KR101555673B1 - Manufacturing method for flexible printed circuit board - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a flexible printed circuit board, and more particularly, to a method of manufacturing a flexible printed circuit board, in which a carrier film is attached instead of copper plating, hole plugging printing is performed, To a method of manufacturing a flexible printed circuit board capable of shortening the manufacturing process of the flexible printed circuit board, reducing the cost cost and the process cost, and making the flexible printed circuit board thinner.

Description

TECHNICAL FIELD [0001] The present invention relates to a flexible printed circuit board (FPC)

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a flexible printed circuit board, and more particularly, to a method of manufacturing a flexible printed circuit board, in which a carrier film is attached instead of copper plating, hole plugging printing is performed, To a method of manufacturing a flexible printed circuit board capable of shortening the manufacturing process of the flexible printed circuit board, reducing the cost cost and the process cost, and making the flexible printed circuit board thinner.

2. Description of the Related Art Generally, a printed circuit board (hereinafter referred to as " printed circuit board ") has a structure in which a conductor pattern is formed of an electrically conductive material such as copper foil on an electrical insulator, Passive components such as resistors, capacitors, and coils, and acoustic or image devices are mounted in a mutually connected state to perform other functions while supporting other components.

Such a printed circuit board is applied to a household appliance such as a washing machine, a TV, and a refrigerator as well as a router, a server, a satellite, and an automobile, which are system boards. Communication equipment, etc., network equipment for information communication, and display device, the demand for a printed circuit board suitable for the expanding industry is rapidly increasing.

As the functions of various electronic products become increasingly complicated and diverse, the circuit pattern of the printed circuit board is required to be miniaturized as the size of the electronic product gradually becomes smaller and slim, and a variety of fine circuit patterning methods It is designed.

Korean Patent Laid-Open No. 2010-0021145 (Patent Document 1) discloses a method of manufacturing a flexible copper-clad laminate by forming half-etching (copper foil thickness: 4 μm to 8 μm) on a flexible flexible copper-clad laminate on both sides, A second step (S51) of electroless copper plating to impart conductivity to the through-holes formed in the flexible copper-clad laminate, a step (S51) of forming a copper alloy laminate by electroplating (S53) of applying a photosensitive resist to the material and then exposing the exposed material to light, a fifth step (S53) of exposing the exposed product to a sheet, PRE-PREG is placed between two or more double-side laminates manufactured through the above-mentioned step (S54) and the above-mentioned fifth step (S54) A sixth step (S56) of adhering in a vacuum state (-500 mmHg to -760 mmHg) (S58) for removing the contamination (SMEAR) generated during the entire hole machining operation, and an eighth step (S59) for performing chemical copper electroplating (5 to 20 μm) And a ninth step (S60) of patterning the plated product on the outer layer, and a method of manufacturing the multilayer flexible printed circuit.

 The prior art has an advantage that a via hole can be easily formed without using expensive equipment. However, since copper is plated to impart conductivity to a via hole, the thickness of the substrate becomes thick, the manufacturing cost of the dry film increases, , And the coverlay is adhered in the form of a film, thereby complicating the process.

In addition, when hole plugging is performed using ink in a via hole, ink leaks to contaminate the surface of the copper-clad laminate, the ink around the via hole is cured and swells up, and then the foreign matter is removed through belt polishing or the like do. Therefore, the number of manufacturing processes increases, and it takes a lot of time for each process, resulting in a decrease in productivity and an increase in process cost.

Accordingly, there is a need to develop various technologies for eliminating unnecessary processes in a printed circuit board manufacturing process, lowering the cost of raw materials, and thinning a printed circuit board.

Korea Patent Publication No. 2010-0021145

In order to solve the above problems, it is an object of the present invention to provide a method of manufacturing a flexible printed circuit board in which manufacturing costs are reduced and unnecessary manufacturing processes are eliminated to reduce production costs. More specifically, instead of the copper plating, a carrier film is adhered and hole plugging printing is carried out to reduce the cost of expensive copper plating and to manufacture a thin film type, and to manufacture a flexible printed circuit board after a conventional post- And a method thereof.

