CN105578753B - Rigid-flex board and preparation method thereof - Google Patents

Abstract

A flexible-rigid combined board comprises a flexible substrate layer, a copper foil layer stacked on the flexible substrate layer, a covering film attached to the copper foil layer, a rigid layer stacked on the covering film and a circuit layer stacked on the rigid layer, wherein the circuit layer is provided with a window penetrating through the flexible substrate layer so as to divide the circuit layer into two parts which are arranged oppositely, the flexible substrate layer is partially exposed in the window, and the flexible substrate layer is connected between the two parts of the circuit layer. According to the rigid-flexible combined board and the preparation method thereof provided by the embodiment of the invention, the windowing penetrating through the circuit layer to the flexible base material layer is arranged, and the flexible base material layer is exposed to the two parts of the circuit layer, so that when the rigid-flexible combined board needs to be divided, the division can be realized only by cutting off the part of the flexible base material layer exposed to the windowing by using the punching die, the situation that the punching die is damaged possibly caused by cutting off multiple layers of hard materials is avoided, and the service life of the punching die is prolonged.

Description

Rigid-flex board and preparation method thereof

technical field

The invention relates to the technical field of circuit boards, in particular to a rigid-flex board and a preparation method thereof.

Background technique

Rigid-flex boards are more and more widely used because they have the properties of both soft boards and rigid boards.

At present, when making soft and hard boards, usually the soft board and the hard board are produced separately, and then the soft board and the hard board are pressed and connected. Due to this method, the connecting ribs between the soft and hard boards and the process side are connected by the direct extension of the hard board part. When the board is divided later, because the connecting ribs are covered with hard boards and soft boards, therefore, The sub-board mold needs to die-cut multi-layer hard boards and soft boards to form. Due to the high hardness of the hard board, during punching, the punching of the multi-layered soft board and hard board may damage the punching die, which in turn affects the use of the punching die.

Contents of the invention

In view of this, the present invention provides a rigid-flex board that prevents damage to the punching die and improves the service life of the punching die and a preparation method thereof.

In the first aspect, the present invention provides a rigid-flex board. The rigid-flex board includes a flexible base material layer, a copper foil layer stacked on the flexible base material layer, and a copper foil layer attached to the copper foil layer. A cover film, a hard layer laminated on the cover film, and a circuit layer laminated on the hard layer, the circuit layer is provided with a window penetrating to the flexible base material layer, so that the The circuit layer is divided into two opposite parts, the flexible substrate layer is partly exposed to the window, and the part of the flexible substrate layer exposed to the window is connected between the two parts of the circuit layer .

Wherein, the two parts of the circuit layer are respectively a first part and a second part, the first part is provided with a ground hole penetrating to the copper foil layer, and the second part is provided with a process edge.

Wherein, the inner wall of the ground hole is pasted with an electromagnetic shielding film.

Wherein, the copper foil layer has two layers, which are the first copper foil layer and the second copper foil layer arranged on the opposite sides of the flexible base material layer, and the covering film has two layers, which are the first covering film and the second copper foil layer respectively. film and a second cover film, the first cover film is attached to the first copper foil layer, and the second cover film is attached to the second copper foil layer.

In the second aspect, the present invention also provides a method for preparing the above-mentioned rigid-flex board, the method comprising the following steps:

Etching wiring on the flexible substrate layer to obtain a copper foil layer, the copper foil layer including wiring areas, reserved areas, and trimming areas arranged side by side;

attaching a cover film on the copper foil layer, so that the cover film completely covers the copper foil layer;

removing the covering film on the reserved area;

removing the reserved area to expose part of the flexible substrate layer;

A hard board is provided, and the hard board includes a main board, a connecting board and a sub-board arranged side by side;

Pressing the hard board onto the cover film, so that the main board and the sub-board are attached to the wiring area and the trimming area respectively;

The connecting plate is removed to expose the part of the flexible substrate layer.

Wherein, after the step "removing the connecting plate to expose the part of the flexible substrate layer", the following steps are further included:

Drilling holes on the main board and penetrating them to the copper foil layer to obtain ground holes;

Remove any residue inside the ground hole.

Wherein, the hole wall of the ground hole is pasted with an electromagnetic shielding film.

