WO2017204553A1

WO2017204553A1 - Fine-wiring flexible circuit board and manufacturing method therefor

Info

Publication number: WO2017204553A1
Application number: PCT/KR2017/005402
Authority: WO
Inventors: 박광수
Original assignee: (주) 화인켐
Priority date: 2016-05-27
Filing date: 2017-05-24
Publication date: 2017-11-30
Also published as: KR101893503B1; KR20170133874A

Abstract

The present invention relates to a fine-wiring flexible circuit board for forming double-sided wiring on both a top part and a bottom part of an insulation layer of a flexible board, and a manufacturing method therefor.

Description

Microcircuit flexible circuit board and manufacturing method thereof

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flexible circuit board for microwiring and a method of manufacturing the same. More particularly, the present invention relates to a flexible circuit board for microwiring and a method of manufacturing the same.

The rapid development of integration in the electronics industry has led to the development of surface mount technology that directly mounts small chips and their components, resulting in thinner and smaller electronic components, making them easier to embed in more complex and narrow spaces. I need something.

In response to these demands, flexible printed circuit boards (FPCBs) have been developed. In the case of a double-sided flexible printed circuit board (FPCB) according to the prior art, copper foil layers are formed on both sides of an insulating layer such as polyimide, respectively, and vias are formed. After connecting the wirings on both sides, the copper foil layers were formed by etching the respective copper layers.

As a related art, in Korean Patent Laid-Open Publication No. 10-2004-0005404, a plurality of through holes are continuously drilled in a dynamic layer plate by a roll-to-roll method using a UV laser drill in a dynamic layer plate, and the through holes are formed through metal plating. After connecting the upper and lower copper foils by applying conductivity to the upper and lower surfaces of the dynamic layer plate, the dry film is adhered to the upper and lower surfaces of the dynamic layer plate by using a roll-to-roll method, and the necessary circuit patterns are formed by exposing, developing and etching the dynamic layer plate by the roll-to-roll method. A method for manufacturing a circuit board is described.

Referring to the prior art, including the prior art described above in more detail with reference to Figure 1, in Figure 1a) drilling on a flexible substrate formed on both sides of the copper foil layer (2, 2 ') on the top and bottom of the polyimide (1) The via hole 3 is formed, and in FIG. 1B), the copper plating layer 4 is formed on the upper surface of the copper foil layer and the surface of the via hole through electroplating or electroless plating. In FIG. 1C, the upper copper plating layer is formed. And forming a photoresist layer 5 such as DFR on the bottom, and developing and patterning the photoresist layer in FIG. 1 d), and using the patterned photoresist layer in FIG. 1 e). After patterning the copper foil layers 2, 2 'and the copper plating layer 4 to the desired wiring form through etching, the adhesive layer 6 and the polyimide are commonly used as coverlay layers in FIG. 1F). The coverlay layer comprising layer (7) is flexible By adhering to both surfaces of the copper plating layer on a board | substrate, the double-sided flexible printed circuit board in which both surfaces were insulated by the coverlay layer can be formed.

However, in the case of such a double-sided flexible printed circuit board according to the related art, as the wiring circuit, the copper foil layers 2 and 2 'and the plating layer 4 formed thereon are etched using a photoresist such as DFR ( Since the desired wiring pattern is formed by FIG. 1 e), a large loss of the pattern is generated, and thus, a width between the upper and lower portions of the wiring layer is not constant or a finer pattern is not formed. There is a problem in precise wiring formation.

Therefore, in order to cope with the high integration of electronic components, the necessity of research and development on the flexible circuit board for micro wiring, which can be further increased in the wiring pattern even in the flexible circuit board, is continuously required.

Accordingly, in order to solve the above problems, the present invention corresponds to the integration of electronic components, and enables wiring patterns to be formed at a high density, and enables formation of fine wiring patterns. It is an object of the present invention to provide a flexible circuit board for fine wiring and a method of manufacturing the same.

The present invention provides a flexible circuit board for fine wiring for forming double-sided wiring on upper and lower portions of the following flexible substrate insulating layer, comprising: a substrate sheet layer made of a polymer material or a metal material; A release layer formed on the entire upper surface of the substrate sheet layer and having a stronger adhesive strength with the substrate sheet layer than the second copper foil layer; A second copper foil layer formed on the upper surface of the release layer; A first wiring layer having predetermined wirings formed on the second copper foil layer; It is formed on the first wiring layer, and comprises at least one polymer material selected from a thermoplastic resin, an epoxy resin, an acrylic resin, the first wiring layer is wrapped in the coverlay adhesive layer to be insulated to form an embedded pattern structure A coverlay adhesive layer; A flexible substrate insulating layer formed on an upper front surface of the coverlay adhesive layer and made of a polymer material; A first copper foil layer formed by plating on the flexible substrate insulating layer; And a second wiring layer having predetermined wirings formed on the first copper foil layer, wherein the second wiring layer penetrates through the first copper foil layer, the flexible substrate insulating layer, and the coverlay adhesive layer to conduct electricity between the first wiring layer and the second wiring layer. It provides a flexible circuit board for micro-wiring comprising at least one or more vias.

The present invention also provides a flexible circuit board for fine wiring for forming double-sided wiring on the upper and lower portions of the flexible substrate insulating layer, the second copper foil layer for supporting the following first wiring layer; A first wiring layer having predetermined wirings formed on the second copper foil layer; It is formed on the first wiring layer, and comprises at least one polymer material selected from a thermoplastic resin, an epoxy resin, an acrylic resin, the first wiring layer is wrapped in the coverlay adhesive layer to be insulated to form an embedded pattern structure A coverlay adhesive layer; A flexible substrate insulating layer formed on an upper front surface of the coverlay adhesive layer and made of a polymer material; A first copper foil layer formed by plating on the flexible substrate insulating layer; And a second wiring layer having predetermined wirings formed on the first copper foil layer, wherein the second wiring layer penetrates through the first copper foil layer, the flexible substrate insulating layer, and the coverlay adhesive layer to conduct electricity between the first wiring layer and the second wiring layer. It provides a flexible circuit board for micro-wiring comprising at least one or more vias.

In one embodiment, the thickness of the coverlay adhesive layer may be in the range of 5 to 50 um, the flexible substrate insulating layer has a thickness of 5 um to 100 um, polyimide, polyester, polyphenylene sulfate, polyester It may include any material selected from sulfone, polyethyl ketone, aramid, polycarbonate, polyarylate, polyamideimide, polyamide.

In one embodiment, the flexible substrate insulating layer and the first copper foil layer may include an electroless nickel plating layer formed by electroless nickel plating in a thickness of 0.05 to 5 um.

