KR102488685B1 - Flexible printed circuit board with emi shielding sheet and method of fabricating thereof - Google Patents

Abstract

A flexible circuit board attached with an electromagnetic wave shielding sheet and a manufacturing method thereof are provided. A flexible circuit board with an electromagnetic wave shielding sheet may include a base film having a wiring pattern formed on one surface, a first insulating layer covering the wiring pattern, a nonwoven fabric having a plated surface attached to the first insulating layer by an adhesive layer, and the above. vias formed through the base film, the first insulating layer, the conductive adhesive layer, and the nonwoven fabric, and a first metal layer connected to the vias on the plated nonwoven fabric; and a second insulating layer covering the metal layer.

Description

Flexible circuit board with electromagnetic wave shielding sheet and method for manufacturing the same

The present invention relates to a flexible circuit board having an electromagnetic wave shielding sheet attached thereto and a method for manufacturing the same, and more particularly, to a flexible circuit board having improved electromagnetic wave shielding performance by attaching an electromagnetic wave shielding sheet using a plated nonwoven fabric and a method for manufacturing the same. .

Electromagnetic waves are a form of energy generated by the use of electricity and are composite waves of electric and magnetic fields. Electric fields are shielded by all conductive objects, but magnetic fields have strong penetrability that passes through all objects, especially Magnetic fields are known to have harmful effects on the human body.

These electromagnetic waves are emitted from electric devices and power lines such as home appliances, wireless communication systems, control systems, power systems, high-frequency devices, and lighting devices in use around us. It has been shown to have great potential for development.

Due to the recent development of electronic devices, especially small mobile devices that support next-generation wireless communication standards such as 5G, there are many cases in which communication means using high-frequency signals ranging from 5 to 6 GHz and up to 24 to 100 GHz (mmWave) are used. are losing Demand for an effective shielding means for parts in electronic devices is also increasing due to increased radio wave emission due to the use of high frequency bands.

A technical problem to be solved by the present invention relates to a flexible circuit board attached with an electromagnetic wave shielding sheet using a plated nonwoven fabric so as to have improved electromagnetic wave shielding efficiency and a manufacturing method thereof.

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

In order to achieve the above technical problem, a flexible circuit board having an electromagnetic wave shielding sheet attached thereto according to some embodiments of the present invention includes a base film having a wiring pattern formed thereon, a first insulating layer covering the wiring pattern, and the first insulating layer. A nonwoven fabric attached by a conductive adhesive layer on a layer and having a plated surface, a via formed through the base film, the first insulating layer, the conductive adhesive layer and the nonwoven fabric, and a first metal layer connected to the via on the plated nonwoven fabric; and a second insulating layer covering the first metal layer.

In some embodiments of the present invention, the non-woven fabric may include a non-woven fabric layer to which the conductive adhesive layer is adsorbed and a general non-woven fabric layer composed of only plated fibrous tissue.

In some embodiments of the present invention, the first metal layer and the via are integrally formed

In some embodiments of the present invention, a ground layer formed on the other surface of the base film, a second metal layer covering the ground layer and integrally formed with the via, and a third insulating layer formed on the second metal layer can include more.

In some embodiments of the present invention, the plating of the plated nonwoven fabric may include at least one of metals such as copper, nickel, gold, palladium, tin, aluminum, or alloys thereof.

In some embodiments of the present invention, at least one film having a conductive pattern may be further included between the wiring pattern and the first insulating layer.

A flexible circuit board with an electromagnetic wave shielding sheet attached thereto according to some other embodiments of the present invention for achieving the above technical problem includes a base film having a wiring pattern formed on one surface, a first insulating layer covering the wiring pattern, and the first insulating layer covering the wiring pattern. On the insulating layer, attached by a conductive adhesive layer, a nonwoven fabric having a plated surface, a second insulating layer covering the nonwoven fabric, a ground layer formed on the other surface of the base film, a metal layer covering the ground layer, and the metal layer and a third insulating layer formed thereon.

In some embodiments of the present invention, vias penetrating the base film, the first insulating layer, the conductive adhesive layer, and the nonwoven fabric and integrally formed with the metal layer may be further included.

