CN116583022A

CN116583022A - Flexible circuit board manufacturing method and flexible circuit board

Info

Publication number: CN116583022A
Application number: CN202310505613.XA
Authority: CN
Inventors: 文丽梅; 李帜; 陈卓如; 邓承文
Original assignee: Zhuhai Jingwang Flexible Circuit Co ltd
Current assignee: Zhuhai Jingwang Flexible Circuit Co ltd
Priority date: 2023-05-06
Filing date: 2023-05-06
Publication date: 2023-08-11

Abstract

The application relates to the technical field of circuit board manufacturing, and discloses a manufacturing method of a flexible circuit board and the flexible circuit board, wherein the manufacturing method comprises the following steps: providing a substrate and a laser-proof film, wherein the substrate is provided with a first surface and a second surface, the first surface is provided with a circuit area and a non-circuit area, the laser-proof film is attached to the second surface, and the laser-proof film comprises a first film layer and a first adhesive layer; cutting the base material and the anti-laser film by using laser to obtain a cutting gap; removing the substrate corresponding to the non-circuit area; attaching a first covering film on the first surface, wherein the first covering film comprises a second film layer and a second adhesive layer, and the adhesive force between the second adhesive layer and the base material is larger than that between the first adhesive layer and the base material; the anti-laser film is peeled from the second face. The manufacturing method of the flexible circuit board can solve the problem of high production cost caused by frequent updating of the cutting die when the flexible circuit board is developed and manufactured by adopting a conventional cutting die cutting process.

Description

Flexible circuit board manufacturing method and flexible circuit board

Technical Field

The application relates to the technical field of circuit board manufacturing, in particular to a manufacturing method of a flexible circuit board and the flexible circuit board.

Background

In recent years, flexible circuit boards associated with new energy battery packs are increasingly applied, the flexible circuit boards are larger in size, and currently mainly used raw materials mainly comprise FCCL (Flexible Copper Clad Laminate )/pure copper foil, and the main forming mode is an etching process or a cutting die cutting process.

When the flexible circuit board is manufactured by adopting the conventional cutting die cutting process, the cost of the cutting die is high, and a plurality of sample stages exist in one flexible circuit board development project, so that the updating and changing probability of the wiring design of the circuit on the flexible circuit board is high, and the cost of the cutting die for opening the corresponding circuit is high.

Disclosure of Invention

The application provides a manufacturing method of a flexible circuit board and the flexible circuit board, which can solve the problem of higher production cost caused by frequent updating of a cutting die when the flexible circuit board is developed and manufactured by adopting a conventional cutting die cutting process.

In a first aspect, an embodiment of the present application provides a method for manufacturing a flexible circuit board, including:

providing a substrate and a laser-proof film, wherein the substrate is provided with a first surface and a second surface which are opposite, the first surface is provided with a circuit area and a non-circuit area which are connected, the laser-proof film is attached to the second surface, the laser-proof film comprises a first film layer and a first adhesive layer, and the first adhesive layer is arranged between the substrate and the first film layer;

cutting the base material and the anti-laser film along the edge of the circuit area by using laser from one side of the base material, which is away from the anti-laser film, to obtain a cutting gap, wherein the depth of the cutting gap is larger than the thickness of the base material, and the depth of the cutting gap is smaller than or equal to the sum of the thickness of the base material and the thickness of the first adhesive layer;

removing the substrate corresponding to the non-circuit area;

attaching a first covering film on the first surface, wherein the first covering film comprises a second film layer and a second adhesive layer, the second adhesive layer is arranged between the base material and the second film layer, and the bonding force between the second adhesive layer and the base material is larger than that between the first adhesive layer and the base material;

and peeling the anti-laser film from the second surface.

In some of these embodiments, after the laser-light-blocking film is peeled from the second side, the method further comprises:

attaching a second covering film on the second surface, wherein the second covering film comprises a third film layer and a third adhesive layer, and the third adhesive layer is arranged between the base material and the third film layer;

and pressing the base material, the first cover film and the second cover film.

In some embodiments, after the substrate, the first cover film, and the second cover film are subjected to the lamination process, the substrate, the first cover film, and the second cover film are subjected to the baking process.

In some of these embodiments, the substrate is aluminum foil.

