JP7747845B2 - Flexible printed circuit board, electronic device including same, and method for manufacturing flexible printed circuit board - Google Patents

Description

The present invention relates to a flexible printed circuit board, an electronic device including the same, and a method for manufacturing the flexible printed circuit board.

Recently, with the miniaturization of electronic devices, chip-on-film (COF) packaging technology using flexible printed circuit boards has been used. Flexible printed circuit boards and COF packaging technology using the same have been used in, for example, liquid crystal display devices (Li
OLEDs (Quad Crystal Displays, LCDs) and Organic Light Emitting Diodes (Organic Light Emitting Diodes)
The present invention is used in flat panel displays (FPDs) such as OLED displays (Micro-Light Emitting Diodes).

Flexible printed circuit boards are flexible and therefore prone to breaking or bending when used in electronic devices. However, when a flexible printed circuit board is used while being bent, the durability of the flexible printed circuit board may be reduced at the bent portions.

In particular, after forming a conductive wiring pattern, a plating layer is formed to protect the wiring pattern or to ensure bonding strength with electronic components. The plating layer contains an alloy layer (IMC layer) formed by mutual diffusion of materials contained in the wiring pattern and the plating layer during or after plating.
This alloy layer is relatively harder than the wiring pattern, and therefore reduces flexibility, which can be a major cause of cracks when the flexible printed circuit board is bent.

Meanwhile, in order to prevent cracks from occurring at bent portions of a flexible printed circuit board, it is preferable to form a protective layer covering the wiring pattern after the wiring pattern is formed, and then form a plating layer on the terminal portion. However, when plating the terminal portion, there is a risk of a problem in which a local battery phenomenon occurs at the boundary between the protective layer and the plating layer, resulting in the formation of a void. Korean Patent Publication No. 2000-62154 (hereinafter referred to as "Prior Art 1") is disclosed to solve this problem. However, Prior Art 1 is intended to prevent the local battery phenomenon, and does not take into consideration circuit defects at bent portions of the flexible printed circuit board, so there is still a risk of circuit defects at the bent portions.

The present invention provides a flexible printed circuit board (FPC) and an electronic device including the same, which have improved product reliability by including a plating layer formed as a thin film in a bending region.

Another technical problem to be solved by the present invention is to provide a method for manufacturing a flexible printed circuit board having improved product reliability by including a plating layer formed as a thin film in a bending region.

The technical problems of the present invention are not limited to the above-mentioned technical problems, and other technical problems not mentioned above will be clearly understood by those skilled in the art from the following description.

To achieve the above technical objectives, one embodiment of the present invention provides a flexible printed circuit board comprising a base film including a bending region, a first region, and a second region, wherein the bending region is disposed between the first region and the second region; a plurality of first wiring patterns formed on one surface of the base film; a first plating layer covering the plurality of first wiring patterns; a first protective layer formed on the bending region of the base film to cover the first plating layer; and a second plating layer formed to cover the first plating layer where the first protective layer is not formed, wherein the first plating layer on the bending region has a thickness of 0.05 to 0.
It is formed to a thickness of 25 μm.

In some embodiments of the present invention, the first wiring pattern may include an element connection portion, and the first protective layer may not be formed on the element connection portion.

In some embodiments of the present invention, the second plating layer may be formed to cover the element connection portion.

In some embodiments of the present invention, a plurality of second wiring patterns are formed on the other surface of the base film, which is the surface opposite to the one surface; a third plating layer covering the second wiring patterns; and a second plating layer formed on the bending region of the base film so as to cover the third plating layer.
The semiconductor device may further include a protective layer and a third plating layer formed to cover the third plating layer where the second protective layer is not formed.

In some embodiments of the present invention, the third plating layer may be formed to a thickness of 0.05 to 0.25 μm.

In some embodiments of the present invention, the base film may further include a via formed inside the base film, electrically connecting the first wiring pattern and the second wiring pattern.

In some embodiments of the present invention, the second plating layer may be formed to be thicker than the first plating layer.

A method for manufacturing a flexible printed circuit board according to an embodiment of the present invention for achieving the above technical object includes providing a base film including a bending region, a first region, and a second region, the bending region being disposed between the first region and the second region, forming a plurality of first wiring patterns on one surface of the base film, forming a first plating layer to cover the plurality of first wiring patterns, forming a first protective layer on the bending region of the base film to cover the first plating layer, and forming a second plating layer to cover the first plating layer on which the first protective layer is not formed, and the first plating layer on the bending region has a thickness of 0.05 to 0.05 mm.
It is formed to a thickness of 25 μm.