In some embodiments of the present invention, the non-woven fabric may include a non-woven fabric layer to which the conductive adhesive layer is adsorbed and a general non-woven fabric layer composed of only plated fibrous tissue.

A method for manufacturing a flexible circuit board having an electromagnetic wave shielding sheet attached thereto according to some embodiments of the present invention for achieving the above technical problem includes providing a base film having a conductive pattern formed on one surface thereof, and a first layer on the base film. Forming an insulating layer and a nonwoven fabric having a plated surface to be sequentially laminated, forming a via hole through the base film, the first insulating layer, and the nonwoven fabric having a plated surface, and forming a via by filling the via hole. includes

In some embodiments of the present invention, the forming step of sequentially stacking the first insulating layer and the surface-plated nonwoven fabric on the base film may include aligning the nonwoven fabric to which the first insulating layer and the adhesive layer are attached on the base film. and bonding by pressing in a hot press method.

In some embodiments of the present invention, forming the via by filling the via hole may further include forming a metal layer covering the nonwoven fabric, but the metal layer and the via may be formed at the same time.

In some embodiments of the present invention, the surface-plated nonwoven fabric may be formed by electroless plating a metal material on the fiber structure.

In some embodiments of the present invention, a step of forming a second insulating layer covering the metal layer is further included, wherein the forming of the second insulating layer is performed by pressing an insulating film on the metal layer by a hot press method to adhere the insulating film to the metal layer. steps may be included.

In some embodiments of the present invention, the surface-plated nonwoven fabric is adhered to the first insulating layer through the adhesive layer, and the surface-plated nonwoven fabric has the adhesive layer adsorbed to include only the nonwoven fabric layer and the plated fibrous tissue A general non-woven fabric layer may be included.

In some embodiments of the present invention, prior to the step of forming via holes through the base film, the first insulating layer, and the nonwoven fabric having a plated surface, forming a second insulating layer covering the nonwoven fabric; , The via hole is formed through the base film, the first insulating layer, the surface-plated nonwoven fabric, and the second insulating layer.

In some embodiments of the present invention, the surface-plated nonwoven fabric may be formed by electrolytically plating a metal material on a fiber structure.

Details of other embodiments are included in the detailed description and drawings.

The flexible circuit board to which the electromagnetic wave shielding sheet is attached according to the embodiment of the present invention has excellent diffuse reflection and absorption of incident electromagnetic waves due to the fiber structure of the plated nonwoven fabric included in the electromagnetic wave shielding sheet, and due to the metal layer formed on the nonwoven fabric The influence of interference due to reflected electromagnetic waves can also be reduced.

In addition, when the metal layer is not formed on the non-woven fabric, the plating layer of the non-woven fabric is formed relatively thick through electroplating, so that low-frequency and high-frequency band blocking effects can be obtained together.

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

1 is a cross-sectional view of a flexible circuit board to which an electromagnetic wave shielding sheet according to some embodiments of the present invention is attached.
2 is a view for explaining the function of a flexible circuit board to which an electromagnetic wave shielding sheet is attached according to some embodiments of the present invention.
3 is a cross-sectional view of a flexible circuit board to which an electromagnetic wave shielding sheet according to some other embodiments of the present invention is attached.
4 is a cross-sectional view of a flexible circuit board to which an electromagnetic wave shielding sheet according to another exemplary embodiment of the present invention is attached.
5 is a flowchart illustrating a method of manufacturing a flexible circuit board having an electromagnetic wave shielding sheet attached thereto according to some embodiments of the present invention.
6 to 9 are diagrams for explaining an intermediate process of a method of manufacturing a flexible circuit board having an electromagnetic wave shielding sheet attached thereto according to some embodiments of the present invention.
10 to 11 are intermediate-step views for explaining a method of manufacturing a flexible circuit board having an electromagnetic wave shielding sheet attached thereto according to another embodiment of the present invention.