Further, a method of manufacturing a flexible printed circuit board that can simplify the coverlay forming process by using a liquid-type photo imaging coverlay instead of a conventional film-type coverlay and exhibit a low spring back property is provided .

It is another object of the present invention to provide a flexible printed circuit board manufactured by a method of manufacturing a flexible printed circuit board.

According to another aspect of the present invention, there is provided a method of manufacturing a copper-clad laminate, including the steps of: (S1) attaching a first carrier film to one surface of a copper-clad laminate; Forming a via hole on a surface to which the first carrier film is attached (S2); Attaching a second carrier film to a back surface of the copper-clad laminate (S3); (S4) hole-plugging a conductive paste on one surface of the copper-clad laminate; (S5) coating a liquid photosensitive material on one side or both sides of the hole-plugged copper-clad laminate; And forming a circuit pattern on one or both sides of the coated copper-clad laminate (S6).

In the step S4, the conductive paste may contain 50 to 80 wt% of conductive powder, 1 to 15 wt% of inorganic filler, 1 to 30 wt% of polymer binder, and 0.1 to 5 wt% of additive.

Wherein the conductive powder is at least one selected from the group consisting of carbon nanotubes, graphene, copper, nickel, gold, silver, platinum, tin, palladium and aluminum, and the additives include diethylene glycol monoethyl ether acetate, Glycol monoethyl ether acetate, and diethylene glycol monobutyl ether acetate.

Hole plugging can be performed by using a jig having a via hole formed in the hole filling in the step S4.

1.0 Dv < Dz &lt; 5.0 Dv [Formula 1]

(Where Dv is the average diameter (占 퐉) of the via-holes formed in the copper-clad laminate and Dz is the average diameter (占 퐉) of the via-holes formed in the jig.

The via hole of the copper-clad laminate may have an average diameter of 1 to 30 mu m, and the step S5 may be performed by removing the first carrier film or the first and second carrier films.

The flexible printed circuit board manufacturing method may further include a PIC printing step (S7) in which a liquid imaged coverlay (PIC) composition is applied to the surface of the copper-clad laminate on which the circuit pattern is formed and printed.

Wherein the liquid phase photoimageable cover layer composition is a two-part liquid composition comprising a topical and a curing agent and the subject is a polymeric binder comprising 30 to 50 wt%, a photoinitiator 1 to 5 wt%, an inorganic filler 10 to 20 wt%, an organic solvent 30 to 50 wt% And 1 to 5% by weight of an additive, and the curing agent may include 60 to 85% by weight of a polymer binder, 10 to 30% by weight of an open solvent, and 1 to 10% by weight of a catalyst.

According to another aspect of the present invention, there is provided a flexible printed circuit board manufactured by the method of manufacturing a flexible printed circuit board.

It is preferable that the flexible printed circuit board has a bending test of 50 to 99 times and a springback evaluation value of 2.0 to 4.5 g measured at a test speed of 175 rpm, a test angle of 135 degrees and a load of 0.5 kg using an MIT bending test equipment .

The method of manufacturing a flexible printed circuit board according to the present invention can prevent generation of foreign matter on the surface of a copper foil laminate by applying a carrier film and performing hall plugging printing and by applying a conductive paste using a jig, The flow of the ink is minimized, and there is an advantage that post-processing such as belt polishing after hole plugging is not necessary. As a result, foreign matter on the surface of the copper-clad laminate is reduced to reduce circuit defects, and expansion and contraction of the copper clad laminate by post-processing can be prevented.

In addition, there is an advantage that the manufacturing cost can be reduced by not performing the copper plating, and the copper-clad laminate can be formed into a thin film.

Further, by using a liquid imaged coverlay of a liquid rather than a film type, processes for attaching the coverlay of the film can be omitted, and there is an advantage of exhibiting a low spring back property.

1 is a flowchart illustrating a method of manufacturing a flexible printed circuit board according to an embodiment of the present invention.
2 is a schematic view showing a spring back test method of a flexible printed circuit board according to an embodiment of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, preferred embodiments and methods for measuring properties of a flexible printed circuit board of the present invention will be described in detail. The present invention may be better understood by the following examples, which are for the purpose of illustrating the invention and are not intended to limit the scope of protection defined by the appended claims.

