JP2021040167A - Flexible circuit board and manufacturing method therefor - Google Patents

Abstract

To provide a flexible circuit board and a manufacturing method therefor.SOLUTION: A flexible circuit board 1 comprises: a base film 10; a plurality of first conductive patterns 20 formed on one surface of the base film 10; a first protection layer 30 formed to cover the plurality of first conductive patterns 20; and a first heat dissipation layer 40 covering the first protection layer 30, where the first heat dissipation layer includes a base material and a heat dissipation material contained in the base material.SELECTED DRAWING: Figure 1

Description

The present invention relates to a flexible circuit board and a method for manufacturing the same.

Recently, with the trend toward miniaturization of electronic devices, chip-on-film (COF) packaging technology using a flexible circuit board has been used. Flexible circuit boards and COF packaging technologies using them include, for example, flat panel display devices (Flat Panel Display; LCD) such as liquid crystal display devices (LCD) and organic light emitting display devices (LCD). Used for FPD).

The conductive pattern formed on the flexible circuit board connects the circuit elements and transmits an electric signal transmitted at high speed. On the other hand, due to the miniaturization of electronic devices on which flexible circuit boards are mounted, the flexible circuit boards and the conductive patterns formed on them are being highly integrated, and the heat generated on the conductive patterns due to the integration and refinement is being promoted. The problem of malfunction of circuit elements is emerging.

In order to effectively dissipate the heat generated from the conductive pattern, increase the thickness of the conductive pattern or attach a metal tape made of aluminum or copper to the back surface of the base film on which the conductive pattern is formed to improve heat dissipation characteristics. A method of increasing was introduced. However, such a method may cause problems such as an increase in production cost because it is difficult to realize miniaturization of a flexible circuit board or an additional process is required.

A technical problem to be solved by the present invention is to provide a flexible circuit board having a heat radiating layer containing a heat radiating material on a protective layer covering a conductive pattern and having good heat radiating characteristics.

Another technical problem to be solved by the present invention is to provide a method for manufacturing a flexible circuit board in which a heat radiating layer containing a heat radiating material is formed on a protective layer covering a conductive pattern.

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

The technical issues of the present invention are not limited to the technical issues mentioned above, and other technical issues not mentioned and other technical issues will be clearly understood by ordinary engineers from the following description.

The flexible circuit board according to the embodiment of the present invention for achieving the technical problem covers the base film, a plurality of first conductive patterns formed on one surface of the base film, and the plurality of first conductive patterns. A heat-dissipating layer that covers the first protective layer and the first protective layer formed as described above, and the heat-dissipating layer includes a base material and a first heat-dissipating layer including a heat-dissipating material contained in the base material.

In some embodiments of the present invention, the height of the top surface of the first protective layer from the base film may be the same as or higher than the height of the top surface of the plurality of conductive patterns from the base film.

In some embodiments of the present invention, the top surface of the first heat dissipation layer can be substantially flat.

In some embodiments of the present invention, the thickness ratio of the first protective layer to the first heat dissipation layer can be 2: 8 to 8: 2.

In some embodiments of the present invention, the thickness of the first protective layer is 1 μm to 30 μm, the thickness of the first heat radiation layer is 1 μm to 30 μm, and the thickness of the first protective layer and the first protective layer is 1. The total thickness of the heat dissipation layers can be 2 μm to 60 μm.

In some embodiments of the present invention, the base material may include the same material as the material constituting the first protective layer.

In some embodiments of the present invention, a plurality of second conductive patterns formed on the other surface of the base film facing the one surface, and a second protective layer formed so as to cover the plurality of second conductive patterns. And a second heat radiating layer that covers the second protective layer and contains a heat radiating material inside may be further included.

In some embodiments of the present invention, the first protective layer is formed according to the profiles of the plurality of first conductive patterns, and the upper surface of the first protective layer is the first surface on the first conductive pattern. The second surface between the first surfaces may be provided, and the height of the first surface from the base film may be higher than the height of the second surface from the base film.

In some embodiments of the invention, the first heat dissipation layer can be formed according to the profile of the top surface of the first protective layer.

In some embodiments of the present invention, a plating layer interposed between the first conductive pattern and the first protective layer may be further included.

A method for manufacturing a flexible circuit board according to an embodiment of the present invention for achieving the above technical problems provides a base film in which a plurality of conductive patterns are formed on at least one surface so as to cover the plurality of conductive patterns. This includes forming a protective layer and forming a heat radiating layer containing a heat radiating material mixed inside on the protective layer.