Advantages and features of the present invention, and methods of achieving them, will become clear with reference to the detailed description of the following embodiments taken in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in various different forms, only these embodiments make the disclosure of the present invention complete, and common knowledge in the art to which the present invention belongs. It is provided to fully inform the holder of the scope of the invention, and the present invention is only defined by the scope of the claims. The sizes and relative sizes of components shown in the drawings may be exaggerated for clarity of explanation. Like reference numbers designate like elements throughout the specification, and “and/or” includes each and every combination of one or more of the recited items.

When an element or layer is referred to as being "on" or "on" another element or layer, it is not only directly on the other element or layer, but also when another layer or other element is intervening therebetween. All inclusive. On the other hand, when an element is referred to as “directly on” or “directly on”, it indicates that another element or layer is not intervened.

The spatially relative terms "below", "beneath", "lower", "above", "upper", etc. It can be used to easily describe the correlation between elements or components and other elements or components. Spatially relative terms should be understood as encompassing different orientations of elements in use or operation in addition to the orientations shown in the figures. For example, when flipping elements shown in the figures, elements described as “below” or “beneath” other elements may be placed “above” the other elements. Thus, the exemplary term “below” may include directions of both below and above. Elements may also be oriented in other orientations, and thus spatially relative terms may be interpreted according to orientation.

Terminology used herein is for describing the embodiments and is not intended to limit the present invention. In this specification, singular forms also include plural forms unless specifically stated otherwise in a phrase. As used herein, "comprises" and/or "comprising" does not exclude the presence or addition of one or more other elements other than the recited elements.

Although first, second, etc. are used to describe various elements or components, these elements or components are not limited by these terms, of course. These terms are only used to distinguish one element or component from another. Accordingly, it goes without saying that the first element or component mentioned below may also be the second element or component within the technical spirit of the present invention.

Unless otherwise defined, all terms (including technical and scientific terms) used in this specification may be used in a meaning commonly understood by those of ordinary skill in the art to which the present invention belongs. In addition, terms defined in commonly used dictionaries are not interpreted ideally or excessively unless explicitly specifically defined.

1 is a cross-sectional view of a flexible circuit board to which an electromagnetic wave shielding sheet according to some embodiments of the present invention is attached.

Referring to FIG. 1 , a flexible circuit board to which an electromagnetic wave shielding sheet is attached according to some embodiments of the present invention includes a base film 100 having a wiring pattern 110 formed on one side thereof, and a first insulating layer covering the wiring pattern 110 . (120), non-woven fabric 151 having a surface attached to the first insulating layer 120 by the adhesive layer 131 is plated, the first metal layer 180 and the second metal layer 185, and the first and second metal layers ( 180 and 185 may be included.

The base film 100 may be formed of a flexible material, and may be included as a substrate of the flexible circuit board 1 according to an embodiment of the present invention to allow the flexible circuit board 1 to be bent or folded.

The base film 100 may include, for example, a polyimide film, a PET film, a polyethylene naphthalate film, etc., but the present invention is not limited thereto. A wiring pattern 110 may be formed on one surface of the base film 100 . The wiring pattern 110 may connect signals between devices mounted on the surface of the base film 100 and circuit components. In addition, the wiring pattern 110 may function as a reinforcement pattern, a dummy pattern, a redistribution pattern, or the like on the base film 100 .

Although not shown, the wiring patterns 110 may be formed on both sides of the base film 100 so that the flexible circuit board 1 may be configured as a double-sided board.

In addition to the wiring pattern 110 , ground patterns 111 and 112 may be formed on the base film 100 . As shown in FIG. 1 , the ground patterns 111 and 112 may be formed on at least one surface of the base film 100 . The ground patterns 111 and 112 may ground at least a portion of the wiring pattern 110 .

The wiring pattern 110 and the ground patterns 111 and 112 may include, for example, a conductive material such as copper, but the present invention is not limited thereto. Specifically, the wiring pattern 110 and the ground patterns 111 and 112 may be formed of an electrically conductive material such as gold or aluminum.