1 is a flowchart illustrating a method of manufacturing a flexible printed circuit board according to an embodiment of the present invention.

As shown in FIG. 1, a method of manufacturing a flexible printed circuit board according to an embodiment of the present invention includes the steps of: (S1) attaching a first carrier film to one surface of a copper-clad laminate;

Forming a via hole on a surface to which the first carrier film is attached (S2);

Attaching a second carrier film to a back surface of the copper-clad laminate (S3);

(S4) hole-plugging a conductive paste on one surface of the copper-clad laminate;

(S5) coating a liquid photosensitive material on one side or both sides of the hole-plugged copper-clad laminate; And

Forming a circuit pattern on one side or both sides of the coated copper-clad laminate (S6); .

Hereinafter, a manufacturing method of the flexible printed circuit board of the present invention will be described in more detail.

The step of attaching the first carrier film (S1) according to an embodiment of the present invention is a step of attaching the first carrier film to one surface of the copper-clad laminate, and is performed in order to protect the surface of the copper-clad laminate to be formed with the via-hole. The copper-clad laminate may be an insulating film and a flexible copper clad laminate (FCCL) comprising a pair of copper foils thermally fused to both surfaces of the insulating film. The insulating film is not limited as long as it is a heat-resistant polymer film that is well known in the art, and is preferably a polyimide film.

The thickness of the insulating film and the copper foil constituting the copper-clad laminate is not limited, but may be 10 to 100 탆.

The first carrier film can be used without limitation as long as it is a polymer film excellent in adhesion to a copper foil. Particularly, polypropylene, polystyrene, polyethylene terephthalate, polybutylene terephthalate, polycarbonate, cellulose, cellulose acetate, polymethyl methacrylate, polyimide or copolymer films thereof can be used. As a more practical example, a polyethylene terephthalate film is preferable.

The thickness of the first carrier film of the present invention is not limited, but it is preferably 10 to 80 占 퐉 because of excellent workability. Further, if necessary, a surface treatment or an adhesive layer may be formed to improve the adhesion to the copper foil.

The surface treatment may be selected from a glow discharge treatment, an ultraviolet ray treatment, a corona treatment, a flame treatment, a saponification treatment, and the like. The adhesive layer may be formed by applying an acrylic adhesive layer, but is not limited thereto.

In addition, a pigment may be added to the first carrier film to ensure visibility. The pigment to be added can be used without limitation within the range not affecting the physical properties of the first carrier film and the copper foil laminate.

The via hole forming step S2 according to an embodiment of the present invention is a step of forming a via hole on the surface to which the first carrier film is attached.

The via holes are formed in such a manner as to penetrate both surfaces of the copper-clad laminate, and it is preferable that a plurality of via holes are formed.

Further, the via hole can be formed by processing with a ultraviolet laser drill or a C.N.C. drill on the surface to which the first carrier film is attached.

The average diameter of the via holes is preferably 1 to 30 占 퐉, but the present invention is not limited thereto and can be formed in various sizes and shapes.

The step of attaching the second carrier film (S3) according to an embodiment of the present invention is a step of attaching the second carrier film to the back surface of the copper foil laminate to which the first carrier film is attached.

The second carrier film can be attached to prevent contamination of the surface of the copper clad laminate due to ink flow or the like during hole plugging and to improve workability.

The second carrier film of the present invention is not limited as long as it is a polymer film excellent in adhesion to a copper foil. Particularly, polypropylene, polystyrene, polyethylene terephthalate, polybutylene terephthalate, polycarbonate, cellulose, cellulose acetate, polymethyl methacrylate, polyimide or copolymer films thereof can be used. As a more practical example, a polyethylene terephthalate film is preferable.

The thickness of the second carrier film of the present invention is not limited, but it is preferably 10 to 80 占 퐉 because of excellent workability. Further, if necessary, a surface treatment or an adhesive layer may be formed to improve the adhesion to the copper foil.