In one embodiment, the first copper foil layer may be formed by electroless plating or electroplating in a thickness of 0.5 to 25 um.

In an embodiment, the release layers to the second wiring layers may be sequentially formed below the substrate sheet layer made of the polymer material or the metal material so as to be symmetric with the upper structure of the substrate sheet layer. Can be formed.

In addition, the present invention is a flexible circuit board for micro-wiring in which an upper wiring layer is formed on an upper portion of the flexible substrate insulating layer and a lower wiring layer is formed on a lower portion of the flexible substrate. A lower wiring layer formed thereon; Is formed on the lower wiring layer, and comprises at least one polymer material selected from a thermoplastic resin, an epoxy resin, an acrylic resin, the lower wiring layer is wrapped in the coverlay adhesive layer to be insulated to form an embedded pattern structure Coverlay adhesive layer; A flexible substrate insulating layer formed on an upper front surface of the coverlay adhesive layer and made of a polymer material; And an upper wiring layer on which the wiring according to a predetermined pattern is formed on the flexible substrate insulating layer, wherein at least one via penetrates through the flexible substrate insulating layer and the coverlay adhesive layer to conduct electricity between the upper wiring layer and the lower wiring layer. It provides a flexible circuit board for micro-wiring comprising a.

In addition, the present invention provides a method for producing a flexible circuit board for micro wiring for forming double-sided wiring on the upper and lower portions of the flexible substrate insulating layer, a) a substrate sheet layer made of a polymer material or a metal material; A release layer formed on the entire upper surface of the substrate sheet layer and having a stronger adhesive strength with the substrate sheet layer than the second copper foil layer; A second copper foil layer formed on the upper surface of the release layer; A first wiring layer having predetermined wirings formed on the second copper foil layer; It is formed on the first wiring layer, and comprises at least one polymer material selected from a thermoplastic resin, an epoxy resin, an acrylic resin, the first wiring layer is wrapped in the coverlay adhesive layer to be insulated to form an embedded pattern structure A coverlay adhesive layer; A flexible substrate insulating layer formed on an upper front surface of the coverlay adhesive layer and made of a polymer material; And at least one via hole penetrating through the first copper foil layer, the flexible substrate insulation layer, and the coverlay adhesive layer, the first copper foil layer formed by plating on the flexible substrate insulation layer. Forming a second wiring layer having a predetermined wiring formed on the first copper foil layer of the copper foil; and filling and filling the via hole with copper; And b) separating between the release layer and the second copper foil layer in the flexible circuit board including the second wiring layer and the filled via hole, and detaching the substrate sheet layer and the release layer from the remaining portions. Provided is a method of manufacturing a flexible circuit board.

In addition, in the method of manufacturing a flexible circuit board for microwiring according to the present invention, after the step b), c) the second copper foil layer, the second wiring layer, and the second wiring layer in the first copper foil layer are removed. And forming an upper wiring layer and a lower wiring layer on the upper and lower portions of the flexible substrate insulating layer, and after the c), d) a protective layer on each outer surface of the upper wiring layer and the lower wiring layer. Forming a coverlay film layer as a; may further include.

In addition, after the step c), the present invention includes at least one polymer material selected from a thermoplastic resin, an epoxy resin, and an acrylic resin on each outer surface of the upper wiring layer and the lower wiring layer, and the wiring layer on the substrate to be processed. A coverlay adhesive layer wrapped around the coverlay adhesive layer and insulated to form an embedded pattern structure; A flexible substrate insulating layer formed on an upper front surface of the coverlay adhesive layer and made of a polymer material; And bonding the two flexible copper foil coverlay films to the coverlay adhesive layer and each of the wiring layers, the copper foil layer formed by plating on the flexible substrate insulating layer.

In another aspect, the present invention provides a flexible circuit board for micro-wiring manufactured by the method for producing a flexible circuit board for micro-wiring.

The flexible circuit board for a fine wiring according to the present invention has the above-mentioned process even though the unit process is more complicated than the double-sided wiring forming process according to the prior art in the case of forming double-sided wiring on the upper and lower portions of the flexible substrate insulating layer in the flexible wiring board for the micro-wiring The wiring pattern can be formed at a high density to sufficiently cover the complexity of the microstructure, and there is an advantage in that the formation of the fine wiring pattern is possible.

Further, in the flexible circuit board for fine wiring according to the present invention, in the etching process, the wiring layer to be processed forms an embedded pattern structure by the coverlay adhesive layer, whereby the wiring is an insulating process for forming the fine wiring layer. It can proceed in the state buried in, there is an advantage in the manufacture of fine patterns of the flexible printed circuit board.

1 is a diagram illustrating a method of manufacturing a flexible printed circuit board (FPCB) according to the prior art.

2 is a view showing a cross-section of the flexible copper foil coverlay film according to an embodiment of the present invention.

3 is a diagram illustrating a cross section of a double-sided flexible circuit board obtained by using a flexible copper foil coverlay film according to an embodiment of the present invention.

4 is a diagram illustrating an embodiment of a method of using a flexible copper foil coverlay film in a double-sided flexible circuit board.

5 is a diagram illustrating an embodiment of a method of using a flexible copper foil coverlay film in a double-sided flexible circuit board as a step following FIG. 4 according to the present invention.

6 is a diagram illustrating a method of using a flexible copper foil coverlay film for a double-sided flexible circuit board according to another embodiment of the present invention.

FIG. 7 is a view showing another embodiment of a method of using a flexible copper foil coverlay film for a double-sided flexible circuit board as a subsequent step of FIG. 6 according to the present invention.

8 is a diagram illustrating a method of manufacturing a double-sided flexible circuit board having a multilayer structure according to another embodiment of the present invention.

* Explanation of symbols to understand drawings *

10, 10 ': flexible board insulating layer 11, 11': coverlay adhesive layer

12, 12 ': 1st copper foil layer 16, 16': adhesive layer in a coverlay film

17, 17 ': insulating layer in coverlay film 20: substrate sheet layer

21, 21 ': release layer 22, 22': second copper foil layer

23: photoresist pattern 24, 24 ': first wiring layer

28: photoresist pattern 29, 29 ': second wiring layer

31: upper wiring layer 32: lower wiring layer

33, 33 ': photoresist pattern 34: third wiring layer

34 ': fourth wiring layer 41: second upper wiring layer

42: second lower wiring layer

Hereinafter, with reference to the accompanying drawings will be described in detail a double-sided flexible copper foil flexible circuit board and its manufacturing method. In the accompanying drawings, the dimensions of the structures are shown in an enlarged scale than actual for clarity of the invention. Numbers (eg, first, second, etc.) used in the description process of the present invention are merely an identification symbol for distinguishing one component from another component.

