A window opening method for rigid-flexible board

Abstract

The present invention provides a method for opening windows on a rigid-flexible board. When opening windows at positions corresponding to soft board areas on a PP sheet, a connecting portion is arranged between corresponding positions of adjacent hard board areas, and the PP corresponding to the independent hard board area is connected through the connecting portion, so that the PP corresponding to the independent hard board area is prevented from falling off, and the positioning accuracy of the PP sheet being attached to the core board is improved; at the same time, the protective tape and the stamp hole are used in combination to quickly remove the PP waste on the connecting portion after the rigid-flexible board is formed, and the reliability is good.

Description

Technical Field

[0001] The invention relates to the technical field of printed circuit board manufacturing, and in particular to a method for opening a window on a rigid-flexible board. Background Art

[0002] Rigid-flex PCB, also known as hard-flex PCB, is composed of rigid PCB and flexible PCB selectively laminated together. It has a tight structure and uses metallized holes to form conductive connections. Rigid-flex PCB combines the regularity and toughness of conventional hard PCB with the flexibility and flexibility of soft PCB. It can be moved, bent, folded, twisted, and realize three-dimensional wiring, which greatly saves the installation space of electronic components.

[0003] Window opening and cover removal are the core processes for making rigid-flexible boards. At present, the mainstream window opening process in the industry is mechanical depth-controlled milling. Before pressing, a window is opened on the PP adjacent to the flexible board, and a reverse blind groove is made on the adjacent rigid board core board by mechanical depth control. Then, the rigid board core board, PP and flexible board core board are pressed together. After the drilling, circuit graphics, surface treatment, solder mask and other production are completed, the mechanical depth-controlled milling method is used to connect with the blind groove, and the rigid layer at the window position is removed (i.e., the window is opened) to expose the flexible layer to obtain a rigid-flexible board.

[0004] The hard board area of ​​some rigid-flex boards is discontinuous, so the PP sheet cannot be bonded as a whole. The isolated rigid board areas need to be bonded independently, which requires the PP sheet to be bonded to different rigid board areas multiple times, resulting in low production efficiency. At the same time, the positioning accuracy of the independently bonded PP sheets is poor, which affects product quality. Summary of the invention

[0005] In view of this, the purpose of the present invention is to provide a method for opening windows in a rigid-flexible board. When opening windows at positions corresponding to the soft board area on a PP sheet, a connecting portion is set between positions corresponding to adjacent hard board areas, and the PP corresponding to the independent hard board area is connected through the connecting portion to prevent the PP corresponding to the independent hard board area from falling off, thereby improving the positioning accuracy of the PP sheet attached to the core board; at the same time, the protective tape and the stamp hole are used to quickly remove the PP waste on the connecting portion after the rigid-flexible board is formed, and the reliability is good. .

[0006] In order to solve the above technical problems, the technical solution used in the present invention is:

[0007] A method for opening a window in a rigid-flexible board according to the present invention comprises the following steps:

[0008] S1. Open a window at the position corresponding to the soft board area on the PP sheet, and leave a connecting part between two adjacent hard board areas.

[0009] S2. Drill stamp holes on the connecting parts of the PP sheets.

[0010] S3. Apply protective tape to the PP sheet at the position corresponding to the soft board area and on the connecting part.

[0011] S4, rolling the PP sheet.

[0012] S5. Etch the circuit layer of the core board, and attach a cover film to the position of the core board corresponding to the flexible board area.

[0013] S6. Lay the PP sheet on the core board, and laminate the copper foil on the PP sheet; set the adhesive surface of the protective tape toward the PP sheet, and set the non-adhesive surface of the protective tape toward the core board.

[0014] S7. Remove the protective tape on the PP sheet by peeling off the cover.

[0015] Preferably, S4 specifically comprises: covering the upper and lower surfaces of the PP sheet with glass fiber cloth and then hot pressing with rollers.

[0016] Preferably, in S5, attaching the covering film to the position of the core board corresponding to the soft board area specifically comprises: firstly attaching the covering film to the position of the core board corresponding to the soft board area; and then bonding the covering film to the core board by rapid pressing.

[0017] Preferably, the protective tape extends to the outside of the PP sheet.