In some embodiments of the present invention, forming the heat dissipation layer may include forming the height of the heat dissipation layer from the base film higher than the top surface of the conductive pattern.

According to the flexible circuit board according to the embodiment of the present invention, a heat radiating layer containing a heat radiating material is formed on the base film so that the heat generated from the conductive pattern can be effectively dissipated.

Further, the protective layer interposed between the heat radiating layer and the conductive pattern is formed so as to completely cover the conductive pattern, so that it is possible to prevent a decrease in electrical reliability due to the heat radiating material contained in the heat radiating layer. ..

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

It is sectional drawing of the flexible circuit board by one Embodiment of this invention. It is an enlarged view which enlarged a part of FIG. It is sectional drawing of the flexible circuit board by another embodiment of this invention. It is sectional drawing of the flexible circuit board by another embodiment of this invention. It is a flowchart for demonstrating the manufacturing method of the flexible circuit board by one Embodiment of this invention.

The advantages and features of the present invention, as well as the methods for achieving them, will become clear with reference to the embodiments described in detail below with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, and is realized in various forms different from each other, and the present embodiment merely completes the disclosure of the present invention and is usually used in the technical field to which the present invention belongs. It is provided to fully inform a person who has the knowledge of the invention of the scope of the invention, and the present invention is defined only by the scope of the claims. The size and relative size of the components shown in the drawings may be exaggerated for clarity of description. The same reference code throughout the specification refers to the same component, where "and / or" includes each of the items mentioned and all combinations of one or more.

When an element or layer is referred to as "on" of another element or layer, it is not only directly above the other element or layer, but also with another layer or other element in the middle. Including. On the other hand, when an element is pointed out as "directly on" or "directly above", it means that no other element or layer is interposed in the middle.

Spatically relative terms such as "lower", "beneath", "lower", "above", and "upper" are shown in the drawings. As such, it can be used to easily describe the correlation between one element or component and another element or component. Spatial relative terms should be understood as terms that include, in addition to the directions shown in the drawings, different directions of the elements during use or operation. For example, when the element shown in the drawing is turned upside down, the element described as "below" or "beneath" of the other element is located "above" of the other element. Can be done. Therefore, the exemplary term "down" can include both down and up directions. The device can also be oriented in other directions so that spatially relative terms can be interpreted by orientation.

The terms used herein are for purposes of describing embodiments and are not intended to limit the invention. In the present specification, the singular form also includes the plural form unless otherwise specified. As used herein, "comprises" and / or "comprising" does not preclude the presence or addition of one or more components in addition to those mentioned.

The first, second, etc. are used to describe various elements and components. However, it goes without saying that these components are not limited by these terms. These terms are used solely to distinguish one component from the other. Therefore, it goes without saying that the first element or component referred to below can be the second element or component within the technical idea of the present invention.

Unless otherwise defined, all terms used herein (including technical and scientific terms) may be used in a sense that can be commonly understood by those with ordinary knowledge in the technical field to which the present invention belongs. .. Also, terms defined in commonly used dictionaries are not ideally or over-interpreted unless explicitly defined.

FIG. 1 is a cross-sectional view of a flexible circuit board according to an embodiment of the present invention, and FIG. 2 is an enlarged view of a part of FIG.

Referring to FIGS. 1 and 2, a flexible circuit board according to an embodiment of the present invention may include a base film 10, a first conductive pattern 20, a first protective layer 30, and a first heat dissipation layer 40.

The base film 10 can be made of a flexible material and can be included in the flexible circuit board 1 as a substrate so that the flexible circuit board 1 can be bent or folded. The base film 10 can be, for example, a polyimide film. In contrast, the base film 10 can be a PET film, a polyethylene naphthalate film, a polycarbonate film or an insulating metal leaf. In the flexible circuit board 1 according to the embodiment of the present invention, the case where the base film 10 is a polyimide film will be described.

The first conductive pattern 20 can be formed on the base film 10. The first conductive pattern 20 may be, for example, one in which at least one or more strip-shaped conductors having a constant width are formed. The first conductive pattern 20 can transmit an electrical signal between a circuit element mounted on the base film 10 and an electronic device to which the flexible circuit board 1 is connected.

The first conductive pattern 20 may include, for example, a conductive substance such as copper, but the present invention is not limited thereto. Specifically, the first conductive pattern 20 is made of a substance having electrical conductivity such as gold and aluminum.

