Flexible printed circuit board, electronic device including same, and method for manufacturing flexible printed circuit board

Abstract

To provide a flexible printed circuit board with improved product reliability by including a plating layer formed as a thin film in a bending area, an electronic device including the flexible printed circuit board, and a method of manufacturing the same.SOLUTION: A flexible printed circuit board 1 includes a base film 10 including a bending region 100, a first region 101, and a second region 102, and in which the bending region is located between the first region and the second region, a plurality of first wiring patterns 20 formed on one surface of the base film, a first plated layer covering the plurality of first wiring patterns, a first protective layer 30 formed on the bending region of the base film so as to cover the first plating layer, and a second plated layer formed to cover the first plated layer on which the first protective layer is not formed, and the first plating layer on the bending region is formed with a thickness of 0.05 to 0.25 μm.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a flexible printed circuit board, an electronic device including the same, and a flexible printed circuit board. This relates to a method for manufacturing a substrate. [Background technology]

[0002] Recently, with the miniaturization of electronic devices, chip-on-fill (CFP) technology using flexible printed circuit boards has become increasingly popular. Chip On Film (COF) packaging technology is used. The COF package technology using the printed circuit board is widely used in, for example, liquid crystal display devices (Li quid Crystal Display (LCD) and Organic Light Emitting Diode (OLED) (nic Light Emitting Diode) display devices and other flat It is used in flat panel displays (FPD).

[0003] Flexible printed circuit boards are flexible and will not break or bend when used in electronic devices. When a flexible printed circuit board is used, it is bent. The durability of the flexible printed circuit board may decrease in the damaged areas.

[0004] In particular, after forming a conductive wiring pattern, it is necessary to protect the wiring pattern or to improve the bonding strength with electronic components. To ensure this, a plating layer is formed, but the plating layer is not covered by wiring during or after plating. An alloy layer (IMC layer) formed when materials contained in the pattern and plating layer diffuse into each other This alloy layer is relatively harder than the wiring pattern, so flexibility is reduced. This can be a major cause of cracks when the flexible printed circuit board is bent.

[0005] On the other hand, in order to prevent cracks from occurring at the bent parts of the flexible printed circuit board, After the formation of the turns, it is preferable to form a protective layer to cover the turns, and then form a plating layer on the terminal portion. However, when plating the terminals, cavities may occur at the boundary between the protective layer and the plating layer due to a local battery phenomenon. In order to solve this problem, Korean Patent Publication No. 2000-62154 (hereinafter referred to as "Prior Art 1") discloses However, the prior art 1 is intended to prevent the local battery phenomenon, and is not flexible. Since the circuit failure at the bent part of the PCB is not taken into consideration, there is still a risk of circuit failure at the bent part. It contains inherent danger. Summary of the Invention [Problem to be solved by the invention]

[0006] The technical problem to be solved by the present invention is to provide a plating layer formed as a thin film in a bending region. A flexible printed circuit board having improved reliability of a product by including the same, and an electronic device including the same The present invention aims to provide a device.

[0007] Another technical problem that the present invention aims to solve is the plating formed as a thin film in the bending region. By incorporating layers, we provide a manufacturing method for flexible printed circuit boards that improves product reliability. That's what happens.

[0008] The technical problem of the present invention is not limited to the above-mentioned technical problem, and other technical problems not mentioned above may be solved. The subject matter will be clearly understood by those skilled in the art from the following description. [Means for solving the problem]

[0009] In order to achieve the above technical object, a flexible printed circuit board according to one embodiment of the present invention is provided. The plate is a base film including a bending region, a first region, and a second region, wherein the bending region a base film disposed between the first region and the second region; and a plurality of first wiring patterns formed on one surface of the substrate; and a second wiring pattern covering the plurality of first wiring patterns. a first plating layer formed on the bending region of the base film so as to cover the first plating layer; a first protective layer formed on the first plating layer and a second protective layer formed on the first plating layer; and a second plating layer formed on the bent area, the first plating layer being 0.05 to 0. It is formed to a thickness of 25 μm.