In some embodiments of the present invention, a plurality of second wiring patterns are formed on the other surface of the base film, which is the opposite surface of the one surface, and a third wiring pattern is formed to cover the plurality of second wiring patterns.
The method may further include forming a plating layer, forming a second protective layer on the bending region of the base film to cover the third plating layer, and forming a fourth plating layer to cover the third plating layer on which the second protective layer is not formed.

In some embodiments of the present invention, forming the second plating layer may include forming the second plating layer to a thickness greater than that of the first plating layer.

According to one embodiment of the present invention, there is provided an electronic device comprising: a first circuit element; a second circuit element; and a flexible printed circuit board including: a first region connected to the first circuit element and extending parallel to a connection surface with the first circuit element; a second region connected to the second circuit element and extending parallel to a connection surface with the second circuit element; and a bending region connecting the first region and the second region and allowing bending at an angle of 90 degrees to 180 degrees. The flexible printed circuit board includes a base film; a plurality of wiring patterns formed on at least one surface of the base film; a first plating layer formed to cover the plurality of wiring patterns; a first protective layer formed in the bending region to cover the first plating layer; and a second plating layer formed to cover portions of the first plating layer not formed with the first protective layer. The first plating layer in the bending region is formed to a thickness of 0.05 to 0.25 μm.

In some embodiments of the present invention, the bending region of the flexible printed circuit board may be bent to have a radius of curvature of 0.01 mm to 0.49 mm.

In some embodiments of the present invention, the first region and the second region of the flexible printed circuit board may face each other so as to be at least partially in contact with each other.

According to the flexible printed circuit board and the manufacturing method thereof according to the embodiment of the present invention, by including a first plating layer formed as a thin film on a wiring pattern in a bending region of the flexible printed circuit board, it is possible to prevent cracks from occurring in the plating layer or the wiring pattern due to tension when the flexible printed circuit board is bent.

In addition, a protective layer is formed on the first plating layer in the bent region, and the first plating layer on which the protective layer is not formed is
By forming a second plating layer having a sufficient thickness on the plating layer, it is possible to ensure the bonding strength between the flexible printed circuit board and the circuit element or electronic device.

The effects of the present invention are not limited to those described above, and other effects not described above will be clearly understood by those skilled in the art from the description of the claims.

1 is a top view illustrating a flexible printed circuit board according to an embodiment of the present invention. This is a cross-sectional view taken along A-A' in Figure 1. This is a cross-sectional view taken along B-B' in Figure 1. 1 is a graph showing the results of a bending test of a flexible printed circuit board according to an embodiment of the present invention. FIG. 10 is a cross-sectional view of a flexible printed circuit board according to another embodiment of the present invention. 1 is a cross-sectional view of an electronic device including a flexible printed circuit board according to an embodiment of the present invention. 7 is an enlarged view showing a bending region of a flexible printed circuit board included in the electronic device of FIG. 6. FIG. 1A to 1C are views illustrating intermediate stages of a method for manufacturing a flexible printed circuit board according to an embodiment of the present invention. 1A to 1C are views illustrating intermediate stages of a method for manufacturing a flexible printed circuit board according to an embodiment of the present invention. 1A to 1C are views illustrating intermediate stages of a method for manufacturing a flexible printed circuit board according to an embodiment of the present invention.

The advantages, features, and methods for achieving the same of the present invention will become more apparent from the following detailed description of the embodiments in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be embodied in various different forms. However, the present embodiments are provided solely to complete the disclosure of the present invention and to fully convey the scope of the invention to those skilled in the art. The present invention is defined solely by the scope of the claims. The size and relative sizes of elements in the drawings may be exaggerated for clarity. Throughout the specification, the same reference numerals refer to the same elements, and the term "and/or" includes each and every combination of one or more of the described items.

When an element or layer is described as being "on" another element or layer, it includes not only when it is directly on top of the other element or layer, but also when there is another layer or element between them.
"Directly on" or "directly on" means that there is no intervening element or layer therebetween.