The first protective layer 30 may be formed so as to cover the first conductive pattern 20. The first protective layer 30 may contain an insulating material, which may be, for example, a solder resist. Alternatively, the first protective layer 30 may include a coverlay film.

The first protective layer 30 completely covers the first conductive pattern 20. That is, the level of the upper surface 35 of the first protective layer 30 may be the same as or higher than the level of the uppermost surface 25 of the first conductive pattern 20. Therefore, the height of the upper surface 35 of the base film 10 to the first protective layer 30 may be the same as or higher than the height of the uppermost surface 25 of the base film 10 to the first conductive pattern 20.

Although not shown in FIG. 1, an additional plating layer may be formed between the first conductive pattern 20 and the first protective layer 30 so as to cover the surface of the first conductive pattern 20. Such a plating layer can be formed, for example, by plating a substance such as copper, tin, nickel, palladium, or gold or an alloy thereof on the first conductive pattern 20.

In the flexible circuit board 1 according to the embodiment of the present invention, the upper surface 35 of the first protective layer 30 may be substantially flat. Here, the term “substantially flat” may include the case where some irregularities are formed on the upper surface 35 of the first protective layer 30. However, in spite of such unevenness, when compared with the total thickness of the first protective layer 30, the difference in height between the uppermost part and the lowermost part of the upper surface 35 of the first protective layer 30 is extremely small and is ignored. You may.

In some embodiments of the present invention, after forming the first protective layer 30 on the first conductive pattern 20 in order to form the first protective layer 30 having a flat upper surface, the upper surface 35 of the first protective layer 30 is formed. A step of flattening may be added.

The first heat radiating layer 40 may be formed on the first protective layer 30. The first heat radiating layer 40 may be formed so as to cover the upper surface of the first protective layer 30. As shown in FIG. 1, the first heat radiating layer 40 may be formed so as to completely cover the surface of the first protective layer 30, but the present invention is not limited thereto. The first heat dissipation layer 40 may be formed so as to cover only the region on the first protective layer 30 that overlaps the first conductive pattern 20.

As described above, the height of the upper surface 35 of the first protective layer 30 can be formed to be the same as or higher than the height of the uppermost surface 25 of the first conductive pattern 20, so that the first heat radiation layer 40 covering the first protective layer 30 can be formed. The height of the lower surface 41 may also be formed to be the same as or higher than the height of the uppermost surface 25 of the first conductive pattern 20.

In some embodiments of the present invention, the thickness ratio of the first protective layer 30 to the first heat dissipation layer 40 can be 2: 8 to 8: 2. Here, the thickness of the first protective layer 30 means the height from the upper surface of the first conductive pattern 20 to the upper surface 35 of the first protective layer 30, and the thickness of the first heat radiation layer 40 is the first protective layer. It refers to the height from the lower surface 41 of the first heat radiating layer 40 on the upper surface 35 of 30 to the uppermost surface of the first heat radiating layer 40. When the thickness of the first heat radiating layer 40 is formed to be excessively thin compared to the thickness of the first protective layer 30, the heat radiating effect of the first conductive pattern 20 by the first heat radiating layer 40 is insufficient. On the other hand, if the thickness of the first protective layer 30 is formed to be excessively thin as compared with the first heat radiating layer 40, the insulating property may be lowered, and the first heat dissipation is compared with the thickness of the first protective layer 30. When the 5 thickness of the layer 40 is formed to be excessively thick than necessary, the manufacturing cost of the flexible circuit board 1 may be excessively increased as compared with the increase in the heat dissipation effect.

In some embodiments of the present invention, the thickness of the first protective layer 30 can be 1 μm to 30 μm, the thickness of the first heat dissipation layer 40 can be 1 μm to 30 μm, and the first protective layer 30 and the first protective layer 30. The total thickness of one heat radiation layer 40 may be 2 μm to 60 μm.

The first heat radiating layer 40 may include a base material and a heat radiating material 45. The base material may include, for example, solder resist or coverlay film. In some embodiments of the present invention, the base material of the first heat dissipation layer 40 may include the same material as the first protective layer 30.

The heat radiating material 45 as the heat radiating material contained in the first heat radiating layer 40 may contain a substance having good thermal conductivity, for example, whether it contains a metallic substance such as aluminum or copper or a carbon substance such as graphene or carbon nanotubes. , These compounds may be included.

