KR102425898B1 - Manufacturing method of double side type flexible printed circuit board - Google Patents

Abstract

The present invention relates to a method for manufacturing a double-sided flexible printed circuit board, comprising the steps of applying an insulating material to a master mold, removing a portion corresponding to a terminal portion from the applied insulating material, and applying a first conductive material to the master mold. forming a first terminal portion on a portion from which the insulating material is removed by plating; removing a portion corresponding to the circuit pattern from the applied insulating material; plating the master mold with a second conductive material to form the circuit pattern forming, re-applying an insulating material to the surface on which the circuit pattern is formed, removing a portion corresponding to the terminal portion from the re-applied insulating material, plating the first conductive material on the master mold to obtain an insulating material forming a second terminal portion on the removed portion; removing the applied insulating material and the remaining portions of the re-applied insulating material; attaching an insulating film having an opening to the formed circuit pattern; Separating the flexible printed circuit board on which the insulating film and the circuit pattern are laminated in a master mold, and attaching an insulating film having an opening to the circuit pattern side surface of the flexible printed circuit board. do.

Description

Manufacturing method of double-sided flexible printed circuit board {MANUFACTURING METHOD OF DOUBLE SIDE TYPE FLEXIBLE PRINTED CIRCUIT BOARD}

The present invention relates to a method for manufacturing a double-sided flexible printed circuit board capable of double-sided connection.

Flexible Printed Circuit Board (FPCB) is a board that can be flexibly bent by forming a circuit pattern on a thin insulating film. It is widely used in mobile devices and display devices.

Such flexible printed circuit boards are generally manufactured using a copper clad laminate (FCCL), in which a copper clad layer is laminated on a polyimide film layer, as a substrate (raw material), and laminated, exposed, developed, A method of forming a circuit pattern by performing an operation such as etching is mainly used.

On the other hand, when manufacturing a double-sided flexible printed circuit board to perform circuit connection on both sides of the flexible printed circuit board, a double-sided FCCL substrate is generally used. to be.

Through-holes are formed in these double-sided FCCLs, and the copper foil layers on both sides are electrically connected by plating or the like to enable circuit connection on both sides of the flexible printed circuit board.

When double-sided FCCL is used to manufacture double-sided flexible printed circuit board, double-sided FCCL is expensive compared to single-sided FCCL, and it takes a lot of time and money for the process of forming through-holes and the plating process to electrically connect copper foil layers. There is a problem.

Accordingly, research and development on a method of manufacturing a double-sided flexible printed circuit board based on single-sided FCCL is continued, but there is a problem that damage to the copper foil layer occurs when processing a polyimide film layer in which a copper foil layer is laminated.

In addition, when forming the terminal portion by performing gold plating or the like after forming the circuit pattern, there is a problem in that a process for plating only a desired area becomes complicated.

Meanwhile, the background technology of the present invention is disclosed in Korean Patent Laid-Open No. 10-2018-0016323 (2018.02.14).

The present invention is to solve the problems of the conventional double-sided flexible printed circuit board manufacturing method as described above, and provides a method for manufacturing a double-sided flexible printed circuit board capable of double-sided patterning in a cheaper and simpler method than the conventional method. There is a purpose.

A method for manufacturing a double-sided flexible printed circuit board according to the present invention comprises the steps of applying an insulating material to a master mold; removing a portion corresponding to the terminal portion from the applied insulating material: forming a first terminal portion on the portion from which the insulating material is removed by plating the master mold with a first conductive material; removing a portion corresponding to the circuit pattern from the applied insulating material; forming the circuit pattern by plating a second conductive material on the master mold; re-applying an insulating material to the surface on which the circuit pattern is formed; removing a portion corresponding to the terminal portion from the re-applied insulating material: forming a second terminal portion on the portion from which the insulating material is removed by plating the first conductive material on the master mold; removing the remaining portions of the applied insulating material and the re-applied insulating material; attaching an insulating film having an opening to the formed circuit pattern; separating the flexible printed circuit board on which the insulating film and the circuit pattern are laminated in the master mold; and attaching an insulating film having an opening to the circuit pattern side surface of the flexible printed circuit board.