The spatially relative terms "below" and "beneath" are
Terms such as "over,""above,""upper," and the like may be used to easily describe the relationship of one element or component to another, as illustrated. Spatially relative terms should be understood to include different orientations of elements in use or operation in addition to the orientation shown. For example, if an element is upside down as shown, it will not be "below" or "beneath" the other element.
An element described as "above" another element may be located "above" another element.
Thus, the exemplary term "below" can encompass both an orientation of below and above, and elements may also be oriented in other directions, in which case spatially relative terms should be interpreted accordingly.

The terms used in this specification are for the purpose of describing the embodiments and are not for the purpose of limiting the present invention. In this specification, the singular form includes the plural form unless the context clearly dictates otherwise. Furthermore, the words "comprise" and/or "comprising" do not exclude the presence or addition of one or more other elements in addition to the elements listed.

Although terms such as "first" and "second" are used to describe various elements or components, it should be understood that these elements or components are not limited by these terms. These terms are used merely to distinguish one component from another. Therefore, a first element or component referred to below may also be a second element or component within the technical concept of the present invention.

Unless otherwise defined, all terms (including technical and scientific terms) used herein may be used in the sense commonly understood by those skilled in the art to which the present invention pertains. Furthermore, terms defined in commonly used dictionaries are not to be interpreted ideally or excessively unless explicitly defined otherwise.

FIG. 1 is a top view illustrating a flexible printed circuit board according to an embodiment of the present invention;
2 and 3 are cross-sectional views taken along lines AA' and BB' in FIG. 1, respectively.

1 to 3, a flexible printed circuit board 1 according to an embodiment of the present invention may include a base film 10, first wiring patterns 20 and 21, first protective layers 30 and 31, a first plating layer 40, and a second plating layer 50.

The base film 10 can be made of a flexible material and is included in the flexible printed circuit board 1 as a base material, allowing the flexible printed circuit board 1 to bend or fold.

The base film 10 may include a bending region 100, a first region 101, and a second region 102. The bending region 100 may be disposed between the first region 101 and the second region 102.
When the flexible printed circuit board 1 is mounted to an electronic device, the bending region 100 may be a region that is mounted in a bent state, whereas the first region 101 and the second region 102 may be regions that are not bent when the flexible printed circuit board 1 is mounted to an electronic device.

The base film 10 may be, for example, a polyimide film. Alternatively, the base film 10 may be made of PET (Polyethylene Terephthalate).
The base film 10 may be an insulating film such as a PET film, a polyethylene naphthalate film, or a polycarbonate film, or a metal foil such as an aluminum oxide foil. In the flexible printed circuit board 1 according to one embodiment of the present invention, the base film 10 is described as a polyimide film.

The base film 10 may have insulating properties, that is, when wiring patterns 20 and 120 are formed on both sides of a flexible printed circuit board (2 in FIG. 4) according to another embodiment of the present invention, as will be described later, the base film 10 can insulate the wiring patterns 20 and 120 from being electrically connected to each other.

However, the present invention is not limited to this, and the base film 10 may include vias (not shown) therein that electrically connect the wiring patterns 20 and 120 .

The base film 10 may include an element placement area 12. The element placement area 12 includes:
This may be a region where circuit elements electrically connected to the flexible printed circuit board 1 are arranged.

A plurality of first wiring patterns 20 may be formed on the base film 10. The first wiring patterns 20 may be, for example, strip-shaped wiring patterns having a certain width. The plurality of first wiring patterns 20 may be continuously formed at predetermined intervals on one surface of the base film 10.

The first wiring pattern 20 may include a conductive material such as metal. Specifically, the first wiring pattern 20 may be a conductive wire for transmitting an electrical signal or a transparent conductive wire for transmitting capacitance due to touch. More specifically, the first wiring pattern 20 may include a conductive material such as copper, but the present invention is not limited thereto, and the first wiring pattern 20 may also include a material such as gold or aluminum.

2 and 3, the first wiring pattern 20 of the flexible printed circuit board according to an embodiment of the present invention may be formed in one layer, but the present invention is not limited thereto. The flexible printed circuit board 1 may include a multi-layer printed circuit having two or more layers.

The first wiring patterns 20 and 21 may include an element connection portion 15.
can overlap with the element placement region 12 of the base film 10 .

The element connection part 15 may include a terminal electrically connected to a circuit element disposed on the element placement area 12. That is, when the circuit element is mounted using a chip-on-film (COF) or film-on-glass (FOG) method, the element connection part 15 may be a terminal formed on the first wiring pattern 20. Such a circuit element may include, for example, a semiconductor chip IC, a sensor, a light-emitting diode (LED), etc., but the present invention is not limited thereto.