In some of these embodiments, the cutting slit has opposing first and second sidewalls, a projection of the first sidewall on the first face coinciding with an edge of the routing region, and a projection of the second sidewall on the first face being located in the non-routing region.

In some embodiments, the laser includes a first laser and a second laser, and the cutting slit includes a first slit and a second slit, where the first slit and the second slit are disposed along an arrangement direction of the line region and the non-line region;

cutting the substrate and the anti-laser film along the edge of the line area by using laser from the side of the substrate facing away from the anti-laser film to obtain a cutting gap, comprising:

cutting the substrate and the anti-laser film along the edge of the circuit area by using the first laser from one side of the substrate, which is away from the anti-laser film, to obtain a first gap, wherein the side wall, which is close to the circuit area, of the first gap is a first side wall, and the projection of the side wall, which is opposite to the first side wall, of the first gap on the first surface is a first projection;

and cutting the substrate and the anti-laser film by using the second laser along the first projection from one side of the substrate, which is far away from the anti-laser film, so as to obtain a second gap, wherein the side wall of the second gap, which is far away from the circuit area, is a second side wall.

In some of these embodiments, the width of the cutting slit is greater than or equal to 20 μm.

In some of these embodiments, the depth of the cutting slit is equal to the sum of one half of the thickness of the first glue layer and the thickness of the substrate.

In some of these embodiments, attaching a first cover film to the first side includes:

pseudo-attaching the first cover film to the first surface;

and pressing the base material, the anti-laser film and the first covering film.

In a second aspect, an embodiment of the present application provides a flexible circuit board, where the flexible circuit board is processed by the method for manufacturing a flexible circuit board according to the first aspect.

The manufacturing method of the flexible circuit board provided by the embodiment of the application has the beneficial effects that: the laser is firstly used for cutting the base material and the anti-laser film along the edge of the circuit area from one side of the base material, which is far away from the anti-laser film, so as to obtain a cutting gap, the depth of the cutting gap is larger than the thickness of the base material, the depth of the cutting gap is smaller than or equal to the sum of the thickness of the base material and the thickness of the first adhesive layer, the base material corresponding to the non-circuit area is removed, the base material corresponding to the rest non-circuit area can directly form a circuit, and the first cover film is attached to the first surface, the first cover film comprises a second film layer and a second adhesive layer, the second adhesive layer is arranged between the base material and the second film layer, the adhesive force between the second adhesive layer and the base material is larger than the adhesive force between the first adhesive layer and the base material, so that the anti-laser film can be directly peeled from the second surface, a knife die cutting process is not needed in the whole process, and in a plurality of sample stages in the flexible circuit board development process, when the wiring design of the circuit on the flexible circuit board changes, only the anti-laser film is needed to be replaced, and the position of the cutting gap is adjusted, and the production cost is also lower.

Compared with the prior art, the flexible circuit board provided by the application has similar beneficial effects as compared with the prior art, and the manufacturing method of the flexible circuit board provided by the application is not repeated here.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the embodiments or the description of the prior art will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a flow chart of a method of fabricating a flexible circuit board in one embodiment of the application;

FIG. 2 is a schematic illustration of a substrate and a laser-light-protective film in one embodiment of the application;

FIG. 3 is a schematic illustration of a cut slit obtained in the substrate and anti-laser film shown in FIG. 2;

FIG. 4 is a schematic view of removing the substrate corresponding to the non-circuit area in FIG. 3;

FIG. 5 is a schematic illustration of attaching a first cover film to the first side of the substrate shown in FIG. 4;

FIG. 6 is a schematic view of the release of the laser-light-blocking film from the second side of the substrate shown in FIG. 5;

FIG. 7 is a schematic illustration of attaching a second cover film to the second side of the substrate shown in FIG. 6;

FIG. 8 is a schematic illustration of the lamination process of the substrate, first cover film and second cover film shown in FIG. 7;

FIG. 9 is an enlarged view of a portion of the portion A of FIG. 3;

fig. 10 is a schematic view of a cutting slit in another embodiment.

The meaning of the labels in the figures is:

10. a substrate; 11. a first face; 111. a line area; 112. a non-line area; 12. a second face;

20. a laser-proof film; 21. a first film layer; 22. a first adhesive layer;

30. cutting the gap; 301. a first sidewall; 302. a second sidewall; 31. a first slit; 32. a second slit;

40. a first cover film; 41. a second film layer; 42. a second adhesive layer;

50. a second cover film; 51. a third film layer; 52. and a third adhesive layer.