The surface treatment may be selected from a glow discharge treatment, an ultraviolet ray treatment, a corona treatment, a flame treatment, a saponification treatment, and the like. The adhesive layer may be formed by applying an acrylic adhesive layer, but is not limited thereto.

Also, a pigment may be added to the second carrier film in order to ensure visibility. The pigment to be added can be used without limitation within the range not affecting the physical properties of the second carrier film and the copper foil laminate.

The hole plugging step (S4) according to an embodiment of the present invention is a step of hole plugging a conductive paste onto one surface of a copper foil laminate having via holes.

The conductive paste of the present invention preferably contains 50 to 80 wt% of conductive powder, 1 to 15 wt% of inorganic filler, 1 to 30 wt% of polymer binder, and 0.1 to 5 wt% of additive.

The conductive powder is preferably one or more selected from the group consisting of carbon nanotubes, graphene, copper, nickel, gold, silver, platinum, tin, palladium and aluminum, more preferably silver.

The average particle diameter of the conductive powder is preferably 1 to 500 nm, more preferably 20 to 500 nm. When the average particle diameter of the conductive powder is less than 1 nm, coagulation occurs in the conductive paste and the conductive paste is not uniformly coated on the via hole, thereby decreasing the conductivity and shorting the circuit.

The inorganic filler may be an inorganic filler such as silica or the like that is used in the art.

The polymer binder may be selected from the group consisting of an epoxy type, a cellulose type, an acrylic type, a vinyl chloride type, a vinyl acetate type, a polyvinyl alcohol type, a polyurethane type and a polyester type, May be used.

The additive is added in order to uniformly mix the polymer binder such as a solvent, a coupling agent, a leveling agent, and the conductive powder so as to improve the stability of the conductive paste. The additive of the present invention is not limited as long as it is an additive for electroconductive pastes well known in the art, in particular, selected from diethylene glycol monoethyl ether acetate, dipropylene glycol monoethyl ether acetate and diethylene glycol monobutyl ether acetate It is effective to use one kind or two or more kinds.

It is preferable to perform hole plugging using a jig having a via hole formed in the hole plugging step S4 at the time of hole plugging.

1.0 Dv < Dz &lt; 5.0 Dv [Formula 1]

(Where Dv is the average diameter (占 퐉) of the via-holes formed in the copper-clad laminate and Dz is the average diameter (占 퐉) of the via-holes formed in the jig.

By using the jig having the via holes formed in the above range, it is possible to prevent the conductive paste from contaminating the surface of the copper-clad laminate and uniformly coat the via holes using the minimum amount. Therefore, it is possible to reduce the defective circuit when the printed circuit board is manufactured.

When the average diameter of the via holes formed in the jig is less than 1.0 Dv, the via hole coating time may be prolonged, and the via holes may not be uniformly coated when the copper foil stacked body and the via holes of the jig are displaced, Problems can arise. In addition, in case of exceeding 5.0 Dv, the effect of use of the jig is insignificant, so that the surface of the copper-clad laminate may be contaminated, and the required amount of the conductive paste may increase, resulting in an increase in the material cost.

The step S5 of coating a liquid photosensitive material according to an embodiment of the present invention is a step of coating a liquid photosensitive solder resist (LPR) on one side or both sides of the hole-plugged copper foil laminate.

Here, the liquid photosensitive material (LPR) may be used without limitation as long as it is a liquid photosensitive material well known in the art. The liquid photosensitive material may include a silicone resin or an epoxy resin in order to improve chemical resistance, and may include a photosensitive (meth) acrylate compound for controlling the sensitivity during the exposure process and improving the bonding strength with the copper-clad laminate .

The liquid photosensitive material coating step (S5) may be performed by removing the first carrier film or the first carrier film and the second carrier film. The first carrier film or the second carrier film serves as a protective film of the copper-clad laminate. This can prevent stains, contamination, and the like on one surface or both surfaces of the copper-clad laminate even after hole plugging of the via-hole. Accordingly, omitting the step of removing the stain or contamination of the copper-clad laminate, the process cost is reduced, and the defective circuit can be remarkably reduced when the flexible printed circuit board is manufactured.