The forming of the first terminal part of the present invention includes plating the first conductive material on the master mold and then plating a third conductive material, and the forming of the second terminal part includes: and plating the first conductive material after plating the third conductive material on the master mold.

In the present invention, the first conductive material is gold, the second conductive material is copper, the third conductive material is nickel, the insulating material is urethane, and the insulating film is a polyimide film.

In the present invention, the circuit pattern is characterized in that it is formed to a thickness of 3um to 250um.

The method for manufacturing a double-sided flexible printed circuit board according to the present invention forms a circuit pattern including a terminal portion through plating, and attaches a conductive film having an opening on both sides of the formed circuit pattern, respectively, in a cheaper and simpler method than the conventional method. It has the effect of making it possible to manufacture a double-sided flexible printed circuit board capable of double-sided patterning.

In addition, the method for manufacturing a flexible printed circuit board according to the present invention has an effect of reducing the manufacturing cost of the flexible printed circuit board by allowing plating of only a desired area to be easily performed when gold is plated on the terminal portion.

1 is a flowchart illustrating a method of manufacturing a double-sided flexible printed circuit board according to an embodiment of the present invention.
2 to 11 are exemplary views for explaining a method of manufacturing a double-sided flexible printed circuit board according to an embodiment of the present invention.

Hereinafter, an embodiment of a method for manufacturing a double-sided flexible printed circuit board according to the present invention will be described with reference to the accompanying drawings. In this process, the thickness of the lines or the size of the components shown in the drawings may be exaggerated for clarity and convenience of explanation. In addition, the terms to be described later are terms defined in consideration of functions in the present invention, which may vary according to intentions or customs of users and operators. Therefore, definitions of these terms should be made based on the content throughout this specification.

1 is a flowchart for explaining a method for manufacturing a double-sided flexible printed circuit board according to an embodiment of the present invention, and FIGS. 2 to 11 illustrate a method for manufacturing a double-sided flexible printed circuit board according to an embodiment of the present invention As an exemplary view for the following, a method for manufacturing a double-sided flexible printed circuit board according to an embodiment of the present invention will be described with reference to this.

2 to 11, only the cross-section of the board is shown to explain the manufacturing process of the double-sided flexible printed circuit board, and the implementation of a conventional circuit pattern, such as a circuit pattern in which the circuit pattern is connected in a circle, is widely known in the technical field of the present invention. Since it corresponds to the content, a detailed description thereof will be omitted.

As shown in FIG. 1 , in the method for manufacturing a double-sided flexible printed circuit board according to an embodiment of the present invention, urethane 2 is first applied to the master mold 1 ( S10 ). That is, as shown in FIG. 2, according to the plating method, the urethane 2, which is not plated unlike the master mold 1, is applied to the master mold 1 to form an insulating coating layer, so that plating of only the desired area is performed. make it possible to perform At this time, the urethane (2) may be applied to a thickness of 3um ~ 250um.

Meanwhile, in the case of the master mold 1, it may be composed of SUS (stainless steel), etc., but in addition, it may be composed of various materials capable of performing smooth plating.

In this embodiment, it has been described that urethane is used as the insulating coating layer, but in addition, the insulating coating layer may be formed using a urethane mixture (a mixture of urethane and acrylic), Teflon, or the like.

Next, the portion 3 corresponding to the terminal portion is removed from the applied urethane 2 (S20). That is, as shown in FIG. 3 , only the area desired for plating is removed from the applied urethane 2 , so that plating can be performed only on the area corresponding to the terminal part.

Removal of the urethane 2 may be configured such that only the desired area is removed, for example by means of a laser. That is, by irradiating a laser beam on the surface of the master mold 1 on which the urethane 2 is laminated, the urethane 2 in the corresponding area can be removed. At this time, the removal of the urethane (2) may be performed to a thickness of 3um ~ 250um corresponding to the thickness of the urethane (2). That is, by adjusting the output specifications (power, frequency, etc.) of the laser, the removal of the urethane 2 is performed, but the master mold 1 can be not affected.