The present invention provides a flexible copper foil coverlay film for forming double-sided wiring on the top and bottom of the flexible substrate insulating layer.

Generally, a coverlay film is used for the purpose of protecting a wiring part, and is formed by laminating | stacking the film material for coverlays made from synthetic resins, such as a polyimide resin, and an adhesive bond layer. In the case of such a coverlay film can be covered by touching the adhesive layer side of the coverlay film to the wiring portion of the circuit board using a method such as a hot press to cover the wiring portion of the printed circuit board.

Here, the adhesive layer is required to have high adhesion to both the circuit wiring patterns such as copper wiring and the film material for coverlay, and in the case of the film material for copper lay, polyimide, polyester, polyphenylene sulfate, polyester sulfone Insulation materials, such as polyethyl ketone, aramid, polycarbonate, polyarylate, polyamideimide, and polyamide, may be used.

On the other hand, the flexible copper foil coverlay film used in the present invention is characterized by including a first copper foil layer formed by plating on top of an insulating material such as polyimide, which is an upper layer in a conventional coverlay film.

The structure of the flexible copper foil coverlay film which concerns on this invention is shown in FIG.

As shown in FIG. 2, the flexible copper foil coverlay film according to the present invention includes at least one polymer material selected from a thermoplastic resin, an epoxy resin, and an acrylic resin, and the wiring layer on the substrate to be treated is applied to the following coverlay adhesive layer. A coverlay adhesive layer 11 wrapped and insulated to form an embedded pattern structure; A flexible substrate insulating layer 10 formed on an upper front surface of the coverlay adhesive layer and made of a polymer material; And a first copper foil layer 12 formed by plating on the flexible substrate insulating layer.

In the present invention, a desired wiring layer may be formed on the upper and lower portions of the flexible copper foil coverlay film based on the flexible substrate insulating layer 10, and in FIG. 3, a double-sided flexible circuit finally obtained by using the flexible copper foil coverlay film. The cross section of the substrate is shown.

More specifically, as shown in FIG. 3, the upper wiring layer 31 derived from the first copper foil layer (described later) and the wiring layer formed on the first copper foil layer on the flexible substrate insulating layer 10. ) Is formed, and the cover layer adhesive layer 11 and the second copper foil layer (described later) and the second copper foil layer formed on the lower portion of the cover layer adhesive layer below the flexible substrate insulating layer 10 A lower wiring layer 32 derived from one wiring layer is formed, and

conventional coverlay films

16, 16 ', 17, and 17' are laminated on each outer side of the upper wiring layer and the lower wiring layer to manufacture a double-sided flexible circuit board. Can be.

Meanwhile, the coverlay adhesive layer 11 of the flexible copper foil coverlay film according to the present invention is a portion which is directly bonded to a metal wiring layer, which is a circuit surface of a flexible circuit board, through a press, and is bonded. It is insulated while enclosing the circuit and serves as an embedded. With this feature, it is possible to eliminate the loss of the width of the wiring layer in the subsequent etching process.

Herein, the term 'embedded' refers to a state in which a part, an element, or a wiring is embedded in a specific device, wherein the circuit of the metal wiring layer in the printed circuit board is applied to the flow of the adhesive in the coverlay adhesive layer in a subsequent process such as a pressing process. Insulation by wrapping means to be built.

According to the present invention, the double-sided flexible circuit board obtained by using the copper foil coverlay film according to the present invention is a wiring layer to be processed in proceeding an etching process rather than a method of forming a wiring layer through etching or the like according to the prior art. By forming the embedded pattern structure by the coverlay adhesive layer, the etching process for forming the fine wiring layer can be performed while the wiring is buried in the insulating layer, which is advantageous in forming the fine pattern of the flexible printed circuit board. have.

The coverlay adhesive layer may have a thickness in the range of 5 to 50 um.

In addition, it may include at least one polymer material selected from a thermoplastic resin, an epoxy resin, an acrylic resin.

More specifically, the coverlay adhesive layer may include a thermosetting resin having a crosslinkable functional group so as to function to be cured through crosslinking between molecules after pressing, and for this purpose, an epoxy polymer resin or an acrylic polymer is generally included in a polyimide film. It may comprise a resin.

Here, the epoxy resin may include at least one of bisphenol A type epoxy, bisphenol F type epoxy, and phenol novolac type epoxy.

It may also include thermoplastic resins capable of controlling flow, such as acrylonitrile-butadiene copolymer, and the like, and bromine-based flame retardants or phosphorus-based flame retardants may be added to have a level of flame retardance that must be satisfied as an electronic component. Can lose.

In addition, the adhesive layer may include a filler and a curing agent, the filler may include at least one of an inorganic filler and an phosphine type filler, and the hardener may be an amine type curing agent. at least one of a type hardener, a phenol type hardener, and an acid anhydride type hardener.

As an exemplary configuration of the adhesive layer, 100 to 250 parts by weight of the thermoplastic resin, may include 100 to 250 parts by weight of epoxy resin, 40 to 100 parts by weight of filler, 20 to 50 parts by weight of the curing agent.

In addition, the flexible substrate insulating layer 10 formed on the upper front surface of the coverlay adhesive layer and made of a polymer material has a thickness of 5 um to 100 um, polyimide, polyester, polyphenylene sulphate, polyester sulfone, and polyethylenol. It may include any material selected from ketones, aramids, polycarbonates, polyarylates, polyamideimides, polyamides, and preferably polyimides may be used.

In addition, the flexible substrate insulating layer may be subjected to surface treatment such as hydrolysis, corona discharge, low temperature plasma, physical surface irregularities treatment, and easily adhesive coating treatment, if necessary.

Meanwhile, the first copper foil layer 12 formed on the flexible substrate insulating layer 10 may be formed by plating. In this case, the first copper foil layer may be formed by electroplating or electroless plating, and, when directly formed on the flexible substrate insulating layer, is formed by electroless plating.

Meanwhile, in the present invention, an electroless nickel plating layer (not shown) formed between the flexible substrate insulating layer and the first copper foil layer by electroless nickel plating has a thickness of 0.05 to 5 um, preferably 0.05 to 3 um. It may include.

In the case of the electroless nickel plated layer, when the thickness is 0.05 um or less, the adhesion with the electroplating layer to be formed on the electroless plated layer may be reduced, and when the thickness is greater than .5 um, the ductility decreases due to warpage. Since cracks may have disadvantages, it is desirable to have a thickness within the above-described range.