A first plating layer 40 may be formed on the plurality of first wiring patterns 20. The first plating layer 40 may be formed to cover the upper and side surfaces of the first wiring patterns 20. The first plating layer 40 may be formed of 0
The thickness of the first plating layer 40 will be described with reference to FIG.

FIG. 4 is a graph showing the results of a bending test of the flexible printed circuit board 1 according to one embodiment of the present invention, and Table 1 is a table showing the results of the bending test of FIG. 4 in numerical form.

In the flexible printed circuit board according to one embodiment of the present invention, the first plating layer 40 was formed to a thickness of 0.05 to 0.5 μm, and then a bending test was performed by repeatedly bending the bending region 100 of the flexible printed circuit board. The number of times that a crack first occurred in the wiring pattern 20 was recorded and is shown in Table 1 and FIG. 4, respectively.

As can be seen from Table 1 and FIG. 4, when the thickness of the first plating layer 40 is 0.05, 0.1, 0
When the thicknesses were 0.15, 0.2, and 0.25 μm, the first cracks occurred at 381 and 35 μm, respectively.
This was observed at 0.4, 302, 252 and 179 times.
When the thickness of the first plating layer 40 was 0.05 μm, the durability against cracking on the wiring pattern in the bending test was the highest, and the number of initial cracks decreased by about 30 to 50 times for every 0.05 μm increase in thickness of the first plating layer 40.

However, when the thickness of the first plating layer 40 is 0.3 μm, the number of cracks that occurred initially was 4.
The thickness of the first plating layer 40 begins to decrease sharply three times, decreasing from 0.35, 0.4, 0.
When the thickness was 45 and 0.5 μm, the first cracks were observed after 17 times, 5 times, 1 time, and 1 time, respectively.

Therefore, the first plating layer 4 of the flexible printed circuit board 1 according to the embodiment of the present invention
The thickness of the first plating layer 40 can be 0.05 to 0.25 μm.
If the thickness is larger than 0.05 μm, the durability of the flexible printed circuit board 1 against bending may be rapidly reduced, as shown in the bending test results shown in FIG.
Forming the first plating layer 40 to a thickness of less than .mu.m may make it difficult to form the first plating layer 40 by electroplating or electroless plating.

Generally, when the first plating layer 40 is formed to cover both the upper and side surfaces of the plurality of first wiring patterns 20, the first plating layer 40 formed on the bending region 100 of the base film 10 may hinder the first wiring patterns 20 from deforming into a desired shape. This is because, as in the bending test results, when the first plating layer is 0.
This is particularly noticeable when the thickness is greater than 25 μm, and the tensile stress applied to the first wiring pattern 20 in the bent region 100 can increase the possibility of cracks occurring on the wiring pattern or plating layer.

However, in the flexible printed circuit board according to the embodiment of the present invention, the first plating layer 40 is not formed.
By forming the first plating layer 40 to a thickness of 0.05 to 0.25 μm, it can withstand at least 179 bends in a bending test. In other words, by forming the first plating layer 40 thin so as to have the thickness within the above-mentioned range, it is possible to improve the operational reliability of the flexible printed circuit board 1 that is mounted on an electronic device in a bent state in the bending region 100 without restricting the deformation of the first wiring pattern 20.

The first plating layer 40 can prevent corrosion of the plurality of first wiring patterns 20 and can improve the bonding strength between the element connection portion 15 and the circuit element connected thereto.
The first plating layer 40 may include, for example, a metal such as tin (Sn), nickel (Ni), gold (Au), palladium (Pd), or aluminum (Al).

The first protective layer 30 may be formed to cover a portion of the first plating layer 40. More specifically, the first protective layer 30 may be formed on the bending region 100 of the base film 10 to cover the first plating layer 40. The first protective layer 30 may be formed in the bending region 100 so as to separate the bending region 100 and the first plating layer 40.
The first region 101 or the second region 102 may be formed up to the boundary therebetween.
The first protective layer 30 may be formed so as to extend partially inside the region 102. On the other hand, the first protective layer 30 does not have to be formed on the element connection portion 15 of the first wiring pattern 20.

The first protective layer 30 may include, for example, a resist ink, but is not limited to this, and the first protective layer 30 may also include a coverlay film.