[0018] Preferably, the core board is a core board.

[0019] Preferably, the protective tape is a high temperature tape.

[0020] Preferably, the covering film is a high-temperature covering film.

[0021] Preferably, the PP sheet is a low-glue PP sheet.

[0022] Compared with the prior art, the beneficial effects of the method for opening a window of a rigid-flexible board described in the present invention are mainly reflected in: opening a window on the PP sheet, removing the PP in the position of the PP sheet corresponding to the soft board area, and preventing the PP from adhering to the core board; at the same time, through the reserved connection part, the connection part connects the PP in the independent hard board area to each other, and prevents the PP corresponding to the independent hard board area from falling off; and then when the PP is bonded to the chip, the whole PP sheet can be bonded to the core board, which is efficient; at the same time, the independent hard board areas are connected by the connection part, and the positioning accuracy of the PP sheet bonded to the core board is improved. By setting a covering film on the chip. The mechanical strength of the core board is improved, and the insulation performance of the core board is enhanced to prevent circuit oxidation and short circuit.

[0023] The protective tape is used in conjunction with the stamp hole to quickly remove the PP waste on the connection part after the rigid-flex board is formed; by removing the protective tape, the connection part of the PP sheet is separated from the rigid board area, thereby removing the PP waste on the connection part.

[0024] At the same time, the PP sheet is rolled to achieve a close fit between the protective tape and the PP sheet; at the same time, the upper and lower surfaces of the PP sheet are covered with glass fiber cloth, and the glass fiber cloth is pressed against the PP sheet. The glass fiber cloth enhances the tensile strength, bending strength and impact strength of the PP sheet, while improving the heat resistance and stability of the PP sheet.

[0025] The protective tape is easily removed by extending the protective tape to the outside of the PP sheet and by contacting the protective tape extending to the outside of the PP sheet to tear the protective tape.

[0026] When opening windows at positions corresponding to the soft board areas on the PP sheet, the present invention sets a connecting portion between corresponding positions of adjacent hard board areas, and connects the PP corresponding to the independent hard board area through the connecting portion, so as to avoid the PP corresponding to the independent hard board area from falling off, thereby improving the positioning accuracy of the PP sheet attached to the core board; at the same time, the protective tape and the stamp hole are used in combination to quickly remove the PP waste on the connecting portion after the rigid-flexible board is formed, so as to have good reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The above and other purposes, features and advantages of the present invention will become more clear by more specific description of the preferred embodiments of the present invention shown in the accompanying drawings. The same reference numerals indicate the same parts in all the accompanying drawings, and the accompanying drawings are not deliberately scaled to the actual size, and the focus is on illustrating the main purpose of the present invention.

[0028] Figure 1 It is a top view of the rigid-flex board before the cover is opened in the present invention.

[0029] Figure 2 for Figure 1 Sectional view of AA.

[0030] Figure 3 It is a top view of the rigid-flex board after the cover is removed in the present invention.

[0031] Figure 4 It is a top view of the PP sheet in the present invention.

[0032] Figure 5 It is a bottom view of the protective film of the present invention attached to the PP sheet.

[0033] Figure 6 It is a top view of the core board of the present invention attached with the covering film.

[0034] Figure 7 It is a top view of the PP sheet and the core board after being laminated in the present invention.

[0035] Description of the drawings: core board 1, covering film 11; PP sheet 2, connecting part 21, stamp hole 22; copper foil 3; protective tape 4, handle part 41; soft board area 5; hard board area 6. DETAILED DESCRIPTION

[0036] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments, so that those skilled in the art can better understand the present invention and implement it. However, the embodiments cited are not intended to limit the present invention. In the present embodiment, it should be understood that the orientations or positional relationships indicated by terms such as "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", and "outside" are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention.

[0037] It should be noted that when an element is considered to be "connected" to another element, it may be directly connected to the other element and integrated therewith, or there may be an intermediate element at the same time. The terms "installed", "one end", "the other end" and similar expressions used in the present invention are for illustrative purposes only.