A first insulating layer 120 may be formed to cover the wiring pattern 110 and the ground pattern 111 . The first insulating layer 120 may include a flexible insulator material, and may include a coverlay film or a solder resist. When the first insulating layer 120 is formed using a hot press process as in the manufacturing method of a flexible circuit board described later using FIG. 5 or the like, the first insulating layer 120 may be attached using a coverlay film. can

A plated nonwoven fabric 151 may be attached to the first insulating layer 120 using the adhesive layer 131 . The plated nonwoven fabric 151 may function as a shielding sheet for shielding electromagnetic waves generated from the wiring pattern 110 .

The adhesive layer 131 may include, for example, a film including a thermoplastic resin or a thermosetting resin.

The plated nonwoven fabric 151 may include a nonwoven fabric layer 145 in which a portion of the adhesive layer 131 is melted and adsorbed during the bonding process with the general nonwoven fabric layer 141 . That is, in the process of attaching the nonwoven fabric 151 on which the adhesive layer 131 is plated with a conductive tape to the first insulating layer 120, when the hot press method is used to attach the nonwoven fabric 151, a portion of the adhesive layer 131 is melted and the plated nonwoven fabric ( 151) can be adsorbed between tissues. At this time, the thickness between the adsorbed nonwoven fabric layer 145 and the general nonwoven fabric layer 141 may be, for example, 1:1, but the present invention is not limited thereto.

The plated nonwoven fabric 151 may be, for example, a coating layer formed on the surface and/or inside the textile tissue formed by overlapping materials such as liquid crystal polymer (LCP) or polyethylene terephthalate (PET). . The plating layer may include, for example, at least one of copper, nickel, gold, palladium, tin, aluminum, or an alloy thereof, but the present invention is not limited thereto. On the plated nonwoven fabric 151, the nonwoven fabric may be formed to a thickness of, for example, 1 μm or less.

As described above, the nonwoven fabric may increase the effect of internal absorption and diffuse reflection of electromagnetic waves due to the irregular fiber structure on which the surface is plated. A shielding effect by the plated nonwoven fabric 151 may be improved due to the internal absorption and diffuse reflection effects. A detailed description of this will be given later.

A first metal layer 180 may be formed on the plated nonwoven fabric 151 . In addition, a second metal layer 185 may be formed on the other surface of the base film 100 on which the ground pattern 112 is formed. The first metal layer 180 and the second metal layer 185 may include, for example, a conductive material such as copper. The first metal layer 180 functions as an electromagnetic wave shielding layer on one side of the flexible circuit board 1 on which the wiring pattern 110 is formed, and the second metal layer 185 functions as an electromagnetic wave shielding layer on the other side of the flexible circuit board 1. can do. Also, the first metal layer 180 and the second metal layer 185 may be connected to the ground patterns 111 and 112 to provide a ground potential.

A via 170 may be formed to pass through the base film 100 , the first insulating layer 120 and the plated nonwoven fabric 151 . The via 170 may connect the first metal layer 180 and the second metal layer 185 . In some embodiments, the via 170 , the first metal layer 180 and the second metal layer 185 may be integrally formed. As will be described later, this includes a process of forming vias 170 by filling via holes penetrating the base film 100, the first insulating layer 120, and the plated nonwoven fabric 151, and the plated nonwoven fabric 151 and the ground This is because the process of forming the first metal layer 180 and the second metal layer 185 by covering the pattern 112 can be performed simultaneously.

A second insulating layer 190 may be formed to cover the first metal layer 180 and the second metal layer 185 . The second insulating layer 190 may include, for example, an insulating material such as a coverlay film or a solder resist. The second insulating layer 190 may protect both sides of the flexible circuit board 1 by surrounding them.

2 is a view for explaining the function of a flexible circuit board to which an electromagnetic wave shielding sheet is attached according to some embodiments of the present invention.

Referring to FIG. 2 , a mechanism for blocking electromagnetic waves generated from a flexible circuit board 1 to which an electromagnetic wave shielding sheet according to an embodiment of the present invention is attached will be described. Electromagnetic waves 101 are generated from the conductive pattern 110 formed on the base film 100 or a circuit element connected thereto and radiated toward the plated nonwoven fabric 151 and the first metal layer 180 .