[0010] In some embodiments of the present invention, the first wiring pattern includes an element connection portion, The first protective layer may not be formed on the element connection portion.

[0011] In some embodiments of the present invention, the second plating layer is formed so as to cover the element connection portion. The slits may be formed as follows.

[0012] In some embodiments of the present invention, the surface opposite to the one surface of the base film is a plurality of second wiring patterns formed on the surface; and 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. a protective layer and a second protective layer formed to cover the third plating layer on which the second protective layer is not formed; The plated layer may further include a third plating layer.

[0013] In some embodiments of the present invention, the third plating layer has a thickness of 0.05 to 0.25 μm. It may be further formed.

[0014] In some embodiments of the present invention, the first wiring pattern is formed inside the base film. The semiconductor device may further include a via that electrically connects the line and the second wiring pattern.

[0015] In some embodiments of the present invention, the second plating layer is thicker than the first plating layer. It may be formed.

[0016] In order to achieve the above technical object, a flexible printed circuit board according to one embodiment of the present invention is provided. The method for manufacturing the plate includes providing a base film including a bending region, a first region, and a second region. the bending region is disposed between the first region and the second region, and the base film a plurality of first wiring patterns formed on one surface of the substrate, the plurality of first wiring patterns being covered with the first wiring patterns; A first plating layer is formed on the bending region of the base film so as to cover the first plating layer. A first protective layer is formed to cover the first plating layer on which the first protective layer is not formed. forming a second plating layer, wherein the first plating layer on the bent region has a thickness of 0.05 to 0 It is formed to a thickness of 0.25μm.

[0017] In some embodiments of the present invention, the surface opposite to the one surface of the base film is A plurality of second wiring patterns are formed on the surface, and a third wiring pattern is formed to cover the plurality of second wiring patterns. forming a plating layer on the bending region of the base film so as to cover the third plating layer; A second protective layer is formed to cover the third plating layer on which the second protective layer is not formed. The method may further include forming a fourth plating layer.

[0018] In some embodiments of the present invention, forming the second plating layer may include The thickness of the plating layer may be formed to be thicker than that of the plating layer.

[0019] In order to achieve the above technical object, an electronic device according to one embodiment of the present invention comprises a first circuit element, a second circuit element; and a connection surface connected to the first circuit element and connected to the first circuit element. A first region extending in parallel, connected to a second circuit element, and extending in parallel to a connection surface with the second circuit element. a second region extending from the first region to the second region, and connecting the first region and the second region, the second region being at an angle of 90 degrees to 180 degrees; a flexible printed circuit board including a bending region that can be bent by the bending of the flexible printed circuit board; The support substrate includes a base film, a plurality of layers formed on at least one surface of the base film, and a first plating layer formed to cover the plurality of wiring patterns; a first protective layer formed in the recessed region to cover the first plating layer; a second plating layer formed to cover the first plating layer where no plating layer is formed, The first plating layer in the bent region is formed to a thickness of 0.05 to 0.25 μm.

[0020] In some embodiments of the present invention, the bending region of the flexible printed circuit board is The bending radius may be 0.01 mm to 0.49 mm.

[0021] In some embodiments of the present invention, a first region of the flexible printed circuit board and The two regions may be opposed so that at least a portion of each region is in contact with the other. [Effects of the Invention]

[0022] According to the flexible printed circuit board and the manufacturing method thereof according to the embodiment of the present invention, The first plating layer is formed as a thin film on the wiring pattern in the bending area of ​​the flexible printed circuit board. By including the above, when the flexible printed circuit board is bent, the plating layer or This can prevent cracks from occurring in the wiring pattern.

[0023] 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 with sufficient thickness on the plating layer, This ensures a strong bond between the printed circuit board and the circuit element or electronic device.