The first protective layer 30 can protect the first wiring pattern 20 from external impacts and corrosive substances.

The second plating layer 50 may be formed to cover a portion of the first plating layer 40. Specifically,
The second protective layer 30 is formed on the first plating layer 40 so as to cover the upper surface and the side surface of the first plating layer 40 where the first protective layer 30 is not formed.
A plating layer 50 may be formed. The second plating layer 50 may include the same material as the first plating layer 40.

The second plating layer 50 can be formed thicker than the first plating layer 40. That is, the first plating layer 40 is formed to a thickness of 0.05 to 0.25 μm to prevent cracks that may occur on the first wiring pattern 20 in the bend region 100, and the thin thickness of the first plating layer 40 may reduce the bonding strength between the element connection portion 15 and the circuit element or electronic device. The second plating layer 50 is formed thicker than the first plating layer 40, thereby improving the bonding strength between the element connection portion 15 and the circuit element or electronic device.

Figure 5 is a cross-sectional view of a flexible printed circuit board according to another embodiment of the present invention.

Referring to FIG. 5, a flexible printed circuit board 2 according to another embodiment of the present invention includes a first
The base film 10 may include a second wiring pattern 120, a second protective layer 130, a third plating layer 140, and a fourth plating layer 150 formed on the other side opposite to the side on which the wiring pattern 20 is formed.

The plurality of second wiring patterns 120 may be formed on the opposite side of the base film 10 from the side on which the first wiring patterns 20 are formed. The plurality of second wiring patterns 120 may be formed at positions corresponding to the plurality of first wiring patterns 20. However, the present invention is not limited thereto, and the plurality of second wiring patterns 120 may be arranged in a shape different from the plurality of first wiring patterns 20 according to the circuit design.

The second wiring patterns 120 may be continuously formed at predetermined intervals on the other surface of the base film 10 and may contain a conductive material such as copper, similar to the first wiring patterns 20 .

The first wiring pattern 20 and the second wiring pattern 120 can be electrically insulated by the base film 10. If necessary, a via (not shown) electrically connecting the first wiring pattern 20 and the second wiring pattern 120 may be formed in the base film 10.

The third plating layer 140 may be formed to cover the second wiring pattern 120. The third plating layer 140 may cover the top and side surfaces of the second wiring pattern 120.
The third plating layer 40 may be formed to the same thickness as the first plating layer 40. That is, the third plating layer 140 may be formed to a thickness of 0.05 to 0.25 μm.

If the third plating layer 140 is formed thicker than 0.25 μm, there is a risk that the durability against cracks that occur in the wiring pattern when the bending region 100 of the base film 10 is bent may be reduced, as previously described for the first plating layer 40.

A second protective layer 130 may be formed in the bending region 100 of the base film 10 to cover the third plating layer 140, and a fourth plating layer 150 may be formed on the third plating layer 140 where the second protective layer 130 is not formed.

The fourth plating layer 150 is formed thicker than the third plating layer 140.
This can prevent a decrease in the bonding strength between the element connection portion 15 and the circuit element or electronic device, which may occur when the element connection portion 15 is formed to a thickness of 0.05 to 0.25 μm.

FIG. 6 is a cross-sectional view of an electronic device including a flexible printed circuit board according to some embodiments of the present invention.

Referring to FIG. 6 , an electronic device 3 according to an embodiment of the present invention may include a flexible printed circuit board 5 , a display panel 200 , a substrate 300 and a driving element 400 .

The display panel 200 and the substrate 300 can be electrically connected by a flexible printed circuit board 5. The display panel 200 can display an image, and the substrate 300
can generate signals for driving the display panel 200.
0 may be a PCB substrate or another flexible printed circuit board.

The driving element 400 can be disposed on a flexible printed circuit board 5. More specifically,
The driving element 400 can be arranged in an element arrangement region (12 in FIG. 1) of the flexible printed circuit board 5. The driving element 400 can be, for example, a DDIC (Display Integrated Circuit) that drives a display panel.
A driver IC may be used.

Here, the display panel 200, the substrate 300, the driving elements 400, etc. are exemplary circuit elements that can be connected to the flexible printed circuit board 5, but the present invention is not limited thereto. That is, it will be obvious to those skilled in the art that the electronic device 3 of the present invention can be used in any case where the flexible printed circuit board 5 is bent at a predetermined angle and connected to the circuit elements.