The radiated electromagnetic waves 101 are incident on the plated nonwoven fabric 151 . Compared to general metallic electromagnetic wave shielding layers, incident electromagnetic waves are reflected once or partially transmitted on the surface, the plated nonwoven fabric 151 diffusely reflects electromagnetic waves incident to the inside by including a plated fibrous structure, resulting in relatively improved shielding and absorption effects. can have In addition, the amount of metal required for shielding or shielding characteristics are excellent compared to shielding layers in which a polymer material containing a conventional metal powder is used.

Also, as shown in FIG. 2 , some of the electromagnetic waves diffusely reflected inside the plated nonwoven fabric 151 may be incident to the interface 155 between the plated nonwoven fabric 151 and the first metal layer 180 . At this time, the first metal layer 180 may reflect incident electromagnetic waves back into the plated nonwoven fabric 151 .

In the case of having a double-layered shielding structure of a general shielding layer and a metal layer, the electromagnetic wave emitted from the conductive pattern or element is reflected from the surface of the shielding layer or the metal layer and re-injected into the conductive pattern or element, resulting in a problem of intensifying electromagnetic wave interference. there is.

However, in the flexible circuit board 1 used according to the embodiment of the present invention, electromagnetic waves reflected by the first metal layer 180 cause irregular reflection inside the plated nonwoven fabric 151 again, so that double shielding and absorption effects can be obtained. Therefore, the influence of electromagnetic wave interference generated by incident back to the conductive pattern or element can be reduced that much. In addition, the plated nonwoven fabric 151 has an excellent effect of blocking electromagnetic waves in a high frequency band, and the first and second metal layers 180 and 185 have an excellent effect of blocking electromagnetic waves in a low frequency band. By combining these, the blocking effect of electromagnetic waves that may occur in the flexible circuit board 1 can be further improved.

In addition, the first metal layer 180 is connected to the second metal layer 185 through the via 170 , and the second metal layer 185 is connected to the ground pattern 112 . Accordingly, the ground potential for electromagnetic wave shielding of the first and second metal layers 180 and 185 can be stably maintained.

3 is a cross-sectional view of a flexible circuit board to which an electromagnetic wave shielding sheet according to some other embodiments of the present invention is attached.

Referring to FIG. 3 , a flexible circuit board 2 with an electromagnetic wave shielding sheet attached according to some other embodiments of the present invention may include a multi-layer board composed of a first base film 200 and a second base film 205. can

A first wiring pattern 210 may be formed on the first base film 200 and a second wiring pattern 215 may be formed on the second base film 205 . Although FIG. 2 shows a two-layer substrate structure composed of a first base film 200 and a second base film 205, the flexible circuit board 2 according to the embodiment of the present invention has a first base film 200 ) and the second base film 205 does not exclude a multi-layer substrate of three or more layers including an additional base film.

The first insulating layer 220 sequentially formed on the second wiring pattern 215, the nonwoven fabric 251 having a plated surface attached to the first insulating layer 220 by the adhesive layer 231, and the first metal layer 280 ) and the second metal layer 285 and the second insulating layer 290 covering them have the same structure as that of the flexible circuit board 1 previously described with reference to FIG. 1 , so descriptions thereof are omitted.

4 is a flowchart illustrating a method of manufacturing a flexible circuit board having an electromagnetic wave shielding sheet attached thereto according to some other embodiments of the present invention.

Referring to FIG. 4 , the flexible circuit board 3 with the electromagnetic wave shielding sheet attached according to some other embodiments of the present invention is a plated nonwoven fabric ( 351) and the second insulating layer 390, a metal layer is not formed.

In addition, in the flexible circuit board 3 of this embodiment, the metal layer of the plated nonwoven fabric 351 may be formed thicker than the metal layer of the plated nonwoven fabrics 151 and 251 included in the previously described embodiment. For example, if the metal layers of the nonwoven fabrics 151 and 251 included in the above-described embodiment are formed to have a thickness of about 1 μm or less, the metal layer of the plated nonwoven fabric 351 may be formed to have a thickness of several μm. .