[0024] The effects of the present invention are not limited to the effects described above, and other effects not described above are included in the claims. This will be clear to those skilled in the art from the description. [Brief explanation of the drawings]

[0025] [Figure 1] 1 is a top view illustrating a flexible printed circuit board according to an embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view taken along the line AA' in FIG. [Figure 3] FIG. 2 is a cross-sectional view taken along the line BB' in FIG. [Figure 4] 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. [Figure 5] FIG. 10 is a cross-sectional view of a flexible printed circuit board according to another embodiment of the present invention. [Figure 6] 1 is a cross-sectional view of an electronic device including a flexible printed circuit board according to an embodiment of the present invention. [Figure 7] 7 is an enlarged view showing a bending region of a flexible printed circuit board included in the electronic device of FIG. 6. FIG. [Figure 8] 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. [Figure 9] 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. [Figure 10] 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. DETAILED DESCRIPTION OF THE INVENTION

[0026] The advantages, features and methods of achieving the same of the present invention will be described in detail below with the accompanying drawings. However, the present invention will be elucidated with reference to the embodiments disclosed below. However, the present invention is not limited to this embodiment and may be realized in various different forms. The above statements are merely provided for the purpose of completeness of the disclosure and are not to be construed as limiting the scope of the invention. The present invention is provided so that those skilled in the art will fully understand the scope of the invention. The dimensions and relative sizes of the components shown are for illustrative purposes only. The figures may be exaggerated for clarity. Reference numbers refer to the same element, and "and / or" refers to each and every listed item. Includes all combinations of one or more.

[0027] Describing elements or layers as being "on" other elements or layers If it is directly above another element or layer, or if there is another layer between them, This includes all cases where an element is "directly on" the other. When a device is described as being "directly on" or "directly above," there must be another element or This indicates that no layers are interposed.

[0028] The spatially relative terms "below" and "beneath" are "ower," "above," "upper," etc. are used as shown The correlation between one element or component and another element or component can be easily described. Spatially relative terms can be used in addition to the directions shown. It should be understood that this term encompasses different orientations of an element during operation or performance. For example, if an element is shown upside down, it may 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. Other orientations are possible, in which case spatially relative terms should be interpreted accordingly.

[0029] The terms used in this specification are intended to describe the embodiments and are not intended to limit the present invention. In this specification, the singular forms "a," "an," and "the" also refer to the plural forms unless the context clearly dictates otherwise. Also, "comprise" and / or "comprising" are used interchangeably. This does not preclude the presence or addition of one or more other components in addition to the components listed.

[0030] Although terms such as "first," "second," etc. are used to describe various elements or components, However, these elements or components are not limited by these terms. These terms are used simply to distinguish one component from another. Therefore, the first element or component referred to below is within the technical concept of the present invention. It may also be the second element or component.

[0031] Unless otherwise defined, all terms used herein (including technical and scientific terms) (including the above) is commonly understood by a person having ordinary skill in the technical field to which the present invention pertains. In addition, terms defined in commonly used dictionaries may be used in a clear manner. Unless otherwise defined, they are not to be interpreted ideally or excessively.

[0032] 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.

[0033] 1 to 3, a flexible printed circuit board 1 according to an embodiment of the present invention is , a base film 10, first wiring patterns 20, 21, first protective layers 30, 31, a first metal The plating layer 40 and the second plating layer 50 may be included.

[0034] The base film 10 can be made of a flexible material and is attached to the flexible printed circuit board 1. It is included as a base material and allows the flexible printed circuit board 1 to bend and fold. .

[0035] The base film 10 includes a bending region 100, a first region 101, and a second region 102. The bending region 100 can be disposed between the first region 101 and the second region 102. When the flexible printed circuit board 1 is mounted in an electronic device, the bending region 100 On the other hand, the first area 101 and the second area 102 may be areas where the flexible This may be a region that cannot be bent when the flexible printed circuit board 1 is mounted in an electronic device.