After the step (S20), gold and nickel are plated to form the terminal portions 4 and 5 (the first terminal portion) (S30). That is, in the manufacturing process of the flexible printed circuit board, gold and nickel portions, not circuit patterns, are first formed, but the shape of the urethane 2 is controlled in a relatively easy manner so that plating is performed only on the desired portions.

For example, a method of placing the master mold 1 in a tank filled with a solution for plating, etc., and performing plating by an electroplating method may be used. At this time, unlike the surface of the master mold 1, plating is not performed on the portion where the insulating urethane 2 is laminated.

Alternatively, electroless plating may be performed, but the plating may be performed only on the master mold 1 by selecting a catalyst according to the physical properties of the master mold 1 and the insulating coating layer (urethane 2 ).

In this embodiment, the configuration of the apparatus for performing the plating process or the specific plating method corresponds to a technique well known in the technical field of the present invention, and since various embodiments are available, a more detailed description will be omitted.

At this time, as shown in FIG. 4 , gold 4 is first plated and then nickel 5 is plated so that the terminal portion made of gold 4 is exposed as an outer shell.

Then, a portion corresponding to the circuit pattern is removed from the applied urethane 2 (S40), and the circuit pattern 6 is formed by plating copper (S50). That is, similarly to the above-described steps (S20) and (S30), the shape of the urethane 2 may be deformed so that plating is performed only on a desired area. As shown in FIG. 5 , the circuit pattern 6 is plated on the remaining area after the terminal portions 4 and 5 are formed to form the terminal portions 4 and 5 on the circuit pattern 6 .

The thickness of the circuit pattern 6 to be plated may be made within the thickness of the urethane 2, and may have a thickness of 3 μm to 250 μm.

After the step (S50), as shown in FIGS. 6 and 7, the urethane (2') is applied again on the surface on which the circuit pattern 6 is formed (S60), and the terminal part in the applied urethane (2') Remove the portion (3 ') corresponding to (S70). That is, a terminal portion is again formed on the other side of the circuit pattern 6 on which the terminal portions 4 and 5 are formed to enable double-sided connection, but urethane 2' is applied again so that only the desired portion is plated with gold. It is possible to prevent the phenomenon of gold plating on unnecessary parts.

After the step (S70), gold (4') and nickel (5') are plated to form terminal parts 4' and 5' (second terminal part) (S80). That is, as shown in FIG. 8 , terminal portions may be formed on both surfaces of the circuit pattern 6 . Meanwhile, in the present embodiment, it has been described that the terminal portions are formed at the same position on both sides of the circuit pattern 6, but these terminal portions may be formed at different positions.

Meanwhile, in the above step, nickel (5') is first plated, and then gold (4') is plated so that the terminal portion made of gold 4 is exposed as an outer shell.

In this embodiment, the first conductive material is gold, the second conductive material is copper, and the third conductive material is nickel. it might be

In addition, the plating method of each conductive material may be different from each other.

After the step (S80), the remaining portion of the applied urethane (2, 2') is removed (S90). That is, when the terminal portion and the circuit pattern 6 on both sides are plated, the residual urethane (2, 2') that is no longer needed can be removed.

Next, an insulating film 7 having an opening corresponding to the terminal portion is attached to the circuit pattern 6 (S100). The insulating film 7 may be, for example, a polyimide film, but may also be a film made of another insulating material.

This insulating film 7 may be attached to the circuit pattern 6 by an adhesive method, for example, by laminating an adhesive layer on the circuit pattern 6 or applying an adhesive and attaching the insulating film 7, an adhesive layer or A method of attaching the insulating film 7 provided with an adhesive to the circuit pattern 6 may be used, and a thermosetting adhesive or an adhesive sheet may be utilized.

When the insulating film 7 is attached in this way, a cross section as shown in FIG. 9 can be represented.

After the step (S70), the flexible printed circuit board is separated from the master mold (S110). Since the circuit pattern 6 is laminated on the insulating film 7 according to the above-described step S100, as shown in FIG. 10, it is separated from the master mold 1 to obtain a flexible printed circuit board.

This separation process may be performed by peeling the product from the master mold 1 , and a mechanical method, a chemical method, or an electrochemical method may be selected as needed.

Thereafter, an insulating film 7 ′ having an opening corresponding to the terminal portion is attached to the side of the circuit pattern 6 side among both sides of the separated flexible printed circuit board (S120).