This difference may be due to the fact that no metal layer is formed between the plated nonwoven fabric 351 and the second insulating layer 390 . That is, the flexible circuit board 1 described with reference to FIG. 1 uses a combination of the plated nonwoven fabric 151 and the first and second metal layers 180 and 185 to block electromagnetic waves in a high frequency band and electromagnetic waves in a low frequency band. Obtaining the blocking effect is as described above.

However, since the metal layer is not formed between the plated nonwoven fabric 351 and the second insulating layer 390 in the flexible circuit board 3 of FIG. 4 , it is necessary to compensate for the electromagnetic wave blocking effect in the low frequency band. At this time, by forming the thickness of the plating layer of several μm during plating of the plated nonwoven fabric 351, the electromagnetic wave shielding sheet can be configured so that the plated nonwoven fabric 351 obtains excellent blocking effect in both high and low frequency bands. .

In addition, in order to obtain the thickness of the plating layer of the plated nonwoven fabric 351 as described above, plating of the plated nonwoven fabric 351 may be performed by an electrolytic plating method.

Other than the plated non-woven fabric 351, other components of the present invention have the same structure as the flexible circuit board 1 described above with reference to FIG. 1, and thus descriptions thereof are omitted.

5 is a flowchart illustrating a method of manufacturing a flexible circuit board having an electromagnetic wave shielding sheet attached thereto according to some embodiments of the present invention.

Referring to FIG. 5, in the method of manufacturing a flexible circuit board with an electromagnetic wave shielding sheet attached according to an embodiment of the present invention, forming an electromagnetic wave shielding sheet by attaching an adhesive layer to one surface of a nonwoven fabric plated on one surface (S110), one side Providing a flexible circuit board on which a conductive pattern is formed (S120), sequentially stacking and adhering a first insulating layer and an electromagnetic wave shielding sheet on the conductive pattern of the flexible circuit board (S130), the flexible circuit board and the electromagnetic wave shielding sheet It may include forming a via hole passing through (S140), forming a metal layer filling the via hole and covering the upper surface of the electromagnetic wave shielding sheet (S150), and forming a second insulating layer on the metal layer (S160). . The above steps will be described in more detail using FIGS. 5 to 8 .

6 to 9 are diagrams for explaining an intermediate process of a method of manufacturing a flexible circuit board having an electromagnetic wave shielding sheet attached thereto according to some embodiments of the present invention.

Referring to FIG. 6, an electromagnetic wave shielding sheet 150 composed of a base film 100 on which a conductive pattern 110 is formed, a first insulating layer 120, and a plated nonwoven fabric 140 to which an adhesive layer 130 is attached is prepared. do.

The non-woven fabric 140 may be formed as a plating layer on the surface of the fiber structure constituting the non-woven fabric 140 of at least one of metals such as copper, nickel, gold, palladium, tin, and aluminum or alloys thereof. Plating the nonwoven fabric 140 may include, for example, performing electroless plating on the nonwoven fabric 140 with a plating solution containing a reducing agent.

The first insulating layer 120 and the electromagnetic wave shielding sheet 150 are sequentially stacked and aligned at the attachment positions on the base film 100, and the first insulating layer 120 and the electromagnetic wave shielding sheet 150 are conductive by using heat. It is adhered onto the pattern (111). The first insulating layer 120 and the electromagnetic wave shielding sheet 150 may be bonded to the conductive pattern 110 by, for example, hot pressing.

When the first insulating layer 120 and the electromagnetic wave shielding sheet 150 are compressed by a hot press method, air bubbles may escape between the plated nonwoven fabrics 140 . As a result, the possibility of air bubbles occurring between the nonwoven fabrics 151 during the subsequent formation of the first and second metal layers 180 and 185 can be reduced, and appearance defects in the device mounting process that can be additionally performed on the flexible circuit board 1 can be reduced. Possibilities may also decrease.