Detailed Description

The present application will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present application more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the application.

It will be understood that when an element is referred to as being "mounted" or "disposed" on another element, it can be directly on the other element or be indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or be indirectly connected to the other element.

Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present application, the meaning of "a plurality" is two or more, unless explicitly defined otherwise.

Reference in the specification to "one embodiment," "some embodiments," or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in one or more embodiments of the application. Thus, appearances of the phrases "in one embodiment," "in some embodiments," "in other embodiments," and the like in the specification are not necessarily all referring to the same embodiment, but mean "one or more but not all embodiments" unless expressly specified otherwise. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

In order to describe the technical scheme of the application, the following description is made with reference to specific drawings and embodiments.

Referring to fig. 1, 2 and 3, in a first aspect, an embodiment of the present application provides a method for manufacturing a flexible circuit board, including:

s100: a substrate 10 and a laser-proof film 20 are provided, the substrate 10 has a first surface 11 and a second surface 12 opposite to each other, the first surface 11 has a circuit area 111 and a non-circuit area 112, the laser-proof film 20 is attached to the second surface 12, the laser-proof film 20 includes a first film layer 21 and a first adhesive layer 22, and the first adhesive layer 22 is disposed between the substrate 10 and the first film layer 21.

Specifically, the substrate 10 is a conductive substrate 10, such as FCCL, pure copper foil or other conductive metal foil, and the substrate 10 corresponding to the circuit region 111 needs to be used as a circuit in the subsequent process, and the substrate 10 corresponding to the non-circuit region 112 needs to be removed.

It will be appreciated that the anti-laser film 20 may further include a release film layer (not shown) attached to the first adhesive layer 22 and facing away from the first film layer 21, wherein the release film layer is peeled off from the first adhesive layer 22 before the anti-laser film 20 is attached to the second surface 12, the first adhesive layer 22 may be made of a pressure sensitive adhesive such as an AD (Acrylonitrile Butadiene) or an acrylonitrile-butadiene adhesive, and the anti-laser film 20 is attached to the second surface 12 by using a film laminating machine, and the substrate 10 and the anti-laser film 20 may be cut for use after the attachment is completed.

It should be noted that, the first film layer 21 is a base film of a laser film, and the first film layer 21 can be prepared by nano grinding, dispersing, and multi-layer optical precision coating and compounding a plurality of special metal oxide materials, so that the specific wave band is absorbed and reflected while the high light transmission and high definition are maintained, the complete form is maintained, the very good carrier supporting effect is achieved, and the laser blocking effect can be achieved by more than 99.99%.

Alternatively, the thickness of the release film layer, the thickness of the first adhesive layer 22 and the thickness of the first film layer 21 are 25 μm, 10 μm and 100 μm, respectively. The thickness of the release film layer, the thickness of the first adhesive layer 22, and the thickness of the first film layer 21 may also take other values.

S200: the substrate 10 and the anti-laser film 20 are cut along the edge of the line area 111 from the side of the substrate 10 facing away from the anti-laser film 20 using a laser to obtain a cut slit 30, the depth of the cut slit 30 being greater than the thickness of the substrate 10, the depth of the cut slit 30 being less than or equal to the sum of the thickness of the substrate 10 and the thickness of the first glue layer 22.

Specifically, laser cutting data corresponding to the line region 111 and the non-line region 112 may be designed, and then the laser cutting data may be introduced into a laser apparatus, by which the substrate 10 and the laser shielding film 20 are cut along the edge of the line region 111 from the side of the substrate 10 facing away from the laser shielding film 20 using laser.

It will be appreciated that the laser does not cut the first film layer 21, so that the first film layer 21 can well bear and support the substrate 10, and the substrate 10 and the first adhesive layer 22 cut by the laser will be gasified.

In this embodiment, the depth of the cutting slit 30 is equal to the sum of half the thickness of the first adhesive layer 22 and the thickness of the substrate 10, so as to ensure that the laser can cut through the substrate 10.