A circuit pattern forming step (S6) according to an embodiment of the present invention is a step of forming a circuit pattern on a liquid-phase photosensitive material-coated copper-clad laminate.

The circuit pattern formation can be performed by a process of exposure, development, etching (etching), and peeling to form a circuit of a desired pattern.

The exposure is to cure a certain area in the form of a circuit pattern using ultraviolet rays or light emitting diodes (LEDs) to form the liquid photosensitive material in a circuit pattern.

This phenomenon means the removal of uncured portions of the liquid photosensitive material using a chemical agent. Only the circuit pattern portion remains on one or both surfaces of the copper-clad laminate through the development.

The etching means etching a certain area of the copper-clad laminate corresponding to the developed area according to the pattern of the circuit using the chemical, and the circuit pattern is formed on the copper foil.

Finally, peeling can be performed to remove the remaining liquid photosensitive material circuit pattern on one side or both sides of the copper-clad laminate using a chemical agent.

The chemicals for developing, etching, and peeling can be used without limitation as long as they are chemically known in the art.

In addition, the manufacturing method of the flexible circuit board of the present invention may further include a PIC printing step (S7). The PIC printing step is a step of applying a liquid imaged coverlay (PIC) composition to the surface of the copper-clad laminate on which the circuit pattern is formed and printing.

Conventionally, a method in which a film type coverlay is thermally welded or an adhesive is applied to contact the copper-clad laminate is used, but this method has a disadvantage in that the process is complicated and takes a long time.

However, the present invention has an advantage that a coverlay can be formed by a simple process by applying a liquid photo-imaging cover-lay composition and photo-curing it. In addition, it can exhibit a lower spring back characteristic than a conventional film type coverlay.

The spring back property is a kind of repulsive force measured by the method shown in Fig. A cylindrical specimen of a certain standard is rounded to form a cylindrical shape so as to have a certain standard diameter, and a certain load is applied to the specimen so that the diameter reaches a predetermined standard. At this time, the measured weight can be judged as repulsive force. The smaller the measured weight, the weaker the repulsive force, and the larger the measured weight, the greater the repulsive force.

The above liquid imaged coverlay (PIC) composition is a two-part liquid composition comprising a base and a curing agent. The base is composed of 30 to 50% by weight of a polymer binder, 1 to 5% by weight of a photoinitiator, 10 to 20% Wherein the curing agent comprises 60 to 85% by weight of a polymer binder, 10 to 30% by weight of an open solvent, and 1 to 10% by weight of a catalyst, wherein the curing agent comprises 30 to 50% by weight of an organic solvent and 1 to 5% It is not.

 The polymeric binder of the subject mainly comprises an acrylic polymer, and the inorganic filler may include silica, barium sulfate and the like.

In addition, the polymer binder of the curing agent mainly includes an epoxy resin and a urethane acrylate resin, and may include a catalyst that is an amine compound.

The subject and curing agent may further include pigments, dyes, defoaming agents, coupling agents, organic solvents, and the like within the range not impairing the physical properties, but are not limited thereto.

In addition, after the PIC printing step, the flexible printed circuit board is subjected to a printing step of displaying the model name of the product, a version thereof, a layout of the parts, etc., a surface processing step of the flexible printed circuit board, a BBT ) Inspection step can be further performed.

The present invention also relates to a flexible circuit board manufactured by the above-described method for manufacturing a flexible printed circuit board.

The flexible printed circuit board preferably has a bending test of 50 to 99 times measured at a test speed of 175 rpm, a test angle of 135 degrees, and a load of 0.5 kg using an MIT bending test apparatus, and the springback property is 2.0 to 4.5 g It is effective.

Hereinafter, a method for producing a flexible printed circuit board of the present invention will be described in detail with reference to examples and comparative examples.

Property measurement

1. Flexibility evaluation

Test specimens of 180 mm × 7.9 mm were prepared and measured 10 times for breakage or cracking several times at a test speed of 175 rpm, a test angle of 135 °, R = 0.38 mm, and a load of 0.5 kg using an MIT bending test equipment. Respectively.