Referring to FIG. 7 , a laminated structure of a first insulating layer 120 , an adhesive layer 131 , and a plated nonwoven fabric 151 is formed on the conductive pattern 110 . As described above, a portion of the adhesive layer 130 is melted by heat applied during the bonding process and adsorbed to the plated nonwoven fabric 140, thereby forming the adsorbed nonwoven fabric layer 145. Therefore, the plated nonwoven fabric 151 may have a two-layer structure of the adsorbed nonwoven fabric layer 145 and the general nonwoven fabric layer 141 .

Subsequently, referring to FIG. 8 , via holes 160 are formed to pass through the base film 100 , the first insulating layer 120 and the plated nonwoven fabric 151 . The via hole 160 may be formed by penetrating the structure using, for example, punching, drilling, or laser.

Referring to FIG. 9 , a via 170 is formed to fill the via hole 160 . In this case, the first metal layer 180 covering the plated nonwoven fabric 151 and the second metal layer 185 covering the ground pattern 112 may be formed together. Accordingly, the via 170, the first metal layer 180, and the second metal layer 185 may be integrally formed.

Forming the via 170, the first metal layer 180, and the second metal layer 185 is performed by applying a conductive material such as a conductive paste on the inside of the via hole 160, the plated nonwoven fabric 151, and the ground pattern 112. It may include filling and electroplating with a material such as copper. The via 170, the first metal layer 180, and the second metal layer 185 are integrally formed and electrically connected to the ground pattern 112, so that the first metal layer 180 and the second metal layer 185 shield electromagnetic waves and It can function as a ground layer.

Subsequently, as shown in FIG. 1 , a second insulating layer 190 is formed to cover the first and second metal layers 180 and 185 . The second insulating layer 190 may be adhered to the first and second metal layers 180 and 185 by compressing a flexible insulating material such as a coverlay film using a hot press method.

10 to 11 are intermediate-step views for explaining a method of manufacturing a flexible circuit board having an electromagnetic wave shielding sheet attached thereto according to another embodiment of the present invention. This corresponds to illustratively describing the manufacturing method of the flexible circuit board 3 described with reference to FIG. 4 . The manufacturing method described in this embodiment is similar to the process of FIG. 7 in the embodiment of the manufacturing method described above.

However, in this embodiment, there is a difference in performing electroplating in which the nonwoven fabric is pretreated and catalyzed during plating of the plated nonwoven fabric 351 . Through this, a metal layer having a thickness of several μm may be formed on the surface of the plated nonwoven fabric 351 .

Referring to FIG. 10 , a second insulating layer 390 is formed on the plated nonwoven fabric 351, and the base film 300 and the first insulating layer 220. A via hole 360 is formed to pass through the plated nonwoven fabric 351 and the second insulating layer 390 .

The second insulating layer 390 may be formed on the plated nonwoven fabric 351 by hot pressing a flexible insulating material such as a coverlay film.

Subsequently, when the adhesion of the second insulating layer 390 is completed, via holes 360 are formed to penetrate the base film 300, the first insulating layer 320, the plated nonwoven fabric 351, and the second insulating layer 390. is formed The via hole 360 may be formed by penetrating the structure using, for example, punching, drilling, or laser.

Referring to FIG. 11 , a via 370 is formed to fill the via hole 360 . At this time, the metal layer 380 covering the ground pattern 312 may be formed together with the plated nonwoven fabric 351 . Accordingly, the via 370 and the metal layer 385 may be integrally formed. Subsequently, as shown in FIG. 4 , a third insulating layer 395 may be formed to cover the metal layer 385 .

Although the embodiments of the present invention have been described with reference to the accompanying drawings, those skilled in the art can realize that the present invention can be implemented in other specific forms without changing the technical spirit or essential features. you will be able to understand Therefore, the embodiments described above should be understood as illustrative in all respects and not limiting.