It will also be appreciated that the substrate 10 corresponding to the non-circuit region 112 may be designed to enable the full portion of the web to be formed, facilitating subsequent removal of the waste.

Alternatively, the substrate 10 and the anti-laser film 20 may be cut along the edges of the line area 111 from the side of the substrate 10 facing away from the anti-laser film 20 using a UV laser.

S300: referring to fig. 4, the substrate 10 corresponding to the non-circuit region 112 is removed.

Specifically, the substrate 10 corresponding to the non-wiring region 112 may be removed manually or by machine.

It can be understood that after the substrate 10 corresponding to the non-circuit region 112 is removed, the substrate 10 corresponding to the remaining circuit region 111 directly forms a circuit.

It is further understood that, since the substrate 10 is adhered to the first film layer 21 by the first adhesive layer 22, the substrate 10 corresponding to the circuit region 111 will not be randomly moved when the substrate 10 corresponding to the non-circuit region 112 is removed.

S400: referring to fig. 5, a first cover film 40 is attached to the first surface 11, the first cover film 40 includes a second film layer 41 and a second adhesive layer 42, the second adhesive layer 42 is disposed between the substrate 10 and the second film layer 41, and the adhesion between the second adhesive layer 42 and the substrate 10 is greater than the adhesion between the first adhesive layer 22 and the substrate 10.

Specifically, the first cover film 40 may be attached to the first surface 11 manually or mechanically. The second glue layer 42 may also be AD glue.

Alternatively, in order to make the first cover film 40 closely adhere to the first surface 11, the first cover film 40 may be first pseudo-adhered to the first surface 11, and then the substrate 10, the laser light shielding film 20, and the first cover film 40 may be subjected to a lamination process, such as a vacuum cold press process (temperature 100 ℃, pressure 20kg/cm2, time 30 seconds).

S500: referring to fig. 6, the anti-laser film 20 is peeled from the second surface 12.

Specifically, the first cover film 40 may be attached to the first surface 11 manually or mechanically.

It will be appreciated that since the adhesion between the second adhesive layer 42 and the substrate 10 is greater than the adhesion between the first adhesive layer 22 and the substrate 10, the substrate 10 corresponding to the circuit region 111 will still adhere to the second adhesive layer 42.

According to the manufacturing method of the flexible circuit board provided by the embodiment of the application, the substrate 10 and the anti-laser film 20 are cut along the edge of the line area 111 from one side of the substrate 10, which is far away from the anti-laser film 20, to obtain the cutting gap 30, the depth of the cutting gap 30 is larger than the thickness of the substrate 10, the depth of the cutting gap 30 is smaller than or equal to the sum of the thickness of the substrate 10 and the thickness of the first adhesive layer 22, the substrate 10 corresponding to the non-line area 112 is removed, so that the substrate 10 corresponding to the non-line area 112 is left to directly form a line, and the first cover film 40 is attached to the first surface 11, the first cover film 40 comprises the second film layer 41 and the second adhesive layer 42, the adhesive force between the second adhesive layer 42 and the substrate 10 is larger than the adhesive force between the first adhesive layer 22 and the substrate 10, the anti-laser film 20 can be directly peeled from the second surface 12, the whole process does not need to use a knife die cutting process, and in a plurality of sample stages in the development process of the flexible circuit board, when the flexible circuit board is updated, the line layout is designed, the position of the anti-laser film 20 can be changed, and the cost of the anti-laser film is adjusted only is low.

Referring to fig. 6, 7 and 8, in some embodiments, after the anti-laser film 20 is peeled from the second surface 12, the method further includes:

first, a second cover film 50 is attached to the second surface 12, where the second cover film 50 includes a third film layer 51 and a third adhesive layer 52, and the third adhesive layer 52 is disposed between the substrate 10 and the third film layer 51.

Next, the base material 10, the first cover film 40, and the second cover film 50 are subjected to a lamination process.

By adopting the above-described configuration, the first cover film 40 and the second cover film 50 can be bonded to the first surface 11 and the second surface 12 of the base material 10, respectively.

Alternatively, the third glue layer 52 may be an AD glue. The second cover film 50 may be first attached to the second surface 12, and then the substrate 10, the first cover film 40, and the second cover film 50 may be subjected to a lamination process, such as a vacuum hot press process (temperature 100 ℃ C., pressure 20 kg/cm) ² Time 30 seconds).

