 351. Specifically, the first conductive layers 32 of the two rigid boards 30 are both provided with the first notch 351.

[0061] Please refer to Figure 6 , in the second embodiment of the present application, the notch includes a second notch 352, and step S3 further includes:

[0062] S32: Provide the second notch 352 at a position on the second conductive layer 34 corresponding to the second portion 22. The second notch 352 penetrates through the second conductive layer 34, and the second insulating layer 33 is exposed at the second notch 352. Specifically, the first conductive layers 32 of the two rigid boards 30 are both provided with the second notch 352.

[0063] Please refer to Figure 8 , in the third embodiment of the present application, the notch includes a third notch 353, and step S3 further includes:

[0064] S33: Provide the third notch 353 at a position on the first insulating layer 31 corresponding to the second portion 22. The third notch 353 does not penetrate through the first insulating layer 31. Specifically, the first conductive layers 32 of the two rigid boards 30 are both provided with the third notch 353.

[0065] S4: Please refer to Figure 4 , press the rigid board 30 and the flexible board 10 so that the rigid board 30 corresponding to the second portion 22 is flush with the other parts of the rigid board 30, and obtain the rigid-flex board 100.

[0066] In this embodiment, step S4 further includes:

[0067] S41: Part of the first insulating layer 31 and / or part of the second insulating layer 33 fills into the first notch 351, thereby reducing the warping and deformation of the rigid board 30.

[0068] Please refer to Figure 7 , in the second embodiment of the present application, step S4 further includes:

[0069] S42: The second portion 22 abuts against part of the first conductive layer 32 and the first insulating layer 31 and warps upward. At the same time, part of the first insulating layer 31 fills into the second notch 352, thereby reducing the warping and deformation of the outer surface of the rigid board 30.

[0070] Please refer to Figure 9, in the third embodiment of the present application, step S4 further includes:

[0071] S43: Part of the second insulating layer 33 is filled into the third notch 353, thereby reducing the warping and deformation of the outer surface of the rigid board 30.

[0072] In this embodiment, during the process of laminating the rigid board 30 and the flexible board 10, part of the rigid board 30 will warp and twist. In particular, the part of the rigid board 30 corresponding to the second part 22 will warp and twist in the thickness direction B, and this warping and twisting can be absorbed by the notch 35 until the notch 35 is squeezed and filled, thereby reducing the manifestation of warping and twisting on the surface of the rigid board 30, which is beneficial to improving the flatness of the rigid board 30 after lamination. It can be understood that if the rigid board 30 is not provided with the notch 35, the part of the rigid board 30 corresponding to the second part 22 will bulge in the thickness direction B, and this bulge will be directly reflected on the outer surface of the rigid board 30, thereby reducing the flatness of the rigid board 30 after lamination.

[0073] Please refer to Figure 5 , in this embodiment, the manufacturing method of the rigid-flex board 100 further includes the steps:

[0074] S5: A second protective layer 40 is provided on the side of the rigid board 30 facing away from the flexible board 10. That is, the second protective layer 40 is provided on the second conductive layer 34. The material of the second protective layer 40 includes epoxy resins, polyimide, and liquid photo-imageable (LPI). The second protective layer 40 is used to protect the un-welded part of the second conductive layer 34 on the rigid board 30 from oxidation and prevent short circuits during the welding process. At the same time, the second protective layer 40 also provides a certain degree of electrical insulation.

[0075] In addition, please refer to Figure 5, an embodiment of the present application further provides a flexible-rigid printed circuit board 100, including a flexible board 10, a first protective layer 20, and a rigid board 30. The flexible board 10 has an extending direction A. Along the extending direction A, the flexible board 10 is divided into a first area 11 and a second area 12 connecting the first area 11. The first protective layer 20 includes a first part 21 and a second part 22 connecting the first part 21. The first part 21 covers the first area 11, and the second part 22 covers a part of the second area 12. The rigid board 30 is disposed in the second area 12. The rigid board 30 is provided with a notch 35 corresponding to the second part 22. The notch 35 is used to reduce the height difference caused by the second part 22, so that the rigid board 30 corresponding to the second part 22 is flush with other parts of the rigid board 30.

[0076] Wherein, the rigid board 30 includes a first insulating layer 31, a first conductive layer 32, a second insulating layer 33, and a second conductive layer 34. The first insulating layer 31 and the second insulating layer 33 are relatively spaced apart. One side of the first insulating layer 31 facing away from the second insulating layer 33 is connected to the second area 12. The first conductive layer 32 is connected between the first insulating layer 31 and the second insulating layer 33. The second conductive layer 34 is connected to one side of the second insulating layer 33 facing away from the first conductive layer 32.

[0077] In this embodiment, the notch includes a first notch 351. The first notch 351 is disposed at the first conductive layer 32 corresponding to the second part 22, and part of the first insulating layer 31 and / or part of the second insulating layer 33 is filled into the first notch 351.

[0078] Please refer to Figure 7 , in the second embodiment of the present application, the notch includes a second notch 352. The second notch 352 is disposed at the second conductive layer 34 corresponding to the second part 22, and part of the second insulating layer 33 is filled into the second notch 352.

