A processing technique for multilayer flexible board with blind slot and through hole structure

Abstract

The present application relates to the technical field of flexible plate production, and particularly relates to a processing technology of multilayer flexible plate with blind groove and blind hole structure, which comprises the following steps: providing a carrier plate, drilling micro-holes, first copper electroplating, filling the micro-holes, first circuit layer manufacturing, pressing a first cover film, forming a first PAD, printing protective ink, windowing glue, pressing a copper foil, forming a blind groove between the copper foil and the protective ink, forming a blind hole, second copper electroplating, second circuit layer manufacturing, third circuit layer manufacturing, removing the protective ink, pressing a second cover film, and the like. The present application adopts the structure of epoxy glue windowing and copper foil to solve the risk of cutting the flexible plate by laser opening the blind groove. In addition, the protective ink is printed in the blind groove to prevent the copper foil from breaking and protect the first PAD in the inner layer. In addition, the micro-holes on one side of the blind groove are manufactured by the filling process to solve the problem of uneven surface of the laser-drilled plate in the blind groove, ensure the reliability of the holes, and reduce the risk.

Description

Technical Field

[0001] This invention relates to the field of flexible board manufacturing technology, specifically to a processing technology for a multi-layer flexible board with a blind groove and blind hole structure. Background Technology

[0002] With the increasing integration of circuit boards and the ultra-thin development of flexible boards, flexible and rigid-flex HDI boards have become the preferred design in high-end applications, satisfying both the need for small size and compact design while also meeting the complex functions of products. Multilayer flexible boards with blind slots are often manufactured using laser cutting, but due to the thinness of the flexible board, depth control is difficult, and the flexible layer is easily damaged during cutting. Furthermore, previously, flexible blind slot boards in the industry did not have blind via structures. Summary of the Invention

[0003] The purpose of this invention is to address the aforementioned shortcomings in the prior art by providing a processing technology for multilayer flexible boards with blind slots and blind holes.

[0004] The objective of this invention is achieved through the following technical solution: a processing technology for a multilayer flexible plate with a blind slot and blind hole structure, comprising the following steps:

[0005] S1. Provide a double-sided copper-clad core board as a carrier board; perform micro-hole drilling on the carrier board;

[0006] S2. Perform a first copper plating process on the copper layers on both sides of the core board; and fill the micropores with the first copper plating.

[0007] S3. The first circuit layer is fabricated on the copper layer on the bottom surface of the core board and the first electroplated copper on the bottom surface.

[0008] S4. A first cover film is laminated to one side of the first circuit layer; a window is made in the first cover film to form a first PAD on the first electroplated copper;

[0009] S5. Apply protective ink to the surface of the first cover film and the first PAD;

[0010] S6. Apply adhesive to the other side of the first circuit layer and make a window in the adhesive.

[0011] S7. Press copper foil onto the bottom of the adhesive; a blind groove is formed between the copper foil and the protective ink;

[0012] S8. Drill through holes at the openings in the adhesive to create blind vias on the other side of the first circuit layer.

[0013] S9. A second copper plating process is performed on the top surface of the first copper plating, the bottom surface of the copper foil, and the inner wall of the blind hole.

[0014] S10. A second circuit layer is fabricated on the copper layer, the first electroplated copper layer, and the second electroplated copper layer on the top surface of the core board; a third circuit layer is fabricated on the copper foil and the second electroplated copper layer.

[0015] S11. Remove the protective ink;

[0016] S12, a second cover film is laminated onto the second circuit layer and the third circuit layer; a window is made in the second cover film to form a second PAD on the second electroplated copper on the top surface.

[0017] The present invention is further configured such that, in step S6, the adhesive is an epoxy adhesive.

[0018] The present invention is further configured such that, in step S7, after pressing copper foil onto the bottom surface of the adhesive, blind grooves are formed between the protective inks by etching the copper foil and creating grooves in the adhesive.

[0019] The present invention is further configured such that, in step S8, the copper layer on the top surface of the core board and the copper foil are etched during the first electroplating of copper, and through holes are drilled in the core board to form blind holes at the openings of the adhesive.

[0020] The present invention is further configured such that the copper foil and the copper layers on both sides of the core board have the same thickness.