When the electroless nickel plating layer is formed in the present invention, the first copper foil layer formed on the nickel plating layer may be formed by electrolytic plating or electroless plating, and preferably, when the nickel electroless plating layer is formed, 1 The copper foil layer may be formed by electroplating.

The electroless nickel plating layer may be a pretreatment step of forming a roughness of the insulation layer by immersing or spraying a flexible substrate insulation layer under basic conditions including a metal salt, and for nickel electroless plating after the pretreatment step. The method may include forming a seed layer, and forming an electroless nickel plating layer on the insulating layer on which the seed layer is formed.

For example, as the pretreatment step under basic conditions in the pretreatment step, the surface area of the flexible substrate may be increased by immersion or spraying in an alkaline aqueous solution including at least one selected from NH 3, KOH, NaOH, and an organic amine, and then drying. And it can enhance the adhesion with the plating layer, wherein the alkaline aqueous solution used may be an aqueous solution of 0.01 ~ 1 M concentration.

As the metal salt contained in the aqueous solution in the pretreatment step, an aqueous solution of a transition metal salt or any one of metal salts selected from Ga, Ge, In, Sn, Sb, Pb, and Bi may be used. In this case, the metal salt may be any one selected from a transition metal or any one metal halide, metal sulfate, or metal acetate selected from Ga, Ge, In, Sn, Sb, Pb, and Bi.

Immersion time of the flexible substrate in the basic aqueous solution containing the metal salt may have a range of 10 seconds to 30 minutes, preferably 30 seconds to 10 minutes. In this case, the temperature of the aqueous solution to be immersed may have a range of 0 degrees to 40 degrees, preferably immersed at room temperature (25 degrees).

In the present invention, when the pretreatment step for forming the seed layer is performed, the adhesion between the electroless nickel plated layer and the substrate is more improved than the method of forming the seed layer without performing the pretreatment step to form the electroless nickel plated layer. Can be.

On the other hand, after the pretreatment step, the seed layer forming step for nickel electroless plating may be formed to quickly form an electroless nickel plating layer on the flexible substrate insulating layer, and to form a suitable strength with the flexible substrate insulating layer to help combine it. Do it. At this time, the component of the seed layer may include any one metal component selected from Au, Ag, Pt, Cu, Ni, Fe, Pd, Co or their alloys, preferably as the seed metal layer Palladium salt can be used. In this case, it may further contain other transition metal components other than palladium which is the seed metal component.

In the present invention, the forming of the seed layer may be performed by selectively converting the flexible substrate insulating layer subjected to the pretreatment step into any one metal salt selected from Au, Ag, Pt, Cu, Ni, Fe, Pd, Co, or an alloy thereof. , Immersing in an aqueous solution containing a reducing agent for reducing the metal salt.

In this case, the immersion time of the flexible substrate in the aqueous solution may have a range of 10 seconds to 30 minutes, preferably 30 seconds to 10 minutes. In this case, the temperature of the aqueous solution to be immersed may have a range of 0 degrees to 40 degrees, preferably immersed at room temperature (25 degrees).

In the present invention, the pretreatment step for forming the seed layer on the flexible substrate, or the step of forming the seed layer is by immersing the substrate in an aqueous solution and then applying an ultrasonic wave to the immersed substrate, thereby promoting a reaction and adhesion to the plating layer Can be improved.

Subsequently, the electroless nickel plating layer may be formed using a nickel salt, a reducing agent, a complex, or the like, to form an electroless plating layer on the substrate.

The electroless plating may be performed by reducing nickel ions with a reducing agent by reducing and depositing nickel on a substrate or the like using a plating solution in which a compound containing nickel ions and a reducing agent are mixed.

The electroless plating is performed for 1 to 60 minutes so that an electroless plating layer having a thickness required to be immersed in a plating bath containing a plating solution including a reducing agent, an additive, and a stabilizer is plated on the flexible substrate insulating layer. Non-limiting examples include formaldehyde, hydrazine or salts thereof, cobalt sulfate (II), formalin, glucose, glyoxylic acid, hydroxyalkylsulfonic acid or salts thereof, hypophosphoric acid or salts thereof, boron hydride compounds, dialkyls Amine borane and the like, in addition to the various reducing agents may be used depending on the type of metal.

Furthermore, the electroless plating solution may include a complexing agent for preventing the solution containing nickel salt from being reduced in the liquid phase and a pH adjusting agent for maintaining the electroless plating solution at an appropriate pH so that the reducing agent is oxidized. Can be.

As an exemplary configuration of the flexible substrate insulating layer, the coverlay adhesive layer and the first copper foil layer according to the present invention, an insulating film (5 to 100 μm) / adhesive layer (5 to 50 μm) / electrostatic such as a polyimide film or an aramid film Sea nickel plating layer (0.05 to 5 ㎛) / the first copper foil layer (0.5 to 25 ㎛) may have a range.

On the other hand, the flexible copper foil coverlay film may further include a release film or a release paper as a protective film to protect the coverlay adhesive layer 11, can be used immediately in the field by removing the protective film immediately before actual use. .

The flexible copper foil coverlay film according to the present invention can be applied to the manufacture of a double-sided flexible printed circuit board having a fine pattern of higher density.

4 is a view showing an embodiment of a method of using a flexible copper foil coverlay film according to the present invention for a double-sided flexible circuit board, and forming double-sided wiring on the upper and lower portions of the flexible substrate insulating layer in the flexible copper foil coverlay film. It can be used in the manufacture of a flexible circuit board (Fig. 4d) for fine wiring.

The microcircuit flexible circuit board shown in FIG. 4D may further include a substrate sheet layer 20 made of a polymer material or a metal material; A release layer 21 formed on the upper surface of the substrate sheet layer and having a stronger adhesive strength with the substrate sheet layer than the second copper foil layer; A second copper foil layer 22 formed on the upper surface of the release layer; A first wiring layer 24 having predetermined wirings formed on the second copper foil layer; It is formed on the first wiring layer, and comprises at least one polymer material selected from a thermoplastic resin, an epoxy resin, an acrylic resin, the first wiring layer is wrapped in the coverlay adhesive layer to be insulated to form an embedded pattern structure Coverlay adhesive layer 11; A flexible substrate insulating layer 10 formed on an upper front surface of the coverlay adhesive layer and made of a polymer material; And a first copper foil layer 12 formed by plating on the flexible substrate insulating layer.

The flexible circuit board for microwiring shown in FIG. 4D may be manufactured by steps a) to d) described below.