[0036] The base film 10 may be, for example, a polyimide film. The base film 10 is made of PET (Polyethylene Terephthalate). ) film, polyethylene naphthalate film, polycarbonate film, etc. It may be a film or a metal foil such as aluminum oxide foil. In the flexible printed circuit board 1 according to the present invention, the base film 10 is a polyimide film. He explains that this is the case.

[0037] The base film 10 can have insulating properties. Wiring patterns on both sides of a flexible printed circuit board (2 in FIG. 4) according to another embodiment of the present invention. When the wiring patterns 20 and 120 are formed, the wiring patterns 20 and 120 are not electrically connected to each other. It can be insulated like this.

[0038] However, the present invention is not limited to this, and the base film 10 may be provided with a Vias (not shown) may also be included to electrically connect the line patterns 20, 120.

[0039] The base film 10 may include an element placement area 12. The element placement area 12 may include: This may be an area where circuit elements electrically connected to the flexible printed circuit board 1 are arranged. .

[0040] A plurality of first wiring patterns 20 can be formed on the base film 10. The pattern 20 may be, for example, a wiring pattern formed in a strip shape having a certain width. The first wiring pattern 20 can be formed continuously at predetermined intervals on one surface of the base film 10. do.

[0041] The first wiring pattern 20 can include a conductive material such as a metal. The wiring pattern 20 is a conductive wiring for transmitting an electric signal or a static electricity generated by touch. The first wiring pattern may be a transparent conductive wiring for transmitting capacitance. 20 may comprise a conductive material such as copper, although the invention is not limited thereto. Alternatively, the first wiring pattern 20 may include a material such as gold or aluminum.

[0042] As shown in FIGS. 2 and 3, a flexible print according to an embodiment of the present invention The first wiring pattern 20 of the substrate can be formed in one layer, but the present invention is not limited to this. The flexible printed circuit board 1 can include two or more multilayer printed wiring layers. do.

[0043] 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.

[0044] The element connection portion 15 is a terminal that is electrically connected to a circuit element arranged on the element arrangement region 12. That is, the element connection portion 15 may include a chip-on-film (COF) or or Film On Glass (FOG) method to mount circuit elements In this case, it may be a terminal formed on the first wiring pattern 20. For example, semiconductor chips (IC), sensors, light-emitting diodes (LED), etc. It may include, but the invention is not limited to,

[0045] A first plating layer 40 may be formed on the plurality of first wiring patterns 20. The first plating layer 40 may be formed by The first plating layer 40 may be formed to cover the top and side surfaces of the first wiring pattern 20. The thickness of the first plating layer 40 can be 0.05 to 0.25 μm. and Table 1.

[0046] FIG. 4 shows the results of a bending test of the flexible printed circuit board 1 according to one embodiment of the present invention. 4 is a graph, and Table 1 is a table showing the bending test results of FIG. 4 in numerical form.

[0047] [Table 1]

[0048] In the flexible printed circuit board according to one embodiment of the present invention, the thickness of the first plating layer 40 is After forming the flexible printed circuit board so that the thickness is 0.05 to 0.5 μm, the bending area A bending test was carried out by repeatedly bending the area 100. The number of times when the first crack occurred was recorded and is shown in Table 1 and FIG.

[0049] As can be seen from Table 1 and FIG. 4, the thickness of the first plating layer 40 is 0.05, 0.1, 0 When the thickness was 0.15, 0.2, and 0.25 μm, the first crack occurred at 381 and 35 μm, respectively. This was observed at 4, 302, 252, and 179 times. In other words, the thickness of the first plating layer 40 was 0. When the thickness is 0.5 μm, the resistance to cracks on the wiring pattern is the highest in the bending test. In addition, each 0.05 μm increase in the thickness of the first plating layer 40 increases the number of initial cracks by approximately 30 to 50. A decrease in the number of occurrences of

[0050] However, when the thickness of the first plating layer 40 is 0.3 μm, the number of cracks that first occurred is 4. The thickness of the first plating layer 40 begins to decrease sharply three times, from 0.35, 0.4, and 0. When the thickness was 45 and 0.5 μm, the first crack occurred after 17 times, 5 times, 1 time, and 1 time, respectively. was observed.