The flexible printed circuit board 5 includes a bending region 500, a first region 501, and a second region 502.
2.

The first region 501 is connected to the display panel 200.
Although not shown, the first region 501 may include a terminal portion connected to the display panel 200.

The second region 502 is connected to the substrate 300 and can extend parallel to the connection surface with the substrate 300. Similarly, the second region 502 can include a terminal portion connected to the substrate 300.

As shown in the figure, the flexible printed circuit board 5 can be attached to the electronic device 3 so that the first region 501 and the second region 502 are spaced apart and face each other, but the present invention is not limited to this. That is, the first region 501 and the second region 502 may face each other so that at least a portion of them contact each other. That is, the flexible printed circuit board 5 can be attached to the electronic device 3 while being folded using the bending region 500 as a reference line.

The bending region 500 connects the first region 501 and the second region 502 and can be bent at an angle between 90 degrees and 180 degrees.

The bending region 500, the first region 501, and the second region 502 of the flexible printed circuit board 5 are the bending region 100, the first region 501, and the second region 502 included in the base film 10 of the flexible printed circuit board 1 in FIG.
The first and second regions 101 and 102 may correspond to each other.

FIG. 7 is an enlarged view showing a bending region of the flexible printed circuit board included in the electronic device of FIG.

Referring to FIG. 7, the bending region 500 of the flexible printed circuit board has a predetermined radius of curvature r
The electronic device 3 can be attached to the electronic device 3 while holding the electronic device 3.

When the flexible printed circuit board 5 according to the embodiment of the present invention is mounted in the electronic device 3 in a bent state, the total thickness D1 of the flexible printed circuit board 5 may be 0.1 mm to 1 mm.

In one example of a flexible printed circuit board according to an embodiment of the present invention, the total thickness D1 of the flexible printed circuit board 5 may be 0.2 mm, and the cross-sectional thickness D2 may be 0.071 mm. In this case, the radius of curvature r of the bending region of the flexible printed circuit board 5 may be 0.029 mm. This radius of curvature r of the bending region 500 is merely an example, and the radius of curvature of the bending region in the flexible printed circuit board according to some embodiments of the present invention may be 0.01 mm to 0.029 mm.
. It can be 49mm.

8 to 10 are views illustrating intermediate stages of a method for manufacturing a flexible printed circuit board according to an embodiment of the present invention.

8, a plurality of first wiring patterns 20 are formed on one surface of a base film 10. The plurality of first wiring patterns 20 may be formed by, for example, forming a conductive material on one surface of the base film 10 by a sputtering method or a lamination method, followed by a patterning process, or by printing a conductive material on the base film 10.

8 shows that the plurality of first wiring patterns 20 are formed on only one surface of the base film 10, but the present invention is not limited to this. As in the flexible printed circuit board 2 according to the above-described other embodiment of the present invention, the second wiring patterns 120 may also be formed on the other surface of the base film 10, which is the surface opposite to the one surface.

Referring to FIG. 9, a first plating layer 40 may be formed to cover the plurality of first wiring patterns 20 .

The first plating layer 40 may be formed on the first conductive pattern 20 using electroplating or electroless plating of a metal material such as tin, nickel, gold, palladium, or aluminum to a thickness of 0.05 to 0.25 μm.

10, a first protective layer 30 may be formed to cover the first plating layer 40 on the bent region 100. The first protective layer 30 may be formed by applying a resist ink, but the present invention is not limited thereto, and the first protective layer 30 may be formed by laminating a solder resist or a coverlay film.

3, the second plating layer 40 is formed on the first plating layer 40 where the first protective layer 30 is not formed. Similar to the first plating layer 30, the second plating layer 40 may be formed by electrolytic plating or electroless plating of a metal material such as tin, nickel, gold, palladium, or aluminum. To ensure sufficient bonding strength with the circuit element at the element connection portion 15, the second plating layer 40 may be formed thicker than the first plating layer 30.

Although the embodiments of the present invention have been described above with reference to the accompanying drawings, the present invention is not limited to these embodiments and can be manufactured in various different forms, and a person skilled in the art to which the present invention pertains will understand that the present invention can be embodied in other specific forms without changing the technical concept or essential features of the present invention. Therefore, the above-described embodiments should be understood to be illustrative in all respects and not limiting.