This is more specifically, a) preparing a flexible copper foil coverlay film according to the present invention, which comprises a) at least one polymer material selected from a) a thermoplastic resin, an epoxy resin, an acrylic resin, as described above, A coverlay adhesive layer in which the first wiring layer is wrapped around the coverlay adhesive layer and insulated to form an embedded pattern structure; A flexible substrate insulating layer 10 formed on an upper front surface of the coverlay adhesive layer and made of a polymer material; And preparing a flexible copper foil coverlay film comprising a first copper foil layer 12 formed on the flexible substrate insulating layer by plating. b) sheet layer 20; A release layer 21 formed on the upper surface of the substrate sheet layer and having a stronger adhesive strength with the substrate sheet layer than the second copper foil layer; And a second copper foil layer 22 formed on the entire upper surface of the release layer. c) forming a first wiring layer 24 to form a predetermined wiring on the second copper foil layer; And d) bonding the flexible copper foil coverlay film prepared in step a) to the coverlay adhesive layer 11 and the first wiring layer 24 so as to face the first wiring layer 24 so as to face the first wiring layer 24. It comprises; a.

Here, step a) has been described above, and the substrate sheet in step b) will be described in detail.

The configuration of the substrate sheet in step b) is shown in Figure 4a, which includes a substrate sheet layer 20; Release layer 21; And a second copper foil layer 22.

The substrate sheet layer 20 may include a polymer material having an insulating property such as polyester, polyamide, polyimide, FR-4, or the like, in which a copper foil or the like is attached to the insulating material, Preferably, the material is made of a material in which copper foil (Cu Foil) is attached to the polymer material or the safe molecule material, and may have a thickness in a range of 20 to 2000 um, but is not limited thereto.

The substrate sheet layer 20 is used to fabricate a flexible double-sided printed circuit board, but finally corresponds to a component that is removed together with the release layer 21.

On the other hand, the release layer 21 is formed on the entire upper surface of the substrate sheet layer, in order to be removed together with the substrate sheet layer 20, the adhesive strength with the substrate sheet layer 20 side of the second copper foil layer 22 It should be made to be stronger than the adhesive strength with the side, the bonding surface of the release layer and the second copper foil layer may be surface-treated or release agent for easy separation in the future.

The release layer may be made through a surface treatment of a release polymer or a metal layer or chemicals, the thickness may have a range of 0.1 to 100 um, preferably may have a range of 0.3 to 30 um.

On the other hand, the second copper foil layer formed on the upper surface of the release layer has a thickness of 0.3 to 8 um, preferably has a range of 0.5 to 5 um.

Like the first copper foil layer 12, the second copper foil layer 22 may be formed by electroless plating or electroplating, and preferably, may be formed by electroless plating. In addition, the second copper foil layer 22 supports a first wiring layer 24 to be formed later to form a predetermined wiring, and corresponds to a metal layer that is energized with the first wiring layer.

In the case where the thickness of the second copper foil layer 22 in the present invention is not thinned, the thickness to be removed in the etching process of removing the second copper foil layer 22 in a subsequent process may be increased. Therefore, by using the thickness of the second copper foil layer 22 as a copper foil layer that is thinner than or equal to the release layer, the second copper foil layer 22 is made thin, and the second copper foil layer ( The productivity increase can be realized by shortening the process of eliminating 22).

Meanwhile, the step of forming the first wiring layer 24 to form a predetermined wiring on the second copper foil layer, which is the step c), will be described with reference to FIGS. 4B and 4C.

4B is a diagram showing the formation of a resist pattern 23 to form the first wiring layer 24 on the substrate sheet in step b). To this end, a dry resist film layer is formed on the second copper foil layer, and a resist pattern 23 desired is formed through a lithography process including exposure and development.

Subsequently, after copper plating the portion of the second copper foil layer 22 exposed to the resist pattern, stripping the resist pattern 23 is performed on the second copper foil layer on the substrate sheet as shown in FIG. 4C. The first wiring layer 24 can be formed.

In this case, a deposition process such as sputtering may be introduced instead of copper plating, but it is advantageous to use a plating method in consideration of process economics.

In the case of forming the micro wiring layer according to the prior art, it is possible to form the micro wiring layer by etching the copper foil layer using a photoresist method, but in this case, the selective etching of the copper layer is quite difficult and the etching of the fine pattern is performed. In order to solve the difficulty of the present invention, the first wiring layer 24 is formed by a plating method or a deposition method so as to have a finer line width.

As a result, high-density microwiring without deviation between the upper and lower portions of the first wiring layer can be formed.

That is, in the step c), after forming the resist pattern 23, the first wiring layer 24 may be copper plated or deposited to form a finer circuit pattern in a more precise shape.

In the present invention, step d) as a final step for manufacturing the flexible wiring board for the fine wiring is performed by attaching the cover film adhesive layer to the flexible copper foil coverlay film prepared in step a) above the first wiring layer 24 formed in step c). 11) and bonding the first wiring layer 24 to face each other, which is illustrated in FIG. 4D.

In the present invention, the first wiring layer serves to embed the circuit while covering the circuit through the flow of the appropriate coverlay adhesive layer 11 in the coverlay press process. Through this feature, since the wiring layer is buried in the insulating layer, the wiring layer has a characteristic of eliminating the loss of the wiring width of the wiring layer in the subsequent etching process.

The coverlay adhesive layer 11 in the flexible circuit board for fine wiring obtained according to the present invention may have a thickness in the range of 5 to 50 um, the flexible substrate insulating layer 10 has a thickness of 5 um to 100 um, It may include any one material selected from polyimide, polyester, polyphenylene sulfate, polyester sulfone, polyethyl ketone, aramid, polycarbonate, polyarylate, polyamideimide, polyamide, the flexible substrate The insulating layer 10 and the first copper foil layer 12 may include an electroless nickel plating layer formed by electroless nickel plating in a thickness of 0.5 to 5 um.

Meanwhile, the flexible circuit board for fine wiring of the present invention as shown in FIG. 4D may be used as a double-sided flexible printed circuit board in a subsequent process. To this end, the flexible circuit board for fine wiring may additionally include at least one via hole, which is illustrated in FIG. 4E.

The via hole refers to a hole processed for electrical conduction between layers in a printed circuit board. In the present invention, the via hole is formed to connect circuit wirings formed on the upper and lower portions of the flexible substrate insulating layer 10, respectively. A via hole connected to the first wiring layer 24 may be formed through the copper foil layer, the flexible substrate insulating layer, and the coverlay adhesive layer.

Such via holes may be formed by mechanical drilling or laser drilling, and for example, the via holes may be formed by etching by UV or CO 2 laser.

The flexible circuit board for fine wiring including the via hole may be used to manufacture a double-sided flexible printed circuit board through an additional process, which is illustrated in FIG. 5.