2. Spring back evaluation

As shown in Fig. 2, a specimen of 60 mm x 20 mm specimen was prepared to have a cylindrical shape with a diameter of 17 mm, and the weight (g) until the diameter decreased from 17 mm to 10 mm was measured and the average value was shown.

[Example 1]

A first carrier film (JCF-050C, JINSUNG Chemical T, a.) Is attached to one side of a double-sided copper-clad laminate in which electrolytic copper foil (ED foil) having a thickness of 12 μm is laminated on both sides of a polyimide film having a thickness of 20 μm. A via-hole is formed by penetrating the surface to which the first carrier film is attached using an UV laser drill so as to have an average diameter of 20 占 퐉. A second carrier film (JCF-050C, JINSUNG ChemicalT, a.) Is attached to one surface of the copper-clad laminate to which nothing is attached. The surface to which the second carrier film is attached is positioned at the bottom, and then the jig having the via hole with the average diameter of 23 mu m is positioned so as to correspond to the via hole of the copper foil laminate. A conductive paste (SFR-200PIY, Seoul Chemical Industry Co., Ltd.) is coated in a state where the jig is placed and then cured at 150 DEG C for 30 minutes. After curing, the jig, the first carrier film and the second carrier film are removed, and a liquid photosensitive material (ArF photoresist, Dongjin Semichem) is coated on both sides of the copper foil laminate. Subsequently, a circuit pattern was formed on the copper foil by using a photolithography process in the order of exposure, development, etching (etching), and peeling. A liquid photoimageable coverlay composition (PIC INK, Nippon Polytech) was applied to the surface of the copper foil on which the circuit pattern was formed, and light cured to form a coverlay. The physical properties of the flexible printed circuit board manufactured by this method were measured and are shown in Table 1 below.

[Example 2]

A flexible printed circuit board was manufactured in the same manner as in Example 1 except that a double-sided copper-clad laminate in which a rolled copper foil (RA foil) having a thickness of 12 탆 was laminated on both sides of a polyimide film having a thickness of 20 탆 was manufactured. The results are shown in Table 1 below.

[Example 3]

A flexible printed circuit board was manufactured in the same manner as in Example 1, except that a double-side copper foil laminate in which an electrolytic copper foil (ED foil) having a thickness of 12 μm was laminated on both sides of a polyimide film having a thickness of 12 μm was used. Are shown in Table 1 below.

[Example 4]

A flexible printed circuit board was produced in the same manner as in Example 1 except that a double-sided copper-clad laminate in which a 12 μm thick rolled copper foil (RA foil) was laminated on both sides of a polyimide film having a thickness of 12 μm was used. The results are shown in Table 1 below.

[Comparative Example 1]

A flexible printed circuit board was produced in the same manner as in Example 1 except that the first carrier film was not used and hole plugging was performed. Physical properties were measured and shown in Table 1 below.

[Comparative Example 2]

A flexible printed circuit board was produced in the same manner as in Example 1, except that the first and second carrier films were not used and hole plugging was performed. Physical properties of the flexible printed circuit board were measured and are shown in Table 1 below.

[Comparative Example 3]

A hole-plugging was performed without using the first carrier film and the second carrier film, and a flexible printed circuit board was manufactured in the same manner as in Example 1, except that the coverlay film was bonded by heat fusion. The results are shown in Table 1 below.

[Table 1]

As shown in Table 1, in Examples 1 to 4, hole plugging was performed using the first carrier film and the second carrier film, and the coverlay was formed using the liquid photoimageable coverlay composition, It can be seen that a flexible printed circuit board can be manufactured by a simple method by omitting the step. In addition, foreign matter and unevenness on the surface of the copper foil can be remarkably reduced by using the carrier film, and it is found that the circuit breakage and short circuit rarely occur. In addition, it was found that the flexibility and the springback characteristics were improved as compared with the comparative example.