100, 200, 300: base film 110, 210, 310: conductive pattern
120, 220, 320: first insulating layer 130, 131, 231, 331: adhesive layer
151, 251, 351: plated nonwoven fabric 160, 360: via hole
170, 270, 370: vias 180, 280: first metal layer
185, 285: second metal layer 190, 290: second insulating layer

Claims (17)

a base film on one surface of which a wiring pattern is formed;
a first insulating layer covering the wiring pattern;
a nonwoven fabric attached by a conductive adhesive layer on the first insulating layer and having a plated surface;
vias formed through the base film, the first insulating layer, the conductive adhesive layer, and the nonwoven fabric;
a first metal layer connected to the via on the plated non-woven fabric;
a second insulating layer covering the first metal layer;
a ground layer formed on the other surface of the base film;
a second metal layer covering the ground layer and integrally formed with the via; and
Including a third insulating layer formed on the second metal layer,
flexible circuit board. According to claim 1,
The non-woven fabric includes a non-woven fabric layer to which the conductive adhesive layer is adsorbed and a general non-woven fabric layer composed of only plated fibrous tissue,
flexible circuit board. According to claim 1,
The first metal layer and the via are integrally formed,
flexible circuit board. delete According to claim 1,
The plating of the plated nonwoven fabric includes at least one of metals such as copper, nickel, gold, palladium, tin, aluminum, or alloys thereof,
flexible circuit board. According to claim 1,
Further comprising at least one film on which a conductive pattern is formed between the wiring pattern and the first insulating layer,
flexible circuit board. a base film on one surface of which a wiring pattern is formed;
a first insulating layer covering the wiring pattern;
a nonwoven fabric attached to the first insulating layer by a conductive adhesive layer and having a plated surface;
a second insulating layer covering the nonwoven fabric;
a ground layer formed on the other surface of the base film;
a metal layer covering the ground layer; and
Including a third insulating layer formed on the metal layer,
flexible circuit board. According to claim 7,
Further comprising a via penetrating the base film, the first insulating layer, the conductive adhesive layer and the nonwoven fabric and integrally formed with the metal layer,
flexible circuit board. According to claim 7,
The non-woven fabric includes a non-woven fabric layer to which the conductive adhesive layer is adsorbed and a general non-woven fabric layer composed of only plated fibrous tissue,
flexible circuit board. providing a base film having a conductive pattern formed thereon;
Forming a first insulating layer and a nonwoven fabric plated on the surface of the base film to be sequentially laminated on the base film;
forming a via hole through the base film, the first insulating layer, and the nonwoven fabric having a plated surface; and
Forming a via by filling the via hole;
The step of forming a first insulating layer and a nonwoven fabric plated on the surface of the base film to be sequentially laminated on the base film,
Aligning the nonwoven fabric to which the first insulating layer and the adhesive layer are attached on the base film,
Including the step of bonding by pressing by a hot press method,
A method for manufacturing a flexible circuit board. delete According to claim 10,
Forming a via by filling the via hole,
Further forming a metal layer covering the nonwoven fabric, wherein the metal layer and the via are formed at the same time,
A method for manufacturing a flexible circuit board. According to claim 12,
The surface-plated nonwoven fabric is formed by electroless plating of a metal material on the fibrous tissue,
A method for manufacturing a flexible circuit board. According to claim 12,
Further comprising forming a second insulating layer covering the metal layer,
Forming the second insulating layer includes the step of bonding an insulating film on the metal layer by hot pressing,
A method for manufacturing a flexible circuit board. According to claim 10,
The nonwoven fabric having the surface plated is adhered to the first insulating layer through the adhesive layer,
The surface-plated nonwoven fabric includes a nonwoven fabric layer to which the adhesive layer is adsorbed and a general nonwoven fabric layer containing only the plated fibrous tissue,
A method for manufacturing a flexible circuit board. According to claim 10,
Forming a second insulating layer covering the nonwoven fabric before forming a via hole through the base film, the first insulating layer, and the nonwoven fabric having a plated surface;
The via hole is formed through the base film, the first insulating layer, the surface-plated nonwoven fabric, and the second insulating layer,
A method for manufacturing a flexible circuit board. According to claim 16,
The nonwoven fabric having the surface plated,
The surface-plated nonwoven fabric is formed by electroplating a metal material on the fiber tissue,
A method for manufacturing a flexible circuit board.

Images