FIG. 5 is a view showing an embodiment of a method for manufacturing a double-sided flexible circuit board using a flexible circuit board for fine wiring including a flexible copper foil coverlay film according to the present invention.

When the following process for producing a double-sided flexible circuit board according to the present invention in more detail, the microcircuit flexible circuit board having a structure of Figure 5c according to the present invention comprises a) a substrate sheet layer made of a polymer material or a metal material; A release layer formed on the entire upper surface of the substrate sheet layer and having a stronger adhesive strength with the substrate sheet layer than the second copper foil layer; A second copper foil layer formed on the upper surface of the release layer; A first wiring layer having predetermined wirings formed on the second copper foil layer; It is formed on the first wiring layer, and comprises at least one polymer material selected from a thermoplastic resin, an epoxy resin, an acrylic resin, the first wiring layer is wrapped in the coverlay adhesive layer to be insulated to form an embedded pattern structure A coverlay adhesive layer; A flexible substrate insulating layer formed on an upper front surface of the coverlay adhesive layer and made of a polymer material; And a first copper foil layer formed by plating on the flexible substrate insulation layer, wherein the first copper foil layer, at least one via penetrates the flexible substrate insulation layer, and the coverlay adhesive layer. Forming a second wiring layer having a predetermined wiring formed on the first copper foil layer of the copper foil; and filling and filling the via hole with copper; And b) separating between the release layer and the second copper foil layer in the flexible circuit board including the second wiring layer and the filled via hole, and detaching the substrate sheet layer and the release layer from the remaining portions.

Wherein a) is a step of forming a resist pattern 28 in FIG. 5A using the flexible circuit board having the structure of FIG. 4E, and filling the second wiring layer 29 and via holes in FIG. 5B using the same. Performing a step).

More specifically, in FIG. 5A, the resist pattern 28 is formed to form the second wiring layer 29 on the first copper foil layer 12 having the via holes formed by the same process as in FIG. 4B. .

To this end, a photoresist film layer is formed on the first copper foil layer 12 on which the via holes are formed, as in FIG. 4B, and a desired lithography process is performed through lithography including exposure and development. 2 The resist pattern 28 necessary for forming a wiring layer is formed.

In FIG. 5B, the second wiring layer 29 is formed using the resist pattern 28, and the resist pattern 28 is removed.

Referring to the flexible circuit board for micro-wiring shown in FIG. 5b in more detail, this is a flexible circuit board for micro-wiring for forming double-sided wiring on the upper and lower portions of the following flexible substrate insulating layer, a substrate sheet made of a polymer material or a metal material layer; A release layer formed on the entire upper surface of the substrate sheet layer and having a stronger adhesive strength with the substrate sheet layer than the second copper foil layer; A second copper foil layer formed on the upper surface of the release layer; A first wiring layer having predetermined wirings formed on the second copper foil layer; It is formed on the first wiring layer, and comprises at least one polymer material selected from a thermoplastic resin, an epoxy resin, an acrylic resin, the first wiring layer is wrapped in the coverlay adhesive layer to be insulated to form an embedded pattern structure A coverlay adhesive layer; A flexible substrate insulating layer formed on an upper front surface of the coverlay adhesive layer and made of a polymer material; A first copper foil layer formed by plating on the flexible substrate insulating layer; And a second wiring layer having predetermined wirings formed on the first copper foil layer, wherein the second wiring layer penetrates through the first copper foil layer, the flexible substrate insulating layer, and the coverlay adhesive layer to conduct electricity between the first wiring layer and the second wiring layer. Corresponding to the flexible circuit board for micro-wiring comprising at least one or more vias.

In order to manufacture the flexible circuit board for the microwiring having the structure of FIG. 5B, after the first copper foil layer 12 exposed to the resist pattern is copper plated or deposited in the state where the resist pattern 28 is formed, the resist By removing strips of the pattern 28, the second wiring layer 29 may be formed on the first copper foil layer. In this case, metal vias are formed in the via holes by plating or deposition.

The second wiring layer 29 according to the present invention is preferably plated in consideration of process advantages and economical efficiency, and similarly to the first wiring layer 24, the wiring layer by an etching process using a photoresist method of the copper foil layer according to the prior art. It has the advantage of having a finer line width.

On the other hand, step b) in the method for manufacturing a flexible circuit board for microwiring of the present invention is a step of separating between the release layer and the second copper foil layer, the second wiring layer 29 is formed, the via hole is filled After the vias are formed, the substrate sheet layer 20 and the release layer 21 are removed.

In FIG. 5C, the release layer 21 and the second layer may be fabricated to manufacture a double-sided flexible circuit including a second wiring layer 29 and a first copper foil layer 12, a first wiring layer 24, and a second copper foil layer 22. The step of separating the substrate sheet layer and the release layer by separating the two copper foil layers 22 is illustrated.

Referring to the flexible circuit board for fine wiring shown in FIG. 5C in more detail, it includes a second copper foil layer for supporting the first wiring layer; A first wiring layer having predetermined wirings formed on the second copper foil layer; It is formed on the first wiring layer, and comprises at least one polymer material selected from a thermoplastic resin, an epoxy resin, an acrylic resin, the first wiring layer is wrapped in the coverlay adhesive layer to be insulated to form an embedded pattern structure A coverlay adhesive layer; A flexible substrate insulating layer formed on an upper front surface of the coverlay adhesive layer and made of a polymer material; A first copper foil layer formed by plating on the flexible substrate insulating layer; And a second wiring layer having predetermined wirings formed on the first copper foil layer, wherein the second wiring layer penetrates through the first copper foil layer, the flexible substrate insulating layer, and the coverlay adhesive layer to conduct electricity between the first wiring layer and the second wiring layer. Corresponding to the flexible circuit board for micro-wiring comprising at least one or more via holes.

By separating between the release layer 21 and the second copper foil layer 22 in FIG. 5C, the release layer is desorbed, but the second copper foil layer 22 existing under the first wiring layer 24 remains. . In this case, the second copper foil layer 22 may be removed together with a portion of the second wiring layer 29 and the first copper foil layer 12 by etching in a later process.

Here, the etching process may be formed by dry or wet etching, preferably a wet method may be used, through which the second copper foil layer 22, the second wiring layer 29, and the first copper foil layer 12 are formed. By removing the portion where the second wiring layer is not formed, the upper wiring layer 31 and the lower wiring layer 32 can be formed on the upper and lower portions of the flexible substrate insulating layer 10.