On the other hand, in Comparative Example 1, the conductive paste did not flow under the copper-clad laminate by using only the second carrier film, but the surface on which the jig was placed had stains and some belt polishing was required. In Comparative Example 2, And the second carrier film were not used, belt polishing was performed on both sides of the copper foil laminate. The process cost of polishing the belt was remarkably increased, and it was found that the flexibility was decreased due to the difficulty in controlling the shrinkage rate of the copper-clad laminate in the subsequent process.

In Comparative Example 3, by using a film other than the liquid photoimageable cover layer composition, it was found that the workability was reduced by heat fusion by hand one by one and it was difficult to precisely match the coverlay open point.

Accordingly, the method of manufacturing a flexible printed circuit board according to the present invention can simplify a complicated manufacturing process to reduce a process time and cost, and can provide a flexible printed circuit board having excellent flexibility and springback characteristics and capable of controlling expansion and contraction There are advantages to be able to.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. It is clear that the present invention can be suitably modified and applied in the same manner. Therefore, the above description does not limit the scope of the present invention, which is defined by the limitations of the following claims.

Claims (11)

(S1) attaching a first carrier film to one surface of a copper foil laminate composed of an insulating film and a pair of copper foils thermally fused to both surfaces of the insulating film;
(S2) forming a via hole passing through both surfaces of the copper foil laminate on a surface to which the first carrier film is attached;
Attaching a second carrier film to a back surface of the copper-clad laminate (S3);
(S4) hole-plugging a conductive paste on one surface of the copper-clad laminate;
Coating a liquid photosensitive material on either or both surfaces of the hole-plugged copper-clad laminate (S5);
(S6) forming a circuit pattern by performing processes of exposure, development, etching, and peeling on one or both surfaces of the coated copper foil laminate; And
And a PIC printing step (S7) in which a liquid imaged coverlay (PIC) composition is applied to the surface of the copper-clad laminate having the circuit pattern formed thereon and printed,
Wherein the liquid phase photoimageable cover layer composition is a two-part liquid composition comprising a topical and a curing agent and the subject is a polymeric binder comprising 30 to 50 wt%, a photoinitiator 1 to 5 wt%, an inorganic filler 10 to 20 wt%, an organic solvent 30 to 50 wt% And 1 to 5 wt% of an additive, wherein the curing agent comprises 60 to 85 wt% of a polymer binder, 10 to 30 wt% of an organic solvent, and 1 to 10 wt% of a catalyst.
The method according to claim 1,
Wherein the conductive paste comprises 50 to 80% by weight of the conductive powder, 1 to 15% by weight of the inorganic filler, 1 to 30% by weight of the polymeric binder, and 0.1 to 5% by weight of the additive.
3. The method of claim 2,
Wherein the conductive powder is at least one selected from carbon nanotubes, graphene, copper, nickel, gold, silver, platinum, tin, palladium,
Wherein the additive is one or more selected from the group consisting of diethylene glycol monoethyl ether acetate, dipropylene glycol monoethyl ether acetate and diethylene glycol monobutyl ether acetate.
The method according to claim 1,
Wherein hole plugging is performed using a jig having a via hole formed in the hole filling the hole filling process.
1.0 Dv < Dz &lt; 5.0 Dv [Formula 1]
(Where Dv is the average diameter (占 퐉) of the via-holes formed in the copper-clad laminate and Dz is the average diameter (占 퐉) of the via-holes formed in the jig.
5. The method of claim 4,
Wherein the via-hole of the copper-clad laminate has an average diameter of 1 to 30 占 퐉.
The method according to claim 1,
Wherein the step (S5) is performed by removing the first carrier film or the first carrier film and the second carrier film.
delete delete A flexible printed circuit board produced by the method of manufacturing a flexible printed circuit board according to any one of claims 1 to 6.
10. The method of claim 9,
Wherein the flexible printed circuit board has a bending test of 50 to 99 times measured at a test speed of 175 rpm, a test angle of 135 degrees and a load of 0.5 kg using an MIT bending test equipment.
10. The method of claim 9,
Wherein the flexible printed circuit board has a spring back evaluation value of 2.0 to 4.5 g.

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