[0079] Please refer to Figure 9 , in the third embodiment of the present application, the notch includes a third notch 353. The third notch 353 is disposed at the first insulating layer 31 corresponding to the second part 22, and part of the first insulating layer 31 is filled into the third notch 353.

[0080] Those of ordinary skill in the art of the present technology should recognize that the above embodiments are only used to illustrate the present application, rather than to limit the present application. As long as within the scope of the spirit of the present application, appropriate changes and variations made to the above embodiments fall within the scope disclosed in the present application.

Claims

1. A manufacturing method of a rigid-flex printed circuit board, characterized in that, Including the steps of: Providing a flexible printed circuit (FPC), the FPC having an extending direction, along which the FPC is divided into a first region and a second region connecting the first region; Providing a first protective layer on the FPC, the first protective layer including a first portion and a second portion connecting the first portion, the first portion covering the first region, and the second portion covering a part of the second region; Providing a rigid board in the second region, the rigid board being stacked with the second portion, the rigid board being provided with a notch corresponding to the second portion, the notch being used to reduce the height difference caused by the second portion, and Pressing the rigid board and the FPC together such that the rigid board corresponding to the second portion is flush with the other parts of the rigid board.

2. The manufacturing method according to claim 1, characterized in that, The rigid board includes a first insulating layer, a first conductive layer, a second insulating layer, and a second conductive layer. The first insulating layer and the second insulating layer are relatively spaced apart. The side of the first insulating layer facing away from the second insulating layer is connected to the second region. The first conductive layer is connected between the first insulating layer and the second insulating layer. The second conductive layer is connected to the side of the second insulating layer facing away from the first conductive layer. The step of "providing a rigid board in the second region" includes: Providing the notch at the second conductive layer corresponding to the second portion; The step of "pressing the rigid board and the FPC together" includes: Filling a part of the second insulating layer into the notch.

3. The manufacturing method according to claim 1, characterized in that, The rigid board includes a first insulating layer, a first conductive layer, a second insulating layer, and a second conductive layer. The first insulating layer and the second insulating layer are relatively spaced apart. The side of the first insulating layer facing away from the second insulating layer is connected to the second region. The first conductive layer is connected between the first insulating layer and the second insulating layer. The second conductive layer is connected to the side of the second insulating layer facing away from the first conductive layer. The step of "providing a rigid board in the second region" includes: Providing the notch at the first conductive layer corresponding to the second portion; The step of "pressing the rigid board and the FPC together" includes: Filling a part of the first insulating layer and / or a part of the second insulating layer into the notch.

4. The manufacturing method according to claim 1, wherein the rigid board comprises a first insulating layer, a first conductive layer, a second insulating layer, and a second conductive layer, the first insulating layer and the second insulating layer are disposed opposite to each other with a spacing therebetween, a side of the first insulating layer facing away from the second insulating layer is connected to the second region, the first conductive layer is connected between the first insulating layer and the second insulating layer, and the second conductive layer is connected to a side of the second insulating layer facing away from the first conductive layer, characterized in that The step of "providing a rigid board in the second region" includes: Providing the notch at the first insulating layer corresponding to the second portion; The step of "pressing the rigid board and the FPC together" includes: Filling a part of the first insulating layer into the notch.

5. The manufacturing method according to claim 1, characterized in that, Further including the step of: Providing a second protective layer on the side of the rigid board facing away from the FPC.

6. A rigid-flex printed circuit board, characterized in that, Including: A flexible printed circuit (FPC), the FPC having an extending direction, along which the FPC is divided into a first region and a second region connecting the first region; A first protective layer, the first protective layer including a first portion and a second portion connecting the first portion, the first portion covering the first region, and the second portion covering a part of the second region; A rigid board, the rigid board being provided in the second region, the rigid board being provided with a notch corresponding to the second portion, the notch being used to reduce the height difference caused by the second portion such that the rigid board corresponding to the second portion is flush with the other parts of the rigid board.

7. The rigid-flex printed circuit board according to claim 6, wherein The rigid board includes a first insulating layer, a first conductive layer, a second insulating layer, and a second conductive layer. The first insulating layer and the second insulating layer are disposed opposite to each other with a gap therebetween. The side of the first insulating layer facing away from the second insulating layer is connected to the second region. The first conductive layer is connected between the first insulating layer and the second insulating layer. The second conductive layer is connected to the side of the second insulating layer facing away from the first conductive layer.

8. The rigid-flex printed circuit board according to claim 7, wherein The notch is disposed at the second conductive layer corresponding to the second portion, and a part of the second insulating layer is filled into the notch.

9. The rigid-flex printed circuit board according to claim 7, wherein The notch is disposed at the first conductive layer corresponding to the second portion, and a part of the first insulating layer and / or a part of the second insulating layer is filled into the notch.

10. The rigid-flex printed circuit board according to claim 7, wherein The notch is disposed at the first insulating layer corresponding to the second portion, and a part of the first insulating layer is filled into the notch.

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