[0021] The beneficial effects of this invention are as follows: This invention uses an epoxy adhesive windowing and copper foil structure. The copper foil etching and adhesive windowing achieve blind slotting, thereby solving the risk of laser blind slotting damaging the flexible board. In addition, protective ink is printed inside the blind slot. The protective ink has the effect of bonding the copper foil to the flexible substrate, solving the problem of copper foil blistering after plasma treatment, preventing copper foil breakage, and protecting the first PAD of the inner layer. Furthermore, the micro-holes on one side of the blind slot are made using a processing and filling process, solving the problem of uneven board surface when laser drilling inside the blind slot, ensuring the reliability of the hole and reducing the risk. Attached Figure Description

[0022] The invention will be further illustrated with reference to the accompanying drawings, but the embodiments in the drawings do not constitute any limitation on the invention. For those skilled in the art, other drawings can be obtained based on the following drawings without any creative effort.

[0023] Figure 1 This is a schematic diagram of the structure after micro-hole drilling in this invention;

[0024] Figure 2 This is a schematic diagram of the structure after the first electroplating copper treatment according to the present invention;

[0025] Figure 3 This is a schematic diagram of the structure after the first circuit layer of the present invention has been fabricated;

[0026] Figure 4This is a schematic diagram of the structure of the present invention after the first cover film is pressed together;

[0027] Figure 5 This is a schematic diagram of the structure after the protective ink of this invention has been applied;

[0028] Figure 6 This is a schematic diagram of the structure of the pressed copper foil of the present invention;

[0029] Figure 7 This is a schematic diagram of the structure after drilling a through hole in this invention;

[0030] Figure 8 This is a schematic diagram of the structure after the second electroplating of copper according to the present invention;

[0031] Figure 9 This is a schematic diagram of the structure after the fabrication of the second circuit layer and the third circuit layer of the present invention;

[0032] Figure 10 This is a schematic diagram of the structure of the present invention after the protective ink has been removed;

[0033] Figure 11 This is a schematic diagram of the structure after the second cover film of the present invention is laminated; wherein: 11, copper layer; 12, core board; 13, micropore; 2, first electroplated copper; 21, first circuit layer; 3, first cover film; 31, first PAD; 4, protective ink; 41, blind groove; 5, adhesive; 6, copper foil; 7, blind hole; 8, second electroplated copper; 81, second circuit layer; 82, third circuit layer; 9, second cover film; 91, second PAD. Detailed Implementation

[0034] The present invention will be further described in conjunction with the following embodiments.

[0035] Depend on Figures 1 to 11 As can be seen, the processing technology of a multilayer flexible board with a blind groove 41 and a blind hole 7 structure described in this embodiment includes the following steps:

[0036] S1. A core board 12 with double-sided copper clad layers 11 is provided as a carrier board; micro-holes 13 are drilled on the carrier board to form a structure as shown in the image. Figure 1 As shown, the micro-hole 13 penetrates the core board 12 and the copper layers 11 on both sides of the core board 12;

[0037] S2. A first copper plating 2 process is performed on the copper layers 11 on both sides of the core board 12; and the micropores 13 are filled by the first copper plating 2, thereby forming a... Figure 2 In the state shown, the first electroplated copper 2 completely covers the copper layer 11 on both sides of the core board 12 and the micropores 13.

[0038] S3. A first circuit layer 21 is fabricated on the copper layer 11 on the bottom surface of the core board 12 and the first electroplated copper 2 on the bottom surface; thereby forming a circuit layer 21. Figure 3The state shown;

[0039] S4. A first cover film 3 is pressed onto one side of the first circuit layer 21; a window is made in the first cover film 3 to form a first PAD 31 on the first electroplated copper 2; thereby forming a... Figure 4 The state shown;

[0040] S5. Apply protective ink 4 to the surfaces of the first cover film 3 and the first PAD 31; thereby forming a protective ink such as Figure 5 The state shown;

[0041] S6. Apply adhesive 5 to the other side of the first circuit layer 21 and make a window in the adhesive 5.

[0042] S7. Press copper foil 6 onto the bottom surface of adhesive 5; a blind groove 41 is formed between copper foil 6 and protective ink 4; thus forming a... Figure 6 The state shown;

[0043] S8. Drill a through hole at the opening of glue 5 to form a blind hole 7 on the other side of the first circuit layer 21; thus forming a... Figure 7 As shown in the diagram, blind hole 7 penetrates the entire multilayer flexible plate.

[0044] S9. A second copper plating process 8 is performed on the top surface of the first electroplated copper 2, the bottom surface of the copper foil 6, and the inner wall of the blind hole 7; thereby forming a... Figure 8 The state shown

[0045] S10. A second circuit layer 81 is fabricated on the copper layer 11, the first electroplated copper 2, and the second electroplated copper 8 on the top surface of the core board 12; a third circuit layer 82 is fabricated on the copper foil 6 and the second electroplated copper 8; thereby forming a circuit layer 81. Figure 9 The state shown

[0046] S11, Remove the protective ink 4; thus forming a... Figure 10 The state shown;

[0047] S12, a second cover film 9 is laminated onto the second circuit layer 81 and the third circuit layer 82; a window is made in the second cover film 9 to form a second PAD 91 on the second electroplated copper 8 on the top surface. This forms a... Figure 11 The state shown.