In some embodiments of the present invention, the heat radiating material 45 may include spherical heat radiating balls, but the present invention is not limited thereto. The heat radiating material 45 can have a polyhedral shape such as a hexahedron, and can be mixed with the base substance of the first heat radiating layer 40 and can transfer the heat generated in the first conductive pattern 20 into the air without any shape limitation. It can be applied to the present invention.

In the flexible circuit board 1 according to the embodiment of the present invention, the heat radiating material 45 contained in the first heat radiating layer 40 can promote the heat generated from the first conductive pattern 20 to be released to the outside. Therefore, the influence of heat received from the heat generated in the first conductive pattern 20 by the circuit element and the electronic device mounted on the first conductive pattern 20 by the first heat radiation layer 40 is reduced, and the operation reliability of the flexible circuit board 1 is reduced. Can increase.

Further, forming the first heat radiating layer 40 on the first protective layer 30 in this way is more advantageous from the viewpoint of the production process and the production cost than the case where a separate metal tape is formed on the back surface of the base film 10.

On the other hand, in the flexible circuit board 1 according to the embodiment of the present invention, the first heat radiating layer 40 can be separated from the first conductive pattern 20 by the first protective layer 30. Not only that, the height of the upper surface 35 of the first protective layer 30 is formed to be the same as or higher than the height of the uppermost surface 25 of the first conductive pattern 20, so that the first heat radiation is generated between the plurality of first conductive patterns 20. The heat radiating material 45 included in the layer 40 and the first heat radiating layer 40 is not located.

When the first heat radiating layer 40 containing the heat radiating material 45 is interposed between the first conductive patterns 20 on the base film 10, the heat radiating material 45 reacts with moisture or the like and flows between the first conductive patterns 20. The leakage current formed in can reduce the insulating effect between the plurality of first conductive patterns 20. Therefore, the operation reliability of the flexible circuit board 1 may be lowered.

However, in the first heat radiating layer 40 of the flexible circuit board 1 according to the embodiment of the present invention, the heat radiating material 45 included in the first heat radiating layer 40 and the first heat radiating layer 40 is formed between the plurality of first conductive patterns 20. Since it is not located, even when the heat radiating material 45 in the first heat radiating layer 40 reacts with moisture, it is possible to prevent a leakage current from being generated between the first conductive patterns 20 and to have an effect between the first conductive patterns 20. Can be insulated.

FIG. 3 is a cross-sectional view of a flexible circuit board according to another embodiment of the present invention. Hereinafter, the description of the parts common to the above-described embodiment will be omitted, and the differences will be mainly described.

Referring to FIG. 3, the flexible circuit board 2 according to another embodiment of the present invention has different shapes of the first protective layer 130 and the first heat radiating layer 140 from the flexible circuit board of the above-described embodiment.

The upper surface 135 of the first protective layer 130 may be formed along the profile of the upper surface of the first conductive pattern 20. That is, the upper surface 135 of the first protective layer 130 includes the first surface 136 on the first conductive pattern 20 and the second surface 137 between the first surface 136, and the height of the base film 10 to the first surface 136. Is higher than the height of the second surface 137.

On the other hand, the upper surface 135 of the first protective layer 130 may still be the same as or higher than the height of the uppermost surface of the first conductive pattern 20, although it is formed along the profile of the upper surface of the first conductive pattern 20. .. That is, the level of the second surface 137, which is lower than the height of the first surface 136 of the upper surface 135 of the first protective layer 130, is still formed to be the same as or higher than the level of the uppermost surface of the first conductive pattern 20, and the first conductive pattern. It is possible to prevent the heat radiating material contained in the first heat radiating layer 140 and the first heat radiating layer 40 from being located between the first conductive patterns 20 between 20. Therefore, despite the deformed shape of the upper surface 135 of the first protective layer 130, the insulating effect between the first protective layer 130 and the first heat radiating layer 140 between the first conductive patterns 20 can be maintained as it is.

By forming the first protective layer 130 along the profile of the upper surface of the first conductive pattern 20, the shape of the first heat radiating layer 140 covering the first protective layer 130 is also formed along the profile of the first protective layer 130. Can be done. Therefore, the upper surface of the first heat radiating layer 140 may include the first surface 141 on the first conductive pattern 20 and the second surface 142 between the first surfaces, and the height of the first surface 141 is the second. It may be higher than the height of the surface 142.