[0051] Therefore, the first plating layer 4 of the flexible printed circuit board 1 according to one embodiment of the present invention The thickness of the first plating layer 40 can be formed to 0.05 to 0.25 μm. When the thickness is larger than 1 μm, the flexible print is not uniform, as shown in the bending test results in Figure 4 and Table 1. In contrast, if the bending resistance of the substrate 1 is 0.05, the bending resistance of the substrate 1 may be reduced. Forming the first plating layer 40 to a thickness of less than 1 μm can be achieved by electrolytic plating or electroless plating. There is a risk that the first plating layer 40 formed by plating is not easy to plate.

[0052] Generally, the first plating layer 40 covers both the top and side surfaces of the plurality of first wiring patterns 20. When the base film 10 is formed as described above, the first plating formed on the bent region 100 of the base film 10 The layer 40 prevents the first wiring pattern 20 from being deformed into a desired shape. This is because, as shown in the bending test results above, the first plating layer is 0. This is particularly noticeable when the first wiring pattern in the bent region 100 is formed to a thickness of more than 25 μm. The tensile stress applied to the turn 20 may cause cracks on the wiring pattern or plating layer. It can increase the likelihood of occurrence.

[0053] However, in the flexible printed circuit board according to the embodiment of the present invention, the first plating layer 40 is 0 By forming it to a thickness of 0.05 to 0.25 μm, it can be bent at least 179 times in a bending test. That is, the thickness range is as described above. By forming the first plating layer 40 thin, deformation of the first wiring pattern 20 is limited. The flexible printed circuit board is attached to the electronic device in a bent state without bending the bending region 100. The operational reliability of the plate 1 can be improved.

[0054] The first plating layer 40 can prevent the plurality of first wiring patterns 20 from corroding. This can improve the bonding strength between the element connection portion 15 and the circuit element connected thereto. The first plating layer 40 is made of, for example, tin (Sn), nickel (Ni), gold (Au), palladium (Pd), or the like. It may contain metals such as platinum (Pd) and aluminum (Al).

[0055] The first protective layer 30 may be formed to cover a portion of the first plating layer 40. More specifically, A first protective layer is formed on the bent region 100 of the base film 10 so as to cover the first plating layer 40. The first protective layer 30 can be formed in the bending region 100. 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. It does not have to be formed on the element connection portion 15 of the pattern 20 .

[0056] The first protective layer 30 may include, but is not limited to, a resist ink. Instead, the first protective layer 30 may include a coverlay film.

[0057] The first protective layer 30 protects the first wiring pattern 20 from external impacts and corrosive substances. This can be done.

[0058] 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 side surfaces of the first plating layer 40 where the first protective layer 30 is not formed. A plating layer 50 can be formed. The second plating layer 50 contains the same material as the first plating layer 40. It is possible.

[0059] The second plating layer 50 can be formed thicker than the first plating layer 40. The layer 40 is a crack that may occur on the first wiring pattern 20 in the bent region 100. To prevent cracks, the first plating is formed to a thickness of 0.05 to 0.25 μm. The thin thickness of the layer 40 reduces 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, and The bonding strength between the terminal connection portion 15 and the circuit element or electronic device can be improved.

[0060] FIG. 5 is a cross-sectional view of a flexible printed circuit board according to another embodiment of the present invention.

[0061] Referring to FIG. 5, a flexible printed circuit board 2 according to another embodiment of the present invention includes a first The wiring pattern 20 is formed on the other surface of the base film 10, which is the opposite surface of the base film 10. The second wiring pattern 120, the second protective layer 130, the third plating layer 140 and the fourth plating layer It can contain 150.