[0048] Specifically, this embodiment uses an epoxy resin windowing and copper foil 6 structure. The copper foil 6 is etched and the adhesive 5 is used to create a blind groove 41, which solves the risk of laser blind groove 41 cutting the flexible board. In addition, protective ink 4 is printed inside the blind groove 41. The protective ink 4 has the function of bonding the copper foil 6 to the flexible substrate, solving the problem of copper foil 6 bulging after plasma treatment, preventing copper foil 6 from cracking, and protecting the first PAD 31 of the inner layer. In addition, the microhole 13 on one side of the blind groove 41 is made by processing and filling process, which solves the problem of uneven board surface in the laser drilling inside the blind groove 41, ensures the reliability of the hole, and reduces the risk.

[0049] In this embodiment, a multilayer flexible board processing technology with a blind groove 41 and blind hole 7 structure is described. In step S6, the adhesive 5 is epoxy adhesive. This configuration eliminates the need for laser grooving, thus mitigating the risk of laser cutting the flexible board through the blind groove 41.

[0050] The multilayer flexible board processing technology with blind groove 41 and blind hole 7 described in this embodiment involves step S7, where copper foil 6 is pressed onto the bottom surface of adhesive 5; then, blind groove 41 is formed between protective ink 4 by etching copper foil 6 and creating grooves in adhesive 5. This design eliminates the need for laser grooving, thus mitigating the risk of laser-cut blind groove 41 damaging the flexible board.

[0051] The multilayer flexible board processing technology with a blind slot 41 and blind hole 7 structure described in this embodiment involves etching the copper layer 11 on the top surface of the core board 12 and the copper foil 6 during the first copper electroplating in step S8, and drilling through holes in the core board 12 to form blind holes 7 at the openings of the adhesive 5. This setup eliminates the need for laser grooving, thus mitigating the risk of laser-cut blind slots 41 damaging the flexible board.

[0052] This embodiment describes a multilayer flexible board manufacturing process with a blind slot 41 and blind hole 7 structure, wherein the copper foil 6 and the copper layers 11 on both sides of the core board 12 have the same thickness. This configuration ensures the structural stability of the multilayer flexible board. Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the present invention.

Claims

1. A processing method for a multilayer flexible plate with a blind slot and through-hole structure, comprising the following steps: S1. A core board with double-sided copper clad layer is provided as a carrier board, and micro-holes are drilled on the carrier board, wherein the micro-holes penetrate the core board and the copper layers on both sides of the core board. S2. A first electroplating copper treatment is performed on the copper layers on both sides of the core board, and the micropores are filled by the first electroplating copper. The first electroplating copper completely covers the copper layers and micropores on both sides of the core board. S3. The first circuit layer is fabricated on the copper layer on the bottom surface of the core board and the first electroplated copper on the bottom surface. S4. A first cover film is pressed onto one side of the first circuit layer, and a window is made in the first cover film to form a first PAD on the first electroplated copper. S5. Apply protective ink to the surface of the first cover film and the first PAD; S6. Apply adhesive to the other side of the first circuit layer and make a window in the adhesive. S7. Press copper foil onto the bottom of the adhesive to form a blind groove between the copper foil and the protective ink. This blind groove is formed between the protective ink by etching the copper foil and creating grooves in the adhesive. S8. Drill through holes at the opening of the adhesive to form through holes on the other side of the first circuit layer. Etch the first electroplated copper, the copper layer on the top surface of the core board and the copper foil. Drill through holes in the core board to form through holes with the opening of the adhesive. S9. A second copper plating process is performed on the top surface of the first copper plating, the bottom surface of the copper foil, and the inner wall of the through hole. S10. A second circuit layer is fabricated on the copper layer, the first electroplated copper and the second electroplated copper on the top surface of the core board, and a third circuit layer is fabricated on the copper foil and the second electroplated copper. S11. Remove the protective ink; S12. A second cover film is laminated onto the second circuit layer and the third circuit layer, and a window is made in the second cover film to form a second PAD on the second electroplated copper on the top surface.

2. The processing technology for a multi-layer flexible plate with a blind slot and through-hole structure according to claim 1, characterized in that: In step S6, the adhesive is epoxy adhesive.

3. The processing technology for a multi-layer flexible plate with a blind slot and through-hole structure according to claim 1, characterized in that: The copper foil and the copper layers on both sides of the core board have the same thickness.

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