It will be appreciated that the second glue layer 42 and the third glue layer 52 may be joined together after the lamination process is performed on the substrate 10, the first cover film 40 and the second cover film 50.

Alternatively, after the lamination process is performed on the base material 10, the first cover film 40, and the second cover film 50, the baking process is performed on the base material 10, the first cover film 40, and the second cover film 50. So arranged, the substrate 10, the first cover film 40, and the second cover film 50 can be tightly connected together.

The first cover film 40 and the second cover film 50 may be provided with open holes for exposing a portion of the substrate 10 corresponding to the portion of the circuit area 111, and the portion of the substrate 10 corresponding to the portion of the circuit area 111 may be directly subjected to the operation of the soldering device, so that more processes are omitted.

Optionally, after baking the substrate 10, the first cover film 40 and the second cover film 50, the substrate 10, the first cover film 40 and the second cover film 50 may be subjected to laser profile cutting to obtain a flexible circuit board finished product, and further, functional test, thermal shock delamination test, bonding force test, peeling test, and the like may be further performed.

Along with the more application of new energy battery package protection flexible circuit board in recent years, the flexible circuit board has larger size and higher requirements on heat conduction and electric conduction performance, the current pure copper foil used conventionally as a conductor of a circuit can not meet the use requirements, the circuit conductor with quick heat conduction and better electric conduction is required to be used for replacing the circuit conductor, and the current pure copper foil manufacturing circuit is manufactured by commonly selecting an etching process, so that the environment is also adversely affected.

Based on this, in some of these embodiments, the substrate 10 is aluminum foil. By the arrangement, the heat conductivity and the electric conductivity of the flexible circuit board can be improved, the environment can be protected, and the production cost is reduced.

It should be noted that, two materials of copper and aluminum are compared: aluminum has good heat and electrical conductivity, and when the aluminum has the same cross section and length as copper, the electrical conductivity of aluminum is about 61% of copper, and if aluminum and copper have the same weight and different cross sections (equal length), the electrical conductivity of aluminum is 200% of copper, and the price of aluminum is lower than copper. Thus, the conductivity of aluminum with the same quality is improved.

Referring to fig. 3 and 9, in some embodiments, the cutting slit 30 has a first side wall 301 and a second side wall 302 opposite to each other, where the projection of the first side wall 301 on the first face 11 coincides with the edge of the line area 111, and the projection of the second side wall 302 on the first face 11 is located in the non-line area 112.

Thus, the substrate 10 and the first adhesive layer 22 corresponding to the cutting slit 30 are removed conveniently, and the substrate 10 corresponding to the circuit region 111 is not damaged.

Alternatively, the width W of the cutting slit 30 is greater than or equal to 20 μm in order to better remove the substrate 10 corresponding to the non-wiring region 112. In this embodiment, the width W of the cutting slit 30 is equal to 20 μm.

It will be appreciated that the width W of the cutting slit 30 is the distance between the first side wall 301 and the second side wall 302.

Alternatively, the laser light includes a first laser light and a second laser light, the cutting slit 30 includes a first slit 31 and a second slit 32, and the first slit 31 and the second slit 32 are disposed along the arrangement direction of the line region 111 and the non-line region 112.

It is understood that the first slit 31 and the second slit 32 may or may not be in communication.

With continued reference to fig. 3 and 9, cutting the substrate 10 and the anti-laser film 20 along the edge of the line area 111 from the side of the substrate 10 facing away from the anti-laser film 20 using laser light to obtain a cut slit 30 includes:

s201: the substrate 10 and the anti-laser film 20 are cut along the edge of the line area 111 from the side of the substrate 10 facing away from the anti-laser film 20 using a first laser to obtain a first slit 31, the side wall of the first slit 31 close to the line area 111 being a first side wall 301, the projection of the side wall of the first slit 31 opposite to the first side wall 301 on the first face 11 being a first projection (not shown in the figure).

S202: the substrate 10 and the anti-laser film 20 are cut along a first projection from the side of the substrate 10 facing away from the anti-laser film 20 using a second laser to obtain a second slit 32, and the side wall of the second slit 32 facing away from the line area 111 is a second side wall 302.