Wherein, after the step "removing the connecting plate to expose the part of the flexible substrate layer", the following steps are further included:

Cutting off the part of the flexible substrate layer by using a punching die to separate the sub-board from the main board.

Wherein, the sub-board is provided with a process edge.

Wherein, in the step of "removing the cover film on the reserved area", specifically include:

Die-cutting the covering film on the reserved area by using a die-cutting die to remove the covering film.

In the rigid-flex board and its preparation method provided by the embodiments of the present invention, a window is opened on the circuit layer through to the flexible substrate layer, and the part of the flexible substrate layer exposed to the window is used to connect the circuit The two parts of the layer, so that when it is necessary to separate the rigid-flex board, it is only necessary to use a die-cutting die to cut off the part of the flexible base layer exposed to the window, and then the board can be realized. Due to the softness of the flexible substrate layer, it is easy to cut, replacing the existing method of cutting directly on the circuit layer to the flexible substrate layer, and avoiding the cutting of multi-layer hard materials that may cause the die-cutting mold to appear In case of damage, the service life of the punching die is improved.

Description of drawings

In order to illustrate the technical solution of the present invention more clearly, the accompanying drawings used in the implementation will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some implementations of the present invention. As far as the skilled person is concerned, other drawings can also be obtained based on these drawings on the premise of not paying creative work.

Fig. 1 is a schematic cross-sectional view of a rigid-flex board provided by an embodiment of the present invention;

Fig. 2 is a flowchart of a method for preparing a rigid-flex board provided by an embodiment of the present invention.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

For the convenience of description, spatial relative terms such as "under", "below", "below", "over", "upper" and other spatial relative terms can be used to describe the One element or feature shown in relationship to another element or feature(s). It will be understood that when an element or layer is referred to as being "on," "connected to," or "coupled to" another element or layer, it can be directly on, directly on, or directly on the other element or layer. Connected or coupled to another element or layer, or intervening elements or layers may be present.

It should be understood that the terminology used herein is only used to describe specific embodiments, not to limit the present invention. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms unless the context clearly dictates otherwise. Further, when used in this specification, the term "comprises" and/or "comprises" indicates the existence of said features, integers, steps, elements and/or components, but does not exclude one or more other features, integers, The presence or addition of steps, elements, components and/or combinations thereof. The following descriptions in the specification are preferred implementation modes for implementing the present invention, but the descriptions are for the purpose of illustrating the general principles of the present invention, and are not intended to limit the scope of the present invention. The scope of protection of the present invention should be defined by the appended claims.

Please refer to FIG. 1 , a rigid-flex board 100 provided by the present invention includes a flexible substrate layer 10 , a copper foil layer 20 , a cover film 30 , a hard layer 40 and a circuit layer 50 . The copper foil layer 20 is stacked on the flexible substrate layer 10 , and the cover film 30 is attached on the copper foil layer 20 . The hard layer 40 is stacked on a side of the copper foil layer 20 away from the flexible substrate layer 10 . The circuit layer 50 is stacked on the hard layer 40, and the circuit layer 50 is provided with a window 51 penetrating to the flexible substrate layer 10, so as to divide the circuit layer 50 into two oppositely arranged part. A portion of the flexible substrate layer 10 is exposed to the opening 51 , and a portion of the flexible substrate layer 10 exposed to the opening 51 is connected between two parts of the circuit layer 50 . It can be understood that the rigid-flex board 100 can be applied to a mobile terminal, which can be a mobile phone, a tablet computer, a notebook computer, etc., and the rigid-flex board 100 is responsible for the connection between the electronic components in the mobile terminal. conductive.

In the rigid-flex board 100 provided by the embodiment of the present invention, a window 51 penetrating to the flexible substrate layer 10 is opened on the circuit layer 50, and the flexible substrate layer 10 is exposed to the window. 51 to connect the two parts of the circuit layer 50, so that when the rigid-flex board 100 needs to be divided, only the flexible substrate layer 10 needs to be exposed to the part of the window 51 by using a punching die. Cutting out can realize split board. Because the flexible base material layer 10 is flexible, it is easy to cut off, replacing the existing method of cutting directly on the circuit layer to the flexible base material layer, preventing the direct cutting of hard materials such as circuit layers and hard layers. The damage caused to the punching die improves the service life of the punching die.