Accordingly, as shown in FIG. 11, the circuit pattern 6 has a form in which insulating films 7 and 7' are laminated on both sides, respectively, and openings corresponding to the terminal portions are formed in the insulating films 7 and 7'. Because it is formed, it is possible to connect a circuit to the terminal part from both sides.

That is, the openings formed in the insulating films 7 and 7 ′ allow the terminal portions to be exposed, thereby enabling the connection of circuits or devices.

The openings formed in the insulating films 7 and 7 ′ may have various shapes, such as a hole shape or a rectangular shape, depending on the printed circuit board to be manufactured, and a plurality of openings may be formed.

Here, the insulating film 7 ′ may be, for example, a polyimide film, but may be a film of another insulating material. In addition, the insulating films 7 and 7 ′ respectively laminated on both sides of the circuit pattern 6 may be made of different materials.

In this embodiment, the laminated thickness of the terminal part may be thicker than the part where only the circuit pattern 6 is present due to the influence of the terminal part, but the laminated thickness of the terminal part may be relatively thin compared to the laminated thickness of the circuit pattern 6 have.

Thereafter, the product may be completed through a hot press operation or the like, and the subsequent process may be the same as a conventional manufacturing method of a flexible printed circuit board.

After this process, the part can be mounted using the terminal part of the opening formed on both sides as a contact point.

A conductive connection member may be used between these parts and the exposed terminal part, and for example, a conductive adhesive, conductive cream, solder, or the like may be used.

The flexible printed circuit board manufactured in this way can be completed as a product through external processing such as altar.

Between the above-described processes, additional processes (eg, washing processes, drying processes, etc.) for product production may be added as needed.

On the other hand, the present invention can be carried out in a flexible printed circuit board manufacturing facility configured to perform each process such as coating, laser irradiation, plating, attaching, peeling, etc., and the control device of the manufacturing facility controls the operation of each process. can Such a manufacturing facility may additionally include a robot arm, a conveying belt, etc. for conveying products between each process, and various equipment may be added in addition. In addition, the control device may include a computer-readable storage medium for storing instructions for controlling the manufacturing equipment to perform each process, and the storage medium is combined with the processor to cause the processor to perform each step of the present invention. can be

Although the present invention has been described with reference to the embodiment shown in the drawings, this is merely exemplary, and those of ordinary skill in the art to which various modifications and equivalent other embodiments are possible. will understand Therefore, the technical protection scope of the present invention should be defined by the following claims.

1: master mold
2, 2`: Urethane
3, 3`: terminal area
4, 4`, 5, 5`: terminal part
6: Circuit pattern
7, 7`: insulating film

Claims (4)

applying an insulating material to the master mold;
removing the portion corresponding to the terminal portion from the applied insulating material:
plating a first conductive material on the master mold to form a first terminal portion on a portion from which the insulating material is removed;
removing a portion corresponding to the circuit pattern from the applied insulating material;
forming the circuit pattern by plating a second conductive material on the master mold;
re-applying an insulating material to the surface on which the circuit pattern is formed;
removing the portion corresponding to the terminal portion from the re-applied insulating material:
plating the first conductive material on the master mold to form a second terminal portion on the portion from which the insulating material is removed;
removing the remaining portions of the applied insulating material and the re-applied insulating material;
attaching an insulating film having an opening to the formed circuit pattern;
separating the flexible printed circuit board on which the insulating film and the circuit pattern are laminated in the master mold; and
and attaching an insulating film having an opening to the surface of the flexible printed circuit board on the circuit pattern side.
According to claim 1,
The forming of the first terminal part includes plating the first conductive material on the master mold and then plating a third conductive material,
The forming of the second terminal part comprises plating a third conductive material on the master mold and then plating the first conductive material.
3. The method of claim 2,
wherein the first conductive material is gold, the second conductive material is copper, the third conductive material is nickel, the insulating material is urethane, and the insulating film is a polyimide film. Circuit board manufacturing method.
According to claim 1,
The circuit pattern is a double-sided flexible printed circuit board manufacturing method, characterized in that formed to a thickness of 3um to 250um.

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