Claims (10)

a base film including a bending region, a first region, and a second region, the bending region being disposed between the first region and the second region;
a plurality of first wiring patterns formed on one surface of the base film;
a first plating layer covering the plurality of first wiring patterns;
a first protective layer formed on the bending region of the base film to cover the first plating layer;
a second plating layer formed to cover the first plating layer where the first protective layer is not formed,
a flexible printed circuit board , wherein the first plating layer on the bending region covers both an upper surface and a side surface of the first wiring pattern and is formed to a thickness of 0.1 to 0.25 μm , the second plating layer is thicker than the first plating layer and is formed on the upper surface and a side surface of the first plating layer, and the radius of curvature of the bending region is set to a value between 0.01 mm and 0.49 mm based on a total thickness, which is the thickness of the flexible printed circuit board after the flexible printed circuit board is bent, and a cross-sectional thickness, which is the thickness of the flexible printed circuit board before the flexible printed circuit board is bent . the first wiring pattern includes an element connection portion,
The flexible printed circuit board according to claim 1 , wherein the first protective layer is not formed on the element connection portion. The flexible printed circuit board according to claim 2, wherein the second plating layer is formed to cover the element connection portion. a plurality of second wiring patterns formed on the other surface of the base film, the other surface being the opposite surface of the one surface;
a third plating layer covering the second wiring pattern;
a second protective layer formed on the bending region of the base film to cover the third plating layer;
The flexible printed circuit board according to claim 1 , further comprising a fourth plating layer formed to cover the third plating layer where the second protective layer is not formed. The flexible printed circuit board of claim 4, wherein the third plating layer is formed to a thickness of 0.05 to 0.25 μm. The flexible printed circuit board of claim 4, further comprising a via located inside the base film, electrically connecting the first wiring pattern and the second wiring pattern. providing a base film including a bending region, a first region, and a second region, the bending region being disposed between the first region and the second region;
forming a plurality of first wiring patterns on one surface of the base film;
forming a first plating layer to cover the plurality of first wiring patterns;
forming a first protective layer on the bending region of the base film to cover the first plating layer;
forming a second plating layer to cover the first plating layer where the first protective layer is not formed;
a method for manufacturing a flexible printed circuit board, wherein the first plating layer on the bending region covers both an upper surface and a side surface of the first wiring pattern and is formed to a thickness of 0.1 to 0.25 μm , the second plating layer is thicker than the first plating layer and is formed on the upper surface and the side surface of the first plating layer, and the radius of curvature of the bending region is set to a value between 0.01 mm and 0.49 mm based on a total thickness which is the thickness of the flexible printed circuit board after the flexible printed circuit board is bent and a cross-sectional thickness which is the thickness of the flexible printed circuit board before the flexible printed circuit board is bent . forming a plurality of second wiring patterns on the other surface of the base film, the other surface being the opposite surface of the one surface;
forming a third plating layer to cover the plurality of second wiring patterns;
forming a second protective layer on the bending region of the base film to cover the third plating layer;
The method for manufacturing a flexible printed circuit board according to claim 7 , further comprising forming a fourth plating layer to cover the third plating layer where the second protective layer is not formed. a first circuit element and a second circuit element; and
a flexible printed circuit board including: a first region connected to the first circuit element and extending parallel to a connection surface with the first circuit element; a second region connected to a second circuit element and extending parallel to a connection surface with the second circuit element; and a bending region connecting the first region and the second region and capable of being bent at an angle of 90 degrees to 180 degrees;
The flexible printed circuit board is
Base film,
a plurality of wiring patterns formed on at least one surface of the base film;
a first plating layer formed to cover the plurality of wiring patterns;
a first protective layer formed in the bending region to cover the first plating layer; and a second plating layer formed in the bending region to cover the first plating layer where the first protective layer is not formed,
an electronic device, wherein the first plating layer in the bending region covers both the upper surface and the side surface of the wiring pattern and is formed to a thickness of 0.1 to 0.25 μm , the second plating layer is thicker than the first plating layer and is formed on the upper surface and the side surface of the first plating layer, and the radius of curvature of the bending region is set to a value between 0.01 mm and 0.49 mm based on a total thickness which is the thickness of the flexible printed circuit board after the flexible printed circuit board is bent and a cross-sectional thickness which is the thickness of the flexible printed circuit board before the flexible printed circuit board is bent . The electronic device according to claim 9 , wherein at least a portion of the first region and the second region of the flexible printed circuit board face each other and contact each other.