In this embodiment, the flexible substrate layer 10 can be made of materials such as polyimide or polyethylene terephthalate PET, so as to arrange the copper on the flexible substrate layer 10. foil layer 20 , and the flexible substrate layer 10 can provide an insulating environment for the copper foil layer 20 , so as to etch signal traces and ground traces on the copper foil layer 20 . Preferably, the thickness of the flexible substrate layer 10 may be 20 μm.

In this embodiment, the copper foil layer 20 is a plate with copper foil on the film, and the ground traces and signal traces on the copper foil layer 20 are formed by etching the copper foil according to the predetermined wiring structure. . The ground traces and signal traces on the copper foil layer 20 can be integrated, the signal traces on the copper foil layer 20 realize electrical conduction between electrical components, the ground traces on the copper foil layer 20 grounding.

In this embodiment, the copper foil layer 20 has two layers, namely the first copper foil layer 21 and the second copper foil layer 22 arranged on opposite sides of the flexible base material layer 10, the first copper foil layer Layer 21 is provided with a via hole 211 penetrating to the second copper foil layer 22, and a conductive member (not shown) is provided in the via hole 221, and the conductive member is connected to the first copper foil layer. 21 and the second copper foil layer 22, so that the first copper foil layer 21 and the second copper foil layer 22 realize signal conduction.

In this embodiment, the covering film 30 can be formed by thermocompression using polyester material. The cover film 30 is pasted on the copper foil layer 20 by adhesive. Specifically, the cover film 30 is completely attached to the copper foil layer 20, and partially covers the signal traces and ground traces on the copper foil layer 20, so as to protect the signal traces on the copper foil layer 20. wires and grounding wires are not broken or damaged, and at the same time, the adhesive bonding method can also make the connection between the cover film 30 and the copper foil layer 20 tighter, and prevent the cover film layer 30 from shifting. However, the part of the wires exposed from the cover film 30 cannot be protected.

Further, the cover film 30 has two layers, namely a first cover film 31 and a second cover film 32, the first cover film 31 is attached to the first copper foil layer 21, and the second cover film The film 32 is attached to the second copper foil layer 22 . In order to realize the grounding of the first copper foil layer 21 and the second copper foil layer 22, a grounding window (not shown) is opened on the first cover film 31, and the grounding window can be etched by laser. Part of the first covering film 31 is etched away to expose part of the first copper foil layer 21 .

In this embodiment, the hard layer 40 is made of polyethylene, and the hard layer 40 has insulating properties, so that the circuit layer 50 and the copper foil layer 20 are isolated from each other, thereby facilitating the soft-hard combination. The circuit arrangement of the board 100 is diversified.

In this embodiment, the circuit layer 50 may also be formed by etching process of copper foil. Circuits may be provided on the circuit layer 50 , so as to increase the circuit layout of the rigid-flex board 100 .

In this embodiment, the opening 51 may be formed by punching or laser etching. In order to make the edge of the formed rigid-flex board 100 relatively flat, the window 51 may be a rectangular window. The opening 51 divides the circuit layer 50 into a first part 52 and a second part 53, the first part 52 is provided with a ground hole 521 penetrating to the copper foil layer 20, and the second part 53 is provided with There is craft edge 531 . Specifically, the ground hole 521 may be one or more, and the ground hole 521 may be a round hole or a square hole or the like. And in order to ensure its grounding performance, an electromagnetic shielding film (not shown) is pasted on the hole wall of the grounding hole 521 to shield electromagnetic signals and ensure the grounding between the circuit layer 50 and the copper foil layer 20. , preventing the direct connection between the circuit layer 50 and the copper foil layer 20 from causing a short circuit.

Please refer to Figure 2, the method for preparing the rigid-flex board provided by the embodiment of the present invention, the method includes the following steps:

S1: Etching traces on the flexible substrate layer to obtain a copper foil layer, the copper foil layer including trace areas, reserved areas and trimming areas arranged side by side.

The purpose of this step is to form the copper foil layer on the flexible base material layer, so as to facilitate wiring and connect electronic components, and provide a basis for the rigid-flex board to realize electrical conduction for electronic components. In this embodiment, the copper foil layer is divided into a wiring area, a reserved area, and a trimming area arranged side by side, so that the copper foil layer can be removed according to different areas when removing material, which is convenient production.

S2: Paste a cover film on the copper foil layer, so that the cover film completely covers the copper foil layer.