On the other hand, as in the case of the above-described embodiment, the height of the lower surface of the first heat radiating layer 140 may be the same as or higher than the height of the uppermost surface of the first conductive pattern 20.

In the flexible circuit board 2 according to the present embodiment, since the first protective layer 130 is formed along the profile of the surface of the first conductive pattern 20, the first protective layer is formed according to the shape of the upper surface 135 of the bent first protective layer 130. The surface area of the top surface 135 of 130 can be increased. Further, the increased surface area of the upper surface 135 of the first protective layer 130 may increase the contact area between the first protective layer 130 and the first heat radiating layer 140 accordingly. Therefore, the heat transfer efficiency of the first conductive pattern 20 transmitted to the first heat radiating layer 140 via the first protective layer 130 can be increased.

On the other hand, when the first protective layer 130 is formed along the profile of the first conductive pattern 20, the step of flattening the upper surface of the first protective layer 130 is not performed after the first protective layer 130 is formed. May be good.

FIG. 4 is a cross-sectional view of a flexible circuit board according to another embodiment of the present invention.

Referring to FIG. 4, the flexible circuit board 3 according to the other embodiment of the present invention includes the first conductive pattern 20 of the base film 10 and the second conductive pattern 120, the second protective layer 230, and the second conductive pattern formed on the opposite upper surface. 2 The via 51 penetrating the heat dissipation layer 240 and the base film 10 may be further included.

The second conductive pattern 120 may be formed on the opposite upper surface of the base film 10 on which the first conductive pattern 20 is formed. The second conductive pattern 120 may include at least one band-shaped conductor having a constant width like the first conductive pattern 20.

The second conductive pattern 120 can be electrically connected to the first conductive pattern 20 via a via 51 penetrating the substrate. The via 51 can fill the via hole 50 formed through the base film 10. The via 51 may contain a conductive substance such as copper or gold or an alloy thereof as in the first and second conductive patterns 20 and 120. Although not shown in FIG. 4, one or more additional metal layers may be included between the inner wall of the via hole 50 and the via 51.

FIG. 4 shows a case where the first conductive pattern 20 and the second conductive pattern 120 are formed at positions corresponding to the center of the base film 10, but the present invention is not limited thereto. The arrangement of the first and second conductive patterns 20 and 120 may differ depending on the design of the flexible circuit board 1 and the arrangement of the circuit elements mounted therein, to ordinary engineers in the technical field to which the present invention belongs. It will be self-evident.

A second protective layer 230 may be formed so as to cover the second conductive pattern 120. The second protective layer 230 may be formed so as to completely cover the second conductive pattern 120, similarly to the first protective layer 30. Therefore, the height of the upper surface of the second protective layer 230 from the other surface of the base film 10 may be the same as or higher than the height of the uppermost surface of the second conductive pattern 120.

A second heat radiating layer 240 may be formed on the second protective layer 230. The second heat radiating layer 240 may include a base substance which is an insulating substance and a heat radiating material contained in the base substance. The first heat radiating layer 40 and the second heat radiating layer 240 may contain the same substance. That is, the base substance and the heat radiating layer constituting the first heat radiating layer 40 and the second heat radiating layer 240 may contain the same substance.

As shown in FIG. 4, the second heat radiating layer 240 may be formed so as to completely cover the second protective layer 230, and unlike this, the second heat radiating layer 240 is formed with the second conductive pattern 120. It may be formed so as to cover only the upper surface of the second protective layer 230 on the region.

By forming the upper surface of the second protective layer 230 at the same level as or higher than the level of the upper surface of the second conductive pattern 120, the second heat radiating layer 240 does not intervene between the second conductive patterns 120. Is as explained. Therefore, such a shape of the second heat radiating layer 240 helps to release the heat generated in the second conductive pattern 120 into the air, and at the same time, a leakage current is generated between the second conductive pattern 120 and the heat radiating material. It is possible to prevent this from occurring and reducing the operational reliability of the flexible circuit board 3.

FIG. 5 is a flowchart for explaining a method of manufacturing a flexible circuit board according to an embodiment of the present invention.

Referring to FIGS. 5 and 1, the method of manufacturing a flexible circuit board according to an embodiment of the present invention provides a base film in which a plurality of conductive patterns are formed on at least one surface (S10), and the plurality of conductive patterns. A first protective layer is formed so as to cover the first protective layer (S20), and a heat radiating layer having a heat radiating material formed inside is formed on the first protective layer (S30).