FIG. 5D illustrates a double-sided flexible circuit board with a portion of the second copper foil layer 22, the second wiring layer 29, and the first copper foil layer 12 removed in accordance with the etching process. An upper wiring layer 31 is formed by etching the first copper foil layer 12 and the second wiring layer 29 formed on the first copper foil layer on the upper portion of the flexible substrate insulating layer 10. The lower wiring layer 32 is formed by etching the second copper foil layer 22 formed at the bottom of the substrate.

The flexible wiring board for microwiring according to FIG. 5D is a flexible wiring board for microwiring in which an upper wiring layer is formed on an upper portion of the flexible substrate insulating layer and a lower wiring layer is formed on a lower portion of the flexible wiring board. A lower wiring layer in which wiring according to a preset pattern is formed; Is formed on the lower wiring layer, and comprises at least one polymer material selected from a thermoplastic resin, an epoxy resin, an acrylic resin, the lower wiring layer is wrapped in the coverlay adhesive layer to be insulated to form an embedded pattern structure Coverlay adhesive layer; A flexible substrate insulating layer formed on an upper front surface of the coverlay adhesive layer and made of a polymer material; And an upper wiring layer on which the wiring according to a predetermined pattern is formed on the flexible substrate insulating layer, wherein at least one via penetrates through the flexible substrate insulating layer and the coverlay adhesive layer to conduct electricity between the upper wiring layer and the lower wiring layer. It characterized by including.

That is, the upper wiring layer 31 is derived from the first copper foil layer 12 and the second wiring layer 29 formed on the first copper foil layer, and the second wiring layer in the first copper foil layer 12 is formed. It is important to completely remove the portion that is not formed so that the upper wiring layer 31 forms a circuit according to the pattern of the second wiring layer 29.

In addition, although the lower wiring layer 32 originates from the 1st wiring layer 24 and the 2nd copper foil layer 22, a circuit is formed according to the pattern of the 1st wiring layer 24 by removing the 2nd copper foil layer 22 substantially. To be.

In addition, the said 1st copper foil layer 12 and the 2nd copper foil layer 22 in this invention can have the same thickness, considering that it removes by an etching process.

Finally, the present invention is a step of forming a coverlay film layer as a protective layer on each outer surface of the upper wiring layer and the lower wiring layer, the double-sided flexible circuit board formed with the upper wiring layer 31 and the lower wiring layer 32 according to Figure 5e It may further include;

Here, the coverlay film layer used for use as a protective layer may attach a coverlay film that is commonly used.

5E shows a coverlay film having a conventional structure including an adhesive layer 16 and an insulating layer 17 on the upper wiring layer 31 and the lower wiring layer 32, respectively, by closely contacting both sides of the wiring layer on the flexible printed circuit board. 2 shows a double-sided flexible circuit board in which both surfaces are insulated by the coverlay layer.

In addition, the present invention can provide a flexible circuit board for microwiring obtained by the method for producing a double-sided flexible circuit board described above.

On the other hand, the flexible circuit board for fine wiring containing the flexible copper foil coverlay film in this invention can improve manufacturing efficiency by forming the same structure not only in the upper part of the board | substrate sheet layer 20 but also in the lower part of a board | substrate sheet layer.

More specifically, the present invention, in the flexible circuit board for micro-wiring according to Figure 5b, the substrate sheet layer 20 made of the polymer material or metal material; at the bottom of the additional structure to be symmetrical with the upper structure of the substrate sheet layer In addition, the release layer 21 'to the second wiring layer 29' may be formed in order, and a flexible circuit board (structure of FIG. 7B) for fine wiring with via holes formed may be provided.

6 and 7 illustrate steps for forming an additional double-sided micro-wiring flexible circuit board at the bottom of the substrate sheet layer 20. Referring to FIGS.

More specifically, in FIG. 6, the release layer 21 ′ to the first copper foil layer 12 ′ are further formed under the substrate sheet layer 20 so as to be symmetric to the upper structure of the substrate sheet layer. The structure of the flexible circuit board for wiring is illustrated, and FIG. 7 illustrates a method of manufacturing a plurality of double-sided flexible printed circuit boards using the flexible circuit board for microwiring according to FIG. 6.

Each of the processes illustrated in FIGS. 6 and 7 is the same as the description of the processes illustrated in FIGS. 4 and 6, and thus, a person skilled in the art may appropriately select and apply the processes. .

On the other hand, the double-sided flexible circuit board for micro-wiring of the present invention may additionally include a plurality of wiring layers each of the wiring on both sides through the stack.

This will be described in detail with reference to FIG. 8.

FIG. 8 is a diagram illustrating a method of manufacturing a double-sided flexible circuit board having a multilayer structure according to another embodiment of the present invention, wherein each of the upper and lower wiring layers of the double-sided flexible circuit board having the structure of FIG. Adhering the flexible copper foil coverlay film according to the present invention to the outer surface (FIG. 8A), forming a via hole thereto (FIG. 8B), and the copper foil layer 12 positioned outside of each flexible copper foil coverlay film 12 ') to form resist patterns 33 and 33' (FIG. 8C), after which the third and fourth wiring layers 34 and 34 'are formed using the resist patterns 33 and 33'. In the forming step (FIG. 8D), finally, the copper foil layer 12 is removed from the portion where the third wiring layer 34 and the third wiring layer are not formed, and the fourth wiring layer 34 ′ and the fourth wiring layer are not formed. The second upper wiring layer 41 and the second lower wiring layer 42 are formed by removing the copper foil layer 12 'of the portion. Forming step (FIG. 8E).

Here, the double-sided flexible printed circuit board having the structure of FIG. 8A has an upper wiring layer 31 and a lower wiring layer 32 formed on the upper and lower portions of the flexible substrate insulating layer, and then each outer side surface of the upper wiring layer and the lower wiring layer. A coverlay adhesive layer comprising at least one polymer material selected from a thermoplastic resin, an epoxy resin, and an acrylic resin, wherein the wiring layer on the substrate to be treated is wrapped in the following coverlay adhesive layer and insulated to form an embedded pattern structure ; A flexible substrate insulating layer formed on an upper front surface of the coverlay adhesive layer and made of a polymer material; And bonding the coverlay adhesive layer and the respective wiring layer to the two flexible copper foil coverlay films including; and a copper foil layer formed by plating on the flexible substrate insulating layer.

Detailed steps of the method for manufacturing a double-sided flexible circuit board having the structure of FIG. 8A are the same as those described above in the manufacture of the flexible circuit board having the structure of FIG. 4D or 6D, and the structure of FIGS. 8B to 8E will be described later. Manufacturing of the flexible circuit board having the same as described in the process described in Figures 6 and 7 described above will correspond to a method that can be applied by those skilled in the art as appropriate.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flexible circuit board for microwiring and a method of manufacturing the same.