[0038] This embodiment provides a rigid-flexible board, such as Figure 1-2 As shown; it includes a core board 1, a PP sheet 2 is provided on both sides of the core board 1, and a copper foil 3 is provided on both sides of the PP sheet 2. A covering film 11 is provided at a position corresponding to the soft board area 5 on the surface of the core board 1, and the covering film 11 is located between the core board 1 and the PP sheet 2; a window is opened at a position corresponding to the soft board area 5 on the PP sheet 2, and a connecting portion 21 is left between two adjacent hard board areas 6; a stamp hole 22 and a protective tape 4 are provided on the connecting portion 21, and the adhesive surface of the protective tape 4 is arranged toward the PP sheet 2, and the non-adhesive surface of the protective tape 4 is arranged toward the core board 1; the protective tape 4 is located between the covering film 11 and the connecting portion 21 of the PP sheet 2.

[0039] In this embodiment, handles 41 are provided at both ends of the protective tape 4 along the length direction of the protective tape 4, and the handles 41 are not in contact with the connecting portion 21 and a gap is provided therebetween; the handles 41 are used to tear off the protective tape 4; and the protective tape 4 is torn off to remove the PP waste on the connecting portion 21.

[0040] This embodiment provides a method for opening a window on a rigid-flexible board. Figure 1-7 As shown, the following steps are included:

[0041] S1. A window is opened at a position corresponding to the soft board area 5 on the PP sheet 2, and a connecting portion 21 is left between two adjacent hard board areas 6.

[0042] S2. Drill stamp holes 22 on the connecting portion 21 of the PP sheet 2.

[0043] S3 , attaching the protective tape 4 to the position of the PP sheet 2 corresponding to the soft board area 5 and the connecting portion 21 .

[0044] S4, rolling the PP sheet 2.

[0045] S5 , etching the circuit layer of the core board 1 , and attaching the cover film 11 to the position of the core board 1 corresponding to the flexible board area 5 .

[0046] S6. Lay the PP sheet 2 on the core board 1, and laminate the copper foil 3 on the PP sheet 2; set the adhesive surface of the protective tape 4 toward the PP sheet 2, and set the non-adhesive surface of the protective tape 4 toward the core board 1.

[0047] S7, remove the protective tape 4 on the PP sheet 2 by uncovering.

[0048] In a preferred embodiment, the PP sheet 2 is a low-flow PP sheet 2; the core board 1 is a core core board 1; the protective tape 4 is a high-temperature tape; the cover film 11 is a high-temperature cover film 11; specifically, the protective tape 4 is a PI tape, and the high-temperature cover film 11 is a PI cover film 11. In this embodiment, the etching of the circuit layer of the core board 1, electroplating and the production of the outer layer circuit are all existing technologies and are not described here.

[0049] Before performing S7, the outer layer drilling, copper deposition, full-board electroplating, outer layer circuit making, solder mask making and surface treatment (nickel and gold deposition) of the rigid-flexible combination board are also included; in this embodiment, the outer layer drilling, copper deposition, full-board electroplating, outer layer circuit making, solder mask making and surface treatment of the rigid-flexible combination board are all existing technologies and will not be reiterated here.

[0050] The present invention performs window opening on the PP sheet 2, removes the PP at the position of the PP sheet 2 corresponding to the soft board area 5, and prevents the PP from adhering to the core board 1; at the same time, a connection portion 21 is reserved, and the connection portion 21 connects the PP of the independent hard board area 6 to each other, so as to prevent the PP of the independent hard board area 6 from falling off; and then when the PP is bonded to the chip, the whole PP sheet 2 can be bonded to the core board 1, which is efficient; at the same time, the independent hard board areas 6 are connected by the connection portion 21, which ensures the integrity of the PP sheet 2 and improves the positioning accuracy of the PP sheet 2 bonded to the core board 1.

[0051] By rolling the PP sheet 2, the protective tape 4 is closely attached to the PP sheet 2; by setting a cover film 11 on the chip, the mechanical strength of the core board 1 is improved, and the insulation performance of the core board 1 is enhanced to prevent circuit oxidation and short circuit.

[0052] The protective tape 4 cooperates with the stamp hole 22 to remove the PP waste on the connecting part 21 after the rigid-flexible board is formed; by removing the protective tape 4, the connecting part 21 of the PP sheet 2 is separated from the hard board area 6, thereby removing the PP waste on the connecting part 21.