[0062] The plurality of second wiring patterns 120 are formed on the base film on which the first wiring patterns 20 are formed. The plurality of second wiring patterns 120 may be formed on the opposite side of the first wiring pattern 10. It may be formed at a position corresponding to the pattern 20. However, the present invention is not limited to this. Instead, a plurality of second wiring patterns 120 are arranged in accordance with the circuit design. It is also possible to arrange the electrodes in a number of different shapes from those of the electrode 20.

[0063] The plurality of second wiring patterns 120 are arranged continuously at predetermined intervals on the other surface of the base film 10. Similarly to the first wiring pattern 20, the conductive material may include copper or the like.

[0064] The first wiring pattern 20 and the second wiring pattern 120 are electrically connected by the base film 10. If necessary, the first wiring pattern 20 and the second wiring pattern 21 can be formed in the base film 10. Vias (not shown) that electrically connect to the line pattern 120 may also be formed.

[0065] 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 140 can be formed to the same thickness as the first plating layer 40. It can be formed to a thickness of 0.05 to 0.25 μm.

[0066] When the third plating layer 140 is formed to a thickness of more than 0.25 μm, the thickness of the base film 10 The durability against cracks that occur in the wiring pattern when bending the bending region 100 is reduced. The risk is similar to that described above for the first plating layer 40.

[0067] The second protective layer is formed in the bending region 100 of the base film 10 so as to cover the third plating layer 140. The second protective layer 130 can be formed on the third plating layer 140 where the second protective layer 130 is not formed. A fourth plating layer 150 can be formed.

[0068] The fourth plating layer 150 is formed thicker than the third plating layer 140. Element connections that may occur due to the formation of a thickness of 0.05 to 0.25 μm This can prevent a decrease in the bonding strength between the portion 15 and the circuit element or electronic device.

[0069] 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. FIG.

[0070] Referring to FIG. 6, an electronic device 3 according to an embodiment of the present invention includes a flexible printed circuit board. The plate 5 may include a display panel 200 , a substrate 300 and a driving element 400 .

[0071] The display panel 200 and the substrate 300 are electrically connected by a flexible printed circuit board 5. The display panel 200 can display an image, and the substrate 300 can generate signals to drive the display panel 200. 0 may be a PCB substrate or another flexible printed circuit board.

[0072] The driving element 400 can be disposed on a flexible printed circuit board 5. More specifically, The driving element 400 can be arranged in the element arrangement area (12 in FIG. 1) of the flexible printed circuit board 5. The driving element 400 may be, for example, a DDIC (Display Digital Integrated Circuit) that drives a display panel. ay Driver IC).

[0073] Here, the display panel 200, the substrate 300, the driving element 400, etc. are flexible. 5. The present invention is not limited to these. That is, in the electronic device 3 of the present invention, the flexible printed circuit board 5 is not It is possible in any case if the cable is bent to form a It is understood that the above is obvious to a person having ordinary skill in the art. It will be possible to do this.

[0074] The flexible printed circuit board 5 includes a bending region 500, a first region 501, and a second region 502. It may contain 2.

[0075] The first area 501 is connected to the display panel 200. Although not shown, the first region 501 can extend parallel to the connection surface with the disk. It may include a terminal portion that is connected to the spray panel 200.

[0076] The second region 502 is connected to the substrate 300 and extends parallel to the surface connected to the substrate 300. Similarly, the second region 502 may include a terminal portion that is connected to the substrate 300. do.

[0077] As shown in the figure, the first area 501 and the second area 502 of the flexible printed circuit board 5 are However, the present invention is not limited to this. That is, at least a part of the first region 501 and the second region 502 do not contact each other. That is, the flexible printed circuit board 5 may be arranged such that the bending region 500 is the base. It can be attached to the electronic device 3 while folded as a directrix.