Claims

As a flexible circuit board for micro wiring for forming double-sided wiring on the upper and lower portions of the flexible substrate insulating layer,

A substrate sheet layer made of a polymer material or a metal material;

A release layer formed on the entire upper surface of the substrate sheet layer and having a stronger adhesive strength with the substrate sheet layer than the second copper foil layer;

A second copper foil layer formed on the upper surface of the release layer;

A first wiring layer having predetermined wirings formed on the second copper foil layer;

It is formed on the first wiring layer, and comprises at least one polymer material selected from a thermoplastic resin, an epoxy resin, an acrylic resin, the first wiring layer is wrapped in the coverlay adhesive layer to be insulated to form an embedded pattern structure A coverlay adhesive layer;

A flexible substrate insulating layer formed on an upper front surface of the coverlay adhesive layer and made of a polymer material;

A first copper foil layer formed by plating on the flexible substrate insulating layer; And

And a second wiring layer having predetermined wirings formed on the first copper foil layer.

And at least one via penetrating through the first copper foil layer, the flexible substrate insulating layer, and the coverlay adhesive layer to conduct electricity between the first wiring layer and the second wiring layer.
As a flexible circuit board for micro wiring for forming double-sided wiring on the upper and lower portions of the flexible substrate insulating layer,

A second copper foil layer supporting the following first wiring layer;

A first wiring layer having predetermined wirings formed on the second copper foil layer;

It is formed on the first wiring layer, and comprises at least one polymer material selected from a thermoplastic resin, an epoxy resin, an acrylic resin, the first wiring layer is wrapped in the coverlay adhesive layer to be insulated to form an embedded pattern structure A coverlay adhesive layer;

A flexible substrate insulating layer formed on an upper front surface of the coverlay adhesive layer and made of a polymer material;

A first copper foil layer formed by plating on the flexible substrate insulating layer; And

And a second wiring layer having predetermined wirings formed on the first copper foil layer.

And at least one via penetrating through the first copper foil layer, the flexible substrate insulating layer, and the coverlay adhesive layer to conduct electricity between the first wiring layer and the second wiring layer.
The method according to claim 1 or 2,

The thickness of the coverlay adhesive layer is in the range of 5 to 50 um, the flexible circuit board for microwiring.
The method according to claim 1 or 2,

The flexible substrate insulating layer has a thickness of 5 um to 100 um,

For microwiring comprising any one material selected from polyimide, polyester, polyphenylene sulfate, polyester sulfone, polyethyl ketone, aramid, polycarbonate, polyarylate, polyamideimide, polyamide Flexible circuit board.
The method according to claim 1 or 2,

And an electroless nickel plating layer formed by electroless nickel plating in a range of 0.05 to 5 um in thickness between the flexible substrate insulating layer and the first copper foil layer.
The method of claim 1,

The release layer to the second wiring layer of claim 1 are sequentially formed in the lower portion of the substrate sheet layer made of the polymer material or the metal material so as to be symmetric to the upper structure of the substrate sheet layer, and further, vias are formed. A flexible circuit board for microwiring, characterized in that.
As a flexible wiring board for micro wiring, an upper wiring layer is formed on an upper portion of a flexible substrate insulating layer, and a lower wiring layer is formed on a lower portion, respectively.

A lower wiring layer in which wiring according to a predetermined pattern is formed below the flexible substrate insulating layer and the coverlay adhesive layer;

Is formed on the lower wiring layer, and comprises at least one polymer material selected from a thermoplastic resin, an epoxy resin, an acrylic resin, the lower wiring layer is wrapped in the coverlay adhesive layer to be insulated to form an embedded pattern structure Coverlay adhesive layer;

A flexible substrate insulating layer formed on an upper front surface of the coverlay adhesive layer and made of a polymer material; And

And an upper wiring layer having wirings formed in a predetermined pattern on the flexible substrate insulating layer.

And at least one via penetrating through the flexible substrate insulating layer and the coverlay adhesive layer to conduct electricity between the upper wiring layer and the lower wiring layer.
As a method of manufacturing a flexible circuit board for micro wiring for forming double-sided wiring on the upper and lower portions of the flexible substrate insulating layer,

a) a substrate sheet layer made of a polymer material or a metal material; A release layer formed on the entire upper surface of the substrate sheet layer and having a stronger adhesive strength with the substrate sheet layer than the second copper foil layer; A second copper foil layer formed on the upper surface of the release layer; A first wiring layer having predetermined wirings formed on the second copper foil layer; It is formed on the first wiring layer, and comprises at least one polymer material selected from a thermoplastic resin, an epoxy resin, an acrylic resin, the first wiring layer is wrapped in the coverlay adhesive layer to be insulated to form an embedded pattern structure A coverlay adhesive layer; A flexible substrate insulating layer formed on an upper front surface of the coverlay adhesive layer and made of a polymer material; And at least one via hole penetrating through the first copper foil layer, the flexible substrate insulation layer, and the coverlay adhesive layer, the first copper foil layer formed by plating on the flexible substrate insulation layer. Forming a second wiring layer having a predetermined wiring formed on the first copper foil layer of the copper foil; and filling and filling the via hole with copper; And

b) separating between the release layer and the second copper foil layer in the flexible circuit board including the second wiring layer and the filled via hole, and detaching the substrate sheet layer and the release layer from the remaining portions. Method of manufacturing a circuit board.
The method of claim 8,

After step b) above,

c) forming an upper wiring layer and a lower wiring layer on the upper and lower portions of the flexible substrate insulating layer by removing the second copper foil layer and the portion of the second wiring layer and the first wiring layer in which the second wiring layer is not formed; Method of manufacturing a flexible circuit board for microwiring further comprising a.
The method of claim 9,

After step c),

d) forming a coverlay film layer as a protective layer on each of the outer side surfaces of the upper wiring layer and the lower wiring layer.
The method of claim 9,

After the step c), the outer surface of each of the upper wiring layer and the lower wiring layer, at least one polymer material selected from a thermoplastic resin, an epoxy resin, an acrylic resin, the wiring layer on the substrate to be treated is the following coverlay A coverlay adhesive layer wrapped around the adhesive layer and insulated to form an embedded pattern structure; A flexible substrate insulating layer formed on an upper front surface of the coverlay adhesive layer and made of a polymer material; And bonding two flexible copper foil coverlay films to the coverlay adhesive layer and each of the wiring layers, the copper foil layer formed by plating on top of the flexible substrate insulating layer. Method of manufacturing a flexible circuit board.
The flexible circuit board for micro wiring manufactured by the method in any one of Claims 9-11.