It will be appreciated that step S201 and step S202 may be performed separately or simultaneously, and if step S201 and step S202 are performed simultaneously, the substrate 10 and the anti-laser film 20 are cut simultaneously by the side of the substrate 10 facing away from the anti-laser film 20 along the edge of the line region 111 using the first laser and the second laser.

In this embodiment, the first slit 31 and the second slit 32 are connected, the spot diameters of the first laser and the second laser are 10 μm, the first laser and the second laser are used to cut the substrate 10 and the anti-laser film 20 along the edge of the line region 111 from the side of the substrate 10 facing away from the anti-laser film 20, and the width W of the cut slit 30 is 20 μm.

Referring to fig. 10, in another embodiment, the first slit 31 and the second slit 32 are not connected, the spot diameters of the first laser and the second laser are 10 μm, the substrate 10 and the anti-laser film 20 are cut by the side of the substrate 10 facing away from the anti-laser film 20 along the edge of the line region 111 at the same time by using the first laser and the second laser, and the width W1 of the obtained cut slit 30 is 25 μm.

In a second aspect, an embodiment of the present application provides a flexible circuit board, which is manufactured by a manufacturing method of the flexible circuit board as in the first aspect.

According to the flexible circuit board provided by the embodiment of the application, when the flexible circuit board is processed, the substrate 10 and the anti-laser film 20 are cut along the edge of the line area 111 from one side of the substrate 10, which is far away from the anti-laser film 20, so as to obtain the cutting gap 30, the depth of the cutting gap 30 is larger than the thickness of the substrate 10, the depth of the cutting gap 30 is smaller than or equal to the sum of the thickness of the substrate 10 and the thickness of the first adhesive layer 22, the substrate 10 corresponding to the non-line area 112 is removed, so that the substrate 10 corresponding to the non-line area 112 is left to directly form a line, and the first cover film 40 is attached to the first surface 11, the first cover film 40 comprises the second film layer 41 and the second adhesive layer 42, the adhesive force between the second adhesive layer 42 and the substrate 10 is larger than the adhesive force between the first adhesive layer 22 and the substrate 10, the anti-laser film 20 can be directly peeled from the second surface 12, the whole process does not need to use a knife die cutting process, and in a plurality of sample stages in the flexible circuit board development process, when the flexible circuit board is updated, the line layout is designed, the position of the anti-laser film 20 can be changed, and the cost of the anti-laser circuit board can be adjusted only is low.

The above embodiments are only for illustrating the technical solution of the present application, and are not limiting; although the application has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present application, and are intended to be included in the scope of the present application.

Claims

1. The manufacturing method of the flexible circuit board is characterized by comprising the following steps:

removing the substrate corresponding to the non-circuit area;

and peeling the anti-laser film from the second surface.

2. The method of manufacturing a flexible wiring board according to claim 1, wherein after the laser light shielding film is peeled from the second surface, the method further comprises:

and pressing the base material, the first cover film and the second cover film.

3. The method for manufacturing a flexible printed circuit board according to claim 2, wherein,

and after the base material, the first cover film and the second cover film are subjected to lamination treatment, baking treatment is performed on the base material, the first cover film and the second cover film.

4. The method of claim 1, wherein the substrate is aluminum foil.

5. The method of claim 1, wherein the cutting slit has a first side wall and a second side wall opposite to each other, a projection of the first side wall on the first surface coincides with an edge of the circuit area, and a projection of the second side wall on the first surface is located in the non-circuit area.

6. The method for manufacturing a flexible circuit board according to claim 5, wherein the laser includes a first laser and a second laser, the cutting slit includes a first slit and a second slit, and the first slit and the second slit are arranged along an arrangement direction of the circuit region and the non-circuit region;

7. The method of manufacturing a flexible wiring board according to claim 5, wherein the width of the cutting slit is 20 μm or more.

8. The method of claim 1, wherein the depth of the cutting slit is equal to a sum of one half of the thickness of the first adhesive layer and the thickness of the base material.

9. The method of manufacturing a flexible wiring board according to any one of claims 1 to 8, wherein attaching a first cover film to the first surface includes:

pseudo-attaching the first cover film to the first surface;

10. A flexible wiring board, characterized in that the flexible wiring board is processed by the manufacturing method of the flexible wiring board according to any one of claims 1 to 9.