The purpose of this step is to protect the traces on the copper foil layer, and to prevent the traces on the copper foil layer from being damaged by using the covering protective effect of the cover film. Preferably, the cover film is pasted on the copper foil layer by pasting.

S3: removing the covering film on the reserved area.

The purpose of this step is to remove the covering film on the reserved area to expose the reserved area.

In this embodiment, the specific steps of this step are as follows:

Die-cutting the covering film on the reserved area by using a die-cutting die to remove the covering film. The way of punching with a punching die can prevent damage to other areas on the copper foil layer, such as the wiring area and the cover film on the trimming area, and the removal of the cover film on the reserved area The effect is better.

S4: removing the reserved area to expose part of the flexible substrate layer.

The purpose of this step is to remove the reserved area, so that part of the flexible substrate layer can be exposed, so as to facilitate subsequent board separation. In this embodiment, the reserved area can be removed by laser etching, because it has the advantages of high efficiency and relatively flat etching surface, thereby preventing damage to the flexible substrate layer.

S5: A hard board is provided, and the hard board includes a main board, a connecting board, and a sub board arranged side by side.

The purpose of this step is to attach the hard board to the above-mentioned flexible substrate layer, so as to form the rigid-flex board. In this embodiment, the sub-board is provided with a process edge, so as to assist the plug-in setting of the hard board when manufacturing the hard board.

S6: Pressing the hard board onto the cover film, so that the main board and the sub-board are attached to the wiring area and the trimming area respectively.

The purpose of this step is to press the hard board and the soft board so as to form the rigid-flex board. Specifically, the hard board and the soft board can be pressed together by means of pressing with a pressing machine, so as to ensure the tightness of the pressing between the two.

S7: removing the connecting plate to expose the part of the flexible substrate layer.

In this embodiment, the connecting plate can be removed by using a punching die, so as to expose the part of the flexible substrate layer. At this time, the flexible base material layer is between the main board and the sub-board, and since the flexible base material layer is a flexible material, its material is relatively soft, so it can facilitate subsequent cutting.

Further, after the step of "removing the connecting plate to expose the part of the flexible substrate layer", the following steps are also included:

S61: Using a punching die to cut off the part of the flexible base material layer, so as to separate the sub-board from the main board.

The purpose of this step is to remove the part of the flexible substrate layer connected between the main board and the sub-board, so as to separate the main board from the sub-board, so as to achieve the purpose of board separation. Because the material of the flexible substrate layer is relatively soft, it can be quickly finished when punching with a punching die, replacing the existing method of punching directly on a whole hard board. Prevent the punching die from being damaged during the punching process, and improve the service life of the punching die.

Further, in order to ensure the grounding performance of the rigid-flex board, after the step of "removing the connecting board to expose the part of the flexible substrate layer", the following steps are also included:

S62: Drilling holes on the main board and penetrating through to the copper foil layer to obtain ground holes.

The purpose of this step is to realize the grounding performance between the main board part of the hard board and the soft board to prevent short circuit. Preferably, the ground hole can be formed by laser drilling, and there can be one, two or more ground holes. In this embodiment, the ground hole may be a circular hole or a square hole or the like.

S63: removing residues in the ground hole.

The purpose of this step is to ensure the residue in the ground hole, so as to prevent the residue remaining in the ground hole from affecting the grounding between the hard board and the soft board.

Furthermore, in order to ensure the grounding between the hard board and the soft board, an electromagnetic shielding film is attached to the hole wall of the grounding hole to shield excess electromagnetic interference and further ensure the grounding effect of the grounding hole.

In the method for preparing a rigid-flex board provided in the embodiments of the present invention, when preparing a soft board, firstly remove the covering film and copper foil layer of the soft board to expose part of the flexible substrate layer; then press the hard board on the soft board. On the board, the material at the position corresponding to part of the flexible substrate layer on the hard board is also removed, so as to expose this part of the flexible substrate layer, so that this part of the flexible substrate layer is connected between the main board and the sub-board of the hard board. When it is necessary to divide the board later, it is only necessary to remove this part of the flexible substrate layer to realize the division of the soft and hard board, which replaces the existing direct punching on the hard board to the soft board to prevent the During the punching process, due to the hard material of the hard board, the punching die is damaged, which improves the service life of the punching die.