The first conductive pattern 20 can be formed, for example, by a semi-additive step in which a resist is formed on the base film 10 and plating is performed by an electrolytic or non-electrolytic method, and a conductive layer is formed on the base film 10. It can also be formed by an etching step of etching the conductive layer.

Forming the first protective layer 30 so as to cover the plurality of first conductive patterns 20 may include forming a solder resist or coverlay film on the first conductive patterns 20 by printing or lamination. The first protective layer 30 needs to be sufficiently formed so that the level of the upper surface of the first protective layer 30 is higher than the level of the uppermost surface of the first conductive pattern 20.

Here, a step of flattening the upper surface after forming the first protective layer 30 in order to keep the level of the upper surface of the first protective layer 30 substantially flat may be added. Flattening the upper surface of the first protective layer 30 may include, for example, pressing the upper surface of the first protective layer 30 with a press.

To form the first heat radiating layer 40 so as to cover the first protective layer 30, a solder resist or a coverlay film containing the heat radiating material 45 is formed on the first protective layer 30 by printing or laminating. May include.

Although the embodiment of the present invention has been described above with reference to the attached drawings, the present invention is not limited to the above-described embodiment and can be manufactured in various forms different from each other, and the technical field to which the present invention belongs. Those who have the usual knowledge of the invention will understand that it can be implemented in other concrete forms without changing the technical ideas and essential features of the present invention. Therefore, it should be understood that the above embodiments are exemplary in all respects and are not limiting.

1, 2, 3 Flexible circuit board,
10 base film,
20 First conductive pattern,
30 First protective layer,
40 First heat dissipation layer,
120 2nd conductive pattern,
230 Second protective layer,
240 Second heat dissipation layer.

Claims (11)

With the base film
A plurality of first conductive patterns formed on one surface of the base film,
A first protective layer formed so as to cover the plurality of first conductive patterns,
A heat radiating layer that covers the first protective layer, the heat radiating layer includes a base substance and a first heat radiating layer containing a heat radiating material contained in the base substance.
The thickness of the first protective layer is the height from the upper surface of the first conductive pattern to the upper surface of the first protective layer.
A flexible circuit board in which the ratio of the thickness of the first protective layer to the thickness of the first heat radiating layer is 2: 8 to 8: 2. The flexible circuit board according to claim 1, wherein the height of the uppermost surface of the first protective layer from the base film is the same as or higher than the height of the uppermost surface of the plurality of first conductive patterns from the base film. The flexible circuit board according to claim 1, wherein the upper surface of the first heat radiating layer is substantially flat. The thickness of the first protective layer is 1 μm to 30 μm.
The thickness of the first heat radiating layer is 1 μm to 30 μm.
The flexible circuit board according to claim 1, wherein the total thickness of the first protective layer and the first heat radiating layer is 2 μm to 60 μm. The flexible circuit board according to claim 1, wherein the base substance contains the same substance as the substance constituting the first protective layer. A plurality of second conductive patterns formed on the other surface of the base film facing the one surface,
A second protective layer formed so as to cover the plurality of second conductive patterns,
The flexible circuit board according to claim 1, further comprising a second heat radiating layer that covers the second protective layer and further includes a heat radiating material inside. The first protective layer is formed according to the profiles of the plurality of first conductive patterns.
The upper surface of the first protective layer includes a first surface on the first conductive pattern and a second surface between the first surfaces.
The flexible circuit board according to claim 1, wherein the height of the first surface from the base film is higher than the height of the second surface from the base film. The flexible circuit board according to claim 7, wherein the first heat radiating layer is formed according to a profile on the upper surface of the first protective layer. The flexible circuit board according to claim 1, further comprising a plating layer interposed between the first conductive pattern and the first protective layer. A base film having a plurality of conductive patterns formed on at least one surface is provided, and a protective layer is formed so as to cover the plurality of conductive patterns.
Including forming a heat radiating layer containing a heat radiating material mixed inside on the protective layer, including forming a heat radiating layer.
The thickness of the protective layer is the height from the upper surface of the conductive pattern to the upper surface of the protective layer.
A method for manufacturing a flexible circuit board, wherein the ratio of the thickness of the protective layer to the heat radiating layer is 2: 8 to 8: 2. The method for manufacturing a flexible circuit board according to claim 10, wherein the height of the uppermost surface of the protective layer from the base film is the same as or higher than the height of the uppermost surface of the plurality of conductive patterns from the base film. ..