[0078] The bending region 500 connects the first region 501 and the second region 502 and is bent at an angle of 90 degrees to 180 degrees. The angle can be bent.

[0079] The bending region 500, the first region 501, and the second region 502 of the flexible printed circuit board 5 are 1, the bending region 100 included in the base film 10 of the flexible printed circuit board 1 of FIG. The first and second regions 101 and 102 can correspond to each other.

[0080] FIG. 7 is an enlarged view of the bending region of the flexible printed circuit board included in the electronic device of FIG. FIG.

[0081] Referring to FIG. 7, a bending region 500 of a 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.

[0082] The flexible printed circuit board 5 according to the embodiment of the present invention is attached to the electronic device 3 in a bent state. When mounted, the total thickness D1 of the flexible printed circuit board 5 is 0.1 mm to 1 mm. could be.

[0083] As an example of a flexible printed circuit board according to an embodiment of the present invention, The total thickness D1 of the substrate 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 is 0.029 mm. The radius of curvature r of the bent region 500 is merely an example and may be different in some embodiments of the present invention. The radius of curvature of the bent region in the flexible printed circuit board according to the embodiment is 0.01 mm to 0. It can be .49mm.

[0084] 8 to 10 illustrate a method for manufacturing a flexible printed circuit board according to an embodiment of the present invention. This is an intermediate stage diagram for clarity.

[0085] Referring to FIG. 8, a plurality of first wiring patterns 20 are formed on one surface of a base film 10. The formation of the plurality of first wiring patterns 20 can be carried out by, for example, sputtering a conductive material. After forming it on one surface of the base film 10 by coating or laminating, Alternatively, a conductive material may be printed on the base film 10. can.

[0086] In FIG. 8, a plurality of first wiring patterns 20 are formed only on one surface of the base film 10. However, the present invention is not limited to this. As in the flexible printed circuit board 2 according to the embodiment, the surface opposite to one surface of the base film 10 A second wiring pattern 120 can also be formed on the other surface.

[0087] Referring to FIG. 9, a first plating layer 40 is formed to cover the first wiring patterns 20. It can be achieved.

[0088] The first plating layer 40 may be made of, for example, tin, nickel, gold, palladium, and aluminum. A metal material such as aluminum is deposited on the first conductive pattern 20 by electroplating or electroless plating. The thickness can be formed to 0.05 to 0.25 μm.

[0089] Referring to FIG. 10, a first protective layer 40 is formed on the bent region 100 to cover the first plating layer 40. The first protective layer 30 can be formed by applying a resist ink. However, the present invention is not limited to this, and solder resist or coverlay film may be used. It may be formed by lamination.

[0090] Referring again to FIG. 3, the first plating layer 40 on which the first protective layer 30 is not formed is The second plating layer 40 is formed by plating the first plating layer 30 with tin and nickel. Metallic materials such as gold, palladium and aluminum are electroplated or The element connection portion 15 can be formed by electrolytic plating. In order to ensure sufficient bonding strength, the second plating layer 40 can be formed thicker than the first plating layer 30. do.

[0091] 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. The present invention is not limited to the above-mentioned form, and can be produced in various different forms. A person having ordinary skill in the art would be able to modify the technical idea or essential features of the present invention. It will be understood that the present invention may be embodied in other specific forms without departing from the spirit or scope of the present invention. It should be understood that the above-described embodiments are illustrative in all respects and are not limiting. It is.

Claims

1. 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 the upper surface and the 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.

2. 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.

3. The flexible printed circuit board according to claim 2 , wherein the second plating layer is formed to cover the element connection portion.

4. 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.

5. 5. The flexible printed circuit board according to claim 4, wherein the third plating layer is formed to a thickness of 0.05 to 0.25 μm.

6. The flexible printed circuit board according to claim 4 , further comprising a via formed inside the base film, the via electrically connecting the first wiring pattern and the second wiring pattern.

7. 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 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.

8. 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.

9. 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 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.

10. 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.

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