In the rigid-flex board and its preparation method provided by the embodiments of the present invention, a window is opened on the circuit layer through to the flexible substrate layer, and the part of the flexible substrate layer exposed to the window is used to connect the circuit The two parts of the layer, so that when it is necessary to separate the rigid-flex board, it is only necessary to use a die-cutting die to cut off the part of the flexible base layer exposed to the window, and then the board can be realized. Due to the softness of the flexible base material layer, it is easy to cut, replacing the existing method of cutting directly on the circuit layer to the flexible base material layer, avoiding the possibility of damage to the die-cutting mold due to the removal of multi-layer hard materials In this case, the service life of the punching die is improved.

In the description of this specification, references to the terms "one embodiment," "some embodiments," "example," "specific examples," "some examples," or the like "first embodiment" etc. A specific feature, structure, material, or characteristic described by an embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

The implementation methods described above do not constitute a limitation to the scope of protection of the technical solution. Any modifications, equivalent replacements and improvements made within the spirit and principles of the above implementation methods shall be included in the protection scope of the technical solution.

Claims (10)

1. A rigid-flex board, characterized in that the rigid-flex board comprises a flexible base material layer, a copper foil layer stacked on the flexible base material layer, and a covering layer attached to the copper foil layer film, a hard layer laminated on the cover film, and a circuit layer laminated on the hard layer, the circuit layer is provided with a window penetrating to the flexible substrate layer, and the opening The window is a rectangular window, the opening divides the circuit layer into two opposite parts, the part of the flexible substrate layer corresponding to the window is completely exposed to the window, and the flexible substrate layer is exposed The part where the window is opened is connected between the two parts of the circuit layer, so that when it is necessary to separate the rigid-flex board, it is only necessary to use a die-cutting die to expose the flexible substrate layer to the opening. Part of the window is cut out. 2. The rigid-flex board according to claim 1, wherein the two parts of the circuit layer are respectively a first part and a second part, and the first part is provided with a ground connection that penetrates to the copper foil layer. holes, and the second part is provided with a process edge. 3. The rigid-flex board according to claim 2, wherein an electromagnetic shielding film is attached to the inner wall of the ground hole. 4. The rigid-flex board according to claim 1, wherein the copper foil layer is two layers, which are respectively a first copper foil layer and a second copper foil layer arranged on opposite sides of the flexible substrate layer. Foil layer, the cover film is two layers, respectively a first cover film and a second cover film, the first cover film is attached to the first copper foil layer, and the second cover film is attached to the Describe the second copper foil layer. 5. A method for preparing the rigid-flex board according to claim 1, characterized in that it comprises the following steps: Etching wiring on the flexible substrate layer to obtain a copper foil layer, the copper foil layer including wiring areas, reserved areas, and trimming areas arranged side by side; attaching a cover film on the copper foil layer, so that the cover film completely covers the copper foil layer; remove all covering film on the reserved area; completely removing the reserved area to expose part of the flexible substrate layer; A hard board is provided, and the hard board includes a main board, a connecting board and a sub-board arranged side by side; Pressing the hard board onto the cover film, so that the main board and the sub-board are attached to the wiring area and the trimming area respectively; Removing the connecting plate to completely expose the part of the flexible base material layer corresponding to the reserved area, so that when it is necessary to divide the rigid-flex board, the flexible base material layer only needs to be cut using a punching die The portion exposed to the fenestration is resected. 6. The preparation method according to claim 5, characterized in that, after the step of "removing the connecting plate to completely expose the part of the flexible substrate layer corresponding to the reserved area", the following steps are further included: Drilling holes on the main board and penetrating them to the copper foil layer to obtain grounding holes; Remove any residue inside the ground hole. 7. The preparation method according to claim 6, wherein an electromagnetic shielding film is attached to the hole wall of the ground hole. 8. The preparation method according to claim 5, characterized in that, after the step of "removing the connecting plate to completely expose the part of the flexible substrate layer corresponding to the reserved area", the following steps are further included: Cutting off the part of the flexible substrate layer by using a punching die to separate the sub-board from the main board. 9. The preparation method according to claim 5, characterized in that, the sub-plate is provided with a process edge. 10. The preparation method according to claim 5, characterized in that, in the step "removing all covering films on the reserved area", specifically comprising: Die-cutting the covering film on the reserved area by using a die-cutting die to remove the covering film.