[0053] When opening windows at positions corresponding to the soft board areas 5 on the PP sheet 2, the present invention sets a connecting portion 21 between corresponding positions of adjacent hard board areas 6, and connects the PP corresponding to the independent hard board area 6 through the connecting portion 21, so as to avoid the PP corresponding to the independent hard board area 6 from falling off, thereby improving the positioning accuracy of the PP sheet 2 on the core board 1; at the same time, the protective tape 4 and the stamp hole 22 are used in combination to quickly remove the PP waste on the connecting portion 21 after the rigid-flexible composite board is formed, so as to have good reliability.

[0054] In the above method,

[0055] In S3, handles 41 are provided at both ends of the protective tape 4, and a gap is provided between the handles 41 and the connecting portion 21. In a preferred embodiment, the protective tape 4 extends to the outside of the PP sheet 2. By extending the protective tape 4 to the outside of the PP sheet 2, the protective tape 4 is torn by contacting the protective tape 4 extending to the outside of the PP sheet 2, so that the protective tape 4 is easily removed.

[0056] S4 specifically includes: covering the upper and lower surfaces of the PP sheet 2 with glass fiber cloth and then performing roller hot pressing; in this embodiment, the parameters of roller hot pressing are: temperature 160°C, pressure 0.4MPa, speed 0.6m / min. Covering the upper and lower surfaces of the PP sheet 2 with glass fiber cloth, pressing the glass fiber cloth and the PP sheet 2 together, the glass fiber cloth enhances the tensile strength, bending strength and impact strength of the PP sheet 2, and improves the heat resistance and stability of the PP sheet 2.

[0057] In S5, the covering film 11 is attached to the position of the core board 1 corresponding to the soft board area 5 by first attaching the covering film 11 to the position of the core board 1 corresponding to the soft board area 5; and then the covering film 11 is bonded to the core board 1 by rapid pressing. In this embodiment, the rapid pressing of the covering film 11 is a prior art and will not be described here.

[0058] In this specification, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0059] In the description of this specification, the description with reference to the terms "preferred embodiment", "further embodiment", "other embodiments" or "specific example" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are contradictory.

[0060] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A method for opening a window in a rigid-flexible board, characterized in that: The following steps are involved: S1. Open a window at the position corresponding to the soft board area on the PP sheet, and leave a connection between two adjacent hard board areas; S2. Drill stamp holes on the connecting parts of the PP sheets; S3. Apply protective tape to the position of the PP sheet corresponding to the soft board area and the connecting part; S4, rolling the PP sheet; S5, etching the circuit layer of the core board, and attaching a cover film to the position of the core board corresponding to the flexible board area; S6. Lay the PP sheet on the core board, and laminate the copper foil on the PP sheet; the adhesive surface of the protective tape is placed toward the PP sheet, and the non-adhesive surface of the protective tape is placed toward the core board; S7. Remove the protective tape on the PP sheet by peeling off the cover.

2. The method for opening a window in a rigid-flexible board according to claim 1, characterized in that: S4 specifically includes: covering the upper and lower surfaces of the PP sheet with glass fiber cloth and then hot pressing with rollers.

3. The method for opening a window in a rigid-flexible board according to claim 1, characterized in that: In S5, attaching the covering film to the position of the core board corresponding to the soft board area specifically includes: firstly attaching the covering film to the position of the core board corresponding to the soft board area; and then bonding the covering film to the core board by rapid pressing.

4. The method for opening a window in a rigid-flexible board according to claim 1, characterized in that: The protective tape extends outside the PP sheet.

5. The method for opening a window in a rigid-flexible board according to claim 1, characterized in that: The core board is a core board.

6. The method for opening a window in a rigid-flexible board according to claim 1, characterized in that: The protective tape is a high temperature tape.

7. The method for opening a window in a rigid-flexible board according to claim 1, characterized in that: The covering film is a high-temperature covering film.

8. The method for opening a window in a rigid-flexible board according to claim 1, characterized in that: The PP sheet is a low-glue PP sheet.

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